rename folders

backend/.gitignore

@@ -0,0 +1,11 @@
+bin/
+target/
+.settings/
+.project
+.classpath
+hs_err*.log
+application.properties
+usernames.txt
+lucene
+
+.vscode

backend/pom.xml

@@ -0,0 +1,138 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>de.champonthis</groupId>
+	<artifactId>buntspecht</artifactId>
+	<version>${revision}</version>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<java.version>17</java.version>
+		<maven.compiler.release></maven.compiler.release>
+		<maven.compiler.source>${java.version}</maven.compiler.source>
+		<maven.compiler.target>${java.version}</maven.compiler.target>
+		<querydsl.version>5.1.0</querydsl.version>
+		<revision>0.4.0</revision>
+	</properties>
+
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>3.3.4</version>
+		<relativePath />
+	</parent>
+
+	<dependencies>
+		<!-- Spring -->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-security</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-data-jpa</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-webflux</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-mail</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.session</groupId>
+			<artifactId>spring-session-jdbc</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-oauth2-client</artifactId>
+		</dependency>
+
+		<!-- Query DSL -->
+		<dependency>
+			<groupId>com.querydsl</groupId>
+			<artifactId>querydsl-apt</artifactId>
+			<version>${querydsl.version}</version>
+			<classifier>jakarta</classifier>
+		</dependency>
+
+		<dependency>
+			<groupId>com.querydsl</groupId>
+			<artifactId>querydsl-jpa</artifactId>
+			<version>${querydsl.version}</version>
+			<classifier>jakarta</classifier>
+		</dependency>
+
+		<!-- Utils -->
+		<dependency>
+			<groupId>commons-validator</groupId>
+			<artifactId>commons-validator</artifactId>
+			<version>1.9.0</version>
+		</dependency>
+
+		<dependency>
+			<groupId>com.google.code.gson</groupId>
+			<artifactId>gson</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.apache.commons</groupId>
+			<artifactId>commons-lang3</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.bouncycastle</groupId>
+			<artifactId>bcprov-jdk18on</artifactId>
+			<version>1.78.1</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.passay</groupId>
+			<artifactId>passay</artifactId>
+			<version>1.6.5</version>
+		</dependency>
+
+		<!-- Datbase -->
+		<dependency>
+			<groupId>org.postgresql</groupId>
+			<artifactId>postgresql</artifactId>
+			<scope>runtime</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+				<configuration>
+					<mainClass>de.champonthis.buntspecht.Application</mainClass>
+					<finalName>buntspecht</finalName>
+					<executable>true</executable>
+					<layout>ZIP</layout>
+				</configuration>
+				<executions>
+					<execution>
+						<id>build-info</id>
+						<goals>
+							<goal>build-info</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+</project>

backend/src/main/java/de/champonthis/buntspecht/Application.java

@@ -0,0 +1,16 @@
+package de.champonthis.buntspecht;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
+
+
+@SpringBootApplication
+public class Application extends SpringBootServletInitializer {
+
+	
+	public static void main(String[] args) {
+		SpringApplication.run(Application.class, args);
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/JPAConfig.java

@@ -0,0 +1,24 @@
+package de.champonthis.buntspecht;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
+
+import com.querydsl.jpa.impl.JPAQueryFactory;
+
+import jakarta.persistence.EntityManager;
+
+@Configuration
+@EnableJpaAuditing
+public class JPAConfig {
+
+	@Autowired
+	private EntityManager em;
+
+	@Bean
+	public JPAQueryFactory jpaQueryFactory() {
+		return new JPAQueryFactory(em);
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/businesslogic/SystemPropertyManager.java

@@ -0,0 +1,74 @@
+package de.champonthis.buntspecht.businesslogic;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+import org.springframework.util.Assert;
+
+import de.champonthis.buntspecht.model.SystemProperty;
+import de.champonthis.buntspecht.repository.SystemPropertyRepository;
+
+@Component
+public class SystemPropertyManager {
+
+	@Autowired
+	private SystemPropertyRepository systemPropertyRepository;
+
+	public boolean has(String key) {
+		return systemPropertyRepository.existsById(key);
+	}
+
+	public String get(String key) {
+		return systemPropertyRepository.findById(key).orElse(new SystemProperty()).getValue();
+	}
+
+	public String get(String key, String defaultValue) {
+		return systemPropertyRepository.findById(key).orElse(new SystemProperty(key, defaultValue)).getValue();
+	}
+
+	public boolean getBoolean(String key) {
+		return getBoolean(key, false);
+	}
+
+	public boolean getBoolean(String key, boolean defaultValue) {
+		return Boolean.valueOf(get(key, String.valueOf(defaultValue)));
+	}
+
+	public int getInteger(String key) {
+		return getInteger(key, 0);
+	}
+
+	public int getInteger(String key, int defaultValue) {
+		return Integer.valueOf(get(key, String.valueOf(defaultValue)));
+	}
+
+	public long getLong(String key) {
+		return getLong(key, 0L);
+	}
+
+	public long getLong(String key, long defaultValue) {
+		return Long.valueOf(get(key, String.valueOf(defaultValue)));
+	}
+
+	public void add(String key, String value) {
+		Assert.isTrue(!systemPropertyRepository.existsById(key),
+				"System Property already exists, use update method to change value!");
+		systemPropertyRepository.save(new SystemProperty(key, value));
+	}
+
+	public void update(String key, String value) {
+		Assert.isTrue(systemPropertyRepository.existsById(key),
+				"System Property does not exists, use add method to add new!");
+		SystemProperty systemProperty = systemPropertyRepository.findById(key).get();
+		systemProperty.setValue(value);
+		systemPropertyRepository.save(systemProperty);
+	}
+
+	public void set(String key, String value) {
+		if (systemPropertyRepository.existsById(key)) {
+			update(key, value);
+		} else {
+			add(key, value);
+		}
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/businesslogic/TurnoverManager.java

@@ -0,0 +1,202 @@
+package de.champonthis.buntspecht.businesslogic;
+
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+import org.springframework.util.StringUtils;
+
+import com.querydsl.core.BooleanBuilder;
+import com.querydsl.core.QueryResults;
+import com.querydsl.core.Tuple;
+import com.querydsl.core.types.Order;
+import com.querydsl.core.types.OrderSpecifier;
+import com.querydsl.core.types.Path;
+import com.querydsl.core.types.Predicate;
+import com.querydsl.jpa.impl.JPAQuery;
+import com.querydsl.jpa.impl.JPAQueryFactory;
+
+import de.champonthis.buntspecht.controller.model.TurnoverFilterModel;
+import de.champonthis.buntspecht.model.QTurnover;
+import de.champonthis.buntspecht.model.Turnover;
+import de.champonthis.buntspecht.repository.TurnoverRepository;
+
+@Service
+public class TurnoverManager {
+
+	@Autowired
+	private TurnoverRepository turnoverRepository;
+	@Autowired
+	private JPAQueryFactory jpaQueryFactory;
+
+	private QTurnover qTurnover = QTurnover.turnover;
+
+	public QueryResults<Turnover> fetch(long limit, long offset, String sortBy, boolean descending,
+			TurnoverFilterModel filter) {
+		return fetch(null, limit, offset, sortBy, descending, filter);
+	}
+
+	public QueryResults<Turnover> fetch(String username, long limit, long offset, String sortBy, boolean descending,
+			TurnoverFilterModel filter) {
+		BooleanBuilder builder = new BooleanBuilder();
+
+		if (StringUtils.hasText(username)) {
+			builder.and(qTurnover.username.eq(username));
+		}
+
+		builder.and(buildFilter(filter));
+
+		JPAQuery<Turnover> query = jpaQueryFactory.from(qTurnover).where(builder.getValue()).select(qTurnover);
+		Long total = query.clone().select(qTurnover.id.countDistinct()).fetchOne();
+
+		if (StringUtils.hasText(sortBy)) {
+			Path<? extends Comparable<?>> path = null;
+			switch (sortBy) {
+				case "created":
+					path = qTurnover.created;
+					break;
+				case "dueDate":
+					path = qTurnover.dueDate;
+					break;
+				case "updated":
+					path = qTurnover.updated;
+					break;
+				case "customer":
+					path = qTurnover.customer;
+					break;
+				case "price":
+					path = qTurnover.price;
+					break;
+				case "timeInvestment":
+					path = qTurnover.timeInvestment;
+					break;
+			}
+			if (path != null) {
+				query.orderBy(new OrderSpecifier<>(descending ? Order.DESC : Order.ASC, path));
+			}
+		}
+
+		List<Turnover> result = query.limit(limit).offset(offset).fetch();
+		return new QueryResults<Turnover>(result, limit, offset, total == null ? 0L : total);
+
+	}
+
+	protected Predicate buildFilter(TurnoverFilterModel filter) {
+		BooleanBuilder builder = new BooleanBuilder();
+
+		if (filter != null) {
+			if (filter.getCreated() != null) {
+				if (filter.getCreated().getMin() != null) {
+					builder.and(qTurnover.created.after(filter.getCreated().getMin()));
+				}
+				if (filter.getCreated().getMax() != null) {
+					builder.and(qTurnover.created.before(filter.getCreated().getMax()));
+				}
+			}
+			if (filter.getDueDate() != null) {
+				if (filter.getDueDate().getMin() != null) {
+					builder.and(qTurnover.dueDate.after(filter.getDueDate().getMin()));
+				}
+				if (filter.getDueDate().getMax() != null) {
+					builder.and(qTurnover.dueDate.before(filter.getDueDate().getMax()));
+				}
+			}
+			if (filter.getUpdated() != null) {
+				if (filter.getUpdated().getMin() != null) {
+					builder.and(qTurnover.updated.after(filter.getUpdated().getMin()));
+				}
+				if (filter.getUpdated().getMax() != null) {
+					builder.and(qTurnover.updated.before(filter.getUpdated().getMax()));
+				}
+			}
+			if (filter.getCustomer() != null) {
+				builder.and(qTurnover.customer.contains(filter.getCustomer()));
+			}
+			if (filter.getMotif() != null) {
+				builder.and(qTurnover.motif.contains(filter.getMotif()));
+			}
+			if (filter.getPrice() != null) {
+				if (filter.getPrice().getMin() != null) {
+					builder.and(qTurnover.price.goe(filter.getPrice().getMin()));
+				}
+				if (filter.getPrice().getMax() != null) {
+					builder.and(qTurnover.price.loe(filter.getPrice().getMax()));
+				}
+			}
+			if (filter.getTimeInvestment() != null) {
+				if (filter.getTimeInvestment().getMin() != null) {
+					builder.and(qTurnover.timeInvestment.goe(filter.getTimeInvestment().getMin()));
+				}
+				if (filter.getTimeInvestment().getMax() != null) {
+					builder.and(qTurnover.timeInvestment.loe(filter.getTimeInvestment().getMax()));
+				}
+			}
+		}
+
+		return builder.getValue();
+	}
+
+	public Turnover get(Long id) {
+		return turnoverRepository.findById(id).orElse(null);
+	}
+
+	public Turnover save(Turnover turnover) {
+		return turnoverRepository.save(turnover);
+	}
+
+	public boolean exists(Long id) {
+		return turnoverRepository.existsById(id);
+	}
+
+	public void delete(Turnover turnover) {
+		turnoverRepository.delete(turnover);
+	}
+
+	public void deleteById(Long id) {
+		turnoverRepository.deleteById(id);
+	}
+
+	public void deleteByUsername(String username) {
+		turnoverRepository.deleteAllInBatch(turnoverRepository.findAll(qTurnover.username.eq(username)));
+	}
+
+	public QueryResults<Tuple> overview(String username, long limit, long offset, String sortBy, boolean descending,
+			TurnoverFilterModel filter) {
+		BooleanBuilder builder = new BooleanBuilder();
+
+		if (StringUtils.hasText(username)) {
+			builder.and(qTurnover.username.eq(username));
+		}
+
+		builder.and(buildFilter(filter));
+
+		JPAQuery<Tuple> query = jpaQueryFactory.from(qTurnover).where(builder.getValue()).groupBy(qTurnover.username)
+				.select(qTurnover.username.as("username"), qTurnover.price.sum().as("price"),
+						qTurnover.timeInvestment.sum().as("timeInvestment"));
+		Long total = query.clone().select(qTurnover.username.countDistinct()).fetchOne();
+
+		if (StringUtils.hasText(sortBy)) {
+			Path<? extends Comparable<?>> path = null;
+			switch (sortBy) {
+				case "username":
+					path = qTurnover.username;
+					break;
+				case "price":
+					path = qTurnover.price;
+					break;
+				case "timeInvestment":
+					path = qTurnover.timeInvestment;
+					break;
+			}
+			if (path != null) {
+				query.orderBy(new OrderSpecifier<>(descending ? Order.DESC : Order.ASC, path));
+			}
+		}
+
+		List<Tuple> result = query.limit(limit).offset(offset)
+				.fetch();
+
+		return new QueryResults<Tuple>(result, limit, offset, total == null ? 0L : total);
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/businesslogic/UserManager.java

@@ -0,0 +1,211 @@
+package de.champonthis.buntspecht.businesslogic;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.lang3.RandomStringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.SmartInitializingSingleton;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.GrantedAuthority;
+import org.springframework.security.core.authority.SimpleGrantedAuthority;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.core.userdetails.UserDetailsService;
+import org.springframework.security.core.userdetails.UsernameNotFoundException;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.security.oauth2.client.authentication.OAuth2AuthenticationToken;
+import org.springframework.stereotype.Service;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+import com.querydsl.core.BooleanBuilder;
+import com.querydsl.core.QueryResults;
+import com.querydsl.core.types.Order;
+import com.querydsl.core.types.OrderSpecifier;
+import com.querydsl.core.types.Path;
+import com.querydsl.jpa.impl.JPAQuery;
+import com.querydsl.jpa.impl.JPAQueryFactory;
+
+import de.champonthis.buntspecht.model.QUser;
+import de.champonthis.buntspecht.model.User;
+import de.champonthis.buntspecht.repository.UserRepository;
+import de.champonthis.buntspecht.security.LocalUserDetails;
+import jakarta.transaction.Transactional;
+
+@Service
+public class UserManager implements UserDetailsService, SmartInitializingSingleton {
+
+	private Logger logger = LoggerFactory.getLogger(UserManager.class);
+
+	@Autowired
+	private UserRepository userRepository;
+	@Autowired
+	private PasswordEncoder passwordEncoder;
+	@Autowired
+	private JPAQueryFactory jpaQueryFactory;
+	@Autowired
+	private TurnoverManager turnoverManager;
+	private QUser qUser = QUser.user;
+
+	@Value("${admin.password:}")
+	private String adminPassword;
+
+	public QueryResults<User> fetch(long limit, long offset, String sortBy, boolean descending, String usernameFilter) {
+		BooleanBuilder builder = new BooleanBuilder();
+
+		if (StringUtils.hasText(usernameFilter)) {
+			builder.and(qUser.username.contains(usernameFilter));
+		}
+
+		JPAQuery<User> query = jpaQueryFactory.from(qUser).where(builder.getValue()).select(qUser);
+		Long total = query.clone().select(qUser.username.countDistinct()).fetchOne();
+
+		if (StringUtils.hasText(sortBy)) {
+			Path<? extends Comparable<?>> path = null;
+			switch (sortBy) {
+				case "username":
+					path = qUser.username;
+					break;
+				case "name":
+					path = qUser.name;
+					break;
+			}
+			if (path != null) {
+				query.orderBy(new OrderSpecifier<>(descending ? Order.DESC : Order.ASC, path));
+			}
+		}
+
+		List<User> result = query.limit(limit).offset(offset).fetch();
+		return new QueryResults<User>(result, limit, offset, total == null ? 0L : total);
+	}
+
+	@Override
+	@Transactional
+	public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
+		User user = getByUsername(username);
+
+		if (user == null) {
+			throw new UsernameNotFoundException(username);
+		}
+
+		List<GrantedAuthority> authorities = new ArrayList<>();
+		if (user.getRoles() != null) {
+			for (String role : user.getRoles()) {
+				authorities.add(new SimpleGrantedAuthority(role));
+			}
+		}
+
+		String passwordHash = user.getPasswordHash();
+
+		if (passwordHash == null) {
+			passwordHash = "";
+		}
+
+		LocalUserDetails userDetails = new LocalUserDetails(username, passwordHash, authorities);
+		return userDetails;
+	}
+
+	@Override
+	public void afterSingletonsInstantiated() {
+		if (!userRepository.exists(qUser.roles.contains("ROLE_ADMIN"))) {
+			if (!StringUtils.hasText(adminPassword)) {
+				adminPassword = RandomStringUtils.random(24, true, true);
+				logger.error("password for 'admin': " + adminPassword);
+			}
+			User admin = new User();
+			admin.setUsername("admin");
+			admin.setRoles(List.of("ROLE_ADMIN", "ROLE_DEBUG"));
+			admin.setPasswordHash(passwordEncoder.encode(adminPassword));
+			admin.setLocale("de");
+			userRepository.save(admin);
+		}
+	}
+
+	@Transactional
+	public User getByUsername(String username) {
+		return userRepository.findOne(qUser.username.equalsIgnoreCase(username)).orElse(null);
+	}
+
+	public User getByExternalId(String externalId) {
+		return userRepository.findOne(qUser.externalId.eq(externalId)).orElse(null);
+	}
+
+	public User getByAuth(Authentication authentication) {
+		if (authentication != null) {
+			if (authentication instanceof UsernamePasswordAuthenticationToken) {
+				UsernamePasswordAuthenticationToken token = (UsernamePasswordAuthenticationToken) authentication;
+				return getByUsername(token.getName());
+			} else if (authentication instanceof OAuth2AuthenticationToken) {
+				OAuth2AuthenticationToken token = (OAuth2AuthenticationToken) authentication;
+				String externalId = token.getAuthorizedClientRegistrationId() + "-" +
+						token.getName();
+				User user = getByExternalId(externalId);
+				if (user == null) {
+					user = new User();
+					user.setExternalId(externalId);
+					String tmpUsername = token.getPrincipal().getAttribute("preferred_username");
+					if (!StringUtils.hasText(tmpUsername)) {
+						tmpUsername = token.getPrincipal().getAttribute("username");
+					}
+					if (!StringUtils.hasText(tmpUsername)) {
+						tmpUsername = token.getPrincipal().getAttribute("name");
+					} else {
+						user.setName(token.getPrincipal().getAttribute("name"));
+					}
+					if (!StringUtils.hasText(tmpUsername)) {
+						tmpUsername = token.getName();
+					}
+					if (!StringUtils.hasText(tmpUsername)) {
+						tmpUsername = "user";
+					}
+					int count = 1;
+					String username = tmpUsername;
+					while (userRepository.exists(qUser.username.equalsIgnoreCase(username))) {
+						username = tmpUsername + "-" + count;
+						count++;
+					}
+
+					user.setUsername(username);
+					user.setEmail(token.getPrincipal().getAttribute("email"));
+					user = userRepository.save(user);
+				}
+				return user;
+			}
+		}
+		return null;
+	}
+
+	public User save(User user) {
+		if (exists(user.getUsername())) {
+			user.setPasswordHash(this.getPasswordHash(user.getUsername()));
+		}
+
+		return userRepository.save(user);
+	}
+
+	public boolean exists(String username) {
+		return userRepository.exists(qUser.username.equalsIgnoreCase(username));
+	}
+
+	public void delete(User user) {
+		turnoverManager.deleteByUsername(user.getUsername());
+		userRepository.delete(user);
+	}
+
+	@Transactional
+	public String getPasswordHash(String username) {
+		Assert.isTrue(userRepository.existsById(username), "User with username '" + username + "' not exists!");
+		return userRepository.findById(username).get().getPasswordHash();
+	}
+
+	public User setPassword(String username, String password) {
+		Assert.isTrue(userRepository.existsById(username), "User with username '" + username + "' not exists!");
+		User user = userRepository.findById(username).get();
+		user.setPasswordHash(passwordEncoder.encode(password));
+		return userRepository.save(user);
+	}
+}

backend/src/main/java/de/champonthis/buntspecht/controller/AuthenticationController.java

@@ -0,0 +1,85 @@
+package de.champonthis.buntspecht.controller;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.ResolvableType;
+import org.springframework.http.HttpStatus;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.security.oauth2.client.registration.ClientRegistration;
+import org.springframework.security.oauth2.client.registration.ClientRegistrationRepository;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import de.champonthis.buntspecht.controller.support.EntityResponseStatusException;
+import de.champonthis.buntspecht.security.LocalUserDetails;
+
+@RestController
+@RequestMapping("/auth")
+public class AuthenticationController extends BaseController {
+
+	private static String authorizationRequestBaseUri = "oauth2/authorization";
+
+	@Autowired(required = false)
+	private ClientRegistrationRepository clientRegistrationRepository;
+
+	@GetMapping
+	public Object me() {
+		Authentication auth = SecurityContextHolder.getContext().getAuthentication();
+		if (auth != null && auth.getPrincipal() instanceof LocalUserDetails) {
+			return (LocalUserDetails) auth.getPrincipal();
+		}
+
+		throw new EntityResponseStatusException(HttpStatus.UNAUTHORIZED);
+	}
+
+	@SuppressWarnings("unchecked")
+	@GetMapping("external")
+	public List<Client> getExternalLoginUrls() {
+		List<Client> clients = new ArrayList<>();
+		if (clientRegistrationRepository != null) {
+			Iterable<ClientRegistration> clientRegistrations = null;
+			ResolvableType type = ResolvableType.forInstance(clientRegistrationRepository).as(Iterable.class);
+			if (type != ResolvableType.NONE && ClientRegistration.class.isAssignableFrom(type.resolveGenerics()[0])) {
+				clientRegistrations = (Iterable<ClientRegistration>) clientRegistrationRepository;
+				clientRegistrations.forEach(registration -> clients.add(new Client(registration.getRegistrationId(),
+						authorizationRequestBaseUri + "/" + registration.getRegistrationId())));
+			}
+		}
+
+		return clients;
+	}
+
+	protected static class Client {
+
+		private String id;
+
+		private String loginUrl;
+
+		public Client(String id, String loginUrl) {
+			super();
+			this.id = id;
+			this.loginUrl = loginUrl;
+		}
+
+		public String getId() {
+			return id;
+		}
+
+		public void setId(String id) {
+			this.id = id;
+		}
+
+		public String getLoginUrl() {
+			return loginUrl;
+		}
+
+		public void setLoginUrl(String loginUrl) {
+			this.loginUrl = loginUrl;
+		}
+
+	}
+}

backend/src/main/java/de/champonthis/buntspecht/controller/BaseController.java

@@ -0,0 +1,32 @@
+package de.champonthis.buntspecht.controller;
+
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.authority.SimpleGrantedAuthority;
+import org.springframework.security.core.context.SecurityContextHolder;
+
+import de.champonthis.buntspecht.security.LocalUserDetails;
+
+public class BaseController {
+
+	protected boolean authenticated() {
+		Authentication auth = SecurityContextHolder.getContext().getAuthentication();
+		return auth != null && auth.isAuthenticated();
+	}
+
+	protected String getCurrentUsername() {
+		LocalUserDetails userDetails = getLocalUserDetails();
+		return userDetails != null ? userDetails.getUsername() : null;
+	}
+
+	protected boolean hasRole(String role) {
+		LocalUserDetails userDetails = getLocalUserDetails();
+		return userDetails != null ? userDetails.getAuthorities().contains(new SimpleGrantedAuthority(role)) : false;
+	}
+
+	protected LocalUserDetails getLocalUserDetails() {
+		Authentication auth = SecurityContextHolder.getContext().getAuthentication();
+		return (auth != null && auth.getPrincipal() instanceof LocalUserDetails)
+				? (LocalUserDetails) auth.getPrincipal()
+				: null;
+	}
+}

backend/src/main/java/de/champonthis/buntspecht/controller/TurnoverController.java

@@ -0,0 +1,174 @@
+package de.champonthis.buntspecht.controller;
+
+import java.time.Instant;
+import java.util.List;
+import java.util.Optional;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.util.StringUtils;
+import org.springframework.validation.Errors;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PatchMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.querydsl.core.QueryResults;
+import com.querydsl.core.Tuple;
+
+import de.champonthis.buntspecht.businesslogic.TurnoverManager;
+import de.champonthis.buntspecht.businesslogic.UserManager;
+import de.champonthis.buntspecht.controller.model.TurnoverFilterModel;
+import de.champonthis.buntspecht.controller.model.TurnoverFilterModel.MinMax;
+import de.champonthis.buntspecht.controller.support.EntityResponseStatusException;
+import de.champonthis.buntspecht.controller.support.RequestBodyErrors;
+import de.champonthis.buntspecht.controller.validation.TurnoverValidator;
+import de.champonthis.buntspecht.model.Turnover;
+import jakarta.transaction.Transactional;
+
+@RestController
+@RequestMapping("/turnovers")
+public class TurnoverController extends BaseController {
+
+	@Autowired
+	private TurnoverManager turnoverManager;
+	@Autowired
+	private UserManager userManager;
+	@Autowired
+	private TurnoverValidator turnoverValidator;
+
+	@PreAuthorize("isAuthenticated()")
+	@GetMapping
+	@Transactional
+	public QueryResults<Turnover> fetch(
+			@RequestParam("limit") Optional<Long> limitParameter,
+			@RequestParam("offset") Optional<Long> offsetParameter,
+			@RequestParam("sort") Optional<String> sort,
+			@RequestParam("descending") Optional<Boolean> descending,
+			@RequestParam("from") Optional<Instant> from,
+			@RequestParam("to") Optional<Instant> to,
+			@RequestParam("created_from") Optional<Instant> fromCreated,
+			@RequestParam("created_to") Optional<Instant> toCreated,
+			@RequestParam("customer") Optional<String> customer,
+			@RequestParam("motif") Optional<String> motif) {
+
+		TurnoverFilterModel filter = new TurnoverFilterModel();
+		filter.setDueDate(new MinMax<Instant>(from.orElse(null), to.orElse(null)));
+		filter.setCreated(new MinMax<Instant>(fromCreated.orElse(null), toCreated.orElse(null)));
+		filter.setCustomer(customer.orElse(null));
+		filter.setMotif(motif.orElse(null));
+
+		return turnoverManager.fetch(getCurrentUsername(), limitParameter.orElse(15L), offsetParameter.orElse(0L),
+				sort.orElse("dueDate"), descending.orElse(false), filter);
+	}
+
+	@PreAuthorize("isAuthenticated()")
+	@GetMapping("/overview")
+	@Transactional
+	public Tuple overview(
+			@RequestParam("limit") Optional<Long> limitParameter,
+			@RequestParam("offset") Optional<Long> offsetParameter,
+			@RequestParam("sort") Optional<String> sort,
+			@RequestParam("descending") Optional<Boolean> descending,
+			@RequestParam("from") Optional<Instant> from,
+			@RequestParam("to") Optional<Instant> to,
+			@RequestParam("created_from") Optional<Instant> fromCreated,
+			@RequestParam("created_to") Optional<Instant> toCreated,
+			@RequestParam("customer") Optional<String> customer,
+			@RequestParam("motif") Optional<String> motif) {
+
+		TurnoverFilterModel filter = new TurnoverFilterModel();
+		filter.setDueDate(new MinMax<Instant>(from.orElse(null), to.orElse(null)));
+		filter.setCreated(new MinMax<Instant>(fromCreated.orElse(null), toCreated.orElse(null)));
+		filter.setCustomer(customer.orElse(null));
+		filter.setMotif(motif.orElse(null));
+
+		List<Tuple> result = turnoverManager.overview(getCurrentUsername(), limitParameter.orElse(15L),
+				offsetParameter.orElse(0L), sort.orElse("username"),
+				descending.orElse(false), filter).getResults();
+
+		if (result.isEmpty()) {
+			return null;
+		}
+
+		return result.get(0);
+	}
+
+	@PreAuthorize("isAuthenticated()")
+	@GetMapping("/{id}")
+	@Transactional
+	public Turnover get(@PathVariable("id") Long id) {
+		Turnover turnover = turnoverManager.get(id);
+
+		if (turnover == null || !getCurrentUsername().equals(turnover.getUsername())) {
+			throw new EntityResponseStatusException(HttpStatus.FORBIDDEN);
+		}
+
+		return turnover;
+	}
+
+	@PreAuthorize("isAuthenticated()")
+	@PostMapping
+	@Transactional
+	public Turnover create(@RequestBody Turnover turnover) {
+		Errors errors = new RequestBodyErrors(turnover);
+		turnoverValidator.validate(turnover, errors);
+
+		if (errors.hasErrors()) {
+			throw new EntityResponseStatusException(errors.getAllErrors(), HttpStatus.CONFLICT);
+		}
+
+		if (!hasRole("ROLE_ADMIN") || !StringUtils.hasText(turnover.getUsername())
+				|| !userManager.exists(turnover.getUsername())) {
+			turnover.setUsername(getCurrentUsername());
+		}
+		turnover.setCreated(Instant.now());
+		turnover.setUpdated(turnover.getCreated());
+		if (turnover.getDueDate() == null) {
+			turnover.setDueDate(turnover.getCreated());
+		}
+
+		return turnoverManager.save(turnover);
+	}
+
+	@PreAuthorize("isAuthenticated()")
+	@PatchMapping
+	@Transactional
+	public Turnover update(@RequestBody Turnover turnover) {
+		Errors errors = new RequestBodyErrors(turnover);
+		turnoverValidator.validate(turnover, errors);
+
+		if (errors.hasErrors() || turnover.getId() == null || turnover.getId() == 0L
+				|| !turnoverManager.exists(turnover.getId())) {
+			throw new EntityResponseStatusException(errors.getAllErrors(), HttpStatus.CONFLICT);
+		}
+
+		if (!hasRole("ROLE_ADMIN")) {
+			Turnover existing = turnoverManager.get(turnover.getId());
+			if (!getCurrentUsername().equals(existing.getUsername())) {
+				throw new EntityResponseStatusException(HttpStatus.FORBIDDEN);
+			}
+			turnover.setUsername(getCurrentUsername());
+		}
+
+		Turnover existing = turnoverManager.get(turnover.getId());
+
+		if (existing.equals(turnover)) {
+			throw new EntityResponseStatusException(HttpStatus.NOT_MODIFIED);
+		}
+
+		if (turnover.getDueDate() == null) {
+			turnover.setDueDate(turnover.getCreated());
+		}
+
+		turnover.setUpdated(Instant.now());
+
+		return turnoverManager.save(turnover);
+	}
+}

backend/src/main/java/de/champonthis/buntspecht/controller/UserController.java

@@ -0,0 +1,84 @@
+package de.champonthis.buntspecht.controller;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.util.StringUtils;
+import org.springframework.validation.Errors;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PatchMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import de.champonthis.buntspecht.businesslogic.UserManager;
+import de.champonthis.buntspecht.controller.model.UserPasswordModel;
+import de.champonthis.buntspecht.controller.support.EntityResponseStatusException;
+import de.champonthis.buntspecht.controller.support.RequestBodyErrors;
+import de.champonthis.buntspecht.controller.validation.PasswordModelValidator;
+import de.champonthis.buntspecht.model.User;
+import jakarta.transaction.Transactional;
+
+@RestController
+@RequestMapping("/users")
+public class UserController extends BaseController {
+
+	@Autowired
+	private UserManager userManager;
+	@Autowired
+	private PasswordEncoder passwordEncoder;
+	@Autowired
+	private PasswordModelValidator passwordModelValidator;
+
+	@PreAuthorize("isAuthenticated()")
+	@GetMapping("/user")
+	@Transactional
+	public User get() {
+		return userManager.getByUsername(getCurrentUsername());
+	}
+
+	@PreAuthorize("isAuthenticated()")
+	@PatchMapping("/user")
+	@Transactional
+	public User updateUser(@RequestBody User user) {
+		if (!getCurrentUsername().equals(user.getUsername())) {
+			throw new EntityResponseStatusException(HttpStatus.UNPROCESSABLE_ENTITY);
+		}
+
+		User orgUser = userManager.getByUsername(user.getUsername());
+
+		orgUser.setName(user.getName());
+		orgUser.setAbout(user.getAbout());
+		orgUser.setDarkTheme(user.isDarkTheme());
+		orgUser.setEmail(user.getEmail());
+		orgUser.setLocale(user.getLocale());
+
+		user = userManager.save(orgUser);
+		return user;
+	}
+
+	@PreAuthorize("isAuthenticated()")
+	@PostMapping("/password")
+	public void changePassword(@RequestBody UserPasswordModel passwordModel) {
+
+		Errors errors = new RequestBodyErrors(passwordModel);
+
+		User user = userManager.getByUsername(getCurrentUsername());
+
+		if (!StringUtils.hasText(passwordModel.getOld())
+				|| !passwordEncoder.matches(passwordModel.getOld(), userManager.getPasswordHash(user.getUsername()))) {
+			errors.rejectValue("old", "UNAUTHORIZED");
+		}
+
+		passwordModelValidator.validate(passwordModel, errors);
+
+		if (errors.hasErrors()) {
+			throw new EntityResponseStatusException(errors.getAllErrors(), HttpStatus.CONFLICT);
+		}
+
+		userManager.setPassword(user.getUsername(), passwordModel.getPassword());
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/controller/admin/DebugController.java

@@ -0,0 +1,118 @@
+package de.champonthis.buntspecht.controller.admin;
+
+import java.time.Instant;
+import java.time.temporal.ChronoUnit;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.SplittableRandom;
+
+import org.apache.commons.lang3.RandomStringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import de.champonthis.buntspecht.model.QUser;
+import de.champonthis.buntspecht.model.Turnover;
+import de.champonthis.buntspecht.model.User;
+import de.champonthis.buntspecht.repository.TurnoverRepository;
+import de.champonthis.buntspecht.repository.UserRepository;
+
+@RestController
+@RequestMapping("/debug")
+public class DebugController {
+
+    private Logger logger = LoggerFactory.getLogger(DebugController.class);
+
+    @Autowired
+    private PasswordEncoder passwordEncoder;
+    @Autowired
+    private UserRepository userRepository;
+    @Autowired
+    private TurnoverRepository turnoverRepository;
+
+    SplittableRandom splittableRandom = new SplittableRandom();
+
+    @PreAuthorize("hasRole('ROLE_DEBUG')")
+    @GetMapping("/random")
+    public void random(
+            @RequestParam("users") Optional<Integer> usersParameter,
+            @RequestParam("minEntries") Optional<Integer> minEntriesParameter,
+            @RequestParam("maxEntries") Optional<Integer> maxEntriesParameter,
+            @RequestParam("days") Optional<Integer> daysParameter) {
+        logger.warn("start random generation");
+
+        long userCount = userRepository.count(QUser.user.username.startsWith("Tätowier"));
+
+        List<String> newUser = new ArrayList<>();
+
+        for (long i = userCount + 1; i <= userCount + usersParameter.orElse(5); i++) {
+            User user = new User();
+            String username = (splittableRandom.nextBoolean() ? "Tätowiererin " : "Tätowierer ") + i;
+            String name = "Random " + RandomStringUtils.randomAlphanumeric(splittableRandom.nextInt(4, 8));
+            user.setUsername(username);
+            user.setName(name);
+            user.setPasswordHash(passwordEncoder.encode(username));
+            user = userRepository.save(user);
+            logger.trace("Created user: '" + username + "'");
+            newUser.add(user.getUsername());
+        }
+
+        logger.info("Created " + usersParameter.orElse(5) + " users");
+
+        Instant startInclusive = Instant.now().minus(daysParameter.orElse(350), ChronoUnit.DAYS);
+        Instant endExclusive = Instant.now();
+
+        for (String username : newUser) {
+            long numEntries = splittableRandom.nextLong(minEntriesParameter.orElse(3), maxEntriesParameter.orElse(20));
+            for (int i = 0; i < numEntries; i++) {
+                Turnover turnover = new Turnover();
+                turnover.setUsername(username);
+                turnover.setCreated(randomDate(startInclusive, endExclusive));
+                turnover.setUpdated(splittableRandom.nextBoolean() ? turnover.getCreated()
+                        : randomDate(turnover.getCreated(), endExclusive));
+                turnover.setDueDate(splittableRandom.nextBoolean() ? turnover.getCreated()
+                        : randomDate(startInclusive, turnover.getCreated()));
+                turnover.setCustomer(RandomStringUtils.randomAlphabetic(splittableRandom.nextInt(3, 10)));
+
+                turnover.setMotif(RandomStringUtils.randomAlphabetic(splittableRandom.nextInt(5, 30)));
+
+                turnover.setPrice(Float.valueOf(String.format("%.2f", splittableRandom.nextFloat(0.01f, 2000f))));
+
+                if (splittableRandom.nextBoolean()) {
+                    turnover.setTimeInvestment(
+                            Float.valueOf(String.format("%.2f", splittableRandom.nextFloat(0.01f, 20f))));
+                }
+
+                if (splittableRandom.nextBoolean()) {
+                    turnover.setRemark(RandomStringUtils.randomAlphabetic(splittableRandom.nextInt(10, 50)));
+                }
+
+                if (splittableRandom.nextInt(5) < 3) {
+                    turnover.setMaterialConsumption(
+                            RandomStringUtils.randomAlphabetic(splittableRandom.nextInt(10, 250)));
+                }
+
+                turnover = turnoverRepository.save(turnover);
+                logger.trace("Created turnover: '" + turnover.getId() + "'");
+            }
+            logger.info("Created " + numEntries + " turnovers of '" + username + "'");
+        }
+
+        logger.warn("finished random generation");
+    }
+
+    protected Instant randomDate(Instant startInclusive, Instant endExclusive) {
+        long startSeconds = startInclusive.getEpochSecond();
+        long endSeconds = endExclusive.getEpochSecond();
+        long random = splittableRandom.nextLong(startSeconds, endSeconds);
+
+        return Instant.ofEpochSecond(random);
+    }
+}

backend/src/main/java/de/champonthis/buntspecht/controller/admin/SystemPropertiesController.java

@@ -0,0 +1,78 @@
+package de.champonthis.buntspecht.controller.admin;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Sort;
+import org.springframework.http.HttpStatus;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import de.champonthis.buntspecht.controller.BaseController;
+import de.champonthis.buntspecht.controller.support.EntityResponseStatusException;
+import de.champonthis.buntspecht.model.SystemProperty;
+import de.champonthis.buntspecht.repository.SystemPropertyRepository;
+
+@RestController
+@RequestMapping("/system/properties")
+public class SystemPropertiesController extends BaseController {
+
+	@Autowired
+	private SystemPropertyRepository systemPropertyRepository;
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@GetMapping()
+	public List<SystemProperty> getProperties(@RequestParam("page") Optional<Integer> pageParameter,
+			@RequestParam("size") Optional<Integer> sizeParameter) {
+		Sort sort = Sort.by("key").ascending();
+		return systemPropertyRepository.findAll(PageRequest.of(pageParameter.orElse(0), sizeParameter.orElse(10), sort))
+				.getContent();
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@GetMapping("/{key}")
+	public SystemProperty getProperty(@PathVariable("key") String key) {
+		if (!systemPropertyRepository.existsById(key)) {
+			throw new EntityResponseStatusException(HttpStatus.NO_CONTENT);
+		}
+
+		return systemPropertyRepository.findById(key).get();
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@PostMapping("")
+	public SystemProperty createOrUpdate(@RequestBody SystemProperty systemProperty) {
+		return systemPropertyRepository.save(systemProperty);
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@PostMapping("/list")
+	public List<SystemProperty> createOrUpdateList(@RequestBody List<SystemProperty> systemProperties) {
+		List<SystemProperty> result = new ArrayList<>();
+		for (SystemProperty systemProperty : systemProperties) {
+			result.add(
+					systemPropertyRepository.save(systemProperty));
+		}
+		return result;
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@DeleteMapping("/{key}")
+	public void deleteProperty(@PathVariable("key") String key) {
+		if (!systemPropertyRepository.existsById(key)) {
+			throw new EntityResponseStatusException(HttpStatus.NOT_MODIFIED);
+		}
+
+		systemPropertyRepository.deleteById(key);
+	}
+}

backend/src/main/java/de/champonthis/buntspecht/controller/admin/TurnoverManagementController.java

@@ -0,0 +1,139 @@
+package de.champonthis.buntspecht.controller.admin;
+
+import java.time.Instant;
+import java.util.Optional;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.validation.Errors;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PatchMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.querydsl.core.QueryResults;
+import com.querydsl.core.Tuple;
+
+import de.champonthis.buntspecht.businesslogic.TurnoverManager;
+import de.champonthis.buntspecht.controller.BaseController;
+import de.champonthis.buntspecht.controller.model.TurnoverFilterModel;
+import de.champonthis.buntspecht.controller.model.TurnoverFilterModel.MinMax;
+import de.champonthis.buntspecht.controller.support.EntityResponseStatusException;
+import de.champonthis.buntspecht.controller.support.RequestBodyErrors;
+import de.champonthis.buntspecht.controller.validation.TurnoverValidator;
+import de.champonthis.buntspecht.model.Turnover;
+import jakarta.transaction.Transactional;
+
+@RestController
+@RequestMapping("/turnovers/manage")
+public class TurnoverManagementController extends BaseController {
+
+	@Autowired
+	private TurnoverManager turnoverManager;
+	@Autowired
+	private TurnoverValidator turnoverValidator;
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@GetMapping
+	@Transactional
+	public QueryResults<Turnover> fetch(
+			@RequestParam("username") Optional<String> usernameParameter,
+			@RequestParam("limit") Optional<Long> limitParameter,
+			@RequestParam("offset") Optional<Long> offsetParameter,
+			@RequestParam("sort") Optional<String> sort,
+			@RequestParam("descending") Optional<Boolean> descending,
+			@RequestParam("from") Optional<Instant> from,
+			@RequestParam("to") Optional<Instant> to,
+			@RequestParam("created_from") Optional<Instant> fromCreated,
+			@RequestParam("created_to") Optional<Instant> toCreated,
+			@RequestParam("customer") Optional<String> customer,
+			@RequestParam("motif") Optional<String> motif) {
+
+		TurnoverFilterModel filter = new TurnoverFilterModel();
+		filter.setDueDate(new MinMax<Instant>(from.orElse(null), to.orElse(null)));
+		filter.setCreated(new MinMax<Instant>(fromCreated.orElse(null), toCreated.orElse(null)));
+		filter.setCustomer(customer.orElse(null));
+		filter.setMotif(motif.orElse(null));
+
+		return turnoverManager.fetch(usernameParameter.orElse(null), limitParameter.orElse(15L),
+				offsetParameter.orElse(0L), sort.orElse("dueDate"), descending.orElse(false), filter);
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@GetMapping("/overview")
+	@Transactional
+	public QueryResults<Tuple> overview(
+			@RequestParam("username") Optional<String> usernameParameter,
+			@RequestParam("limit") Optional<Long> limitParameter,
+			@RequestParam("offset") Optional<Long> offsetParameter,
+			@RequestParam("sort") Optional<String> sort,
+			@RequestParam("descending") Optional<Boolean> descending,
+			@RequestParam("from") Optional<Instant> from,
+			@RequestParam("to") Optional<Instant> to,
+			@RequestParam("created_from") Optional<Instant> fromCreated,
+			@RequestParam("created_to") Optional<Instant> toCreated,
+			@RequestParam("customer") Optional<String> customer,
+			@RequestParam("motif") Optional<String> motif) {
+
+		TurnoverFilterModel filter = new TurnoverFilterModel();
+		filter.setDueDate(new MinMax<Instant>(from.orElse(null), to.orElse(null)));
+		filter.setCreated(new MinMax<Instant>(fromCreated.orElse(null), toCreated.orElse(null)));
+		filter.setCustomer(customer.orElse(null));
+		filter.setMotif(motif.orElse(null));
+		return turnoverManager.overview(usernameParameter.orElse(null), limitParameter.orElse(15L),
+				offsetParameter.orElse(0L), sort.orElse("username"),
+				descending.orElse(false), filter);
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@GetMapping("/{id}")
+	@Transactional
+	public Turnover getById(@PathVariable("id") Long id) {
+		if (!turnoverManager.exists(id)) {
+			throw new EntityResponseStatusException(HttpStatus.NO_CONTENT);
+		}
+
+		return turnoverManager.get(id);
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@PatchMapping
+	@Transactional
+	public Turnover update(@RequestBody Turnover turnover) {
+		Errors errors = new RequestBodyErrors(turnover);
+		turnoverValidator.validate(turnover, errors);
+
+		if (errors.hasErrors()) {
+			throw new EntityResponseStatusException(errors.getAllErrors(), HttpStatus.CONFLICT);
+		}
+
+		Turnover existing = turnoverManager.get(turnover.getId());
+		if (existing.equals(turnover)) {
+			throw new EntityResponseStatusException(HttpStatus.NOT_MODIFIED);
+		}
+
+		if (turnover.getDueDate() == null) {
+			turnover.setDueDate(turnover.getCreated());
+		}
+
+		turnover.setUpdated(Instant.now());
+
+		return turnoverManager.save(turnover);
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@DeleteMapping("/{id}")
+	@Transactional
+	public void deleteById(@PathVariable("id") Long id) {
+		if (!turnoverManager.exists(id)) {
+			throw new EntityResponseStatusException(HttpStatus.NO_CONTENT);
+		}
+
+		turnoverManager.deleteById(id);
+	}
+}

backend/src/main/java/de/champonthis/buntspecht/controller/admin/UserManagementController.java

@@ -0,0 +1,148 @@
+package de.champonthis.buntspecht.controller.admin;
+
+import java.util.List;
+import java.util.Optional;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.validation.Errors;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PatchMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.querydsl.core.QueryResults;
+
+import de.champonthis.buntspecht.businesslogic.UserManager;
+import de.champonthis.buntspecht.controller.BaseController;
+import de.champonthis.buntspecht.controller.admin.validation.UserValidator;
+import de.champonthis.buntspecht.controller.model.UserPasswordModel;
+import de.champonthis.buntspecht.controller.support.EntityResponseStatusException;
+import de.champonthis.buntspecht.controller.support.RequestBodyErrors;
+import de.champonthis.buntspecht.controller.validation.PasswordModelValidator;
+import de.champonthis.buntspecht.model.User;
+import jakarta.transaction.Transactional;
+
+@RestController
+@RequestMapping("/users/manage")
+public class UserManagementController extends BaseController {
+
+	@Autowired
+	private UserManager userManager;
+	@Autowired
+	private UserValidator userValidator;
+	@Autowired
+	private PasswordModelValidator passwordModelValidator;
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@GetMapping
+	@Transactional
+	public QueryResults<User> fetch(
+			@RequestParam("limit") Optional<Long> limitParameter,
+			@RequestParam("offset") Optional<Long> offsetParameter,
+			@RequestParam("sort") Optional<String> sort,
+			@RequestParam("descending") Optional<Boolean> descending,
+			@RequestParam("filter") Optional<String> search) {
+		return userManager.fetch(limitParameter.orElse(15L), offsetParameter.orElse(0L), sort.orElse("username"),
+				descending.orElse(false), search.orElse(""));
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@GetMapping("/pick")
+	@Transactional
+	public List<User> pick(
+			@RequestParam("filter") Optional<String> search) {
+		return userManager.fetch(5L, 0L, "", false, search.orElse("")).getResults();
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@GetMapping("/{username}")
+	@Transactional
+	public User get(@PathVariable("username") String username) {
+		User user = userManager.getByUsername(username);
+
+		if (user == null) {
+			throw new EntityResponseStatusException(HttpStatus.NO_CONTENT);
+		}
+
+		return user;
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@PostMapping
+	@Transactional
+	public User create(@RequestBody User user) {
+		Errors errors = new RequestBodyErrors(user);
+		userValidator.validateNew(user, errors);
+
+		if (errors.hasErrors()) {
+			throw new EntityResponseStatusException(errors.getAllErrors(), HttpStatus.CONFLICT);
+		}
+
+		if (user.getLocale() == null) {
+			user.setLocale("de");
+		}
+
+		return userManager.save(user);
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@PatchMapping
+	@Transactional
+	public User update(@RequestBody User user) {
+		Errors errors = new RequestBodyErrors(user);
+		userValidator.validate(user, errors);
+
+		if (errors.hasErrors()) {
+			throw new EntityResponseStatusException(errors.getAllErrors(), HttpStatus.CONFLICT);
+		}
+
+		if (getCurrentUsername().equals(user.getUsername()) && user.getRoles().indexOf("ROLE_ADMIN") == -1) {
+			user.getRoles().add("ROLE_ADMIN");
+		}
+
+		return userManager.save(user);
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@DeleteMapping("/{username}")
+	@Transactional
+	public void delete(@PathVariable("username") String username) {
+		User user = userManager.getByUsername(username);
+
+		if (user == null || getCurrentUsername().equals(username)) {
+			throw new EntityResponseStatusException(HttpStatus.NOT_MODIFIED);
+		}
+
+		userManager.delete(user);
+	}
+
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@PostMapping("/{username}/password")
+	public void password(@PathVariable("username") String username,
+			@RequestBody UserPasswordModel passwordModel) {
+
+		Errors errors = new RequestBodyErrors(passwordModel);
+
+		User user = userManager.getByUsername(username);
+
+		if (user == null) {
+			throw new EntityResponseStatusException(HttpStatus.NO_CONTENT);
+		}
+
+		passwordModelValidator.validate(passwordModel, errors);
+
+		if (errors.hasErrors()) {
+			throw new EntityResponseStatusException(errors.getAllErrors(), HttpStatus.CONFLICT);
+		}
+
+		userManager.setPassword(user.getUsername(), passwordModel.getPassword());
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/controller/admin/validation/UserValidator.java

@@ -0,0 +1,46 @@
+package de.champonthis.buntspecht.controller.admin.validation;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+import org.springframework.util.StringUtils;
+import org.springframework.validation.Errors;
+import org.springframework.validation.Validator;
+
+import de.champonthis.buntspecht.businesslogic.UserManager;
+import de.champonthis.buntspecht.model.User;
+
+@Component
+public class UserValidator implements Validator {
+
+    @Autowired
+    private UserManager userManager;
+
+    @Override
+    public boolean supports(Class<?> clazz) {
+        return clazz.isAssignableFrom(User.class);
+    }
+
+    @Override
+    public void validate(Object target, Errors errors) {
+        User user = (User) target;
+        if (!StringUtils.hasText(user.getUsername())) {
+            errors.rejectValue("username", "REQUIRED");
+            return;
+        }
+    }
+
+    public void validateNew(Object target, Errors errors) {
+        validate(target, errors);
+
+        if (errors.hasErrors()) {
+            return;
+        }
+
+        User user = (User) target;
+        if (userManager.exists(user.getUsername())) {
+            errors.rejectValue("username", "ALREADY_EXISTS");
+            return;
+        }
+    }
+
+}

backend/src/main/java/de/champonthis/buntspecht/controller/model/TupleSerializer.java

@@ -0,0 +1,28 @@
+package de.champonthis.buntspecht.controller.model;
+
+import java.io.IOException;
+
+import org.springframework.boot.jackson.JsonComponent;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.querydsl.core.Tuple;
+
+@JsonComponent
+public class TupleSerializer extends JsonSerializer<Tuple> {
+
+    @Override
+    public void serialize(Tuple value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
+        if (value.toArray().length > 1) {
+            gen.writeStartArray();
+        }
+        for (Object object : value.toArray()) {
+            gen.writeObject(object);
+        }
+        if (value.toArray().length > 1) {
+            gen.writeEndArray();
+        }
+    }
+
+}

backend/src/main/java/de/champonthis/buntspecht/controller/model/TurnoverFilterModel.java

@@ -0,0 +1,98 @@
+package de.champonthis.buntspecht.controller.model;
+
+import java.time.Instant;
+
+public class TurnoverFilterModel {
+
+    private MinMax<Instant> created;
+    private MinMax<Instant> dueDate;
+    private MinMax<Instant> updated;
+    private String customer;
+    private String motif;
+    private MinMax<Float> price;
+    private MinMax<Float> timeInvestment;
+
+    public MinMax<Instant> getCreated() {
+        return created;
+    }
+
+    public void setCreated(MinMax<Instant> created) {
+        this.created = created;
+    }
+
+    public MinMax<Instant> getDueDate() {
+        return dueDate;
+    }
+
+    public void setDueDate(MinMax<Instant> dueDate) {
+        this.dueDate = dueDate;
+    }
+
+    public MinMax<Instant> getUpdated() {
+        return updated;
+    }
+
+    public void setUpdated(MinMax<Instant> updated) {
+        this.updated = updated;
+    }
+
+    public String getCustomer() {
+        return customer;
+    }
+
+    public void setCustomer(String customer) {
+        this.customer = customer;
+    }
+
+    public String getMotif() {
+        return motif;
+    }
+
+    public void setMotif(String motif) {
+        this.motif = motif;
+    }
+
+    public MinMax<Float> getPrice() {
+        return price;
+    }
+
+    public void setPrice(MinMax<Float> price) {
+        this.price = price;
+    }
+
+    public MinMax<Float> getTimeInvestment() {
+        return timeInvestment;
+    }
+
+    public void setTimeInvestment(MinMax<Float> timeInvestment) {
+        this.timeInvestment = timeInvestment;
+    }
+
+    public static class MinMax<T> {
+
+        private T min;
+        private T max;
+
+        public MinMax(T min, T max) {
+            this.min = min;
+            this.max = max;
+        }
+
+        public T getMin() {
+            return min;
+        }
+
+        public void setMin(T min) {
+            this.min = min;
+        }
+
+        public T getMax() {
+            return max;
+        }
+
+        public void setMax(T max) {
+            this.max = max;
+        }
+
+    }
+}

backend/src/main/java/de/champonthis/buntspecht/controller/model/UserPasswordModel.java

@@ -0,0 +1,32 @@
+package de.champonthis.buntspecht.controller.model;
+
+public class UserPasswordModel {
+
+    private String old;
+    private String password;
+    private String password2;
+
+    public String getOld() {
+        return old;
+    }
+
+    public void setOld(String old) {
+        this.old = old;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public String getPassword2() {
+        return password2;
+    }
+
+    public void setPassword2(String password2) {
+        this.password2 = password2;
+    }
+}

backend/src/main/java/de/champonthis/buntspecht/controller/support/ControllerExceptionHandler.java

@@ -0,0 +1,23 @@
+package de.champonthis.buntspecht.controller.support;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.context.request.WebRequest;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
+
+
+@ControllerAdvice
+public class ControllerExceptionHandler extends ResponseEntityExceptionHandler {
+
+	
+	@ExceptionHandler(value = { EntityResponseStatusException.class })
+	protected ResponseEntity<Object> handleResponseEntityStatusException(RuntimeException exception,
+			WebRequest request) {
+		EntityResponseStatusException entityResponseStatusException = (EntityResponseStatusException) exception;
+		return handleExceptionInternal(exception, entityResponseStatusException.getBody(), new HttpHeaders(),
+				entityResponseStatusException.getStatus(), request);
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/controller/support/EntityResponseStatusException.java

@@ -0,0 +1,56 @@
+package de.champonthis.buntspecht.controller.support;
+
+import org.springframework.core.NestedRuntimeException;
+import org.springframework.http.HttpStatus;
+import org.springframework.util.Assert;
+
+import jakarta.annotation.Nullable;
+
+
+public class EntityResponseStatusException extends NestedRuntimeException {
+
+	private static final long serialVersionUID = 1L;
+
+	private final HttpStatus status;
+
+	@Nullable
+	private final Object body;
+
+	
+	public EntityResponseStatusException(HttpStatus status) {
+		this(null, status);
+	}
+
+	
+	public EntityResponseStatusException(@Nullable Object body, HttpStatus status) {
+		this(body, status, null);
+	}
+
+	
+	public EntityResponseStatusException(@Nullable Object body, HttpStatus status, @Nullable Throwable cause) {
+		super(null, cause);
+		Assert.notNull(status, "HttpStatus is required");
+		this.status = status;
+		this.body = body;
+	}
+
+	
+	public HttpStatus getStatus() {
+		return this.status;
+	}
+
+	
+	@Nullable
+	public Object getBody() {
+		return this.body;
+	}
+
+	/*
+	 * @see org.springframework.core.NestedRuntimeException#getMessage()
+	 */
+	@Override
+	public String getMessage() {
+		return this.status + (this.body != null ? " \"" + this.body + "\"" : "");
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/controller/support/JsonStringBodyControllerAdvice.java

@@ -0,0 +1,101 @@
+package de.champonthis.buntspecht.controller.support;
+
+import java.io.IOException;
+import java.lang.reflect.Type;
+
+import org.springframework.core.MethodParameter;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpInputMessage;
+import org.springframework.http.MediaType;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.http.converter.StringHttpMessageConverter;
+import org.springframework.http.server.ServerHttpRequest;
+import org.springframework.http.server.ServerHttpResponse;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.servlet.mvc.method.annotation.RequestBodyAdvice;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonPrimitive;
+
+
+@ControllerAdvice
+public class JsonStringBodyControllerAdvice implements RequestBodyAdvice, ResponseBodyAdvice<String> {
+
+	private Gson gson = new Gson();
+
+	/*
+	 * @see org.springframework.web.servlet.mvc.method.annotation.RequestBodyAdvice#
+	 * supports(org.springframework.core.MethodParameter, java.lang.reflect.Type,
+	 * java.lang.Class)
+	 */
+	@Override
+	public boolean supports(MethodParameter methodParameter, Type targetType,
+			Class<? extends HttpMessageConverter<?>> converterType) {
+		return targetType instanceof Class && String.class.equals((Class<?>) targetType);
+	}
+
+	/*
+	 * @see org.springframework.web.servlet.mvc.method.annotation.RequestBodyAdvice#
+	 * beforeBodyRead(org.springframework.http.HttpInputMessage,
+	 * org.springframework.core.MethodParameter, java.lang.reflect.Type,
+	 * java.lang.Class)
+	 */
+	@Override
+	public HttpInputMessage beforeBodyRead(HttpInputMessage inputMessage, MethodParameter parameter, Type targetType,
+			Class<? extends HttpMessageConverter<?>> converterType) throws IOException {
+		return inputMessage;
+	}
+
+	/*
+	 * @see org.springframework.web.servlet.mvc.method.annotation.RequestBodyAdvice#
+	 * afterBodyRead(java.lang.Object, org.springframework.http.HttpInputMessage,
+	 * org.springframework.core.MethodParameter, java.lang.reflect.Type,
+	 * java.lang.Class)
+	 */
+	@Override
+	public Object afterBodyRead(Object body, HttpInputMessage inputMessage, MethodParameter parameter, Type targetType,
+			Class<? extends HttpMessageConverter<?>> converterType) {
+		body = ((String) body).replaceAll("^\"|\"$", "");
+		return body;
+	}
+
+	/*
+	 * @see org.springframework.web.servlet.mvc.method.annotation.RequestBodyAdvice#
+	 * handleEmptyBody(java.lang.Object, org.springframework.http.HttpInputMessage,
+	 * org.springframework.core.MethodParameter, java.lang.reflect.Type,
+	 * java.lang.Class)
+	 */
+	@Override
+	public Object handleEmptyBody(Object body, HttpInputMessage inputMessage, MethodParameter parameter,
+			Type targetType, Class<? extends HttpMessageConverter<?>> converterType) {
+		return body;
+	}
+
+	/*
+	 * @see
+	 * org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice#
+	 * supports(org.springframework.core.MethodParameter, java.lang.Class)
+	 */
+	@Override
+	public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
+		return converterType == StringHttpMessageConverter.class;
+	}
+
+	/*
+	 * @see
+	 * org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice#
+	 * beforeBodyWrite(java.lang.Object, org.springframework.core.MethodParameter,
+	 * org.springframework.http.MediaType, java.lang.Class,
+	 * org.springframework.http.server.ServerHttpRequest,
+	 * org.springframework.http.server.ServerHttpResponse)
+	 */
+	@Override
+	public String beforeBodyWrite(String body, MethodParameter returnType, MediaType selectedContentType,
+			Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request,
+			ServerHttpResponse response) {
+		response.getHeaders().set(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE);
+		return gson.toJson(new JsonPrimitive(body));
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/controller/support/RequestBodyErrors.java

@@ -0,0 +1,37 @@
+package de.champonthis.buntspecht.controller.support;
+
+import org.springframework.lang.Nullable;
+import org.springframework.validation.AbstractBindingResult;
+
+
+public class RequestBodyErrors extends AbstractBindingResult {
+
+	@Nullable
+	private final Object target;
+
+	
+	public RequestBodyErrors(@Nullable Object target) {
+		super("request-body");
+		this.target = target;
+	}
+
+	/*
+	 * @see org.springframework.validation.AbstractBindingResult#getTarget()
+	 */
+	@Override
+	public Object getTarget() {
+		return target;
+	}
+
+	/*
+	 * @see
+	 * org.springframework.validation.AbstractBindingResult#getActualFieldValue(java
+	 * .lang.String)
+	 */
+	@Override
+	protected Object getActualFieldValue(String field) {
+		// Not necessary
+		return null;
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/controller/validation/PasswordModelValidator.java

@@ -0,0 +1,85 @@
+package de.champonthis.buntspecht.controller.validation;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.passay.CharacterRule;
+import org.passay.EnglishCharacterData;
+import org.passay.LengthRule;
+import org.passay.PasswordData;
+import org.passay.PasswordValidator;
+import org.passay.Rule;
+import org.passay.RuleResult;
+import org.passay.RuleResultDetail;
+import org.passay.WhitespaceRule;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+import org.springframework.validation.Errors;
+import org.springframework.validation.Validator;
+
+import de.champonthis.buntspecht.businesslogic.SystemPropertyManager;
+import de.champonthis.buntspecht.controller.model.UserPasswordModel;
+
+@Component
+public class PasswordModelValidator implements Validator {
+
+    @Autowired
+    private SystemPropertyManager systemPropertyManager;
+
+    public static final String SYSTEM_PROPERTY_PASSWORD_RULE_WHITESPACE = "password.rule.whitespace";
+    public static final String SYSTEM_PROPERTY_PASSWORD_RULE_LENGTH = "password.rule.length";
+    public static final String SYSTEM_PROPERTY_PASSWORD_RULE_UPPERCASE = "password.rule.uppercase";
+    public static final String SYSTEM_PROPERTY_PASSWORD_RULE_DIGIT = "password.rule.digit";
+    public static final String SYSTEM_PROPERTY_PASSWORD_RULE_SPECIAL = "password.rule.special";
+
+    @Override
+    public boolean supports(Class<?> clazz) {
+        return clazz.isAssignableFrom(UserPasswordModel.class);
+    }
+
+    @Override
+    public void validate(Object target, Errors errors) {
+        UserPasswordModel passwordModel = (UserPasswordModel) target;
+
+        List<Rule> rules = new ArrayList<Rule>();
+
+        if (systemPropertyManager.getBoolean(SYSTEM_PROPERTY_PASSWORD_RULE_WHITESPACE, true)) {
+            rules.add(new WhitespaceRule());
+        }
+
+        int length = systemPropertyManager.getInteger(SYSTEM_PROPERTY_PASSWORD_RULE_LENGTH, 8);
+        if (length > 0) {
+            rules.add(new LengthRule(length, 4096));
+        }
+
+        int uppercase = systemPropertyManager.getInteger(SYSTEM_PROPERTY_PASSWORD_RULE_UPPERCASE, 1);
+        if (uppercase > 0) {
+            rules.add(new CharacterRule(EnglishCharacterData.UpperCase, uppercase));
+        }
+
+        int digit = systemPropertyManager.getInteger(SYSTEM_PROPERTY_PASSWORD_RULE_DIGIT, 1);
+        if (digit > 0) {
+            rules.add(new CharacterRule(EnglishCharacterData.Digit, digit));
+        }
+
+        int special = systemPropertyManager.getInteger(SYSTEM_PROPERTY_PASSWORD_RULE_SPECIAL, 1);
+        if (special > 0) {
+            rules.add(new CharacterRule(EnglishCharacterData.Special, special));
+        }
+
+        PasswordValidator validator = new PasswordValidator(rules);
+        PasswordData password = new PasswordData(passwordModel.getPassword());
+        RuleResult result = validator.validate(password);
+
+        if (!result.isValid()) {
+            for (RuleResultDetail ruleResultDetail : result.getDetails()) {
+                errors.rejectValue("password", ruleResultDetail.getErrorCode());
+            }
+        }
+
+        if (!passwordModel.getPassword().equals(passwordModel.getPassword2())) {
+            errors.rejectValue("password2", "NOT_MATCH");
+        }
+    }
+
+}

backend/src/main/java/de/champonthis/buntspecht/controller/validation/TurnoverValidator.java

@@ -0,0 +1,38 @@
+package de.champonthis.buntspecht.controller.validation;
+
+import org.springframework.stereotype.Component;
+import org.springframework.util.StringUtils;
+import org.springframework.validation.Errors;
+import org.springframework.validation.Validator;
+
+import de.champonthis.buntspecht.model.Turnover;
+
+@Component
+public class TurnoverValidator implements Validator {
+
+    @Override
+    public boolean supports(Class<?> clazz) {
+        return clazz.isAssignableFrom(Turnover.class);
+    }
+
+    @Override
+    public void validate(Object target, Errors errors) {
+        Turnover turnover = (Turnover) target;
+
+        if (!StringUtils.hasText(turnover.getCustomer())) {
+            errors.rejectValue("customer", "REQUIRED");
+        }
+
+        if (!StringUtils.hasText(turnover.getMotif())) {
+            errors.rejectValue("motif", "REQUIRED");
+        }
+
+        if (turnover.getPrice() == 0) {
+            errors.rejectValue("price", "REQUIRED");
+        }
+
+        if (turnover.getPrice() < 0) {
+            errors.rejectValue("price", "POSITIVE_VALUE");
+        }
+    }
+}

backend/src/main/java/de/champonthis/buntspecht/i18n/businesslogic/I18nManager.java

@@ -0,0 +1,143 @@
+package de.champonthis.buntspecht.i18n.businesslogic;
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.util.List;
+import java.util.Map.Entry;
+import java.util.stream.Collectors;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.SmartInitializingSingleton;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.ResourceLoader;
+import org.springframework.stereotype.Component;
+import org.springframework.util.StringUtils;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+
+import de.champonthis.buntspecht.i18n.model.I18n;
+import de.champonthis.buntspecht.i18n.repository.I18nRepository;
+
+
+@Component
+public class I18nManager implements SmartInitializingSingleton {
+
+	private Logger logger = LoggerFactory.getLogger(I18nManager.class);
+
+	@Autowired
+	private I18nRepository i18nRepository;
+
+	@Autowired
+	private ResourceLoader resourceLoader;
+
+	private Gson gson = new Gson();
+
+	
+	public I18n get(String locale) {
+		return i18nRepository.findById(locale).orElse(null);
+	}
+
+	
+	public JsonObject getLabel(String locale) {
+		I18n i18n = get(locale);
+		if (i18n != null && StringUtils.hasText(i18n.getLabel())) {
+			JsonElement element = JsonParser.parseString(i18n.getLabel());
+			if (element != null && element.isJsonObject()) {
+				return element.getAsJsonObject();
+			}
+		}
+
+		return null;
+	}
+
+	
+	public List<String> getLocales() {
+		return i18nRepository.findAll().stream().map(I18n::getLocale).collect(Collectors.toList());
+	}
+
+	
+	protected void extendJsonObject(JsonObject dest, JsonObject src) {
+		for (Entry<String, JsonElement> srcEntry : src.entrySet()) {
+			String srcKey = srcEntry.getKey();
+			JsonElement srcValue = srcEntry.getValue();
+			if (dest.has(srcKey)) {
+				JsonElement destValue = dest.get(srcKey);
+				if (destValue.isJsonObject() && srcValue.isJsonObject()) {
+					extendJsonObject(destValue.getAsJsonObject(), srcValue.getAsJsonObject());
+				} else {
+					dest.add(srcKey, srcValue);
+				}
+			} else {
+				dest.add(srcKey, srcValue);
+			}
+		}
+	}
+
+	
+	public I18n addLabel(String locale, JsonObject newLabel) {
+		JsonObject label = getLabel(locale);
+
+		if (label == null || label.size() == 0 || label.entrySet().isEmpty()) {
+			label = newLabel;
+		} else {
+			extendJsonObject(label, newLabel);
+		}
+
+		I18n i18n = new I18n();
+		i18n.setLocale(locale);
+		i18n.setLabel(gson.toJson(label));
+
+		return i18nRepository.save(i18n);
+	}
+
+	
+	public I18n setLabel(String locale, JsonObject label) {
+		I18n i18n = new I18n();
+		i18n.setLocale(locale);
+		i18n.setLabel(gson.toJson(label));
+
+		return i18nRepository.save(i18n);
+	}
+
+	
+	public void deleteLabel(String locale) {
+		if (i18nRepository.existsById(locale)) {
+			i18nRepository.deleteById(locale);
+		}
+	}
+
+	/*
+	 * @see org.springframework.beans.factory.SmartInitializingSingleton#
+	 * afterSingletonsInstantiated()
+	 */
+	@Override
+	public void afterSingletonsInstantiated() {
+		try {
+			Resource resource = resourceLoader.getResource("classpath:label");
+
+			if (resource.exists()) {
+				File labelFolder = resource.getFile();
+				if (labelFolder.exists() && labelFolder.isDirectory()) {
+					for (File labelFile : labelFolder.listFiles()) {
+						JsonObject label = JsonParser.parseReader(new FileReader(labelFile, StandardCharsets.UTF_8))
+								.getAsJsonObject();
+
+						String locale = labelFile.getName().replace(".json", "");
+						addLabel(locale, label);
+					}
+				}
+			}
+
+		} catch (IOException e) {
+			logger.warn("cannot read in label folder", e.getMessage());
+		}
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/i18n/controller/I18nController.java

@@ -0,0 +1,83 @@
+package de.champonthis.buntspecht.i18n.controller;
+
+import java.io.IOException;
+import java.util.List;
+
+import jakarta.servlet.http.HttpServletResponse;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonIOException;
+import com.google.gson.JsonObject;
+
+import de.champonthis.buntspecht.controller.BaseController;
+import de.champonthis.buntspecht.i18n.businesslogic.I18nManager;
+
+
+@RestController
+@RequestMapping("/i18n")
+public class I18nController extends BaseController {
+
+	@Autowired
+	private I18nManager i18nManager;
+
+	private Gson gson = new Gson();
+
+	
+	@GetMapping
+	public List<String> getLocales() {
+		return i18nManager.getLocales();
+	}
+
+	
+	@GetMapping("/{locale}")
+	public void getLabel(@PathVariable("locale") String locale, HttpServletResponse response)
+			throws JsonIOException, IOException {
+		JsonObject label = i18nManager.getLabel(locale);
+		if (label != null) {
+			response.setCharacterEncoding("utf-8");
+			gson.toJson(label, response.getWriter());
+		}
+	}
+
+	
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@PostMapping("/{locale}")
+	public void setLabel(@PathVariable("locale") String locale, @RequestBody Object label) {
+		JsonElement element = gson.toJsonTree(label);
+
+		if (element != null && element.isJsonObject()) {
+			i18nManager.setLabel(locale, element.getAsJsonObject());
+		}
+	}
+
+	
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@PutMapping("/{locale}")
+	public void addLabel(@PathVariable("locale") String locale, @RequestBody Object label) {
+		JsonElement element = gson.toJsonTree(label);
+
+		if (element != null && element.isJsonObject()) {
+			i18nManager.addLabel(locale, element.getAsJsonObject());
+		}
+	}
+
+	
+	@PreAuthorize("hasRole('ROLE_ADMIN')")
+	@DeleteMapping("/{locale}")
+	public void deleteLocale(@PathVariable("locale") String locale) {
+		i18nManager.deleteLabel(locale);
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/i18n/model/I18n.java

@@ -0,0 +1,43 @@
+package de.champonthis.buntspecht.i18n.model;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Lob;
+import jakarta.persistence.Table;
+import jakarta.persistence.UniqueConstraint;
+
+
+@Entity
+@Table(name = "i18n", uniqueConstraints = @UniqueConstraint(columnNames = { "locale" }))
+public class I18n {
+
+	@Id
+	@Column(name = "locale", unique = true, nullable = false)
+	private String locale;
+
+	@Lob
+	@Column(name = "label", length = 100000)
+	private String label;
+
+	
+	public String getLocale() {
+		return locale;
+	}
+
+	
+	public void setLocale(String locale) {
+		this.locale = locale;
+	}
+
+	
+	public String getLabel() {
+		return label;
+	}
+
+	
+	public void setLabel(String label) {
+		this.label = label;
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/i18n/repository/I18nRepository.java

@@ -0,0 +1,13 @@
+package de.champonthis.buntspecht.i18n.repository;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.querydsl.QuerydslPredicateExecutor;
+import org.springframework.stereotype.Repository;
+
+import de.champonthis.buntspecht.i18n.model.I18n;
+
+
+@Repository
+public interface I18nRepository extends JpaRepository<I18n, String>, QuerydslPredicateExecutor<I18n> {
+
+}

backend/src/main/java/de/champonthis/buntspecht/model/PersistentLogin.java

@@ -0,0 +1,56 @@
+package de.champonthis.buntspecht.model;
+
+import java.time.Instant;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+
+@Entity
+@Table(name = "persistent_logins")
+public class PersistentLogin {
+
+	@Column(name = "username", length = 64, nullable = false)
+	private String username;
+	@Id
+	@Column(name = "series", length = 64)
+	private String series;
+	@Column(name = "token", length = 64, nullable = false)
+	private String token;
+	@Column(name = "last_used", nullable = false)
+	private Instant last_used;
+
+	public String getUsername() {
+		return username;
+	}
+
+	public void setUsername(String username) {
+		this.username = username;
+	}
+
+	public String getSeries() {
+		return series;
+	}
+
+	public void setSeries(String series) {
+		this.series = series;
+	}
+
+	public String getToken() {
+		return token;
+	}
+
+	public void setToken(String token) {
+		this.token = token;
+	}
+
+	public Instant getLast_used() {
+		return last_used;
+	}
+
+	public void setLast_used(Instant last_used) {
+		this.last_used = last_used;
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/model/SystemProperty.java

@@ -0,0 +1,53 @@
+package de.champonthis.buntspecht.model;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Lob;
+import jakarta.persistence.Table;
+
+
+@Entity
+@Table(name = "system_properties")
+public class SystemProperty {
+
+	@Id
+	@Column(name = "id")
+	private String key;
+	@Lob
+	@Column(name = "value", length = 100000)
+	private String value;
+
+	
+	public SystemProperty() {
+		super();
+	}
+
+	
+	public SystemProperty(String key, String value) {
+		super();
+		this.key = key;
+		this.value = value;
+	}
+
+	
+	public String getKey() {
+		return key;
+	}
+
+	
+	public void setKey(String key) {
+		this.key = key;
+	}
+
+	
+	public String getValue() {
+		return value;
+	}
+
+	
+	public void setValue(String value) {
+		this.value = value;
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/model/Turnover.java

@@ -0,0 +1,171 @@
+package de.champonthis.buntspecht.model;
+
+import java.time.Instant;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Lob;
+import jakarta.persistence.Table;
+
+@Entity
+@Table(name = "turnovers")
+public class Turnover {
+
+    @Id
+    @Column(name = "id", updatable = false, unique = true, nullable = false)
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(name = "username", nullable = false)
+    private String username;
+
+    @Column(name = "created", nullable = false, updatable = false)
+    private Instant created;
+
+    @Column(name = "due_date", nullable = false)
+    private Instant dueDate;
+
+    @Column(name = "updated", nullable = false)
+    private Instant updated;
+
+    @Column(name = "customer", nullable = false)
+    private String customer;
+
+    @Column(name = "motif", nullable = false)
+    private String motif;
+
+    @Column(name = "price", nullable = false)
+    private float price;
+
+    @Column(name = "time_investment", nullable = true)
+    private float timeInvestment;
+
+    @Lob
+    @Column(name = "remark", nullable = true, length = 5000)
+    private String remark;
+
+    @Lob
+    @Column(name = "material_consumption", nullable = true, length = 5000)
+    private String materialConsumption;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public Instant getCreated() {
+        return created;
+    }
+
+    public void setCreated(Instant created) {
+        this.created = created;
+    }
+
+    public Instant getDueDate() {
+        return dueDate;
+    }
+
+    public void setDueDate(Instant dueDate) {
+        this.dueDate = dueDate;
+    }
+
+    public Instant getUpdated() {
+        return updated;
+    }
+
+    public void setUpdated(Instant updated) {
+        this.updated = updated;
+    }
+
+    public String getCustomer() {
+        return customer;
+    }
+
+    public void setCustomer(String customer) {
+        this.customer = customer;
+    }
+
+    public String getMotif() {
+        return motif;
+    }
+
+    public void setMotif(String motif) {
+        this.motif = motif;
+    }
+
+    public float getPrice() {
+        return price;
+    }
+
+    public void setPrice(float price) {
+        this.price = price;
+    }
+
+    public float getTimeInvestment() {
+        return timeInvestment;
+    }
+
+    public void setTimeInvestment(float timeInvestment) {
+        this.timeInvestment = timeInvestment;
+    }
+
+    public String getRemark() {
+        return remark;
+    }
+
+    public void setRemark(String remark) {
+        this.remark = remark;
+    }
+
+    public String getMaterialConsumption() {
+        return materialConsumption;
+    }
+
+    public void setMaterialConsumption(String materialConsumption) {
+        this.materialConsumption = materialConsumption;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (!(obj instanceof Turnover)) {
+            return false;
+        }
+        Turnover turnover = (Turnover) obj;
+        boolean equals = true;
+
+        equals &= dueDate.equals(turnover.getDueDate());
+
+        equals &= id == null && turnover.getId() == null || id.equals(turnover.getId());
+
+        equals &= username == null && turnover.getUsername() == null || username.equals(turnover.getUsername());
+
+        equals &= customer == null && turnover.getCustomer() == null || customer.equals(turnover.getCustomer());
+
+        equals &= motif == null && turnover.getMotif() == null || motif.equals(turnover.getMotif());
+
+        equals &= price == turnover.getPrice();
+
+        equals &= timeInvestment == turnover.getTimeInvestment();
+
+        equals &= remark == null && turnover.getRemark() == null || remark.equals(turnover.getRemark());
+
+        equals &= materialConsumption == null && turnover.getMaterialConsumption() == null
+                || materialConsumption.equals(turnover.getMaterialConsumption());
+
+        return equals;
+    }
+}

backend/src/main/java/de/champonthis/buntspecht/model/User.java

@@ -0,0 +1,133 @@
+package de.champonthis.buntspecht.model;
+
+import java.util.List;
+import java.util.Map;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonInclude.Include;
+
+import jakarta.persistence.CollectionTable;
+import jakarta.persistence.Column;
+import jakarta.persistence.ElementCollection;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Lob;
+import jakarta.persistence.Table;
+import jakarta.persistence.Transient;
+
+@Entity
+@Table(name = "users")
+@JsonInclude(Include.NON_EMPTY)
+public class User {
+
+	@Id
+	@Column(name = "username", nullable = false)
+	private String username;
+	@Column(name = "external_id", nullable = true)
+	private String externalId;
+	@Column(name = "name", nullable = true)
+	private String name;
+	@JsonIgnore
+	@Column(name = "password_hash", nullable = true)
+	private String passwordHash;
+	@ElementCollection(fetch = FetchType.EAGER)
+	@CollectionTable(name = "users_roles")
+	private List<String> roles;
+	@Lob
+	@Column(name = "about", nullable = true, length = 100000)
+	private String about;
+	@Column(name = "email", nullable = true)
+	private String email;
+	@Column(name = "locale", nullable = true, columnDefinition = "varchar(255) default 'de'")
+	private String locale;
+	@Column(name = "dark_theme", nullable = true, columnDefinition = "boolean default false")
+	private boolean darkTheme;
+	@Transient
+	private Map<String, Object> metadata;
+
+	public String getUsername() {
+		return username;
+	}
+
+	public void setUsername(String username) {
+		this.username = username;
+	}
+
+	public String getExternalId() {
+		return externalId;
+	}
+
+	public void setExternalId(String externalId) {
+		this.externalId = externalId;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public String getPasswordHash() {
+		return passwordHash;
+	}
+
+	public void setPasswordHash(String passwordHash) {
+		this.passwordHash = passwordHash;
+	}
+
+	public List<String> getRoles() {
+		return roles;
+	}
+
+	public void setRoles(List<String> roles) {
+		this.roles = roles;
+	}
+
+	public String getAbout() {
+		return about;
+	}
+
+	public void setAbout(String about) {
+		this.about = about;
+	}
+
+	public String getEmail() {
+		return email;
+	}
+
+	public void setEmail(String email) {
+		this.email = email;
+	}
+
+	public String getLocale() {
+		return locale;
+	}
+
+	public void setLocale(String locale) {
+		this.locale = locale;
+	}
+
+	public boolean isDarkTheme() {
+		return darkTheme;
+	}
+
+	public void setDarkTheme(boolean darkTheme) {
+		this.darkTheme = darkTheme;
+	}
+
+	public Map<String, Object> getMetadata() {
+		if (metadata == null) {
+			metadata = Map.of();
+		}
+		return metadata;
+	}
+
+	public void setMetadata(Map<String, Object> metadata) {
+		this.metadata = metadata;
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/repository/SystemPropertyRepository.java

@@ -0,0 +1,14 @@
+package de.champonthis.buntspecht.repository;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.querydsl.QuerydslPredicateExecutor;
+import org.springframework.stereotype.Repository;
+
+import de.champonthis.buntspecht.model.SystemProperty;
+
+
+@Repository
+public interface SystemPropertyRepository
+		extends JpaRepository<SystemProperty, String>, QuerydslPredicateExecutor<SystemProperty> {
+
+}

backend/src/main/java/de/champonthis/buntspecht/repository/TurnoverRepository.java

@@ -0,0 +1,12 @@
+package de.champonthis.buntspecht.repository;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.querydsl.QuerydslPredicateExecutor;
+import org.springframework.stereotype.Repository;
+
+import de.champonthis.buntspecht.model.Turnover;
+
+@Repository
+public interface TurnoverRepository extends JpaRepository<Turnover, Long>, QuerydslPredicateExecutor<Turnover> {
+
+}

backend/src/main/java/de/champonthis/buntspecht/repository/UserRepository.java

@@ -0,0 +1,13 @@
+package de.champonthis.buntspecht.repository;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.querydsl.QuerydslPredicateExecutor;
+import org.springframework.stereotype.Repository;
+
+import de.champonthis.buntspecht.model.User;
+
+
+@Repository
+public interface UserRepository extends JpaRepository<User, String>, QuerydslPredicateExecutor<User> {
+
+}

backend/src/main/java/de/champonthis/buntspecht/security/LocalRememberMeServices.java

@@ -0,0 +1,37 @@
+package de.champonthis.buntspecht.security;
+
+import jakarta.servlet.http.HttpServletRequest;
+
+import org.springframework.security.core.userdetails.UserDetailsService;
+import org.springframework.security.web.authentication.rememberme.PersistentTokenBasedRememberMeServices;
+import org.springframework.security.web.authentication.rememberme.PersistentTokenRepository;
+
+
+public class LocalRememberMeServices extends PersistentTokenBasedRememberMeServices {
+
+	
+	public LocalRememberMeServices(String key, UserDetailsService userDetailsService,
+			PersistentTokenRepository tokenRepository) {
+		super(key, userDetailsService, tokenRepository);
+	}
+
+	/*
+	 * @see org.springframework.security.web.authentication.rememberme.
+	 * AbstractRememberMeServices#rememberMeRequested(javax.servlet.http.
+	 * HttpServletRequest, java.lang.String)
+	 */
+	@Override
+	protected boolean rememberMeRequested(HttpServletRequest request, String parameter) {
+		Object value = request.getAttribute(parameter);
+		if (value != null) {
+			String paramValue = value.toString();
+			if (paramValue.equalsIgnoreCase("true") || paramValue.equalsIgnoreCase("on")
+					|| paramValue.equalsIgnoreCase("yes") || paramValue.equals("1")) {
+				return true;
+			}
+		}
+
+		return super.rememberMeRequested(request, parameter);
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/security/LocalUserDetails.java

@@ -0,0 +1,19 @@
+package de.champonthis.buntspecht.security;
+
+import java.util.Collection;
+
+import org.springframework.security.core.GrantedAuthority;
+import org.springframework.security.core.userdetails.User;
+
+
+public class LocalUserDetails extends User {
+
+	
+	private static final long serialVersionUID = 1L;
+
+	
+	public LocalUserDetails(String username, String password, Collection<? extends GrantedAuthority> authorities) {
+		super(username, password, authorities);
+	}
+
+}

backend/src/main/java/de/champonthis/buntspecht/security/PasswordEncoderConfig.java

@@ -0,0 +1,15 @@
+package de.champonthis.buntspecht.security;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.security.crypto.argon2.Argon2PasswordEncoder;
+
+@Configuration
+public class PasswordEncoderConfig {
+
+	
+	@Bean(name = "passwordEncoder")
+	public Argon2PasswordEncoder passwordEncoder() {
+		return Argon2PasswordEncoder.defaultsForSpringSecurity_v5_8();
+	}
+}

backend/src/main/java/de/champonthis/buntspecht/security/SecurityConfig.java

@@ -0,0 +1,113 @@
+package de.champonthis.buntspecht.security;
+
+import java.util.Collections;
+import java.util.List;
+
+import javax.sql.DataSource;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpStatus;
+import org.springframework.security.config.annotation.method.configuration.EnableMethodSecurity;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.web.SecurityFilterChain;
+import org.springframework.security.web.authentication.HttpStatusEntryPoint;
+import org.springframework.security.web.authentication.RememberMeServices;
+import org.springframework.security.web.authentication.SimpleUrlAuthenticationFailureHandler;
+import org.springframework.security.web.authentication.logout.HttpStatusReturningLogoutSuccessHandler;
+import org.springframework.security.web.authentication.rememberme.JdbcTokenRepositoryImpl;
+import org.springframework.security.web.authentication.rememberme.PersistentTokenBasedRememberMeServices;
+import org.springframework.security.web.authentication.rememberme.PersistentTokenRepository;
+import org.springframework.security.web.util.matcher.AntPathRequestMatcher;
+import org.springframework.web.cors.CorsConfiguration;
+import org.springframework.web.cors.CorsConfigurationSource;
+import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
+
+import de.champonthis.buntspecht.businesslogic.UserManager;
+import de.champonthis.buntspecht.security.handler.FormAuthenticationFailureHandler;
+import de.champonthis.buntspecht.security.handler.OAuth2AuthenticationSuccessHandler;
+
+@EnableWebSecurity
+@EnableMethodSecurity(prePostEnabled = true)
+@Configuration
+public class SecurityConfig {
+
+	@Autowired
+	private UserManager userManager;
+	@Autowired
+	private OAuth2AuthenticationSuccessHandler oAuth2AuthenticationSuccessHandler;
+	@Autowired
+	private DataSource dataSource;
+	@Value("${loginUrl:/login}")
+	private String loginUrl;
+	@Value("${loginTargetUrl:/}")
+	private String loginTargetUrl;
+	@Value("${spring.security.oauth2.client:false}")
+	private boolean oauth2Enabled;
+
+	@Bean
+	public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception {
+
+		if (oauth2Enabled) {
+			oAuth2AuthenticationSuccessHandler.setDefaultTargetUrl(loginTargetUrl);
+			oAuth2AuthenticationSuccessHandler.setRememberMeServices(rememberMeServices());
+		}
+
+		http
+				// crsf
+				.csrf((csrf) -> csrf.disable())
+				// cors
+				// .cors().configurationSource(corsConfigurationSource()).and()
+				// anonymous
+				.anonymous((anonymous) -> anonymous.disable())
+				// login
+				.formLogin((formLogin) -> formLogin.loginPage("/login").defaultSuccessUrl(loginTargetUrl)
+						.failureHandler(new FormAuthenticationFailureHandler(loginUrl)))
+				// remember me
+				.rememberMe((rememberMe) -> rememberMe.rememberMeServices(rememberMeServices()))
+				// logout
+				.logout((logout) -> logout.logoutUrl("/logout")
+						.logoutSuccessHandler(new HttpStatusReturningLogoutSuccessHandler(HttpStatus.OK)))
+				// exception
+				.exceptionHandling((exceptionHandling) -> exceptionHandling
+						.defaultAuthenticationEntryPointFor(new HttpStatusEntryPoint(HttpStatus.UNAUTHORIZED),
+								new AntPathRequestMatcher("/api/**")));
+
+		if (oauth2Enabled) {
+			http.oauth2Login((oauth2Login) -> oauth2Login.successHandler(oAuth2AuthenticationSuccessHandler)
+					.failureHandler(new SimpleUrlAuthenticationFailureHandler(loginUrl + "?externalError"))
+					.loginPage("/login"));
+		}
+
+		return http.build();
+	}
+
+	@Bean
+	public PersistentTokenRepository persistentTokenRepository() {
+		JdbcTokenRepositoryImpl tokenRepository = new JdbcTokenRepositoryImpl();
+		tokenRepository.setDataSource(dataSource);
+		return tokenRepository;
+	}
+
+	@Bean
+	public RememberMeServices rememberMeServices() {
+		PersistentTokenBasedRememberMeServices rememberMeServices = new LocalRememberMeServices("remember-me",
+				userManager, persistentTokenRepository());
+		return rememberMeServices;
+	}
+
+	@Bean
+	public CorsConfigurationSource corsConfigurationSource() {
+		CorsConfiguration configuration = new CorsConfiguration();
+		configuration.setAllowedOriginPatterns(List.of("*"));
+		configuration.setAllowedMethods(Collections.singletonList("*"));
+		configuration.setAllowCredentials(true);
+		configuration.setAllowedHeaders(Collections.singletonList("*"));
+		UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
+		source.registerCorsConfiguration("/**", configuration);
+		return source;
+	}
+}

backend/src/main/java/de/champonthis/buntspecht/security/handler/FormAuthenticationFailureHandler.java

@@ -0,0 +1,28 @@
+package de.champonthis.buntspecht.security.handler;
+
+import java.io.IOException;
+
+import org.springframework.security.core.AuthenticationException;
+import org.springframework.security.web.authentication.SimpleUrlAuthenticationFailureHandler;
+
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
+public class FormAuthenticationFailureHandler extends SimpleUrlAuthenticationFailureHandler {
+
+    private String failureUrl;
+
+    public FormAuthenticationFailureHandler(String failureUrl) {
+        super(failureUrl);
+        this.failureUrl = failureUrl;
+    }
+
+    @Override
+    public void onAuthenticationFailure(HttpServletRequest request, HttpServletResponse response,
+            AuthenticationException exception) throws IOException, ServletException {
+        setDefaultFailureUrl(failureUrl + "?error&username=" + request.getParameter("username"));
+        super.onAuthenticationFailure(request, response, exception);
+        setDefaultFailureUrl(failureUrl);
+    }
+}

backend/src/main/java/de/champonthis/buntspecht/security/handler/OAuth2AuthenticationSuccessHandler.java

@@ -0,0 +1,68 @@
+package de.champonthis.buntspecht.security.handler;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.GrantedAuthority;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.web.authentication.RememberMeServices;
+import org.springframework.security.web.authentication.SavedRequestAwareAuthenticationSuccessHandler;
+import org.springframework.stereotype.Component;
+
+import de.champonthis.buntspecht.businesslogic.UserManager;
+import de.champonthis.buntspecht.model.User;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+
+
+@Component
+public class OAuth2AuthenticationSuccessHandler extends SavedRequestAwareAuthenticationSuccessHandler {
+
+	@Autowired
+	private UserManager userManager;
+
+	private RememberMeServices rememberMeServices;
+
+	/*
+	 * @see org.springframework.security.web.authentication.
+	 * SavedRequestAwareAuthenticationSuccessHandler#onAuthenticationSuccess(javax.
+	 * servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse,
+	 * org.springframework.security.core.Authentication)
+	 */
+	@Override
+	public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response,
+			Authentication authentication) throws IOException, ServletException {
+		User user = userManager.getByAuth(authentication);
+
+		UserDetails userDetails = userManager.loadUserByUsername(user.getUsername());
+
+		List<GrantedAuthority> authorities = new ArrayList<>();
+		authorities.addAll(authentication.getAuthorities());
+		authorities.addAll(userDetails.getAuthorities());
+
+		UsernamePasswordAuthenticationToken newAuthentication = new UsernamePasswordAuthenticationToken(userDetails,
+				null, authorities);
+
+		SecurityContextHolder.getContext().setAuthentication(newAuthentication);
+
+		if (rememberMeServices != null) {
+			request.setAttribute("remember-me", "true");
+			rememberMeServices.loginSuccess(request, response, newAuthentication);
+		}
+
+		handle(request, response, newAuthentication);
+		clearAuthenticationAttributes(request);
+	}
+
+	
+	public void setRememberMeServices(RememberMeServices rememberMeServices) {
+		this.rememberMeServices = rememberMeServices;
+	}
+
+}