import { PointInterface } from "./Websocket/PointInterface";
import { Group } from "./Group";
import { User, UserSocket } from "./User";
import { PositionInterface } from "_Model/PositionInterface";
import { EmoteCallback, EntersCallback, LeavesCallback, MovesCallback } from "_Model/Zone";
import { PositionNotifier } from "./PositionNotifier";
import { Movable } from "_Model/Movable";
import {
    BatchToPusherMessage,
    BatchToPusherRoomMessage,
    EmoteEventMessage,
    ErrorMessage,
    JoinRoomMessage,
    SubToPusherRoomMessage,
    VariableMessage,
    VariableWithTagMessage,
} from "../Messages/generated/messages_pb";
import { ProtobufUtils } from "../Model/Websocket/ProtobufUtils";
import { RoomSocket, ZoneSocket } from "src/RoomManager";
import { Admin } from "../Model/Admin";
import { adminApi } from "../Services/AdminApi";
import { isMapDetailsData, MapDetailsData } from "../Services/AdminApi/MapDetailsData";
import { ITiledMap } from "@workadventure/tiled-map-type-guard/dist";
import { mapFetcher } from "../Services/MapFetcher";
import { VariablesManager } from "../Services/VariablesManager";
import { ADMIN_API_URL } from "../Enum/EnvironmentVariable";
import { LocalUrlError } from "../Services/LocalUrlError";
import { emitErrorOnRoomSocket } from "../Services/MessageHelpers";

export type ConnectCallback = (user: User, group: Group) => void;
export type DisconnectCallback = (user: User, group: Group) => void;

export class GameRoom {
    // Users, sorted by ID
    private readonly users = new Map<number, User>();
    private readonly usersByUuid = new Map<string, User>();
    private readonly groups = new Set<Group>();
    private readonly admins = new Set<Admin>();

    private itemsState = new Map<number, unknown>();

    private readonly positionNotifier: PositionNotifier;
    private versionNumber: number = 1;
    private nextUserId: number = 1;

    private roomListeners: Set<RoomSocket> = new Set<RoomSocket>();

    private constructor(
        public readonly roomUrl: string,
        private mapUrl: string,
        private readonly connectCallback: ConnectCallback,
        private readonly disconnectCallback: DisconnectCallback,
        private readonly minDistance: number,
        private readonly groupRadius: number,
        onEnters: EntersCallback,
        onMoves: MovesCallback,
        onLeaves: LeavesCallback,
        onEmote: EmoteCallback
    ) {
        // A zone is 10 sprites wide.
        this.positionNotifier = new PositionNotifier(320, 320, onEnters, onMoves, onLeaves, onEmote);
    }

    public static async create(
        roomUrl: string,
        connectCallback: ConnectCallback,
        disconnectCallback: DisconnectCallback,
        minDistance: number,
        groupRadius: number,
        onEnters: EntersCallback,
        onMoves: MovesCallback,
        onLeaves: LeavesCallback,
        onEmote: EmoteCallback
    ): Promise<GameRoom> {
        const mapDetails = await GameRoom.getMapDetails(roomUrl);

        const gameRoom = new GameRoom(
            roomUrl,
            mapDetails.mapUrl,
            connectCallback,
            disconnectCallback,
            minDistance,
            groupRadius,
            onEnters,
            onMoves,
            onLeaves,
            onEmote
        );

        return gameRoom;
    }

    public getGroups(): Group[] {
        return Array.from(this.groups.values());
    }

    public getUsers(): Map<number, User> {
        return this.users;
    }

    public getUserByUuid(uuid: string): User | undefined {
        return this.usersByUuid.get(uuid);
    }
    public getUserById(id: number): User | undefined {
        return this.users.get(id);
    }

    public join(socket: UserSocket, joinRoomMessage: JoinRoomMessage): User {
        const positionMessage = joinRoomMessage.getPositionmessage();
        if (positionMessage === undefined) {
            throw new Error("Missing position message");
        }
        const position = ProtobufUtils.toPointInterface(positionMessage);

        const user = new User(
            this.nextUserId,
            joinRoomMessage.getUseruuid(),
            joinRoomMessage.getIpaddress(),
            position,
            false,
            this.positionNotifier,
            socket,
            joinRoomMessage.getTagList(),
            joinRoomMessage.getVisitcardurl(),
            joinRoomMessage.getName(),
            ProtobufUtils.toCharacterLayerObjects(joinRoomMessage.getCharacterlayerList()),
            joinRoomMessage.getCompanion()
        );
        this.nextUserId++;
        this.users.set(user.id, user);
        this.usersByUuid.set(user.uuid, user);
        this.updateUserGroup(user);

        // Notify admins
        for (const admin of this.admins) {
            admin.sendUserJoin(user.uuid, user.name, user.IPAddress);
        }

        return user;
    }

    public leave(user: User) {
        const userObj = this.users.get(user.id);
        if (userObj === undefined) {
            console.warn("User ", user.id, "does not belong to this game room! It should!");
        }
        if (userObj !== undefined && typeof userObj.group !== "undefined") {
            this.leaveGroup(userObj);
        }
        this.users.delete(user.id);
        this.usersByUuid.delete(user.uuid);

        if (userObj !== undefined) {
            this.positionNotifier.leave(userObj);
        }

        // Notify admins
        for (const admin of this.admins) {
            admin.sendUserLeft(user.uuid /*, user.name, user.IPAddress*/);
        }
    }

    public isEmpty(): boolean {
        return this.users.size === 0 && this.admins.size === 0;
    }

    public updatePosition(user: User, userPosition: PointInterface): void {
        user.setPosition(userPosition);

        this.updateUserGroup(user);
    }

    private updateUserGroup(user: User): void {
        user.group?.updatePosition();

        if (user.silent) {
            return;
        }

        if (user.group === undefined) {
            // If the user is not part of a group:
            //  should he join a group?

            // If the user is moving, don't try to join
            if (user.getPosition().moving) {
                return;
            }

            const closestItem: User | Group | null = this.searchClosestAvailableUserOrGroup(user);

            if (closestItem !== null) {
                if (closestItem instanceof Group) {
                    // Let's join the group!
                    closestItem.join(user);
                } else {
                    const closestUser: User = closestItem;
                    const group: Group = new Group(
                        this.roomUrl,
                        [user, closestUser],
                        this.connectCallback,
                        this.disconnectCallback,
                        this.positionNotifier
                    );
                    this.groups.add(group);
                }
            }
        } else {
            // If the user is part of a group:
            //  should he leave the group?
            const distance = GameRoom.computeDistanceBetweenPositions(user.getPosition(), user.group.getPosition());
            if (distance > this.groupRadius) {
                this.leaveGroup(user);
            }
        }
    }

    setSilent(user: User, silent: boolean) {
        if (user.silent === silent) {
            return;
        }

        user.silent = silent;
        if (silent && user.group !== undefined) {
            this.leaveGroup(user);
        }
        if (!silent) {
            // If we are back to life, let's trigger a position update to see if we can join some group.
            this.updatePosition(user, user.getPosition());
        }
    }

    /**
     * Makes a user leave a group and closes and destroy the group if the group contains only one remaining person.
     *
     * @param user
     */
    private leaveGroup(user: User): void {
        const group = user.group;
        if (group === undefined) {
            throw new Error("The user is part of no group");
        }
        group.leave(user);
        if (group.isEmpty()) {
            this.positionNotifier.leave(group);
            group.destroy();
            if (!this.groups.has(group)) {
                throw new Error(
                    "Could not find group " + group.getId() + " referenced by user " + user.id + " in World."
                );
            }
            this.groups.delete(group);
            //todo: is the group garbage collected?
        } else {
            group.updatePosition();
            //this.positionNotifier.updatePosition(group, group.getPosition(), oldPosition);
        }
    }

    /**
     * Looks for the closest user that is:
     * - close enough (distance <= minDistance)
     * - not in a group
     * - not silent
     * OR
     * - close enough to a group (distance <= groupRadius)
     */
    private searchClosestAvailableUserOrGroup(user: User): User | Group | null {
        let minimumDistanceFound: number = Math.max(this.minDistance, this.groupRadius);
        let matchingItem: User | Group | null = null;
        this.users.forEach((currentUser, userId) => {
            // Let's only check users that are not part of a group
            if (typeof currentUser.group !== "undefined") {
                return;
            }
            if (currentUser === user) {
                return;
            }
            if (currentUser.silent) {
                return;
            }

            const distance = GameRoom.computeDistance(user, currentUser); // compute distance between peers.

            if (distance <= minimumDistanceFound && distance <= this.minDistance) {
                minimumDistanceFound = distance;
                matchingItem = currentUser;
            }
        });

        this.groups.forEach((group: Group) => {
            if (group.isFull()) {
                return;
            }
            const distance = GameRoom.computeDistanceBetweenPositions(user.getPosition(), group.getPosition());
            if (distance <= minimumDistanceFound && distance <= this.groupRadius) {
                minimumDistanceFound = distance;
                matchingItem = group;
            }
        });

        return matchingItem;
    }

    public static computeDistance(user1: User, user2: User): number {
        const user1Position = user1.getPosition();
        const user2Position = user2.getPosition();
        return Math.sqrt(
            Math.pow(user2Position.x - user1Position.x, 2) + Math.pow(user2Position.y - user1Position.y, 2)
        );
    }

    public static computeDistanceBetweenPositions(position1: PositionInterface, position2: PositionInterface): number {
        return Math.sqrt(Math.pow(position2.x - position1.x, 2) + Math.pow(position2.y - position1.y, 2));
    }

    public setItemState(itemId: number, state: unknown) {
        this.itemsState.set(itemId, state);
    }

    public getItemsState(): Map<number, unknown> {
        return this.itemsState;
    }

    public async setVariable(name: string, value: string, user: User): Promise<void> {
        // First, let's check if "user" is allowed to modify the variable.
        const variableManager = await this.getVariableManager();

        const readableBy = variableManager.setVariable(name, value, user);

        // TODO: should we batch those every 100ms?
        const variableMessage = new VariableWithTagMessage();
        variableMessage.setName(name);
        variableMessage.setValue(value);
        if (readableBy) {
            variableMessage.setReadableby(readableBy);
        }

        const subMessage = new SubToPusherRoomMessage();
        subMessage.setVariablemessage(variableMessage);

        const batchMessage = new BatchToPusherRoomMessage();
        batchMessage.addPayload(subMessage);

        // Dispatch the message on the room listeners
        for (const socket of this.roomListeners) {
            socket.write(batchMessage);
        }
    }

    public addZoneListener(call: ZoneSocket, x: number, y: number): Set<Movable> {
        return this.positionNotifier.addZoneListener(call, x, y);
    }

    public removeZoneListener(call: ZoneSocket, x: number, y: number): void {
        return this.positionNotifier.removeZoneListener(call, x, y);
    }

    public adminJoin(admin: Admin): void {
        this.admins.add(admin);

        // Let's send all connected users
        for (const user of this.users.values()) {
            admin.sendUserJoin(user.uuid, user.name, user.IPAddress);
        }
    }

    public adminLeave(admin: Admin): void {
        this.admins.delete(admin);
    }

    public incrementVersion(): number {
        this.versionNumber++;
        return this.versionNumber;
    }

    public emitEmoteEvent(user: User, emoteEventMessage: EmoteEventMessage) {
        this.positionNotifier.emitEmoteEvent(user, emoteEventMessage);
    }

    public addRoomListener(socket: RoomSocket) {
        this.roomListeners.add(socket);
    }

    public removeRoomListener(socket: RoomSocket) {
        this.roomListeners.delete(socket);
    }

    /**
     * Connects to the admin server to fetch map details.
     * If there is no admin server, the map details are generated by analysing the map URL (that must be in the form: /_/instance/map_url)
     */
    private static async getMapDetails(roomUrl: string): Promise<MapDetailsData> {
        if (!ADMIN_API_URL) {
            const roomUrlObj = new URL(roomUrl);

            const match = /\/_\/[^/]+\/(.+)/.exec(roomUrlObj.pathname);
            if (!match) {
                console.error("Unexpected room URL", roomUrl);
                throw new Error('Unexpected room URL "' + roomUrl + '"');
            }

            const mapUrl = roomUrlObj.protocol + "//" + match[1];

            return {
                mapUrl,
                policy_type: 1,
                textures: [],
                tags: [],
            };
        }

        const result = await adminApi.fetchMapDetails(roomUrl);
        if (!isMapDetailsData(result)) {
            console.error("Unexpected room details received from server", result);
            throw new Error("Unexpected room details received from server");
        }
        return result;
    }

    private mapPromise: Promise<ITiledMap> | undefined;

    /**
     * Returns a promise to the map file.
     * @throws LocalUrlError if the map we are trying to load is hosted on a local network
     * @throws Error
     */
    private getMap(): Promise<ITiledMap> {
        if (!this.mapPromise) {
            this.mapPromise = mapFetcher.fetchMap(this.mapUrl);
        }

        return this.mapPromise;
    }

    private variableManagerPromise: Promise<VariablesManager> | undefined;

    private getVariableManager(): Promise<VariablesManager> {
        if (!this.variableManagerPromise) {
            this.variableManagerPromise = new Promise<VariablesManager>((resolve, reject) => {
                this.getMap()
                    .then((map) => {
                        const variablesManager = new VariablesManager(this.roomUrl, map);
                        variablesManager
                            .init()
                            .then(() => {
                                resolve(variablesManager);
                            })
                            .catch((e) => {
                                reject(e);
                            });
                    })
                    .catch((e) => {
                        if (e instanceof LocalUrlError) {
                            // If we are trying to load a local URL, we are probably in test mode.
                            // In this case, let's bypass the server-side checks completely.

                            // Note: we run this message inside a setTimeout so that the room listeners can have time to connect.
                            setTimeout(() => {
                                for (const roomListener of this.roomListeners) {
                                    emitErrorOnRoomSocket(
                                        roomListener,
                                        "You are loading a local map. If you use the scripting API in this map, please be aware that server-side checks and variable persistence is disabled."
                                    );
                                }
                            }, 1000);

                            const variablesManager = new VariablesManager(this.roomUrl, null);
                            variablesManager
                                .init()
                                .then(() => {
                                    resolve(variablesManager);
                                })
                                .catch((e) => {
                                    reject(e);
                                });
                        } else {
                            reject(e);
                        }
                    });
            });
        }
        return this.variableManagerPromise;
    }

    public async getVariablesForTags(tags: string[]): Promise<Map<string, string>> {
        const variablesManager = await this.getVariableManager();
        return variablesManager.getVariablesForTags(tags);
    }
}