From 7232bbaef9adedd5244ff5c88777dd73898dc017 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?David=20N=C3=A9grier?= <d.negrier@thecodingmachine.com>
Date: Tue, 11 Aug 2020 22:32:55 +0200
Subject: [PATCH] Adding LayoutManager to position videos as cleverly as
 possible

---
 front/src/WebRtc/HtmlUtils.ts     | 10 ++++
 front/src/WebRtc/LayoutManager.ts | 94 +++++++++++++++++++++++++++++++
 front/src/index.ts                |  2 +-
 3 files changed, 105 insertions(+), 1 deletion(-)
 create mode 100644 front/src/WebRtc/HtmlUtils.ts
 create mode 100644 front/src/WebRtc/LayoutManager.ts

diff --git a/front/src/WebRtc/HtmlUtils.ts b/front/src/WebRtc/HtmlUtils.ts
new file mode 100644
index 00000000..c2e6ff6d
--- /dev/null
+++ b/front/src/WebRtc/HtmlUtils.ts
@@ -0,0 +1,10 @@
+export class HtmlUtils {
+    public static getElementByIdOrFail<T extends HTMLElement>(id: string): T {
+        const elem = document.getElementById(id);
+        if (elem === null) {
+            throw new Error("Cannot find HTML element with id '"+id+"'");
+        }
+        // FIXME: does not check the type of the returned type
+        return elem as T;
+    }
+}
diff --git a/front/src/WebRtc/LayoutManager.ts b/front/src/WebRtc/LayoutManager.ts
new file mode 100644
index 00000000..cf986d0c
--- /dev/null
+++ b/front/src/WebRtc/LayoutManager.ts
@@ -0,0 +1,94 @@
+import {HtmlUtils} from "./HtmlUtils";
+
+export enum LayoutMode {
+    // All videos are displayed on the right side of the screen. If there is a screen sharing, it is displayed in the middle.
+    Presentation = "Presentation",
+    // Videos take the whole page.
+    VideoChat = "VideoChat",
+}
+
+export enum DivImportance {
+    // For screen sharing
+    Important = "Important",
+    // For normal video
+    Normal = "Normal",
+}
+
+/**
+ * This class is in charge of the video-conference layout.
+ * It receives positioning requests for videos and does its best to place them on the screen depending on the active layout mode.
+ */
+export class LayoutManager {
+    private mode: LayoutMode = LayoutMode.Presentation;
+
+    private importantDivs: Map<string, HTMLDivElement> = new Map<string, HTMLDivElement>();
+    private normalDivs: Map<string, HTMLDivElement> = new Map<string, HTMLDivElement>();
+
+    public add(importance: DivImportance, userId: string, html: string): void {
+        const div = document.createElement('div');
+        div.append(html);
+        div.id = "user-"+userId;
+
+        if (importance === DivImportance.Important) {
+            this.importantDivs.set(userId, div);
+
+            // If this is the first video with high importance, let's switch mode automatically.
+            if (this.importantDivs.size === 1 && this.mode === LayoutMode.VideoChat) {
+                this.switchLayoutMode(LayoutMode.Presentation);
+            }
+        } else if (importance === DivImportance.Normal) {
+            this.normalDivs.set(userId, div);
+        } else {
+            throw new Error('Unexpected importance');
+        }
+
+        this.positionDiv(div, importance);
+    }
+
+    private positionDiv(elem: HTMLDivElement, importance: DivImportance): void {
+        if (this.mode === LayoutMode.VideoChat) {
+            const chatModeDiv = HtmlUtils.getElementByIdOrFail<HTMLDivElement>('chat-mode');
+            chatModeDiv.appendChild(elem);
+        } else {
+            if (importance === DivImportance.Important) {
+                const mainSectionDiv = HtmlUtils.getElementByIdOrFail<HTMLDivElement>('main-section');
+                mainSectionDiv.appendChild(elem);
+            } else if (importance === DivImportance.Normal) {
+                const sideBarDiv = HtmlUtils.getElementByIdOrFail<HTMLDivElement>('sidebar');
+                sideBarDiv.appendChild(elem);
+            }
+        }
+    }
+
+    /**
+     * Removes the DIV matching userId.
+     */
+    public remove(userId: string): void {
+        let div = this.importantDivs.get(userId);
+        if (div !== undefined) {
+            div.remove();
+            this.importantDivs.delete(userId);
+            return;
+        }
+
+        div = this.normalDivs.get(userId);
+        if (div !== undefined) {
+            div.remove();
+            this.normalDivs.delete(userId);
+            return;
+        }
+
+        throw new Error('Could not find user ID "'+userId+'"');
+    }
+
+    private switchLayoutMode(layoutMode: LayoutMode) {
+        this.mode = layoutMode;
+
+        for (let div of this.importantDivs.values()) {
+            this.positionDiv(div, DivImportance.Important);
+        }
+        for (let div of this.normalDivs.values()) {
+            this.positionDiv(div, DivImportance.Normal);
+        }
+    }
+}
diff --git a/front/src/index.ts b/front/src/index.ts
index 7634351f..d64a8f2e 100644
--- a/front/src/index.ts
+++ b/front/src/index.ts
@@ -11,7 +11,7 @@ import {FourOFourScene} from "./Phaser/Reconnecting/FourOFourScene";
 import {CustomizeScene} from "./Phaser/Login/CustomizeScene";
 
 const config: GameConfig = {
-    title: "Office game",
+    title: "WorkAdventure",
     width: window.innerWidth / RESOLUTION,
     height: window.innerHeight / RESOLUTION,
     parent: "game",