Migrating screen sharing to using a store

front/src/Stores/ScreenSharingStore.ts

@@ -0,0 +1,180 @@
+import {derived, get, Readable, readable, writable, Writable} from "svelte/store";
+import {peerStore} from "./PeerStore";
+import {localUserStore} from "../Connexion/LocalUserStore";
+import {ITiledMapGroupLayer, ITiledMapObjectLayer, ITiledMapTileLayer} from "../Phaser/Map/ITiledMap";
+import {userMovingStore} from "./GameStore";
+import {HtmlUtils} from "../WebRtc/HtmlUtils";
+import {
+    audioConstraintStore, cameraEnergySavingStore,
+    enableCameraSceneVisibilityStore,
+    gameOverlayVisibilityStore, LocalStreamStoreValue, privacyShutdownStore,
+    requestedCameraState,
+    requestedMicrophoneState, videoConstraintStore
+} from "./MediaStore";
+
+declare const navigator:any; // eslint-disable-line @typescript-eslint/no-explicit-any
+
+/**
+ * A store that contains the camera state requested by the user (on or off).
+ */
+function createRequestedScreenSharingState() {
+    const { subscribe, set, update } = writable(false);
+
+    return {
+        subscribe,
+        enableScreenSharing: () => set(true),
+        disableScreenSharing: () => set(false),
+    };
+}
+
+export const requestedScreenSharingState = createRequestedScreenSharingState();
+
+let currentStream : MediaStream|null = null;
+
+/**
+ * Stops the camera from filming
+ */
+function stopScreenSharing(): void {
+    if (currentStream) {
+        for (const track of currentStream.getVideoTracks()) {
+            track.stop();
+        }
+    }
+    currentStream = null;
+}
+
+let previousComputedVideoConstraint: boolean|MediaTrackConstraints = false;
+let previousComputedAudioConstraint: boolean|MediaTrackConstraints = false;
+
+/**
+ * A store containing the media constraints we want to apply.
+ */
+export const screenSharingConstraintsStore = derived(
+    [
+        requestedScreenSharingState,
+        gameOverlayVisibilityStore,
+        peerStore,
+    ], (
+        [
+            $requestedScreenSharingState,
+            $gameOverlayVisibilityStore,
+            $peerStore,
+        ], set
+    ) => {
+
+        let currentVideoConstraint: boolean|MediaTrackConstraints = true;
+        let currentAudioConstraint: boolean|MediaTrackConstraints = false;
+
+        // Disable screen sharing if the user requested so
+        if (!$requestedScreenSharingState) {
+            currentVideoConstraint = false;
+            currentAudioConstraint = false;
+        }
+
+        // Disable screen sharing when in a Jitsi
+        if (!$gameOverlayVisibilityStore) {
+            currentVideoConstraint = false;
+            currentAudioConstraint = false;
+        }
+
+        // Disable screen sharing if no peers
+        if ($peerStore.size === 0) {
+            currentVideoConstraint = false;
+            currentAudioConstraint = false;
+        }
+
+        // Let's make the changes only if the new value is different from the old one.
+        if (previousComputedVideoConstraint != currentVideoConstraint || previousComputedAudioConstraint != currentAudioConstraint) {
+            previousComputedVideoConstraint = currentVideoConstraint;
+            previousComputedAudioConstraint = currentAudioConstraint;
+            // Let's copy the objects.
+            /*if (typeof previousComputedVideoConstraint !== 'boolean') {
+                previousComputedVideoConstraint = {...previousComputedVideoConstraint};
+            }
+            if (typeof previousComputedAudioConstraint !== 'boolean') {
+                previousComputedAudioConstraint = {...previousComputedAudioConstraint};
+            }*/
+
+            set({
+                video: currentVideoConstraint,
+                audio: currentAudioConstraint,
+            });
+        }
+    }, {
+        video: false,
+        audio: false
+    } as MediaStreamConstraints);
+
+
+/**
+ * A store containing the MediaStream object for ScreenSharing (or null if nothing requested, or Error if an error occurred)
+ */
+export const screenSharingLocalStreamStore = derived<Readable<MediaStreamConstraints>, LocalStreamStoreValue>(screenSharingConstraintsStore, ($screenSharingConstraintsStore, set) => {
+    const constraints = $screenSharingConstraintsStore;
+
+    if ($screenSharingConstraintsStore.video === false && $screenSharingConstraintsStore.audio === false) {
+        stopScreenSharing();
+        requestedScreenSharingState.disableScreenSharing();
+        set({
+            type: 'success',
+            stream: null,
+            constraints
+        });
+        return;
+    }
+
+    let currentStreamPromise: Promise<MediaStream>;
+    if (navigator.getDisplayMedia) {
+        currentStreamPromise = navigator.getDisplayMedia({constraints});
+    } else if (navigator.mediaDevices.getDisplayMedia) {
+        currentStreamPromise = navigator.mediaDevices.getDisplayMedia({constraints});
+    } else {
+        stopScreenSharing();
+        set({
+            type: 'error',
+            error: new Error('Your browser does not support sharing screen'),
+            constraints
+        });
+        return;
+    }
+
+    (async () => {
+        try {
+            stopScreenSharing();
+            currentStream = await currentStreamPromise;
+
+            // If stream ends (for instance if user clicks the stop screen sharing button in the browser), let's close the view
+            for (const track of currentStream.getTracks()) {
+                track.onended = () => {
+                    stopScreenSharing();
+                    requestedScreenSharingState.disableScreenSharing();
+                    previousComputedVideoConstraint = false;
+                    previousComputedAudioConstraint = false;
+                    set({
+                        type: 'success',
+                        stream: null,
+                        constraints: {
+                            video: false,
+                            audio: false
+                        }
+                    });
+                };
+            }
+
+            set({
+                type: 'success',
+                stream: currentStream,
+                constraints
+            });
+            return;
+        } catch (e) {
+            currentStream = null;
+            console.info("Error. Unable to share screen.", e);
+            set({
+                type: 'error',
+                error: e,
+                constraints
+            });
+        }
+    })();
+});