add: scheduler

src/electron/backend/encoding.ts

@@ -1,4 +1,3 @@
-import { Database } from "better-sqlite3";
 import { exec } from "child_process";
 import fs from "fs";
 import path, { join } from "path";
@@ -8,13 +7,15 @@ import { getEncodeCommand } from "../utils/index.js";
 import { getRecordingsDir, getEncodingTempDir, getScreenshotsDir } from "../utils/index.js";
 import cache from "memory-cache";
 import { ENCODING_FRAME_INTERVAL, RECORD_FRAME_RATE as FRAME_RATE } from "./consts.js";
+import { getDatabase } from "../utils/index.js";
 
 const THREE_MINUTES = 180;
 const MIN_FRAMES_TO_ENCODE = THREE_MINUTES * FRAME_RATE;
 const CONCURRENCY = 1;
 
 // Detect and insert encoding tasks
-export function checkFramesForEncoding(db: Database) {
+export function checkFramesForEncoding() {
+	const db = getDatabase();
 	const stmt = db.prepare(`
         SELECT id, imgFilename, createdAt
         FROM frame
@@ -32,12 +33,12 @@ export function checkFramesForEncoding(db: Database) {
 		const lastFramePath = join(getScreenshotsDir(), lastFrame.imgFilename!);
 		if (!fs.existsSync(framePath)) {
 			console.warn("File not exist:", frame.imgFilename);
-			deleteFrameFromDB(db, frame.id);
+			deleteFrameFromDB(frame.id);
 			continue;
 		}
 		if (!fs.existsSync(lastFramePath)) {
 			console.warn("File not exist:", lastFrame.imgFilename);
-			deleteFrameFromDB(db, lastFrame.id);
+			deleteFrameFromDB(lastFrame.id);
 			continue;
 		}
 		const currentFrameSize = sizeOf(framePath);
@@ -73,7 +74,8 @@ export function checkFramesForEncoding(db: Database) {
 	}
 }
 
-function deleteEncodedScreenshots(db: Database) {
+function deleteEncodedScreenshots() {
+	const db = getDatabase();
 	// TODO: double-check that the frame was really encoded into the video
 	const stmt = db.prepare(`
 	    SELECT * FROM frame WHERE encodeStatus = 2 AND imgFilename IS NOT NULL;
@@ -89,7 +91,8 @@ function deleteEncodedScreenshots(db: Database) {
 	}
 }
 
-function _deleteNonExistentScreenshots(db: Database) {
+function _deleteNonExistentScreenshots() {
+	const db = getDatabase();
 	const screenshotDir = getScreenshotsDir();
 	const filesInDir = new Set(fs.readdirSync(screenshotDir));
 
@@ -107,12 +110,13 @@ function _deleteNonExistentScreenshots(db: Database) {
 	}
 }
 
-export async function deleteUnnecessaryScreenshots(db: Database) {
-	deleteEncodedScreenshots(db);
-	//deleteNonExistentScreenshots(db);
+export async function deleteUnnecessaryScreenshots() {
+	deleteEncodedScreenshots();
+	//deleteNonExistentScreenshots();
 }
 
-export function deleteFrameFromDB(db: Database, id: number) {
+export function deleteFrameFromDB(id: number) {
+	const db = getDatabase();
 	const deleteStmt = db.prepare(`
 		DELETE FROM frame WHERE id = ?;
 	`);
@@ -136,7 +140,8 @@ function createMetaFile(frames: Frame[]) {
 }
 
 // Check and process encoding task
-export function processEncodingTasks(db: Database) {
+export function processEncodingTasks() {
+	const db = getDatabase();
 	let tasksPerforming = getTasksPerforming();
 	if (tasksPerforming.length >= CONCURRENCY) return;
 

src/electron/backend/scheduler.ts

@@ -0,0 +1,235 @@
+type TaskId = string;
+type TaskFunction = () => void;
+
+interface Task {
+	id: TaskId;
+	func: TaskFunction;
+	interval?: number;
+	maxInterval?: number;
+	lastRun?: number;
+	nextRun?: number;
+	isPaused: boolean;
+	delayUntil?: number;
+}
+
+export interface TaskStatus {
+    status: "NOT_FOUND" | "PAUSED" | "DELAYED" | "SCHEDULED" | "IDLE";
+    until?: string;
+    nextRun?: string;
+}
+
+export class Scheduler {
+	private tasks: Map<TaskId, Task> = new Map();
+	private timer: NodeJS.Timeout | null = null;
+	private nextTickTime: number | null = null;
+
+	constructor(private readonly minTickInterval: number = 500) {
+		this.start();
+	}
+
+	private start(): void {
+		this.scheduleNextTick();
+	}
+
+	private scheduleNextTick(): void {
+		if (this.timer) {
+			clearTimeout(this.timer);
+		}
+
+		const now = Date.now();
+		let nextTick = now + this.minTickInterval;
+
+		for (const task of this.tasks.values()) {
+            const isTaskPaused = task.isPaused;
+            const isTaskDelayed = task.delayUntil && now < task.delayUntil;
+			if (isTaskPaused || isTaskDelayed) {
+				continue;
+			}
+
+            const nextTaskEarlierThanNextTick = task.nextRun && task.nextRun < nextTick;
+			if (nextTaskEarlierThanNextTick) {
+				nextTick = task.nextRun!;
+			}
+		}
+
+		const delay = Math.max(0, nextTick - now);
+		this.timer = setTimeout(() => this.tick(), delay);
+	}
+
+	private tickSingleTask(
+		task: Task,
+		getNextTick: () => number,
+		updateNextTick: (nextTick: number) => void
+	): void {
+		const now = Date.now();
+		const isTaskPaused = task.isPaused;
+		const isTaskDelayed = task.delayUntil && now < task.delayUntil;
+
+		if (isTaskPaused || isTaskDelayed) {
+			return;
+		}
+
+		const isTaskReadyForIntervalRun = task.interval && task.nextRun && now >= task.nextRun;
+		if (isTaskReadyForIntervalRun) {
+			task.func();
+			task.lastRun = now;
+			task.nextRun = now + task.interval!;
+		}
+
+		const isTaskReadyForMaxIntervalRun =
+			task.maxInterval && task.lastRun && now - task.lastRun >= task.maxInterval;
+		if (isTaskReadyForMaxIntervalRun) {
+			task.func();
+			task.lastRun = now;
+			if (task.interval) {
+				task.nextRun = now + task.interval;
+			}
+		}
+
+		const isTaskNextRunEarlierThanNextTick = task.nextRun && task.nextRun < getNextTick();
+		if (isTaskNextRunEarlierThanNextTick) {
+			updateNextTick(task.nextRun!);
+		}
+	}
+
+	private tick(): void {
+		const now = Date.now();
+		let nextTick = now + this.minTickInterval;
+
+		for (const task of this.tasks.values()) {
+			this.tickSingleTask(
+				task,
+				() => nextTick,
+				(v) => (nextTick = v)
+			);
+		}
+
+		this.scheduleNextTick();
+	}
+
+	/**
+	 * Add a new task to the scheduler.
+	 *
+	 * @param id A unique string identifier for the task.
+	 * @param func The function to be executed by the task.
+	 * @param interval The interval (in milliseconds) between task executions.
+	 * @param maxInterval The maximum time (in milliseconds) that a task can wait before being executed.
+	 * If a task has not been executed in this amount of time, it will be executed immediately.
+	 */
+	addTask(id: TaskId, func: TaskFunction, interval?: number, maxInterval?: number): void {
+		this.tasks.set(id, {
+			id,
+			func,
+			interval,
+			maxInterval,
+			isPaused: false,
+			lastRun: undefined,
+			nextRun: interval ? Date.now() + interval : undefined
+		});
+
+		this.scheduleNextTick();
+	}
+
+	/**
+	 * Trigger a task to execute immediately, regardless of its current state.
+	 *
+	 * If the task is paused or delayed, it will not be executed.
+	 *
+	 * @param id The unique string identifier for the task.
+	 */
+	triggerTask(id: TaskId): void {
+		const task = this.tasks.get(id);
+		if (task && !task.isPaused && (!task.delayUntil || Date.now() >= task.delayUntil)) {
+			task.func();
+			task.lastRun = Date.now();
+			if (task.interval) {
+				task.nextRun = Date.now() + task.interval;
+			}
+		}
+
+		this.scheduleNextTick();
+	}
+
+	/**
+	 * Pause a task, so that it will not be executed until it is resumed.
+	 *
+	 * @param id The unique string identifier for the task.
+	 */
+	pauseTask(id: TaskId): void {
+		const task = this.tasks.get(id);
+		if (task) {
+			task.isPaused = true;
+		}
+
+		this.scheduleNextTick();
+	}
+
+	/**
+	 * Resume a paused task, so that it can be executed according to its interval and maxInterval.
+	 *
+	 * @param id The unique string identifier for the task.
+	 */
+	resumeTask(id: TaskId): void {
+		const task = this.tasks.get(id);
+		if (task) {
+			task.isPaused = false;
+		}
+
+		this.scheduleNextTick();
+	}
+
+	/**
+	 * Delay a task from being executed for a specified amount of time.
+	 *
+	 * @param id The unique string identifier for the task.
+	 * @param delayMs The amount of time in milliseconds to delay the task's execution.
+	 */
+	delayTask(id: TaskId, delayMs: number): void {
+		const task = this.tasks.get(id);
+		if (task) {
+			task.delayUntil = Date.now() + delayMs;
+		}
+
+		this.scheduleNextTick();
+	}
+
+	setTaskInterval(id: TaskId, interval: number): void {
+		const task = this.tasks.get(id);
+		if (task) {
+			task.interval = interval;
+			task.nextRun = Date.now() + interval;
+		}
+
+		this.scheduleNextTick();
+	}
+
+	getTaskStatus(id: TaskId): TaskStatus {
+	    const task = this.tasks.get(id);
+	    if (!task) {
+	        return { status: "NOT_FOUND" };
+	    }
+	    if (task.isPaused) {
+	        return { status: "PAUSED" };
+	    }
+	    if (task.delayUntil && Date.now() < task.delayUntil) {
+	        return {
+	            status: "DELAYED",
+	            until: new Date(task.delayUntil).toLocaleString()
+	        };
+	    }
+	    if (task.nextRun) {
+	        return {
+	            status: "SCHEDULED",
+	            nextRun: new Date(task.nextRun).toLocaleString()
+	        };
+	    }
+	    return { status: "IDLE" };
+	}
+
+	stop(): void {
+		if (this.timer) {
+			clearTimeout(this.timer);
+			this.timer = null;
+		}
+	}
+}

src/electron/backend/screenshot.ts

@@ -1,11 +1,10 @@
 import screenshot from "screenshot-desktop";
-import { getScreenshotsDir } from "../utils/index.js";
+import { getDatabase, getScreenshotsDir } from "../utils/index.js";
 import { join } from "path";
-import { Database } from "better-sqlite3";
 import SqlString from "sqlstring";
 
-export function startScreenshotLoop(db: Database) {
-	return setInterval(() => {
+export function takeScreenshot() {
+	const db = getDatabase();
 	const timestamp = new Date().getTime();
 	const screenshotDir = getScreenshotsDir();
 	const filename = `${timestamp}.png`;
@@ -21,5 +20,4 @@ export function startScreenshotLoop(db: Database) {
 		.catch((err) => {
 			console.error(err);
 		});
-	}, 2000);
 }

src/electron/index.ts

@@ -14,7 +14,7 @@ import initI18n from "./i18n.js";
 import { createMainWindow, createSettingsWindow } from "./createWindow.js";
 import { initDatabase } from "./backend/init.js";
 import { Database } from "better-sqlite3";
-import { startScreenshotLoop } from "./backend/screenshot.js";
+import { takeScreenshot } from "./backend/screenshot.js";
 import { __dirname } from "./dirname.js";
 import { hideDock } from "./utils/index.js";
 import {
@@ -27,16 +27,17 @@ import { serve } from "@hono/node-server";
 import { findAvailablePort } from "./utils/index.js";
 import cache from "memory-cache";
 import { generate as generateAPIKey } from "@alikia/random-key";
+import { Scheduler } from "./backend/scheduler.js";
 
 const i18n = initI18n();
 
 const t = i18n.t.bind(i18n);
 const port = process.env.PORT || "5173";
 const dev = !app.isPackaged;
+const scheduler = new Scheduler();
 
 let tray: null | Tray = null;
 let dbConnection: null | Database = null;
-let screenshotInterval: null | NodeJS.Timeout = null;
 
 let mainWindow: BrowserWindow | null;
 let settingsWindow: BrowserWindow | null;
@@ -109,10 +110,10 @@ app.on("ready", () => {
 		});
 	});
 	initDatabase().then((db) => {
-		screenshotInterval = startScreenshotLoop(db);
-		setInterval(checkFramesForEncoding, 5000, db);
-		setInterval(processEncodingTasks, 10000, db);
-		setInterval(deleteUnnecessaryScreenshots, 20000, db);
+		scheduler.addTask("screenshot", takeScreenshot, 2000, 2000);
+		scheduler.addTask("check-encoding", checkFramesForEncoding, 5000, 10000);
+		scheduler.addTask("process-encoding", processEncodingTasks, 10000, 30000);
+		scheduler.addTask("delete-screenshots", deleteUnnecessaryScreenshots, 20000, 60000);
 		dbConnection = db;
 		cache.put("server:dbConnection", dbConnection);
 	});
@@ -126,7 +127,7 @@ app.on("ready", () => {
 
 app.on("will-quit", () => {
 	dbConnection?.close();
-	if (screenshotInterval) clearInterval(screenshotInterval);
+	scheduler.stop();
 });
 
 ipcMain.on("close-settings", () => {

src/electron/utils/backend/index.ts

@@ -0,0 +1,6 @@
+import { Database } from "better-sqlite3";
+import cache from "memory-cache";
+
+export function getDatabase(): Database {
+	return cache.get("server:dbConnection");
+}

src/electron/utils/index.ts

@@ -3,3 +3,4 @@ export * from "./platform/index.js";
 export * from "./video/index.js";
 export * from "./network/index.js";
 export * from "./logging/index.js";
+export * from "./backend/index.js";