Integrate worker to offload main thread from heavy tasks

wwwroot/core/namecards/nameCardCreator.js

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+import fs from "fs";
+import path from "path";
+import { createCanvas, loadImage, registerFont } from "canvas";
+
+export class NameCardCreator {
+    constructor(templatePath) {
+        this.templatePath = templatePath;
+        this.loadFont("./wwwroot/assets/fonts/Fredoka/static/Fredoka-Bold.ttf")
+    }
+
+    loadFont(fontPath) {
+        const fullPath = path.resolve(fontPath);
+        if (!fs.existsSync(fullPath)) {
+            throw new Error(`Font file not found at ${fullPath}`);
+        }
+        registerFont(fullPath, {family: "Fredoka Bold"});
+    }
+
+    /**
+     * Crée la carte de bienvenue entièrement via Canvas
+     */
+    async getWelcomeCard(avatarPath, name) {
+        try {
+            const canvasWidth = 3000;
+            const canvasHeight = 1000;
+            const canvas = createCanvas(canvasWidth, canvasHeight);
+            const ctx = canvas.getContext("2d");
+
+            const template = await loadImage(this.templatePath);
+            ctx.drawImage(template, 0, 0, canvasWidth, canvasHeight);
+
+            const avatarSize = 675;
+            const avatar = await loadImage(avatarPath);
+
+            const avatarX = 225;
+            const avatarY = (canvasHeight - avatarSize) / 2;
+            ctx.save();
+            ctx.beginPath();
+            ctx.arc(
+                avatarX + avatarSize / 2,
+                avatarY + avatarSize / 2,
+                avatarSize / 2,
+                0,
+                Math.PI * 2,
+                true
+            );
+            ctx.closePath();
+            ctx.clip();
+            ctx.drawImage(avatar, avatarX, avatarY, avatarSize, avatarSize);
+            ctx.restore();
+
+            ctx.lineWidth = 8;
+            ctx.strokeStyle = "#ffffff";
+            ctx.beginPath();
+            ctx.arc(
+                avatarX + avatarSize / 2,
+                avatarY + avatarSize / 2,
+                avatarSize / 2,
+                0,
+                Math.PI * 2,
+                true
+            );
+            ctx.stroke();
+
+            const messageX = avatarX + 1525;
+            const messageY = (canvasHeight / 2)+75;
+            ctx.fillStyle = "#ede6e6";
+            ctx.textAlign = "center";
+            ctx.textBaseline = "middle";
+
+            ctx.font = '115px "Fredoka Bold"';
+
+            const lines = [`Welcome ${name}, to the`, "Spicy Jail ~"];
+            const lineHeight = 130;
+            const startY = messageY - ((lines.length - 1) / 2) * lineHeight;
+
+            lines.forEach((line, i) => {
+                ctx.fillText(line, messageX, startY + i * lineHeight);
+            });
+
+            const result = this.scallDown(canvas, 1500, 500)
+
+            fs.writeFileSync("./tests/result/namecard.png", result);
+            console.log("✅ Name card created: namecard.png");
+            return result;
+        } catch (err) {
+            console.error("Error creating name card:", err);
+            throw err;
+        }
+    }
+
+
+    /**
+     *
+     * @param target
+     * @param width
+     * @param height
+     * @returns {Buffer}
+     */
+    scallDown(target, width, height) {
+        const smallCanvas = createCanvas(width, height);
+        const smallCtx = smallCanvas.getContext('2d');
+
+        smallCtx.drawImage(target, 0, 0, width, height);
+        return smallCanvas.toBuffer();
+    }
+
+}

wwwroot/core/namecards/nameCardWorker.js

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+import { parentPort } from 'worker_threads';
+import {NameCardCreator} from "./nameCardCreator.js";
+
+parentPort.on("message", async (data) => {
+    try {
+        const { templatePath, avatarURL, username } = data;
+
+        const creator = new NameCardCreator(templatePath);
+        const buffer = await creator.getWelcomeCard(avatarURL, username);
+
+        parentPort.postMessage({ result: buffer });
+    } catch (err) {
+        parentPort.postMessage({ error: err.message });
+    }
+});
+
+/*(async () => {
+    try {
+        const { creator, avatarURL, userName } = workerData;
+
+        const buffer = await creator.getWelcomeCard(avatarURL, userName);
+
+        parentPort.postMessage(buffer); // return the buffer to main thread
+    } catch (err) {
+        parentPort.postMessage({ error: err.message });
+    }
+})();*/

wwwroot/core/namecards/workerLauncher.js

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+import path from "path";
+import { Worker } from 'worker_threads';
+import {Logger} from "../logging/logger.js";
+
+function launchWorker({templatePath, avatarURL, username}) {
+    return new Promise((resolve, reject) => {
+        const workerFile = path.resolve('./wwwroot/core/namecards/nameCardWorker.js');
+        const worker = new Worker(workerFile);
+
+        worker.postMessage({templatePath, avatarURL, username});
+
+        worker.on('message', (result) => {
+            resolve(result);
+            worker.terminate()
+                .catch(err => Logger.error("Unable to terminate worker", err.message));
+        });
+
+        worker.on('error', (err) => {
+            reject(err);
+            worker.terminate()
+                .catch(err => Logger.error("Unable to terminate worker", err.message));
+        });
+
+        worker.on('exit', (code) => {
+            if (code !== 0) reject(new Error(`Worker stopped with code ${code}`));
+        });
+    });
+}
+
+export {launchWorker}
+