FIX PixivComics : unscramble pictures (#6270)

* FIX PixivComics : unscramble pictures

* getPages ditched MD5 for SHA256
* getPages  url endpoint is different 
* fetching image need a request header containing scrambling key
* pages are scrambled

* Update PixivComics.mjs

* Update PixivComics.mjs

src/web/mjs/connectors/PixivComics.mjs

@@ -76,13 +76,141 @@ export default class PixivComics extends Connector {
 
     async _getPages(chapter) {
         const timestamp = new Date().toISOString().replace(/\.\d+Z$/, 'Z');
-        const hash = CryptoJS.MD5(timestamp + 'mAtW1X8SzGS880fsjEXlM73QpS1i4kUMBhyhdaYySk8nWz533nrEunaSplg63fzT').toString(CryptoJS.enc.Hex);
-        const uri = new URL(`episodes/${chapter.id}/read`, this.apiURL);
+        const hash = CryptoJS.SHA256(timestamp + 'mAtW1X8SzGS880fsjEXlM73QpS1i4kUMBhyhdaYySk8nWz533nrEunaSplg63fzT').toString(CryptoJS.enc.Hex);
+        const uri = new URL(`episodes/${chapter.id}/read_v3`, this.apiURL);
         const request = new Request(uri, this.requestOptions);
         request.headers.set('x-requested-with', 'pixivcomic');
         request.headers.set('x-client-time', timestamp);
         request.headers.set('x-client-hash', hash);
         const data = await this.fetchJSON(request);
-        return data.data.reading_episode.pages.map(image => this.createConnectorURI(image.url));
+        return data.data.reading_episode.pages.map(image => this.createConnectorURI(image));
     }
-}
+
+    async _handleConnectorURI(payload) {
+        let request = new Request(payload.url, this.requestOptions);
+        request.headers.set('X-Cobalt-Thumber-Parameter-GridShuffle-Key', payload.key);
+        const res = await fetch(request);
+        const blob = await res.blob();
+        const canvas = await this.descrambleImage(blob, payload);
+        const blobFinally = await this._canvasToBlob(canvas);
+        return this._blobToBuffer(blobFinally);
+    }
+
+    async descrambleImage(blob, payload) {
+        const image = await createImageBitmap(blob);
+        const canvas = document.createElement('canvas');
+        canvas.width = payload.width;
+        canvas.height = payload.height;
+        let ctx = canvas.getContext( '2d' );
+
+        ctx.drawImage(image, 0, 0);
+        const i = ctx.getImageData(0, 0, payload.width, payload.height);
+        const l = await descrambleData(i.data, 4, payload.width, payload.height, payload.gridsize, payload.gridsize, '4wXCKprMMoxnyJ3PocJFs4CYbfnbazNe', payload.key, true );
+        const o = new ImageData(l, payload.width, payload.height);
+        ctx.putImageData(o, 0, 0);
+        return canvas;
+    }
+
+    async _canvasToBlob(canvas) {
+        return new Promise(resolve => {
+            canvas.toBlob(data => {
+                resolve(data);
+            }, Engine.Settings.recompressionFormat.value, parseFloat(Engine.Settings.recompressionQuality.value) / 100);
+        });
+    }
+}
+
+class PixivShuffler {
+    next() {
+        let e = 9 * this.tj(5 * this.s[1] >>> 0, 7) >>> 0,
+            t = this.s[1] << 9 >>> 0;
+        return this.s[2] = (this.s[2] ^ this.s[0]) >>> 0,
+        this.s[3] = (this.s[3] ^ this.s[1]) >>> 0,
+        this.s[1] = (this.s[1] ^ this.s[2]) >>> 0,
+        this.s[0] = (this.s[0] ^ this.s[3]) >>> 0,
+        this.s[2] = (this.s[2] ^ t) >>> 0,
+        this.s[3] = this.tj(this.s[3], 11),
+        e;
+    }
+    constructor(e) {
+        if (4 !== e.length) throw Error('seed.length !== 4 (seed.length: '.concat(e.length, ')'));
+        this.s = new Uint32Array(e),
+        0 === this.s[0] &&
+          0 === this.s[1] &&
+          0 === this.s[2] &&
+          0 === this.s[3] &&
+          (this.s[0] = 1);
+    }
+    tj(e, t) {
+        return (e << (t %= 32) >>> 0 | e >>> 32 - t) >>> 0;
+    }
+
+}
+
+function convertWordArrayToUint8Array (wordArray) {
+    var len = wordArray.words.length,
+        u8_array = new Uint8Array(len << 2),
+        offset = 0,
+        word,
+        i;
+    for (i = 0; i < len; i++) {
+        word = wordArray.words[i];
+        u8_array[offset++] = word >> 24;
+        u8_array[offset++] = word >> 16 & 255;
+        u8_array[offset++] = word >> 8 & 255;
+        u8_array[offset++] = word & 255;
+    }
+    return u8_array;
+}
+
+async function descrambleData(e, t, i, r, n, s, a, l, o) {
+
+    let d = Math.ceil(r / s),
+        c = Math.floor(i / n),
+        u = Array(d).fill(null).map(() => Array.from(Array(c).keys()));
+    {
+        let e = a +l;//new TextEncoder().encode(a + l); //key + magicvalue to bytes, for use with subtlecrypto SHA256
+        let t = convertWordArrayToUint8Array(CryptoJS.SHA256(e)); //subtle.digest('SHA-256", e) => return arraybuffer
+        let arrayBuffer = t.buffer.slice(t.byteOffset, t.byteLength + t.byteOffset); //we need to properly pass the ArrayBuffer to make the Uint32Array since we used CryptoJS
+        let i = new Uint32Array(arrayBuffer, 0, 4);
+        let r = new PixivShuffler(i);
+
+        for (let e = 0; e < 100; e++) r.next();
+        for (let e = 0; e < d; e++) {
+            let t = u[e];
+            for (let e = c - 1; e >= 1; e--) {
+                let i = r.next() % (e + 1),
+                    n = t[e];
+                t[e] = t[i],
+                t[i] = n;
+            }
+        }
+    }
+    if (o) for (let e = 0; e < d; e++) {
+        let t = u[e],
+            i = t.map((e, i) => t.indexOf(i));
+        if (i.some(e => e < 0)) throw Error('Failed to reverse shuffle table');
+        u[e] = i;
+    }
+    let h = new Uint8ClampedArray(e.length);
+    for (let a = 0; a < r; a++) {
+        let r = Math.floor(a / s),
+            l = u[r];
+        for (let r = 0; r < c; r++) {
+            let s = l[r],
+                o = r * n,
+                d = (a * i + o) * t,
+                c = s * n,
+                u = (a * i + c) * t,
+                p = n * t;
+            for (let t = 0; t < p; t++) h[d + t] = e[u + t];
+        }
+        {
+            let r = c * n,
+                s = (a * i + r) * t,
+                l = (a * i + i) * t;
+            for (let t = s; t < l; t++) h[t] = e[t];
+        }
+    }
+    return h;
+}