From 53342932d944da3958cd08a5544d04a3841c8622 Mon Sep 17 00:00:00 2001
From: Luca Armaroli <lukaarma@gmail.com>
Date: Sat, 5 Sep 2020 12:37:07 +0200
Subject: [PATCH] first draft of Decrypter

---
 src/Descrypter.ts | 88 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 src/Descrypter.ts

diff --git a/src/Descrypter.ts b/src/Descrypter.ts
new file mode 100644
index 0000000..96483b2
--- /dev/null
+++ b/src/Descrypter.ts
@@ -0,0 +1,88 @@
+import { ApiClient } from './ApiClient';
+import { Session } from './Types';
+
+import crypto from 'crypto';
+import { logger } from './Logger';
+// import Axios from 'axios';
+
+
+/* export async function getDecrypter(playlistUrl: string, session: Session): Promise<crypto.Decipher> {
+    
+    return new Promise<crypto.Decipher>(async (resolve, reject) => {
+        const apiClient = ApiClient.getInstance(session);
+
+        const keyOption = await apiClient.callUrl(playlistUrl, 'get', null, 'text')
+            .then(res => (res?.data as string).split(/\r?\n/)
+                .find(line => line.startsWith('#EXT-X-KEY')));
+
+        if (keyOption) {
+
+            const match = RegExp(/#EXT-X-KEY:METHOD=(.*?),URI="(.*?),IV=0X(.*)/).exec(keyOption);
+
+            if (!match) {
+                throw new Error();
+            }
+
+            const algorithm = match[1].toLowerCase().replace('-', '');
+
+            const key: Buffer = await apiClient.callUrl(match[2], 'get', null, 'arraybuffer')
+                .then(res => res?.data);
+
+            const iv = Buffer.from(match[3].substring(2), 'hex');
+
+            resolve(crypto.createDecipheriv(algorithm, key, iv));
+        }
+        else {
+            reject();
+        }
+    });
+} */
+
+
+export async function getDecrypter(playlistUrl: string, session: Session): Promise<crypto.Decipher> {
+    const apiClient = ApiClient.getInstance(session);
+
+    /* Axios.get(playlistUrl, {
+        headers: {
+            'Authorization': 'Bearer ' + session?.AccessToken,
+            'User-Agent': 'destreamer/3.0 (beta)'
+        },
+        responseType: 'text'
+    })
+    .then(res => logger.warn(res.data.split(/\r?\n/)[0]))
+    .catch(err => logger.error(err)); */
+
+    const keyOption = await apiClient.callUrl(playlistUrl, 'get', null, 'text')
+        .catch(err => logger.debug(err))
+        .then(res => (res?.data as string).split(/\r?\n/)
+            .find(line => line.startsWith('#EXT-X-KEY')));
+
+    if (keyOption) {
+        logger.debug('CRIPTO LINE IN M3U8: ' + keyOption);
+
+        const match = RegExp(/#EXT-X-KEY:METHOD=(.*?),URI="(.*?)",IV=0X(.*)/).exec(keyOption);
+
+        if (!match) {
+            throw new Error('No match for regex');
+        }
+
+        const algorithm = match[1].toLowerCase().replace('-', '');
+
+        const key: Buffer = await apiClient.callUrl(match[2], 'post', null, 'arraybuffer')
+            .then(res => res?.data);
+
+        const iv = Buffer.from(match[3], 'hex');
+
+        return crypto.createDecipheriv(algorithm, key, iv);
+    }
+    else {
+        process.exit(555);
+    }
+}
+
+/*
+const input = fs.createReadStream('test.enc');
+const output = fs.createWriteStream('test.js');
+
+input.pipe(decipher).pipe(output);
+*/