api/bilibili: add support for video parts/episodes

different videos share the same id, kind of weird

api/src/processing/services/bilibili.js

@@ -17,8 +17,14 @@ function extractBestQuality(dashData) {
     return [ bestVideo, bestAudio ];
 }
 
-async function com_download(id) {
-    const html = await fetch(`https://bilibili.com/video/${id}`, {
+async function com_download(id, partId) {
+    const url = new URL(`https://bilibili.com/video/${id}`);
+
+    if (partId) {
+        url.searchParams.set('p', partId);
+    }
+
+    const html = await fetch(url, {
         headers: {
             "user-agent": genericUserAgent
         }
@@ -47,10 +53,15 @@ async function com_download(id) {
         return { error: "fetch.empty" };
     }
 
+    let filenameBase = `bilibili_${id}`;
+    if (partId) {
+        filenameBase += `_${partId}`;
+    }
+
     return {
         urls: [video.baseUrl, audio.baseUrl],
-        audioFilename: `bilibili_${id}_audio`,
-        filename: `bilibili_${id}_${video.width}x${video.height}.mp4`,
+        audioFilename: `${filenameBase}_audio`,
+        filename: `${filenameBase}_${video.width}x${video.height}.mp4`,
     };
 }
 
@@ -89,14 +100,14 @@ async function tv_download(id) {
     };
 }
 
-export default async function({ comId, tvId, comShortLink }) {
+export default async function({ comId, tvId, comShortLink, partId }) {
     if (comShortLink) {
         const patternMatch = await resolveRedirectingURL(`https://b23.tv/${comShortLink}`);
         comId = patternMatch?.comId;
     }
 
     if (comId) {
-        return com_download(comId);
+        return com_download(comId, partId);
     } else if (tvId) {
         return tv_download(tvId);
     }