feat(merge-split): add createMergeGroup IPC handler

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/main.ts

@@ -2387,7 +2387,8 @@ async function cutVideo(
 async function mergeVideos(
     inputFiles: string[],
     outputFile: string,
-    onProgress: (percent: number) => void
+    onProgress: (percent: number) => void,
+    totalDurationSec?: number
 ): Promise<boolean> {
     const ffmpegReady = await ensureFfmpegInstalled();
     if (!ffmpegReady) {
@@ -2397,7 +2398,10 @@ async function mergeVideos(
 
     const ffmpeg = getFFmpegPath();
     const concatFile = path.join(app.getPath('temp'), `concat_${Date.now()}.txt`);
-    const concatContent = inputFiles.map((filePath) => `file '${filePath.replace(/'/g, "'\\''")}'`).join('\n');
+    const concatContent = inputFiles.map((filePath) => {
+        const normalized = filePath.replace(/\\/g, '/');
+        return `file '${normalized.replace(/'/g, "'\\''")}'`;
+    }).join('\n');
     fs.writeFileSync(concatFile, concatContent);
 
     let mergeInputBytes = 0;
@@ -3494,6 +3498,81 @@ ipcMain.handle('retry-failed-downloads', () => {
     return downloadQueue;
 });
 
+ipcMain.handle('create-merge-group', (_, itemIds: string[]) => {
+    const selectedItems = downloadQueue.filter(item => itemIds.includes(item.id));
+
+    if (selectedItems.length < 2) {
+        return downloadQueue;
+    }
+
+    // Validate all are pending
+    if (selectedItems.some(item => item.status !== 'pending')) {
+        return downloadQueue;
+    }
+
+    // Sort chronologically by ISO timestamp (handles same-day different times)
+    const sorted = [...selectedItems].sort((a, b) => new Date(a.date).getTime() - new Date(b.date).getTime());
+
+    // Calculate total duration
+    const totalDurationSec = sorted.reduce((sum, item) => sum + parseDuration(item.duration_str), 0);
+    const totalDurationStr = (() => {
+        const h = Math.floor(totalDurationSec / 3600);
+        const m = Math.floor((totalDurationSec % 3600) / 60);
+        const s = totalDurationSec % 60;
+        const parts: string[] = [];
+        if (h > 0) parts.push(`${h}h`);
+        if (m > 0) parts.push(`${m}m`);
+        if (s > 0 || parts.length === 0) parts.push(`${s}s`);
+        return parts.join('');
+    })();
+
+    // Generate title (language-aware)
+    const first = sorted[0];
+    const isEnglish = config.language === 'en';
+    const title = sorted.length === 2
+        ? `Merge: ${first.title} + ${sorted[1].title}`
+        : `Merge: ${first.title} + ${sorted.length - 1} ${isEnglish ? 'more' : 'weitere'}`;
+
+    // Build merge group
+    const mergeGroup: MergeGroup = {
+        items: sorted.map(item => ({
+            url: item.url,
+            title: item.title,
+            date: item.date,
+            streamer: item.streamer,
+            duration_str: item.duration_str
+        })),
+        mergePhase: 'downloading',
+        currentItemIndex: 0,
+        downloadedFiles: {},
+        totalDurationSec
+    };
+
+    // Create merged queue item
+    const mergedItem: QueueItem = {
+        id: generateQueueItemId(),
+        title,
+        url: first.url,
+        date: first.date,
+        streamer: first.streamer,
+        duration_str: totalDurationStr,
+        status: 'pending',
+        progress: 0,
+        mergeGroup
+    };
+
+    // Find position of first selected item
+    const firstIndex = downloadQueue.findIndex(item => itemIds.includes(item.id));
+
+    // Remove selected items and insert merged item at first position
+    downloadQueue = downloadQueue.filter(item => !itemIds.includes(item.id));
+    downloadQueue.splice(firstIndex >= 0 ? Math.min(firstIndex, downloadQueue.length) : downloadQueue.length, 0, mergedItem);
+
+    saveQueue(downloadQueue);
+    emitQueueUpdated();
+    return downloadQueue;
+});
+
 ipcMain.handle('start-download', async () => {
     downloadQueue = downloadQueue.map((item) => item.status === 'paused' ? { ...item, status: 'pending' } : item);
 

src/preload.ts

@@ -123,6 +123,7 @@ contextBridge.exposeInMainWorld('api', {
     reorderQueue: (orderIds: string[]) => ipcRenderer.invoke('reorder-queue', orderIds),
     clearCompleted: () => ipcRenderer.invoke('clear-completed'),
     retryFailedDownloads: () => ipcRenderer.invoke('retry-failed-downloads'),
+    createMergeGroup: (itemIds: string[]) => ipcRenderer.invoke('create-merge-group', itemIds),
 
     // Download
     startDownload: () => ipcRenderer.invoke('start-download'),