From 443657ceefaecc2313495dccc0ed956a1fedb96a Mon Sep 17 00:00:00 2001
From: Anthony G <1@anthony.sh>
Date: Mon, 10 Aug 2026 14:42:29 +0200
Subject: [PATCH] feat: add yt-dlp download processor

---
 worker/__tests__/processor.test.ts | 88 ++++++++++++++++++++++++++++++
 worker/processor.ts                | 61 +++++++++++++++++++++
 2 files changed, 149 insertions(+)
 create mode 100644 worker/__tests__/processor.test.ts
 create mode 100644 worker/processor.ts

diff --git a/worker/__tests__/processor.test.ts b/worker/__tests__/processor.test.ts
new file mode 100644
index 0000000..968889c
--- /dev/null
+++ b/worker/__tests__/processor.test.ts
@@ -0,0 +1,88 @@
+import { EventEmitter } from 'events'
+import { processDownload } from '../processor'
+import { prisma } from '@/lib/prisma'
+import * as tokenLib from '@/lib/token'
+import * as cp from 'child_process'
+
+jest.mock('@/lib/prisma', () => ({
+  prisma: {
+    download: { findUnique: jest.fn(), update: jest.fn() },
+  },
+}))
+jest.mock('@/lib/token')
+jest.mock('child_process')
+jest.mock('fs', () => ({
+  readdirSync: jest.fn(() => ['uuid-abc.mp4']),
+  statSync: jest.fn(() => ({ size: 1024 })),
+}))
+
+const mockFindUnique = prisma.download.findUnique as jest.Mock
+const mockUpdate = prisma.download.update as jest.Mock
+const mockCreateToken = tokenLib.createToken as jest.Mock
+const mockSpawn = cp.spawn as jest.Mock
+
+const baseDownload = {
+  id: 'dl-1',
+  uuid: 'uuid-abc',
+  url: 'https://youtube.com/watch?v=abc',
+  format: 'mp4',
+  quality: 'best',
+  subtitles: false,
+  extraArgs: null,
+}
+
+function makeChildProcess(exitCode: number, stderrMsg = '') {
+  const proc = new EventEmitter() as any
+  proc.stdout = new EventEmitter()
+  proc.stderr = new EventEmitter()
+  setImmediate(() => {
+    if (stderrMsg) proc.stderr.emit('data', Buffer.from(stderrMsg))
+    proc.emit('close', exitCode)
+  })
+  return proc
+}
+
+describe('processDownload', () => {
+  beforeEach(() => {
+    jest.clearAllMocks()
+    mockFindUnique.mockResolvedValue(baseDownload)
+    mockUpdate.mockResolvedValue({})
+    mockCreateToken.mockResolvedValue('new-token')
+  })
+
+  it('marks download as DONE on yt-dlp exit code 0', async () => {
+    mockSpawn.mockReturnValue(makeChildProcess(0))
+    await processDownload('dl-1')
+    expect(mockUpdate).toHaveBeenCalledWith(
+      expect.objectContaining({
+        where: { id: 'dl-1' },
+        data: expect.objectContaining({ status: 'DONE' }),
+      })
+    )
+  })
+
+  it('creates a token on success', async () => {
+    mockSpawn.mockReturnValue(makeChildProcess(0))
+    await processDownload('dl-1')
+    expect(mockCreateToken).toHaveBeenCalledWith('dl-1')
+  })
+
+  it('marks download as FAILED on non-zero exit code', async () => {
+    mockSpawn.mockReturnValue(makeChildProcess(1, 'unsupported URL'))
+    await processDownload('dl-1')
+    expect(mockUpdate).toHaveBeenCalledWith(
+      expect.objectContaining({
+        data: expect.objectContaining({
+          status: 'FAILED',
+          errorMsg: expect.stringContaining('unsupported URL'),
+        }),
+      })
+    )
+  })
+
+  it('does nothing when download not found', async () => {
+    mockFindUnique.mockResolvedValue(null)
+    await expect(processDownload('nonexistent')).resolves.toBeUndefined()
+    expect(mockSpawn).not.toHaveBeenCalled()
+  })
+})
diff --git a/worker/processor.ts b/worker/processor.ts
new file mode 100644
index 0000000..8d2ad78
--- /dev/null
+++ b/worker/processor.ts
@@ -0,0 +1,61 @@
+import { spawn } from 'child_process'
+import { readdirSync, statSync } from 'fs'
+import path from 'path'
+import { prisma } from '@/lib/prisma'
+import { buildYtdlpArgs } from '@/lib/ytdlp'
+import { createToken } from '@/lib/token'
+import { config } from '../config/app.config'
+
+export async function processDownload(downloadId: string): Promise<void> {
+  const download = await prisma.download.findUnique({ where: { id: downloadId } })
+  if (!download) return
+
+  const args = buildYtdlpArgs({
+    url: download.url,
+    uuid: download.uuid,
+    format: download.format,
+    quality: download.quality,
+    subtitles: download.subtitles,
+    extraArgs: download.extraArgs,
+  })
+
+  let stderr = ''
+
+  await new Promise<void>((resolve) => {
+    const proc = spawn('yt-dlp', args)
+    proc.stderr.on('data', (chunk: Buffer) => { stderr += chunk.toString() })
+
+    proc.on('close', async (code) => {
+      if (code === 0) {
+        const files = readdirSync(config.STORAGE_PATH).filter((f) =>
+          f.startsWith(download.uuid)
+        )
+        const relFile = files[0] ?? null
+        const filePath = relFile ? path.join(config.STORAGE_PATH, relFile) : null
+        const fileSize = filePath ? BigInt(statSync(filePath).size) : null
+
+        await prisma.download.update({
+          where: { id: downloadId },
+          data: {
+            status: 'DONE',
+            filePath,
+            fileName: relFile,
+            fileSize,
+            completedAt: new Date(),
+          },
+        })
+        await createToken(downloadId)
+      } else {
+        await prisma.download.update({
+          where: { id: downloadId },
+          data: {
+            status: 'FAILED',
+            errorMsg: stderr || `yt-dlp exited with code ${code}`,
+            completedAt: new Date(),
+          },
+        })
+      }
+      resolve()
+    })
+  })
+}