feat(offline-downloads): implement offline download

api/routes/offline_downloads.py

@@ -0,0 +1,79 @@
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException
+
+from api.response import success
+from schemas.offline_downloads import OfflineDownloadCreate
+from services.auth import User, get_current_active_user
+from services.logging import LogService
+from services.task_queue import task_queue_service, TaskProgress
+from services.virtual_fs import path_is_directory
+
+
+router = APIRouter(
+    prefix="/api/offline-downloads",
+    tags=["OfflineDownloads"],
+)
+
+
+@router.post("/")
+async def create_offline_download(
+    payload: OfflineDownloadCreate,
+    current_user: Annotated[User, Depends(get_current_active_user)],
+):
+    dest_dir = payload.dest_dir
+    try:
+        is_dir = await path_is_directory(dest_dir)
+    except HTTPException:
+        is_dir = False
+    if not is_dir:
+        raise HTTPException(400, detail="Destination directory not found")
+
+    task = await task_queue_service.add_task(
+        "offline_http_download",
+        {
+            "url": str(payload.url),
+            "dest_dir": dest_dir,
+            "filename": payload.filename,
+        },
+    )
+
+    await task_queue_service.update_progress(
+        task.id,
+        TaskProgress(
+            stage="queued",
+            percent=0.0,
+            bytes_total=None,
+            bytes_done=0,
+            detail="Waiting to start",
+        ),
+    )
+
+    await LogService.action(
+        "route:offline_downloads",
+        f"Offline download task created {task.id}",
+        details={"url": str(payload.url), "dest_dir": dest_dir, "filename": payload.filename},
+        user_id=current_user.id if hasattr(current_user, "id") else None,
+    )
+
+    return success({"task_id": task.id})
+
+
+@router.get("/")
+async def list_offline_downloads(
+    current_user: Annotated[User, Depends(get_current_active_user)],
+):
+    tasks = [t for t in task_queue_service.get_all_tasks() if t.name == "offline_http_download"]
+    data = [t.dict() for t in tasks]
+    return success(data)
+
+
+@router.get("/{task_id}")
+async def get_offline_download(
+    task_id: str,
+    current_user: Annotated[User, Depends(get_current_active_user)],
+):
+    task = task_queue_service.get_task(task_id)
+    if not task or task.name != "offline_http_download":
+        raise HTTPException(status_code=404, detail="Task not found")
+    return success(task.dict())