from fastapi import APIRouter, BackgroundTasks, Depends

from app.clients.llm.base import LLMClient
from app.clients.storage.base import StorageClient
from app.core.config import get_config
from app.core.dependencies import get_llm_client, get_storage_client
from app.core.exceptions import VideoTooLargeError
from app.models.video_models import (
    ExtractFramesRequest,
    VideoAcceptedResponse,
    VideoToTextRequest,
)
from app.services import video_service

router = APIRouter(tags=["Video"])


async def _check_video_size(storage: StorageClient, bucket: str, file_path: str, max_mb: int) -> None:
    size_bytes = await storage.get_object_size(bucket, file_path)
    if size_bytes > max_mb * 1024 * 1024:
        raise VideoTooLargeError(
            f"视频文件大小超出限制（最大 {max_mb}MB，当前 {size_bytes // 1024 // 1024}MB）"
        )


@router.post("/video/extract-frames", response_model=VideoAcceptedResponse, status_code=202)
async def extract_frames(
    req: ExtractFramesRequest,
    background_tasks: BackgroundTasks,
    storage: StorageClient = Depends(get_storage_client),
) -> VideoAcceptedResponse:
    cfg = get_config()
    bucket = cfg["storage"]["buckets"]["source_data"]
    max_mb = cfg["video"]["max_file_size_mb"]
    callback_url = cfg.get("backend", {}).get("callback_url", "")

    await _check_video_size(storage, bucket, req.file_path, max_mb)

    background_tasks.add_task(
        video_service.extract_frames_task,
        req,
        storage,
        callback_url,
    )
    return VideoAcceptedResponse(message="任务已接受，后台处理中", job_id=req.job_id)


@router.post("/video/to-text", response_model=VideoAcceptedResponse, status_code=202)
async def video_to_text(
    req: VideoToTextRequest,
    background_tasks: BackgroundTasks,
    storage: StorageClient = Depends(get_storage_client),
    llm: LLMClient = Depends(get_llm_client),
) -> VideoAcceptedResponse:
    cfg = get_config()
    bucket = cfg["storage"]["buckets"]["source_data"]
    max_mb = cfg["video"]["max_file_size_mb"]
    callback_url = cfg.get("backend", {}).get("callback_url", "")

    await _check_video_size(storage, bucket, req.file_path, max_mb)

    background_tasks.add_task(
        video_service.video_to_text_task,
        req,
        llm,
        storage,
        callback_url,
    )
    return VideoAcceptedResponse(message="任务已接受，后台处理中", job_id=req.job_id)