from fastapi import APIRouter, UploadFile, File, Query, HTTPException

from app.schemas.dataset import (
    DatasetDownloadRequest,
    DatasetDownloadResponse,
    DatasetPreviewResponse,
    DatasetUploadResponse,
    DatasetValidationResult,
)
from app.schemas.background_task import DatasetDownloadTaskResponse
from app.services import dataset_service

router = APIRouter()


@router.post("/download", response_model=DatasetDownloadResponse, status_code=200)
async def download_dataset(req: DatasetDownloadRequest):
    """启动数据集下载后台任务，立即返回 task_id。"""
    result = await dataset_service.download_dataset(req)
    return result


@router.get("/download/{task_id}")
async def get_dataset_download_status(task_id: str):
    """查询数据集下载任务状态。"""
    result = await dataset_service.get_dataset_download_status(task_id)
    if result.get("status") == "not_found":
        raise HTTPException(status_code=404, detail="Download task not found")
    return result


@router.get("/downloads")
async def list_dataset_downloads():
    """列出所有数据集下载任务。"""
    return await dataset_service.list_dataset_downloads()


@router.post("/download/{task_id}/cancel")
async def cancel_dataset_download(task_id: str):
    """取消数据集下载任务。"""
    return await dataset_service.cancel_dataset_download(task_id)


@router.post("/upload", response_model=DatasetUploadResponse, status_code=201)
async def upload_dataset(file: UploadFile = File(...)):
    """上传数据集文件（JSONL / CSV / Parquet / JSON）。"""
    result = await dataset_service.upload_dataset(file)
    return DatasetUploadResponse(**result)


@router.get("/{dataset_id}/preview", response_model=DatasetPreviewResponse)
async def preview_dataset(dataset_id: str, rows: int = Query(default=10, le=100)):
    """预览数据集前 N 行。"""
    result = await dataset_service.preview_dataset(dataset_id, rows)
    return DatasetPreviewResponse(**result)


@router.post("/{dataset_id}/validate", response_model=DatasetValidationResult)
async def validate_dataset(dataset_id: str):
    """校验数据集格式和 Schema。"""
    result = await dataset_service.validate_dataset(dataset_id)
    return DatasetValidationResult(**result)


@router.get("/", response_model=list[DatasetUploadResponse])
async def list_datasets():
    """列出所有已上传数据集。"""
    items = await dataset_service.list_datasets()
    return [DatasetUploadResponse(**item) for item in items]


@router.delete("/{dataset_id}", status_code=200)
async def delete_dataset(dataset_id: str):
    """删除数据集。"""
    return await dataset_service.delete_dataset(dataset_id)