from pathlib import Path

from fastapi import APIRouter
from fastapi.responses import FileResponse

from app.config import settings
from app.core.exceptions import DocumentNotFoundError, ExportError
from app.schemas.export import ExportDocRequest, ExportDocResponse
from app.services.export_service import export_doc

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


def _ok(data: dict) -> dict:
    return {"code": 0, "message": "Success", "data": data}


# ------------------------------------------------------------------ #
# POST /export/doc  导出 .doc 并返回下载链接
# ------------------------------------------------------------------ #
@router.post("/export/doc", summary="导出 .doc 文件")
async def export_document(body: ExportDocRequest) -> dict:
    # 若传入 documentId，按需建立 DB session 同步更新草稿
    if body.document_id:
        try:
            from app.core.database import AsyncSessionLocal
            from app.services.document_service import DocumentService
            from app.schemas.document import UpdateDocumentRequest

            async with AsyncSessionLocal() as db:
                svc = DocumentService(db)
                await svc.update_document(
                    body.document_id,
                    UpdateDocumentRequest(content=body.content),
                )
        except DocumentNotFoundError:
            pass   # 文档不存在不阻塞导出
        except Exception:
            pass   # DB 不可用时同样不阻塞导出

    result = await export_doc(
        file_name=body.file_name,
        content=body.content,
        style_id=body.style_id,
    )

    resp = ExportDocResponse(
        download_url=result["download_url"],
        file_name=result["file_name"],
        expires_at=result["expires_at"],
        style_id=result["style_id"],
    )
    return _ok(resp.model_dump(by_alias=True))


# ------------------------------------------------------------------ #
# GET /files/{filename}  临时文件下载端点
# ------------------------------------------------------------------ #
@router.get("/files/{filename}", summary="下载导出文件", include_in_schema=False)
async def download_file(filename: str) -> FileResponse:
    # FastAPI 有时不会自动解码路径参数，手动解码一次确保中文还原
    from urllib.parse import unquote
    decoded = unquote(filename)
    safe = Path(decoded).name
    file_path = Path(settings.temp_dir) / safe

    if not file_path.exists():
        raise ExportError(f"文件不存在或已过期: {safe}")

    return FileResponse(
        path=str(file_path),
        filename=safe,
        media_type="application/msword",
    )