"""export_record_service.py — 导出记录 CRUD。"""

from pathlib import Path

from sqlalchemy import func, select
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.exceptions import RecordNotFoundError
from app.models.export_record import ExportRecord


class ExportRecordService:
    def __init__(self, db: AsyncSession) -> None:
        self.db = db

    # ------------------------------------------------------------------ #
    # 写入
    # ------------------------------------------------------------------ #

    async def create_record(
        self,
        *,
        user_id: str,
        file_name: str,
        file_path: str,
        file_size: int,
        download_url: str,
        document_id: str | None,
        style_id: str,
    ) -> ExportRecord:
        record = ExportRecord(
            user_id=user_id,
            file_name=file_name,
            file_path=file_path,
            file_size=file_size,
            download_url=download_url,
            document_id=document_id,
            style_id=style_id,
        )
        self.db.add(record)
        await self.db.commit()
        await self.db.refresh(record)
        return record

    # ------------------------------------------------------------------ #
    # 查询列表
    # ------------------------------------------------------------------ #

    async def list_records(
        self,
        user_id: str,
        page: int = 1,
        page_size: int = 20,
        sort_order: str = "desc",
    ) -> tuple[list[ExportRecord], int]:
        """返回 (records, total)。"""
        base_q = select(ExportRecord).where(ExportRecord.user_id == user_id)

        # 总数
        count_q = select(func.count()).select_from(base_q.subquery())
        total: int = (await self.db.execute(count_q)).scalar_one()

        # 分页 + 排序
        order_col = (
            ExportRecord.created_at.desc()
            if sort_order.lower() != "asc"
            else ExportRecord.created_at.asc()
        )
        offset = (page - 1) * page_size
        result = await self.db.execute(
            base_q.order_by(order_col).offset(offset).limit(page_size)
        )
        records = list(result.scalars().all())
        return records, total

    # ------------------------------------------------------------------ #
    # 查询单条（校验归属）
    # ------------------------------------------------------------------ #

    async def get_record(self, record_id: str, user_id: str) -> ExportRecord:
        result = await self.db.execute(
            select(ExportRecord).where(
                ExportRecord.id == record_id,
                ExportRecord.user_id == user_id,
            )
        )
        record = result.scalar_one_or_none()
        if record is None:
            raise RecordNotFoundError(record_id)
        return record

    # ------------------------------------------------------------------ #
    # 硬删除
    # ------------------------------------------------------------------ #

    async def delete_record(self, record_id: str, user_id: str) -> None:
        """删除数据库记录并同步删除磁盘文件。"""
        record = await self.get_record(record_id, user_id)

        # 先删磁盘文件，文件不存在时静默忽略
        try:
            Path(record.file_path).unlink(missing_ok=True)
        except OSError:
            pass

        await self.db.delete(record)
        await self.db.commit()