from datetime import datetime, timezone

from sqlalchemy.orm import Session

from packages.adapters.sqlalchemy_impl.models import GenerationTaskModel
from packages.domain import GenerationTask
from packages.domain.generation_task import GenerationTaskStatus


def _to_domain(model: GenerationTaskModel) -> GenerationTask:
    """Convert ORM model to domain entity."""
    return GenerationTask(
        id=model.id,
        project_id=model.project_id,
        strategy_id=model.strategy_id,
        asset_library_id=model.asset_library_id,
        voice_library_id=model.voice_library_id,
        template_id=model.template_id,
        asset_ids=list(model.asset_ids or []),
        title_ids=list(model.title_ids or []),
        voice_ids=list(model.voice_ids or []),
        status=GenerationTaskStatus(model.status) if model.status else GenerationTaskStatus.PENDING,
        progress=model.progress,
        result_count=int(model.result_count or 0),
        error_message=model.error_message,
        error_info=dict(model.error_info) if model.error_info else {},
        retry_count=model.retry_count or 0,
        auto_retry_enabled=bool(model.auto_retry_enabled),
        auto_retry_max=model.auto_retry_max or 0,
        started_at=model.started_at,
        completed_at=model.completed_at,
        created_by_user_id=model.created_by_user_id,
        source_edit_plan_id=model.source_edit_plan_id or "",
        asset_select_mode=model.asset_select_mode or "",
        batch_id=model.batch_id or "",
        video_title=getattr(model, "video_title", "") or "",
        resolution=getattr(model, "resolution", "") or "",
        bgm_config=dict(getattr(model, "bgm_config", {}) or {}),
        is_preview=bool(getattr(model, "is_preview", False)),
        source_task_id=getattr(model, "source_task_id", "") or "",
        celery_task_id=getattr(model, "celery_task_id", "") or "",
        output_width=getattr(model, "output_width", 1280) or 1280,
        output_height=getattr(model, "output_height", 720) or 720,
        cover_url=getattr(model, "cover_url", "") or "",
        title_config=dict(getattr(model, "title_config", {}) or {}),
        logs=model.logs or "[]",
        created_at=model.created_at,
        updated_at=model.updated_at,
    )


class SQLAlchemyGenerationTaskRepository:
    def __init__(self, session: Session):
        self.session = session

    def create(self, task: GenerationTask) -> GenerationTask:
        model = GenerationTaskModel(
            id=task.id,
            project_id=task.project_id,
            strategy_id=task.strategy_id,
            asset_library_id=task.asset_library_id,
            voice_library_id=task.voice_library_id,
            template_id=task.template_id,
            asset_ids=task.asset_ids,
            title_ids=task.title_ids,
            voice_ids=task.voice_ids,
            status=task.status,
            progress=task.progress,
            result_count=task.result_count,
            error_message=task.error_message,
            error_info=task.error_info or None,
            retry_count=task.retry_count or 0,
            auto_retry_enabled=task.auto_retry_enabled,
            auto_retry_max=task.auto_retry_max or 0,
            started_at=task.started_at,
            completed_at=task.completed_at,
            created_by_user_id=task.created_by_user_id,
            source_edit_plan_id=task.source_edit_plan_id or None,
            asset_select_mode=task.asset_select_mode or "",
            batch_id=task.batch_id or "",
            video_title=task.video_title or "",
            resolution=task.resolution or "",
            bgm_config=task.bgm_config or {},
            is_preview=task.is_preview or False,
            source_task_id=task.source_task_id or "",
            celery_task_id=getattr(task, "celery_task_id", "") or "",
            output_width=task.output_width,
            output_height=task.output_height,
            cover_url=task.cover_url or "",
            title_config=dict(task.title_config) if task.title_config else {},
            logs=task.logs,
            created_at=task.created_at,
            updated_at=task.updated_at,
        )
        self.session.add(model)
        self.session.commit()
        return task

    def get(self, task_id: str) -> GenerationTask | None:
        model = self.session.query(GenerationTaskModel).filter(GenerationTaskModel.id == task_id).first()
        if model is None:
            return None
        return _to_domain(model)

    def list_by_project(self, project_id: str) -> list[GenerationTask]:
        models = (
            self.session.query(GenerationTaskModel)
            .filter(GenerationTaskModel.project_id == project_id)
            .order_by(GenerationTaskModel.created_at.desc())
            .all()
        )
        return [_to_domain(m) for m in models]

    def list_by_user(self, user_id: str) -> list[GenerationTask]:
        models = (
            self.session.query(GenerationTaskModel)
            .filter(GenerationTaskModel.created_by_user_id == user_id)
            .order_by(GenerationTaskModel.created_at.desc())
            .all()
        )
        return [_to_domain(m) for m in models]

    def count_by_user(self, user_id: str) -> int:
        return self.session.query(GenerationTaskModel).filter(GenerationTaskModel.created_by_user_id == user_id).count()

    def count_pending_by_user(self, user_id: str) -> int:
        return (
            self.session.query(GenerationTaskModel)
            .filter(
                GenerationTaskModel.created_by_user_id == user_id,
                GenerationTaskModel.status == GenerationTaskStatus.PENDING.value,
            )
            .count()
        )

    def count_pending_total(self) -> int:
        return (
            self.session.query(GenerationTaskModel)
            .filter(GenerationTaskModel.status == GenerationTaskStatus.PENDING.value)
            .count()
        )

    def count_running_by_user(self, user_id: str) -> int:
        """统计指定用户处于 running 状态的任务数（用于限流提示展示）。"""
        return (
            self.session.query(GenerationTaskModel)
            .filter(
                GenerationTaskModel.created_by_user_id == user_id,
                GenerationTaskModel.status == GenerationTaskStatus.RUNNING.value,
            )
            .count()
        )

    def count_running_total(self) -> int:
        """统计全局处于 running 状态的任务数（worker 实际在执行的任务数）。"""
        return (
            self.session.query(GenerationTaskModel)
            .filter(GenerationTaskModel.status == GenerationTaskStatus.RUNNING.value)
            .count()
        )

    def estimate_avg_duration_seconds(self, limit: int = 20, default_seconds: float = 120.0) -> float:
        """估算最近完成任务的平均耗时（秒），用于 429 限流提示的等待预估。

        取最近 N 条 completed 任务的 (completed_at - started_at) 平均值；
        无足够历史数据时返回 default_seconds。
        用 Python 侧计算差值，避免 SQLite/PostgreSQL 方言差异。
        """
        rows = (
            self.session.query(GenerationTaskModel.started_at, GenerationTaskModel.completed_at)
            .filter(
                GenerationTaskModel.status == GenerationTaskStatus.COMPLETED.value,
                GenerationTaskModel.started_at.isnot(None),
                GenerationTaskModel.completed_at.isnot(None),
            )
            .order_by(GenerationTaskModel.completed_at.desc())
            .limit(limit)
            .all()
        )
        durations = [
            (completed - started).total_seconds()
            for started, completed in rows
            if completed and started and (completed - started).total_seconds() > 0
        ]
        if not durations:
            return default_seconds
        return sum(durations) / len(durations)

    def list_recent_by_user(self, user_id: str, limit: int = 5) -> list[GenerationTask]:
        models = (
            self.session.query(GenerationTaskModel)
            .filter(GenerationTaskModel.created_by_user_id == user_id)
            .order_by(GenerationTaskModel.created_at.desc())
            .limit(limit)
            .all()
        )
        return [_to_domain(m) for m in models]

    def list_latest_completed_preview(self, user_id: str, template_id: str, limit: int = 1) -> list[GenerationTask]:
        """按用户+模板查找最近已完成的预览任务。"""
        models = (
            self.session.query(GenerationTaskModel)
            .filter(
                GenerationTaskModel.created_by_user_id == user_id,
                GenerationTaskModel.template_id == template_id,
                GenerationTaskModel.is_preview,
                GenerationTaskModel.status == "completed",
            )
            .order_by(GenerationTaskModel.created_at.desc())
            .limit(limit)
            .all()
        )
        return [_to_domain(m) for m in models]

    def list_by_source_edit_plan(self, plan_id: str) -> list[GenerationTask]:
        models = (
            self.session.query(GenerationTaskModel)
            .filter(GenerationTaskModel.source_edit_plan_id == plan_id)
            .order_by(GenerationTaskModel.created_at.desc())
            .all()
        )
        return [_to_domain(m) for m in models]

    def list_by_user_filtered(
        self,
        user_id: str,
        *,
        status: str | None = None,
        limit: int | None = None,
        offset: int = 0,
    ) -> list[GenerationTask]:
        """按用户+状态筛选任务列表。"""
        query = self.session.query(GenerationTaskModel).filter(GenerationTaskModel.created_by_user_id == user_id)
        if status:
            query = query.filter(GenerationTaskModel.status == status)
        query = query.order_by(GenerationTaskModel.created_at.desc())
        if offset:
            query = query.offset(offset)
        if limit:
            query = query.limit(limit)
        return [_to_domain(m) for m in query.all()]

    def count_by_user_filtered(
        self,
        user_id: str,
        *,
        status: str | None = None,
    ) -> int:
        """按用户+状态筛选计数。"""
        query = self.session.query(GenerationTaskModel).filter(GenerationTaskModel.created_by_user_id == user_id)
        if status:
            query = query.filter(GenerationTaskModel.status == status)
        return query.count()

    def list_by_project_filtered(
        self,
        project_id: str,
        *,
        status: str | None = None,
        limit: int | None = None,
        offset: int = 0,
    ) -> list[GenerationTask]:
        """按项目+状态筛选任务列表。"""
        query = self.session.query(GenerationTaskModel).filter(GenerationTaskModel.project_id == project_id)
        if status:
            query = query.filter(GenerationTaskModel.status == status)
        query = query.order_by(GenerationTaskModel.created_at.desc())
        if offset:
            query = query.offset(offset)
        if limit:
            query = query.limit(limit)
        return [_to_domain(m) for m in query.all()]

    def count_by_project_filtered(
        self,
        project_id: str,
        *,
        status: str | None = None,
    ) -> int:
        """按项目+状态筛选计数。"""
        query = self.session.query(GenerationTaskModel).filter(GenerationTaskModel.project_id == project_id)
        if status:
            query = query.filter(GenerationTaskModel.status == status)
        return query.count()

    def update(self, task: GenerationTask) -> GenerationTask:
        model = self.session.query(GenerationTaskModel).filter(GenerationTaskModel.id == task.id).first()
        if model is None:
            raise ValueError(f"GenerationTask {task.id} not found")
        model.project_id = task.project_id
        model.asset_library_id = task.asset_library_id
        model.strategy_id = task.strategy_id
        model.voice_library_id = task.voice_library_id
        model.template_id = task.template_id
        model.asset_ids = task.asset_ids
        model.title_ids = task.title_ids
        model.voice_ids = task.voice_ids
        model.status = task.status
        model.progress = task.progress
        model.result_count = task.result_count
        model.error_message = task.error_message
        model.error_info = task.error_info or None
        model.retry_count = task.retry_count or 0
        model.auto_retry_enabled = task.auto_retry_enabled
        model.auto_retry_max = task.auto_retry_max or 0
        model.started_at = task.started_at
        model.completed_at = task.completed_at
        model.source_edit_plan_id = task.source_edit_plan_id or None
        model.asset_select_mode = task.asset_select_mode or ""
        model.batch_id = task.batch_id or ""
        if hasattr(model, "video_title"):
            model.video_title = task.video_title or ""
        if hasattr(model, "resolution"):
            model.resolution = task.resolution or ""
        if hasattr(model, "bgm_config"):
            model.bgm_config = task.bgm_config or {}
        if hasattr(model, "is_preview"):
            model.is_preview = task.is_preview or False
        model.source_task_id = task.source_task_id or ""
        model.celery_task_id = getattr(task, "celery_task_id", "") or model.celery_task_id or ""
        model.output_width = task.output_width
        model.output_height = task.output_height
        model.cover_url = task.cover_url or ""
        model.title_config = dict(task.title_config) if task.title_config else {}
        model.logs = task.logs
        self.session.commit()
        return task

    def cleanup_stale_running(self, timeout_minutes: int = 10) -> int:
        """清理超时未更新的 running 任务（孤儿任务）。

        Returns:
            清理的任务数量（仅计数，保持旧签名兼容）
        """
        items = self.cleanup_stale_running_with_ids(timeout_minutes)
        return len(items)

    def cleanup_stale_running_with_ids(self, timeout_minutes: int = 10) -> list[tuple[str, str]]:
        """同 cleanup_stale_running，但返回 [(task_id, celery_task_id), ...] 供撤销队列消息。"""
        from datetime import timedelta

        cutoff = datetime.now(timezone.utc) - timedelta(minutes=timeout_minutes)
        models = (
            self.session.query(GenerationTaskModel)
            .filter(
                GenerationTaskModel.status == GenerationTaskStatus.RUNNING.value,
                GenerationTaskModel.updated_at < cutoff,
            )
            .all()
        )
        if not models:
            return []
        result: list[tuple[str, str]] = []
        for model in models:
            result.append((model.id, getattr(model, "celery_task_id", "") or ""))
            model.status = GenerationTaskStatus.FAILED.value
            model.error_message = "任务执行中断（worker重启/超时）"
            model.error_info = {
                "error_type": "WorkerInterrupted",
                "message": "任务在运行中中断，可能因 worker 重启或超时",
                "failed_at": datetime.now(timezone.utc).isoformat(),
            }
            model.completed_at = datetime.now(timezone.utc)
        self.session.commit()
        return result

    def cleanup_stale_pending(self, timeout_minutes: int = 30) -> int:
        """清理超时的 pending 任务（未被 Worker 拉取的任务）。

        Returns:
            清理的任务数量（仅计数，保持旧签名兼容）
        """
        items = self.cleanup_stale_pending_with_ids(timeout_minutes)
        return len(items)

    def cleanup_stale_pending_with_ids(self, timeout_minutes: int = 30) -> list[tuple[str, str]]:
        """同 cleanup_stale_pending，但返回 [(task_id, celery_task_id), ...] 供撤销队列消息。"""
        from datetime import timedelta

        cutoff = datetime.now(timezone.utc) - timedelta(minutes=timeout_minutes)
        models = (
            self.session.query(GenerationTaskModel)
            .filter(
                GenerationTaskModel.status == GenerationTaskStatus.PENDING.value,
                GenerationTaskModel.created_at < cutoff,
            )
            .all()
        )
        if not models:
            return []
        error_info = {
            "error_type": "PendingTimeout",
            "message": f"任务在 pending 状态停留超过 {timeout_minutes} 分钟，自动清理",
            "failed_at": datetime.now(timezone.utc).isoformat(),
        }
        result: list[tuple[str, str]] = []
        for model in models:
            result.append((model.id, getattr(model, "celery_task_id", "") or ""))
            model.status = GenerationTaskStatus.FAILED.value
            model.error_message = "pending timeout: auto cleanup"
            model.error_info = error_info
            model.completed_at = datetime.now(timezone.utc)
        self.session.commit()
        return result