"""视频生成任务 finalize 服务（#2024）。

Worker 渲染+上传完成后不再自动入库，标记为 awaiting_cover；用户在 Step5 选好封面
点「完成」时由 API 调用本服务：创建 GeneratedVideo 成品库记录（复用 worker 预计算
的查重结果）、绑定封面、推进任务到 completed。

与 AI 数字人 ``ai_avatar_render_service.finalize_job`` 模式一致，
只是走 GenerationTask 而非 AiAvatarRenderJob。
"""

from __future__ import annotations

import logging
from datetime import UTC, datetime
from typing import Optional

from sqlalchemy.orm import Session

logger = logging.getLogger(__name__)


class GenerationFinalizeError(Exception):
    """finalize 业务错误，code 供 API 层映射 HTTP 状态码。"""

    def __init__(self, message: str, code: str = "FinalizeError", status_code: int = 400):
        super().__init__(message)
        self.code = code
        self.status_code = status_code


class GenerationFinalizeService:
    def __init__(self, db: Session):
        self.db = db

    def finalize_task(self, task_id: str, user_id: str, cover_url: Optional[str] = None):
        """执行 finalize：状态校验 → 幂等 → 绑定封面 → 入库 → 推进 completed。

        Returns:
            GeneratedVideo 领域对象
        """
        from packages.adapters.sqlalchemy_impl.generated_video_repository import (
            SQLAlchemyGeneratedVideoRepository,
        )
        from packages.adapters.sqlalchemy_impl.generation_task_repository import (
            SQLAlchemyGenerationTaskRepository,
        )
        from packages.adapters.sqlalchemy_impl.models import GeneratedVideoModel
        from packages.application.generated_video_finalize import finalize_generated_video

        task_repo = SQLAlchemyGenerationTaskRepository(self.db)
        video_repo = SQLAlchemyGeneratedVideoRepository(self.db)

        task = task_repo.get(task_id)
        if task is None:
            raise GenerationFinalizeError(f"任务 {task_id} 不存在", "TaskNotFound", 404)

        # ── 幂等：已入库直接返回 ─────────────────────────────────
        existing = self.db.query(GeneratedVideoModel).filter(GeneratedVideoModel.generation_task_id == task_id).first()
        if existing is not None:
            logger.info("[finalize] 幂等命中 task=%s video=%s", task_id, existing.id)
            if cover_url and cover_url.strip() and existing.thumbnail_url != cover_url.strip():
                existing.thumbnail_url = cover_url.strip()
                task.cover_url = cover_url.strip()
                self.db.commit()
            if task.status.value != "completed":
                try:
                    task.mark_completed(result_count=1)
                    if cover_url and cover_url.strip():
                        task.cover_url = cover_url.strip()
                    task_repo.update(task)
                    self.db.commit()
                except Exception as e:
                    logger.warning("[finalize] 幂等补 mark_completed 失败: %s", e)
                    self.db.rollback()
            return video_repo.get(existing.id)

        # ── 状态校验 ─────────────────────────────────────────────
        if task.status.value != "awaiting_cover":
            raise GenerationFinalizeError(
                f"任务当前状态 {task.status.value}，无法 finalize（需 awaiting_cover）",
                "InvalidTaskStatus",
                400,
            )

        # ── 封面 ─────────────────────────────────────────────────
        effective_cover = (cover_url or "").strip() if cover_url else (task.cover_url or "").strip()

        # ── 入库+查重（复用 worker 预计算结果） ──────────────────
        try:
            result = finalize_generated_video(
                task=task,
                session=self.db,
                effective_cover_url=effective_cover,
            )
        except ValueError as e:
            raise GenerationFinalizeError(str(e), "RenderedOutputMissing", 400) from e

        video_id = result["video_id"]

        # ── 推进任务 ─────────────────────────────────────────────
        task.mark_completed(result_count=1)
        task.cover_url = effective_cover
        # 清理 rendered_output（体积较大，入库后不再需要）
        meta = dict(task.extra_meta or {})
        meta.pop("rendered_output", None)
        task.extra_meta = meta
        task.updated_at = datetime.now(UTC)
        task_repo.update(task)
        self.db.commit()

        video = video_repo.get(video_id)
        logger.info(
            "[finalize] task=%s finalized -> video=%s cover=%s dup=%s",
            task_id,
            video_id,
            bool(effective_cover),
            result.get("is_duplicate", False),
        )
        return video