"""Task ORM：一个上传完成的视频对应一个转写任务，承载状态机。"""

from __future__ import annotations

from datetime import datetime, timezone

from sqlalchemy import DateTime, Float, Integer, String, Text
from sqlalchemy.orm import Mapped, mapped_column

from ..database import Base


def _now() -> datetime:
    return datetime.now(timezone.utc)


# 任务状态枚举（单一真源，供 scheduler / cache_cleaner / views 引用）
STATUS_UPLOADING = "uploading"   # 虚拟状态：分片上传中（不在 Task 表，由 UploadSession 映射）
STATUS_QUEUED = "queued"
STATUS_EXTRACTING = "extracting"
STATUS_TRANSCRIBING = "transcribing"
STATUS_SEGMENTING = "segmenting"
STATUS_TRANSLATING = "translating"
STATUS_DONE = "done"
STATUS_FAILED = "failed"


class Task(Base):
    __tablename__ = "task"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    # 原始视频文件名（用户上传时的名字）
    filename: Mapped[str] = mapped_column(String(512), nullable=False)
    # 视频在 upload_dir 下的相对路径（提取音频前后可能被删）
    source_path: Mapped[str] = mapped_column(String(1024), nullable=False)
    # 状态机：queued → extracting → transcribing → segmenting → translating → done | failed
    status: Mapped[str] = mapped_column(String(32), nullable=False, default=STATUS_QUEUED, index=True)
    # 0-100 进度
    progress: Mapped[float] = mapped_column(Float, nullable=False, default=0.0)
    # 失败原因
    error: Mapped[str | None] = mapped_column(Text, nullable=True)
    # 输出字幕路径（双语合并 / 英文 / 中文）
    bilingual_srt_path: Mapped[str | None] = mapped_column(String(1024), nullable=True)
    en_srt_path: Mapped[str | None] = mapped_column(String(1024), nullable=True)
    zh_srt_path: Mapped[str | None] = mapped_column(String(1024), nullable=True)

    # ---- 流水线阶段间传递的中间数据（scheduler 调度用）----
    # ffmpeg 提取出的 wav 绝对路径（extract 阶段写，asr 阶段读）
    wav_path: Mapped[str | None] = mapped_column(String(1024), nullable=True)
    # ASR + 断句结果（asr 阶段写 JSON，translate 阶段读）。JSON 序列化的 list[Subtitle]
    segments_json: Mapped[str | None] = mapped_column(Text, nullable=True)

    created_at: Mapped[datetime] = mapped_column(DateTime, default=_now, index=True)
    updated_at: Mapped[datetime] = mapped_column(DateTime, default=_now, onupdate=_now)

    def __repr__(self) -> str:
        return f"<Task id={self.id} {self.filename} status={self.status}>"