from datetime import datetime
from typing import Any

from sqlalchemy import JSON, DateTime, Integer, String, Text
from sqlalchemy.dialects.mysql import BIGINT, TINYINT
from sqlalchemy.orm import Mapped, mapped_column

from app.model.base import Base


class Episode(Base):
    """会话片段（`episodes`）；列与库中实际结构逐列一致。

    列名与类型按 `information_schema.COLUMNS` 核对（18 列，无生成列），
    同名兄弟模型如 `ConversationMessage.handler_id` 既有用法同样使用
    `BIGINT(unsigned=True)`，因此无符号列在此保持一致的映射风格。
    唯一键 `episode_uuid`、`content_hash` 由数据库维护：抽取幂等依赖
    `content_hash` 唯一键，跨存储稳定标识依赖 `episode_uuid`。
    """

    __tablename__ = "episodes"
    id: Mapped[int] = mapped_column(BIGINT(unsigned=True), primary_key=True, autoincrement=True)
    episode_uuid: Mapped[str | None] = mapped_column(String(36), unique=True)
    customer_id: Mapped[int] = mapped_column(BIGINT(unsigned=True), nullable=False)
    session_id: Mapped[str] = mapped_column(String(64), nullable=False)
    start_message_no: Mapped[int | None] = mapped_column(Integer)
    end_message_no: Mapped[int | None] = mapped_column(Integer)
    portals_involved: Mapped[list[Any]] = mapped_column(JSON, nullable=False)
    summary: Mapped[str] = mapped_column(Text, nullable=False)
    extraction_status: Mapped[str] = mapped_column(String(16), nullable=False, default="待提取")
    content_hash: Mapped[str | None] = mapped_column(String(64), unique=True)
    retry_count: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    started_at: Mapped[datetime | None] = mapped_column(DateTime)
    ended_at: Mapped[datetime | None] = mapped_column(DateTime)
    handoff_to_employee_id: Mapped[int | None] = mapped_column(BIGINT(unsigned=True))
    start_at: Mapped[datetime | None] = mapped_column(DateTime)
    end_at: Mapped[datetime | None] = mapped_column(DateTime)
    promoted_to_ltm: Mapped[bool] = mapped_column(
        TINYINT(display_width=1), nullable=False, default=False
    )
    created_at: Mapped[datetime] = mapped_column(DateTime, nullable=False)