"""搜索建议候选词表(固化,worker 每日 ts_stat 刷新)。

- 数据源:articles.title_zh + body_zh_text + commentary + commentary_meituan
- 用途:/api/v1/search/suggestions 返回"高频词"建议(A 方案)
- 刷新:每日凌晨 worker 调 refresh_search_keywords() 全量重建
- 查询:prefix_keys @> ARRAY['美'] 走 GIN 索引(亚毫秒)
"""
from __future__ import annotations

from datetime import datetime

from sqlalchemy import BigInteger, DateTime, Integer, String, Text, func
from sqlalchemy.dialects.postgresql import ARRAY
from sqlalchemy.orm import Mapped, mapped_column

from app.database import Base


class SearchKeyword(Base):
    __tablename__ = "search_keywords"

    id: Mapped[int] = mapped_column(BigInteger, primary_key=True)

    keyword: Mapped[str] = mapped_column(Text, nullable=False)
    # ts_stat / title_extract / manual
    source: Mapped[str] = mapped_column(String(32), nullable=False)
    # 词频或文章数(权重,排序用)
    weight: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    # 预计算前缀数组,['美','美联储','美联储宣'] for '美联储宣布...'
    prefix_keys: Mapped[list[str]] = mapped_column(ARRAY(Text), nullable=False)

    last_seen_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )

    __table_args__ = (
        # db-level unique 留给 alembic 迁移创建(__table_args__ 只是 ORM 侧参考)
        # 实际 UNIQUE 约束在 0009 迁移里建
    )

    def __repr__(self) -> str:
        return f"<SearchKeyword {self.keyword!r} src={self.source} weight={self.weight}>"