"""截图列表搜索：FTS + 子串模糊（兼容中文标签/标题）。"""
from __future__ import annotations

from sqlalchemy import or_, select, text
from sqlalchemy.orm import Session

from app.models.meta import ScreenshotMeta
from app.models.screenshot import Screenshot
from app.models.tag import Tag


def fts_query_string(raw: str) -> str:
    """把用户输入处理成 FTS5 查询串（中英文均支持前缀匹配）。"""
    parts = [p for p in raw.replace("\n", " ").split() if p]
    if not parts:
        return raw
    cleaned: list[str] = []
    for p in parts:
        p = p.replace('"', "").strip()
        if not p:
            continue
        cleaned.append(f'"{p}"*')
    return " ".join(cleaned)


def collect_search_ids(session: Session, q: str, *, limit: int = 5000) -> set[int]:
    """联合 FTS5 与 LIKE 子串搜索，返回匹配的 screenshot id 集合。"""
    q = q.strip()
    if not q:
        return set()

    ids: set[int] = set()
    like = f"%{q}%"

    # 1) FTS5 全文索引
    try:
        fts_sql = text(
            "SELECT rowid FROM screenshots_fts WHERE screenshots_fts MATCH :q LIMIT :lim"
        )
        rows = session.execute(fts_sql, {"q": fts_query_string(q), "lim": limit}).fetchall()
        ids.update(int(row[0]) for row in rows)
    except Exception:
        pass

    # 2) 子串模糊：OCR/AI 文本（解决「三花」匹配「三花猫」）
    meta_ids = session.scalars(
        select(ScreenshotMeta.screenshot_id).where(
            or_(
                ScreenshotMeta.ocr_text.ilike(like),
                ScreenshotMeta.ai_title.ilike(like),
                ScreenshotMeta.ai_summary.ilike(like),
                ScreenshotMeta.ai_suggestion.ilike(like),
            )
        ).limit(limit)
    ).all()
    ids.update(int(i) for i in meta_ids)

    # 3) 标签名子串匹配
    tag_ids = session.scalars(
        select(Screenshot.id)
        .join(Screenshot.tags)
        .where(Tag.name.ilike(like))
        .limit(limit)
    ).all()
    ids.update(int(i) for i in tag_ids)

    return ids