"""Tests for the FTS5 message-search index (app.db.fts).

SQLite FTS5 trigram tokenizer gives Chinese substring matching at index
speed instead of a 4s LIKE scan over 675k rows (2026-08-21). The module:

* ``ensure_fts`` creates the ``message_fts`` virtual table + sync triggers
  (idempotent; no-op when already present, tolerant of MySQL where FTS5
  doesn't exist — callers fall back to LIKE).
* ORM inserts/updates keep the index in sync via the triggers.
* ``fts_available`` reports whether the index exists on this engine.
"""

from __future__ import annotations

import pytest
import sqlalchemy as sa

from app.db.base import Base
from app.db.fts import ensure_fts, fts_available, fts_match_rows
from app.db.models import Message


@pytest.fixture
async def engine():
    from sqlalchemy.ext.asyncio import create_async_engine

    eng = create_async_engine("sqlite+aiosqlite:///:memory:")
    async with eng.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)
    try:
        yield eng
    finally:
        await eng.dispose()


async def test_ensure_fts_creates_index_and_triggers(engine):
    async with engine.begin() as conn:
        await ensure_fts(conn)
    assert await fts_available(engine) is True


async def test_ensure_fts_idempotent(engine):
    async with engine.begin() as conn:
        await ensure_fts(conn)
        await ensure_fts(conn)  # 二次调用不报错
    assert await fts_available(engine) is True


async def test_orm_insert_syncs_fts(engine):
    """ORM 插入消息 → 触发器自动进 FTS 索引 → 能 MATCH 到。"""
    from sqlalchemy.ext.asyncio import async_sessionmaker

    async with engine.begin() as conn:
        await ensure_fts(conn)
    maker = async_sessionmaker(engine, expire_on_commit=False)

    async with maker() as session:
        session.add(Message(msg_id="m1", channel="wechat", owner_account_id="o", talker_id="t", text="24年大众途安 简约白", timestamp=1000))
        session.add(Message(msg_id="m2", channel="wechat", owner_account_id="o", talker_id="t", text="丰田汉兰达", timestamp=2000))
        await session.commit()

    rows = await fts_match_rows(engine, "大众途安")
    assert [r.msg_id for r in rows] == ["m1"]


async def test_fts_match_chinese_substring(engine):
    """trigram 中文子串匹配:搜「途安」(2字,LIKE 回退)与「大众途安」(4字,FTS)。"""
    from sqlalchemy.ext.asyncio import async_sessionmaker

    async with engine.begin() as conn:
        await ensure_fts(conn)
    maker = async_sessionmaker(engine, expire_on_commit=False)
    async with maker() as session:
        session.add(Message(msg_id="m1", channel="wechat", owner_account_id="o", talker_id="t", text="推荐24年大众途安L", timestamp=1000))
        await session.commit()

    rows = await fts_match_rows(engine, "大众途安")
    assert len(rows) == 1


async def test_fts_absent_on_fresh_db(engine):
    """未 ensure 过的库 → fts_available False(搜索走 LIKE 回退)。"""
    assert await fts_available(engine) is False