"""/api/v1/search/* — 搜索建议(autocomplete)。

- GET /api/v1/search/suggestions?q=prefix
  返回:{"query", "titles": [...], "keywords": [...]}
  - titles: 真实文章标题(按 published_at DESC),B 方案
  - keywords: 高频词(按 weight DESC),A 方案
  - 冷启动:任一表空时自动 fallback 到实时 ILIKE / ts_stat
- 鉴权:跟 articles 一致(需要登录)

性能:两个查询都走 GIN 数组索引(prefix_keys @> ARRAY['美']),亚毫秒。
"""
from __future__ import annotations

from fastapi import APIRouter, Depends, Query
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.deps import get_current_user
from app.database import get_session
from app.models.user import User
from app.schemas.search import (
    SearchKeywordItem,
    SearchSuggestionsResponse,
    SearchTitleSuggestionItem,
)
from app.services.search import SearchService

router = APIRouter(prefix="/search", tags=["search"])


@router.get("/suggestions", response_model=SearchSuggestionsResponse)
async def get_suggestions(
    q: str = Query(..., min_length=1, max_length=20, description="搜索前缀"),
    limit: int = Query(10, ge=1, le=20, description="每组最多返回多少"),
    _user: User = Depends(get_current_user),  # 需要登录,跟 articles 一致
    session: AsyncSession = Depends(get_session),
):
    """搜索建议:输入 prefix,返回真实标题 + 高频词两组候选。

    用法:前端搜索框 onChange 时调用,debounce 200ms。
    """
    svc = SearchService(session)
    raw = await svc.suggestions(q=q, limit=limit)
    return SearchSuggestionsResponse(
        query=raw["query"],
        titles=[SearchTitleSuggestionItem(**t) for t in raw["titles"]],
        keywords=[SearchKeywordItem(**k) for k in raw["keywords"]],
    )