"""/api/v1/search/* — 搜索建议(autocomplete,纯 keyword 续接词)。

- GET /api/v1/search/suggestions?q=prefix
  返回:{"query", "keywords": [...]}
  - keywords: 词频续接词(按 weight DESC),输入"美国"→ ["美国", "美国政府", "美国签证", ...]
  - 冷启动:search_keywords 表空时自动 fallback 到实时 ts_stat
- 鉴权:跟 articles 一致(需要登录)

性能:prefix_keys @> ARRAY['美'] 走 GIN 数组索引,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
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="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,返回高频词续接。

    用法:前端搜索框 onChange 时调用,debounce 250ms。
    选词 → 自动填入 q + 触发搜索。
    """
    svc = SearchService(session)
    raw = await svc.suggestions(q=q, limit=limit)
    return SearchSuggestionsResponse(
        query=raw["query"],
        keywords=[SearchKeywordItem(**k) for k in raw["keywords"]],
    )