import json
import threading
import time
from datetime import datetime
from pathlib import Path

from fastapi import FastAPI
from pydantic import BaseModel, Field


class SearchRequest(BaseModel):
    keywords: list[str] = Field(min_length=1, max_length=100)


class JsonlQueryLogger:
    def __init__(self, path: str | Path):
        self.path = Path(path)
        self.path.parent.mkdir(parents=True, exist_ok=True)
        self._lock = threading.Lock()

    def write(self, query: str, candidates: list[dict], elapsed_ms: float) -> None:
        entry = {
            "time": datetime.now().astimezone().isoformat(timespec="milliseconds"),
            "query": query,
            "candidates": candidates,
            "elapsed_ms": round(elapsed_ms, 3),
        }
        line = json.dumps(entry, ensure_ascii=False, separators=(",", ":")) + "\n"
        with self._lock:
            with self.path.open("a", encoding="utf-8", newline="") as file:
                file.write(line)


def register_routes(app: FastAPI, matcher, query_logger):
    @app.post("/v1/search")
    def search(request: SearchRequest) -> dict[str, list[dict]]:
        results = []
        for keyword in request.keywords:
            started_at = time.perf_counter()
            candidates = matcher.search(keyword, limit=3)
            elapsed_ms = (time.perf_counter() - started_at) * 1000
            query_logger.write(keyword, candidates, elapsed_ms)
            results.append({"query": keyword, "candidates": candidates})
        return {"results": results}