import json
import random
from functools import lru_cache
from typing import List, Dict, Any, Optional

from .config import QA_PATH, TOP_QUESTION_IDS


@lru_cache(maxsize=1)
def load_qa_data() -> List[Dict[str, Any]]:
    try:
        return json.loads(QA_PATH.read_text(encoding="utf-8"))
    except Exception:
        return []


def get_question_by_id(qid: int) -> Optional[Dict[str, Any]]:
    for item in load_qa_data():
        if item.get("id") == qid:
            return item
    return None


def get_questions_by_ids(ids: List[int]) -> List[Dict[str, Any]]:
    items = []
    for qid in ids:
        item = get_question_by_id(qid)
        if item:
            items.append(item)
    return items


def random_questions(limit: int = 10) -> List[Dict[str, Any]]:
    data = load_qa_data()
    if not data:
        return []
    if limit >= len(data):
        return data.copy()
    return random.sample(data, limit)


def search_questions(query: str, limit: int = 10) -> List[Dict[str, Any]]:
    """
    简易检索：包含关键词的优先返回，不足则随机补齐。
    """
    data = load_qa_data()
    if not query:
        return random_questions(limit)

    q_lower = query.lower()
    matched = [item for item in data if q_lower in item.get("question", "").lower()]
    # 去重 + 截断
    seen = set()
    results = []
    for item in matched:
        if item["id"] in seen:
            continue
        results.append(item)
        seen.add(item["id"])
        if len(results) >= limit:
            break

    # 不足部分随机补齐
    if len(results) < limit:
        remaining = [x for x in data if x["id"] not in seen]
        random.shuffle(remaining)
        results.extend(remaining[: limit - len(results)])
    return results[:limit]


def top_questions():
    return get_questions_by_ids(TOP_QUESTION_IDS)