import json
import os
from typing import Optional
from _types import AnswerCacheEntry, AnswerCache

CACHE_FILE = "answers_cache.json"

def load_cache(cache_path: str = CACHE_FILE) -> AnswerCache:
    if not os.path.exists(cache_path):
        return {}
    with open(cache_path, "r", encoding="utf-8") as f:
        try:
            return json.load(f)
        except json.JSONDecodeError:
            return {}

def save_cache(cache: AnswerCache, cache_path: str = CACHE_FILE) -> None:
    with open(cache_path, "w", encoding="utf-8") as f:
        json.dump(cache, f, ensure_ascii=False, indent=2)

def cache_answers(questions, cache_path: str = CACHE_FILE) -> AnswerCache:
    """
    Initializes the cache with all answers as incorrect.
    Structure: { task_id: { answer: '', isCorrect: False } }
    """
    cache: AnswerCache = {}
    for q in questions:
        task_id = q.get("task_id")
        if task_id:
            cache[task_id] = {"answer": "", "isCorrect": False}
    save_cache(cache, cache_path)
    return cache

def update_cache_answer(task_id: str, answer: str, is_correct: bool = False, cache_path: str = CACHE_FILE):
    """
    Update the cache with the answer and its correctness status.
    """
    cache = load_cache(cache_path)
    cache[task_id] = {"answer": answer, "isCorrect": is_correct}
    save_cache(cache, cache_path)


def get_cached_answer(task_id: str, cache_path: str = CACHE_FILE) -> Optional[AnswerCacheEntry]:
    """
    Retrieve the cached answer for a given task ID.
    """
    cache = load_cache(cache_path)
    
    return cache.get(task_id)