import json
import os
import time
from typing import Dict, Any, Optional
import diskcache


class Cache:
    def __init__(self, cache_dir: str = "./cache", size_limit_gb: int = 1):
        self.cache_dir = cache_dir
        self.size_limit_bytes = size_limit_gb * 1024 * 1024 * 1024
        self.cache = diskcache.Cache(
            directory=cache_dir,
            size_limit=self.size_limit_bytes,
            eviction_policy='least-recently-used'
        )

    def _make_key(self, method: str, params: Dict[str, Any]) -> str:
        return f"{method}:{json.dumps(params, sort_keys=True)}"

    def get(self, method: str, params: Dict[str, Any]) -> Optional[Dict[str, Any]]:
        key = self._make_key(method, params)
        cached_data = self.cache.get(key)

        if cached_data is None:
            return None

        # Check if cached data has TTL and if it's expired
        if isinstance(cached_data, dict) and '_cache_expiry' in cached_data:
            if time.time() > cached_data['_cache_expiry']:
                # Remove expired entry
                self.cache.delete(key)
                return None
            # Remove cache metadata before returning
            response = cached_data.copy()
            del response['_cache_expiry']
            return response

        return cached_data

    def set(self, method: str, params: Dict[str, Any], response: Dict[str, Any], ttl: Optional[int] = None) -> None:
        key = self._make_key(method, params)

        # Add TTL metadata if specified
        if ttl is not None:
            cached_response = response.copy()
            cached_response['_cache_expiry'] = time.time() + ttl
            self.cache.set(key, cached_response)
        else:
            self.cache.set(key, response)

    def size_check(self) -> Dict[str, Any]:
        stats = self.cache.stats()
        return {
            "size_bytes": stats[1],
            "size_gb": stats[1] / (1024 * 1024 * 1024),
            "count": stats[0],
            "limit_gb": self.size_limit_bytes / (1024 * 1024 * 1024)
        }