# Copyright 2025 - EWAAST Project
# Adapted from Google's appoint-ready architecture
# Licensed under the Apache License, Version 2.0

"""
Disk-based caching for expensive LLM calls.
Adapted directly from appoint-ready's cache.py
"""

from diskcache import Cache
import os
import shutil
import tempfile
import zipfile
import logging

# Initialize cache
cache = Cache(os.environ.get("CACHE_DIR", ".cache"))

# Print cache statistics after loading
try:
    item_count = len(cache)
    size_bytes = cache.volume()
    print(f"EWAAST Cache loaded: {item_count} items, approx {size_bytes} bytes")
except Exception as e:
    print(f"Could not retrieve cache statistics: {e}")


def create_cache_zip():
    """Creates a zip file of the cache for backup/download."""
    temp_dir = tempfile.gettempdir()
    base_name = os.path.join(temp_dir, "ewaast_cache_archive")
    archive_path = base_name + ".zip"
    cache_directory = os.environ.get("CACHE_DIR", ".cache")
    
    if not os.path.isdir(cache_directory):
        logging.error(f"Cache directory not found at {cache_directory}")
        return None, f"Cache directory not found: {cache_directory}"
    
    logging.info("Forcing a cache checkpoint for safe backup...")
    try:
        with Cache(cache_directory) as temp_cache:
            temp_cache.close()
        
        # Clean up temporary files before archiving
        tmp_path = os.path.join(cache_directory, 'tmp')
        if os.path.isdir(tmp_path):
            logging.info(f"Removing temporary cache directory: {tmp_path}")
            shutil.rmtree(tmp_path)

        logging.info(f"Creating zip archive of {cache_directory} to {archive_path}")
        with zipfile.ZipFile(archive_path, 'w', zipfile.ZIP_DEFLATED, compresslevel=9) as zipf:
            for root, _, files in os.walk(cache_directory):
                for file in files:
                    file_path = os.path.join(root, file)
                    arcname = os.path.relpath(file_path, cache_directory)
                    zipf.write(file_path, arcname)
        logging.info("Zip archive created successfully.")
        return archive_path, None
        
    except Exception as e:
        logging.error(f"Error creating zip archive: {e}", exc_info=True)
        return None, f"Error creating zip archive: {e}"