#!/usr/bin/env python3
"""
Download GNoME dataset during Docker build.

This script downloads the core dataset files needed for the MCP service.
It is run during Docker image build to ensure data is available immediately.
"""

import os
import sys
import requests
import logging

logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(levelname)s - %(message)s'
)
logger = logging.getLogger(__name__)

# Configuration
DATA_DIR = os.environ.get("GNOME_DATA_DIR", "/app/gnome_data")
PUBLIC_LINK = "https://storage.googleapis.com/"
BUCKET_NAME = "gdm_materials_discovery"

# Files to download
FILES_TO_DOWNLOAD = [
    # (folder, filename, description)
    ("gnome_data", "stable_materials_summary.csv", "GNoME stable materials summary (~120MB)"),
    ("external_data", "external_materials_summary.csv", "External reference data (~15MB)"),
    ("external_data", "mp_snapshot_summary.csv", "Materials Project snapshot (~10MB)"),
    ("gnome_data", "stable_materials_r2scan.csv", "r²SCAN validation data (~5MB)"),
]


def ensure_directory(path: str):
    """Ensure directory exists."""
    if not os.path.exists(path):
        os.makedirs(path, exist_ok=True)
        logger.info(f"Created directory: {path}")


def download_file(folder: str, filename: str, description: str) -> bool:
    """
    Download a file from Google Cloud Storage.
    
    Returns:
        True if successful, False otherwise
    """
    url = f"{PUBLIC_LINK}{BUCKET_NAME}/{folder}/{filename}"
    output_path = os.path.join(DATA_DIR, filename)
    
    # Skip if already exists
    if os.path.exists(output_path):
        size_mb = os.path.getsize(output_path) / (1024 * 1024)
        logger.info(f"[SKIP] {filename} already exists ({size_mb:.1f} MB)")
        return True
    
    logger.info(f"[DOWNLOAD] {description}")
    logger.info(f"  URL: {url}")
    
    try:
        response = requests.get(url, stream=True, timeout=300)
        response.raise_for_status()
        
        total_size = int(response.headers.get('content-length', 0))
        downloaded = 0
        
        with open(output_path, 'wb') as f:
            for chunk in response.iter_content(chunk_size=8192):
                f.write(chunk)
                downloaded += len(chunk)
                if total_size > 0:
                    progress = (downloaded / total_size) * 100
                    if downloaded % (1024 * 1024) < 8192:  # Log every ~1MB
                        logger.info(f"  Progress: {progress:.1f}%")
        
        size_mb = os.path.getsize(output_path) / (1024 * 1024)
        logger.info(f"  [OK] Downloaded {filename} ({size_mb:.1f} MB)")
        return True
        
    except requests.exceptions.RequestException as e:
        logger.error(f"  [FAILED] Error downloading {filename}: {e}")
        return False
    except Exception as e:
        logger.error(f"  [FAILED] Unexpected error: {e}")
        return False


def main():
    """Main download function."""
    logger.info("=" * 60)
    logger.info("GNoME Dataset Download Script")
    logger.info("=" * 60)
    logger.info(f"Data directory: {DATA_DIR}")
    
    # Ensure data directory exists
    ensure_directory(DATA_DIR)
    
    # Download all files
    success_count = 0
    total_count = len(FILES_TO_DOWNLOAD)
    
    for folder, filename, description in FILES_TO_DOWNLOAD:
        if download_file(folder, filename, description):
            success_count += 1
    
    # Summary
    logger.info("=" * 60)
    logger.info(f"Download complete: {success_count}/{total_count} files")
    
    if success_count >= 2:  # At least gnome_summary and external_summary
        logger.info("Core dataset is ready!")
        
        # List downloaded files
        logger.info("\nDownloaded files:")
        for f in os.listdir(DATA_DIR):
            filepath = os.path.join(DATA_DIR, f)
            if os.path.isfile(filepath):
                size_mb = os.path.getsize(filepath) / (1024 * 1024)
                logger.info(f"  - {f}: {size_mb:.1f} MB")
        
        return 0
    else:
        logger.error("Failed to download core dataset files!")
        return 1


if __name__ == "__main__":
    sys.exit(main())