"""
Database backup script for R2 storage
Exports PostgreSQL database, compresses it, and uploads to Cloudflare R2
"""
import os
import subprocess
import gzip
import shutil
from datetime import datetime
from pathlib import Path
import boto3
from botocore.config import Config
from dotenv import load_dotenv

# Load environment variables
load_dotenv()

# R2 Configuration
R2_ENDPOINT = os.getenv("R2_ENDPOINT")
R2_ACCESS_KEY = os.getenv("R2_ACCESS_KEY")
R2_SECRET_KEY = os.getenv("R2_SECRET_KEY")
R2_BUCKET = os.getenv("R2_BUCKET")

# Database Configuration
DB_HOST = os.getenv("DB_HOST", "localhost")
DB_PORT = os.getenv("DB_PORT", "5432")
DB_NAME = os.getenv("DB_NAME", "recipes_db")
DB_USER = os.getenv("DB_USER", "recipes_user")
DB_PASSWORD = os.getenv("DB_PASSWORD", "recipes_password")

# Backup directory
BACKUP_DIR = Path(__file__).parent / "backups"
BACKUP_DIR.mkdir(exist_ok=True)


def create_db_dump():
    """Create PostgreSQL database dump"""
    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
    dump_file = BACKUP_DIR / f"recipes_db_{timestamp}.sql"
    
    print(f"Creating database dump: {dump_file}")
    
    # Set PGPASSWORD environment variable for pg_dump
    env = os.environ.copy()
    env['PGPASSWORD'] = DB_PASSWORD
    
    # Run pg_dump
    cmd = [
        "pg_dump",
        "-h", DB_HOST,
        "-p", DB_PORT,
        "-U", DB_USER,
        "-d", DB_NAME,
        "-f", str(dump_file),
        "--no-owner",  # Don't include ownership commands
        "--no-acl",    # Don't include access privileges
    ]
    
    try:
        subprocess.run(cmd, env=env, check=True, capture_output=True, text=True)
        print(f"✓ Database dump created: {dump_file}")
        return dump_file
    except subprocess.CalledProcessError as e:
        print(f"✗ Error creating database dump: {e.stderr}")
        raise


def compress_file(file_path):
    """Compress file using gzip"""
    compressed_file = Path(str(file_path) + ".gz")
    
    print(f"Compressing {file_path.name}...")
    
    with open(file_path, 'rb') as f_in:
        with gzip.open(compressed_file, 'wb', compresslevel=9) as f_out:
            shutil.copyfileobj(f_in, f_out)
    
    # Remove uncompressed file
    file_path.unlink()
    
    # Get compression ratio
    original_size = file_path.stat().st_size if file_path.exists() else 0
    compressed_size = compressed_file.stat().st_size
    ratio = (1 - compressed_size / max(original_size, 1)) * 100 if original_size > 0 else 0
    
    print(f"✓ Compressed to {compressed_file.name}")
    print(f"  Original: {original_size / 1024:.2f} KB")
    print(f"  Compressed: {compressed_size / 1024:.2f} KB")
    print(f"  Ratio: {ratio:.1f}% reduction")
    
    return compressed_file


def upload_to_r2(file_path):
    """Upload file to Cloudflare R2"""
    print(f"Uploading {file_path.name} to R2...")
    
    # Configure S3 client for R2
    s3_client = boto3.client(
        's3',
        endpoint_url=R2_ENDPOINT,
        aws_access_key_id=R2_ACCESS_KEY,
        aws_secret_access_key=R2_SECRET_KEY,
        config=Config(
            signature_version='s3v4',
            s3={'addressing_style': 'path'}
        )
    )
    
    # Upload file
    try:
        s3_client.upload_file(
            str(file_path),
            R2_BUCKET,
            file_path.name,
            ExtraArgs={
                'Metadata': {
                    'backup-date': datetime.now().isoformat(),
                    'db-name': DB_NAME,
                }
            }
        )
        print(f"✓ Uploaded to R2: s3://{R2_BUCKET}/{file_path.name}")
        return True
    except Exception as e:
        print(f"✗ Error uploading to R2: {e}")
        raise


def list_r2_backups():
    """List all backups in R2 bucket"""
    print(f"\nListing backups in R2 bucket: {R2_BUCKET}")
    
    s3_client = boto3.client(
        's3',
        endpoint_url=R2_ENDPOINT,
        aws_access_key_id=R2_ACCESS_KEY,
        aws_secret_access_key=R2_SECRET_KEY,
        config=Config(
            signature_version='s3v4',
            s3={'addressing_style': 'path'}
        )
    )
    
    try:
        response = s3_client.list_objects_v2(Bucket=R2_BUCKET)
        
        if 'Contents' not in response:
            print("No backups found")
            return
        
        print(f"\nFound {len(response['Contents'])} backup(s):")
        for obj in sorted(response['Contents'], key=lambda x: x['LastModified'], reverse=True):
            size_mb = obj['Size'] / (1024 * 1024)
            print(f"  - {obj['Key']}")
            print(f"    Size: {size_mb:.2f} MB")
            print(f"    Date: {obj['LastModified']}")
            
    except Exception as e:
        print(f"✗ Error listing backups: {e}")


def cleanup_old_local_backups(keep_last=3):
    """Keep only the last N local backups"""
    backups = sorted(BACKUP_DIR.glob("*.sql.gz"), key=lambda x: x.stat().st_mtime, reverse=True)
    
    if len(backups) > keep_last:
        print(f"\nCleaning up old local backups (keeping last {keep_last})...")
        for backup in backups[keep_last:]:
            print(f"  Removing: {backup.name}")
            backup.unlink()


def main():
    """Main backup process"""
    print("=" * 60)
    print("Database Backup to Cloudflare R2")
    print("=" * 60)
    print()
    
    try:
        # Verify R2 credentials
        if not all([R2_ENDPOINT, R2_ACCESS_KEY, R2_SECRET_KEY, R2_BUCKET]):
            raise ValueError("Missing R2 credentials in environment variables")
        
        # Create database dump
        dump_file = create_db_dump()
        
        # Compress the dump
        compressed_file = compress_file(dump_file)
        
        # Upload to R2
        upload_to_r2(compressed_file)
        
        # List all backups
        list_r2_backups()
        
        # Cleanup old local backups
        cleanup_old_local_backups(keep_last=3)
        
        print("\n" + "=" * 60)
        print("✓ Backup completed successfully!")
        print("=" * 60)
        
    except Exception as e:
        print("\n" + "=" * 60)
        print(f"✗ Backup failed: {e}")
        print("=" * 60)
        raise


if __name__ == "__main__":
    main()