"""
Database restore script from R2 storage
Downloads compressed backup from R2 and restores to PostgreSQL
"""
import os
import subprocess
import gzip
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")

# Restore directory
RESTORE_DIR = Path(__file__).parent / "restores"
RESTORE_DIR.mkdir(exist_ok=True)


def list_r2_backups():
    """List all available backups in 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'),
        region_name='auto'
    )
    
    try:
        response = s3_client.list_objects_v2(Bucket=R2_BUCKET)
        
        if 'Contents' not in response:
            return []
        
        backups = sorted(response['Contents'], key=lambda x: x['LastModified'], reverse=True)
        return backups
        
    except Exception as e:
        print(f"✗ Error listing backups: {e}")
        return []


def download_from_r2(backup_name):
    """Download backup file from R2"""
    local_file = RESTORE_DIR / backup_name
    
    print(f"Downloading {backup_name} from 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'),
        region_name='auto'
    )
    
    try:
        s3_client.download_file(R2_BUCKET, backup_name, str(local_file))
        size_mb = local_file.stat().st_size / (1024 * 1024)
        print(f"✓ Downloaded: {local_file.name} ({size_mb:.2f} MB)")
        return local_file
    except Exception as e:
        print(f"✗ Error downloading from R2: {e}")
        raise


def decompress_file(compressed_file):
    """Decompress gzip file"""
    decompressed_file = Path(str(compressed_file).replace('.gz', ''))
    
    print(f"Decompressing {compressed_file.name}...")
    
    with gzip.open(compressed_file, 'rb') as f_in:
        with open(decompressed_file, 'wb') as f_out:
            f_out.write(f_in.read())
    
    compressed_size = compressed_file.stat().st_size
    decompressed_size = decompressed_file.stat().st_size
    
    print(f"✓ Decompressed to {decompressed_file.name}")
    print(f"  Compressed: {compressed_size / 1024:.2f} KB")
    print(f"  Decompressed: {decompressed_size / 1024:.2f} KB")
    
    return decompressed_file


def restore_database(sql_file):
    """Restore PostgreSQL database from SQL file"""
    print(f"\nRestoring database from {sql_file.name}...")
    print("WARNING: This will overwrite the current database!")
    
    response = input("Are you sure you want to continue? (yes/no): ")
    if response.lower() != 'yes':
        print("Restore cancelled")
        return False
    
    # Set PGPASSWORD environment variable
    env = os.environ.copy()
    env['PGPASSWORD'] = DB_PASSWORD
    
    # Drop and recreate database (optional, comment out if you want to merge)
    print("Dropping existing tables...")
    drop_cmd = [
        "psql",
        "-h", DB_HOST,
        "-p", DB_PORT,
        "-U", DB_USER,
        "-d", DB_NAME,
        "-c", "DROP SCHEMA public CASCADE; CREATE SCHEMA public;"
    ]
    
    try:
        subprocess.run(drop_cmd, env=env, check=True, capture_output=True, text=True)
    except subprocess.CalledProcessError as e:
        print(f"Warning: Could not drop schema: {e.stderr}")
    
    # Restore from backup
    print("Restoring database...")
    restore_cmd = [
        "psql",
        "-h", DB_HOST,
        "-p", DB_PORT,
        "-U", DB_USER,
        "-d", DB_NAME,
        "-f", str(sql_file)
    ]
    
    try:
        subprocess.run(restore_cmd, env=env, check=True, capture_output=True, text=True)
        print("✓ Database restored successfully!")
        return True
    except subprocess.CalledProcessError as e:
        print(f"✗ Error restoring database: {e.stderr}")
        raise


def main():
    """Main restore process"""
    print("=" * 60)
    print("Database Restore from 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")
        
        # List available backups
        print("Available backups:")
        backups = list_r2_backups()
        
        if not backups:
            print("No backups found in R2")
            return
        
        for i, backup in enumerate(backups, 1):
            size_mb = backup['Size'] / (1024 * 1024)
            print(f"{i}. {backup['Key']}")
            print(f"   Size: {size_mb:.2f} MB, Date: {backup['LastModified']}")
            print()
        
        # Select backup
        choice = input(f"Select backup to restore (1-{len(backups)}) or 'q' to quit: ")
        
        if choice.lower() == 'q':
            print("Restore cancelled")
            return
        
        try:
            backup_index = int(choice) - 1
            if backup_index < 0 or backup_index >= len(backups):
                raise ValueError()
        except ValueError:
            print("Invalid selection")
            return
        
        selected_backup = backups[backup_index]['Key']
        
        # Download backup
        compressed_file = download_from_r2(selected_backup)
        
        # Decompress backup
        sql_file = decompress_file(compressed_file)
        
        # Restore database
        restore_database(sql_file)
        
        print("\n" + "=" * 60)
        print("✓ Restore completed successfully!")
        print("=" * 60)
        
    except Exception as e:
        print("\n" + "=" * 60)
        print(f"✗ Restore failed: {e}")
        print("=" * 60)
        raise


if __name__ == "__main__":
    main()