#!/usr/bin/env python3
"""
ATOM Platform Backend Startup Script
Simplified, reliable startup with proper error handling
"""

import os
from pathlib import Path
import signal
import subprocess
import sys
import time


def check_python_version():
    """Check if Python version is compatible"""
    if sys.version_info < (3, 8):
        print("❌ Python 3.8 or higher is required")
        print(f"   Current version: {sys.version}")
        return False
    print(f"✅ Python version: {sys.version.split()[0]}")
    return True

def check_required_packages():
    """Check if required packages are installed"""
    required_packages = [
        'fastapi',
        'uvicorn',
        'requests',
        'pydantic'
    ]
    
    missing_packages = []
    for package in required_packages:
        try:
            __import__(package)
        except ImportError:
            missing_packages.append(package)
    
    if missing_packages:
        print("❌ Missing required packages:")
        for package in missing_packages:
            print(f"   - {package}")
        print("\nInstall with: pip install fastapi uvicorn requests pydantic")
        return False
    
    print("✅ Required packages installed")
    return True

def check_environment():
    """Check environment variables"""
    env_vars = {
        'DATABASE_URL': 'sqlite:///atom_data.db',
        'SECRET_KEY': 'atom-dev-secret-key',
        'DEBUG': 'true'
    }
    
    for var, default in env_vars.items():
        if not os.getenv(var):
            os.environ[var] = default
    
    print("✅ Environment variables configured")
    return True

def setup_directories():
    """Create necessary directories"""
    directories = [
        './data',
        './data/atom_memory',
        './logs',
        './temp'
    ]
    
    for directory in directories:
        Path(directory).mkdir(parents=True, exist_ok=True)
    
    print("✅ Directories created")
    return True

def check_backend_file():
    """Check if main backend file exists"""
    backend_file = './main_api_app.py'
    if not Path(backend_file).exists():
        print(f"❌ Backend file not found: {backend_file}")
        return False
    print("✅ Backend file found")
    return True

def start_backend():
    """Start the backend server"""
    print("\n🚀 Starting ATOM Backend...")
    
    # Import after checking dependencies
    try:
        from main_api_app import app
        import uvicorn

        # Configuration
        host = os.getenv('HOST', '0.0.0.0')
        port = int(os.getenv('PORT', '5058'))
        debug = os.getenv('DEBUG', 'false').lower() == 'true'
        
        print(f"   Host: {host}")
        print(f"   Port: {port}")
        print(f"   Debug: {debug}")
        
        # Start server
        config = uvicorn.Config(
            app=app,
            host=host,
            port=port,
            log_level="info" if not debug else "debug",
            reload=debug
        )
        
        server = uvicorn.Server(config)
        
        # Setup signal handlers
        def signal_handler(sig, frame):
            print("\n🛑 Shutting down backend...")
            server.should_exit = True
        
        signal.signal(signal.SIGINT, signal_handler)
        signal.signal(signal.SIGTERM, signal_handler)
        
        print(f"✅ Backend starting at http://{host}:{port}")
        print("   API Documentation: http://{host}:{port}/docs")
        print("   Press Ctrl+C to stop")
        
        server.run()
        
    except ImportError as e:
        print(f"❌ Failed to import backend: {e}")
        return False
    except Exception as e:
        print(f"❌ Failed to start backend: {e}")
        return False
    
    return True

def show_startup_info():
    """Show startup information"""
    print("\n🔧 ATOM Platform Backend")
    print("=" * 40)
    print("📍 Current Directory: {}".format(os.getcwd()))
    print("🐍 Python Path: {}".format(sys.executable))
    
    # Show config info
    db_url = os.getenv('DATABASE_URL', 'sqlite:///atom_data.db')
    port = os.getenv('PORT', '5058')
    debug = os.getenv('DEBUG', 'false')
    
    print("⚙️  Configuration:")
    print(f"   Database: {db_url}")
    print(f"   Port: {port}")
    print(f"   Debug: {debug}")

def main():
    """Main startup function"""
    print("🌟 ATOM Platform Backend Starting...")
    
    # Pre-startup checks
    checks = [
        ("Python Version", check_python_version),
        ("Required Packages", check_required_packages),
        ("Environment", check_environment),
        ("Directories", setup_directories),
        ("Backend File", check_backend_file)
    ]
    
    all_passed = True
    for check_name, check_func in checks:
        print(f"\n🔍 Checking {check_name}...")
        if not check_func():
            all_passed = False
            break
    
    if not all_passed:
        print("\n❌ Startup checks failed. Please fix the issues above.")
        sys.exit(1)
    
    # Show startup info
    show_startup_info()
    
    # Start backend
    if not start_backend():
        print("\n❌ Backend startup failed.")
        sys.exit(1)
    
    print("\n✅ Backend stopped gracefully.")

if __name__ == "__main__":
    main()