#!/usr/bin/env python3
"""
5 Why Root Cause Analyzer - Application Launcher
Version: 1.0.0
Description: Python script to start both backend and frontend services
"""

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

class Color:
    """ANSI color codes for terminal output"""
    HEADER = '\033[95m'
    OKBLUE = '\033[94m'
    OKCYAN = '\033[96m'
    OKGREEN = '\033[92m'
    WARNING = '\033[93m'
    FAIL = '\033[91m'
    ENDC = '\033[0m'
    BOLD = '\033[1m'
    UNDERLINE = '\033[4m'

class AppLauncher:
    """Main application launcher class"""

    def __init__(self):
        self.project_root = Path(__file__).parent
        self.backend_process = None
        self.frontend_process = None
        self.is_windows = platform.system() == 'Windows'

    def print_banner(self):
        """Print application banner"""
        print(f"\n{Color.HEADER}{Color.BOLD}{'='*70}{Color.ENDC}")
        print(f"{Color.HEADER}{Color.BOLD}  5 Why Root Cause Analyzer - v1.0.0{Color.ENDC}")
        print(f"{Color.HEADER}{Color.BOLD}  Enterprise-grade Root Cause Analysis Tool{Color.ENDC}")
        print(f"{Color.HEADER}{Color.BOLD}{'='*70}{Color.ENDC}\n")

    def print_info(self, message):
        """Print info message"""
        print(f"{Color.OKBLUE}[INFO]{Color.ENDC} {message}")

    def print_success(self, message):
        """Print success message"""
        print(f"{Color.OKGREEN}[SUCCESS]{Color.ENDC} {message}")

    def print_warning(self, message):
        """Print warning message"""
        print(f"{Color.WARNING}[WARNING]{Color.ENDC} {message}")

    def print_error(self, message):
        """Print error message"""
        print(f"{Color.FAIL}[ERROR]{Color.ENDC} {message}")

    def check_node_installed(self):
        """Check if Node.js is installed"""
        try:
            result = subprocess.run(
                ['node', '--version'],
                capture_output=True,
                text=True,
                check=True
            )
            version = result.stdout.strip()
            self.print_success(f"Node.js detected: {version}")
            return True
        except (subprocess.CalledProcessError, FileNotFoundError):
            self.print_error("Node.js is not installed or not in PATH")
            self.print_info("Please install Node.js 18+ from https://nodejs.org/")
            return False

    def check_npm_installed(self):
        """Check if npm is installed"""
        try:
            result = subprocess.run(
                ['npm', '--version'],
                capture_output=True,
                text=True,
                check=True
            )
            version = result.stdout.strip()
            self.print_success(f"npm detected: {version}")
            return True
        except (subprocess.CalledProcessError, FileNotFoundError):
            self.print_error("npm is not installed or not in PATH")
            return False

    def check_dependencies_installed(self):
        """Check if node_modules exists"""
        node_modules = self.project_root / 'node_modules'
        if node_modules.exists():
            self.print_success("Dependencies installed (node_modules found)")
            return True
        else:
            self.print_warning("Dependencies not installed (node_modules not found)")
            self.print_info("Run 'npm install' to install dependencies")
            return False

    def check_env_file(self):
        """Check if .env file exists"""
        env_file = self.project_root / '.env'
        if env_file.exists():
            self.print_success("Environment file (.env) found")
            return True
        else:
            self.print_warning(".env file not found")
            self.print_info("Copy .env.example to .env and configure it")
            return False

    def start_backend(self):
        """Start the backend server"""
        self.print_info("Starting backend server...")

        try:
            # Use 'npm.cmd' on Windows, 'npm' on Unix
            npm_cmd = 'npm.cmd' if self.is_windows else 'npm'

            self.backend_process = subprocess.Popen(
                [npm_cmd, 'run', 'server'],
                cwd=str(self.project_root),
                stdout=subprocess.PIPE,
                stderr=subprocess.STDOUT,
                text=True,
                bufsize=1,
                universal_newlines=True,
                creationflags=subprocess.CREATE_NEW_PROCESS_GROUP if self.is_windows else 0
            )

            # Wait a bit and check if process started successfully
            time.sleep(2)

            if self.backend_process.poll() is None:
                self.print_success("Backend server started successfully")
                self.print_info("Backend running at: http://localhost:3001")
                return True
            else:
                self.print_error("Backend server failed to start")
                return False

        except Exception as e:
            self.print_error(f"Failed to start backend: {str(e)}")
            return False

    def start_frontend(self):
        """Start the frontend development server"""
        self.print_info("Starting frontend development server...")

        try:
            # Use 'npm.cmd' on Windows, 'npm' on Unix
            npm_cmd = 'npm.cmd' if self.is_windows else 'npm'

            self.frontend_process = subprocess.Popen(
                [npm_cmd, 'run', 'client'],
                cwd=str(self.project_root),
                stdout=subprocess.PIPE,
                stderr=subprocess.STDOUT,
                text=True,
                bufsize=1,
                universal_newlines=True,
                creationflags=subprocess.CREATE_NEW_PROCESS_GROUP if self.is_windows else 0
            )

            # Wait a bit and check if process started successfully
            time.sleep(3)

            if self.frontend_process.poll() is None:
                self.print_success("Frontend server started successfully")
                self.print_info("Frontend running at: http://localhost:5173")
                return True
            else:
                self.print_error("Frontend server failed to start")
                return False

        except Exception as e:
            self.print_error(f"Failed to start frontend: {str(e)}")
            return False

    def monitor_processes(self):
        """Monitor both processes and print their output"""
        self.print_info("\n" + "="*70)
        self.print_success("Both services are running!")
        self.print_info("="*70)
        print(f"\n{Color.OKGREEN}{Color.BOLD}Access the application:{Color.ENDC}")
        print(f"  {Color.OKCYAN}Frontend:{Color.ENDC} http://localhost:5173")
        print(f"  {Color.OKCYAN}Backend API:{Color.ENDC} http://localhost:3001")
        print(f"  {Color.OKCYAN}API Health:{Color.ENDC} http://localhost:3001/health")
        print(f"\n{Color.OKGREEN}{Color.BOLD}Test Accounts:{Color.ENDC}")
        print(f"  {Color.OKCYAN}Admin:{Color.ENDC} admin@example.com / Admin@123456")
        print(f"  {Color.OKCYAN}User1:{Color.ENDC} user001@example.com / User@123456")
        print(f"  {Color.OKCYAN}User2:{Color.ENDC} user002@example.com / User@123456")
        print(f"\n{Color.WARNING}Press Ctrl+C to stop all services{Color.ENDC}\n")

        try:
            # Keep the script running and monitor processes
            while True:
                # Check if backend is still running
                if self.backend_process.poll() is not None:
                    self.print_error("Backend process terminated unexpectedly")
                    break

                # Check if frontend is still running
                if self.frontend_process.poll() is not None:
                    self.print_error("Frontend process terminated unexpectedly")
                    break

                time.sleep(1)

        except KeyboardInterrupt:
            self.print_info("\nReceived shutdown signal...")

    def cleanup(self):
        """Clean up and terminate all processes"""
        self.print_info("Shutting down services...")

        # Terminate frontend
        if self.frontend_process and self.frontend_process.poll() is None:
            try:
                if self.is_windows:
                    # On Windows, use taskkill to terminate process tree
                    subprocess.run(
                        ['taskkill', '/F', '/T', '/PID', str(self.frontend_process.pid)],
                        capture_output=True
                    )
                else:
                    self.frontend_process.terminate()
                    self.frontend_process.wait(timeout=5)
                self.print_success("Frontend server stopped")
            except Exception as e:
                self.print_warning(f"Error stopping frontend: {str(e)}")

        # Terminate backend
        if self.backend_process and self.backend_process.poll() is None:
            try:
                if self.is_windows:
                    # On Windows, use taskkill to terminate process tree
                    subprocess.run(
                        ['taskkill', '/F', '/T', '/PID', str(self.backend_process.pid)],
                        capture_output=True
                    )
                else:
                    self.backend_process.terminate()
                    self.backend_process.wait(timeout=5)
                self.print_success("Backend server stopped")
            except Exception as e:
                self.print_warning(f"Error stopping backend: {str(e)}")

        self.print_success("All services stopped successfully")

    def run(self):
        """Main run method"""
        self.print_banner()

        # Pre-flight checks
        self.print_info("Running pre-flight checks...")

        if not self.check_node_installed():
            return 1

        if not self.check_npm_installed():
            return 1

        if not self.check_dependencies_installed():
            self.print_warning("Please run 'npm install' first")
            return 1

        if not self.check_env_file():
            self.print_warning("Please configure .env file first")
            return 1

        self.print_success("All pre-flight checks passed!\n")

        # Start services
        if not self.start_backend():
            self.cleanup()
            return 1

        time.sleep(2)  # Give backend time to start

        if not self.start_frontend():
            self.cleanup()
            return 1

        # Monitor processes
        try:
            self.monitor_processes()
        finally:
            self.cleanup()

        return 0

def main():
    """Main entry point"""
    launcher = AppLauncher()

    try:
        sys.exit(launcher.run())
    except Exception as e:
        print(f"\n{Color.FAIL}[FATAL ERROR]{Color.ENDC} {str(e)}")
        launcher.cleanup()
        sys.exit(1)

if __name__ == '__main__':
    main()