import json
import threading
from http.server import HTTPServer, BaseHTTPRequestHandler
from datetime import datetime, timezone
import logging

from config import HEALTH_CHECK_PORT, HEALTH_CHECK_ENABLED

class HealthCheckHandler(BaseHTTPRequestHandler):
    def do_GET(self):
        if self.path == '/health':
            self.send_health_response()
        elif self.path == '/sensors':
            self.send_sensors_status()
        else:
            self.send_response(404)
            self.end_headers()

    def send_health_response(self):
        """Send basic health check response"""
        health_data = {
            "status": "healthy",
            "timestamp": datetime.now(timezone.utc).isoformat(),
            "service": "modbus-mqtt-bridge",
            "version": "1.0.0"
        }
        
        self.send_response(200)
        self.send_header('Content-type', 'application/json')
        self.end_headers()
        self.wfile.write(json.dumps(health_data, indent=2).encode())

    def send_sensors_status(self):
        """Send detailed sensor status"""
        # Get sensor status from the global sensor tracker
        from sensor_tracker import get_all_sensor_status
        
        sensors_status = get_all_sensor_status()
        
        self.send_response(200)
        self.send_header('Content-type', 'application/json')
        self.end_headers()
        self.wfile.write(json.dumps(sensors_status, indent=2).encode())

    def log_message(self, format, *args):
        """Override to use our logging system"""
        logging.info(f"Health Check - {format % args}")

class HealthCheckServer:
    def __init__(self, port=HEALTH_CHECK_PORT):
        self.port = port
        self.server = None
        self.thread = None

    def start(self):
        """Start the health check server in a separate thread"""
        if not HEALTH_CHECK_ENABLED:
            logging.info("Health check server is disabled")
            return

        try:
            # Bind to all interfaces to make it accessible from outside container
            self.server = HTTPServer(('0.0.0.0', self.port), HealthCheckHandler)
            self.thread = threading.Thread(target=self.server.serve_forever, daemon=True)
            self.thread.start()
            logging.info(f"Health check server started on 0.0.0.0:{self.port}")
            logging.info(f"Health check endpoints:")
            logging.info(f"  - http://0.0.0.0:{self.port}/health")
            logging.info(f"  - http://0.0.0.0:{self.port}/sensors")
        except Exception as e:
            logging.error(f"Failed to start health check server: {e}")
            raise e  # Re-raise to make the issue visible

    def stop(self):
        """Stop the health check server"""
        if self.server:
            self.server.shutdown()
            self.server.server_close()
            logging.info("Health check server stopped")