"""
Flask Application for People Counter Web App
Provides video streaming and real-time count updates via WebSocket.
"""

from flask import Flask, render_template, Response
from flask_socketio import SocketIO, emit
import time
import threading
from camera import Camera

app = Flask(__name__)
app.config['SECRET_KEY'] = 'people-counter-secret-key'
socketio = SocketIO(app, cors_allowed_origins="*")

# Global camera instance
camera = None
count_update_interval = 0.5  # Update counts every 0.5 seconds


def initialize_camera():
    """Initialize the camera."""
    global camera
    try:
        camera = Camera(camera_index=0, process_every_n_frames=3)
        camera.start()
        print("Camera initialized successfully")
        return True
    except Exception as e:
        print(f"Failed to initialize camera: {e}")
        return False


def count_update_thread():
    """Background thread to periodically send count updates via WebSocket."""
    while True:
        time.sleep(count_update_interval)
        if camera:
            counts = camera.get_counts()
            socketio.emit('count_update', counts)
        else:
            # Send zero counts if camera not available
            socketio.emit('count_update', {
                'total_entered': 0,
                'total_exited': 0,
                'current_occupancy': 0
            })


@app.route('/')
def index():
    """Serve the main page."""
    return render_template('index.html')


def generate_frames():
    """Generator function for MJPEG video streaming."""
    while True:
        if camera:
            frame = camera.get_frame()
            if frame:
                yield (b'--frame\r\n'
                       b'Content-Type: image/jpeg\r\n\r\n' + frame + b'\r\n')
            else:
                time.sleep(0.1)
        else:
            time.sleep(0.1)


@app.route('/video_feed')
def video_feed():
    """Video streaming route."""
    return Response(generate_frames(),
                    mimetype='multipart/x-mixed-replace; boundary=frame')


@socketio.on('connect')
def handle_connect():
    """Handle WebSocket connection."""
    print('Client connected')
    if camera:
        counts = camera.get_counts()
        emit('count_update', counts)


@socketio.on('disconnect')
def handle_disconnect():
    """Handle WebSocket disconnection."""
    print('Client disconnected')


@socketio.on('reset_counts')
def handle_reset_counts():
    """Handle reset counts request."""
    if camera:
        camera.reset_counts()
        counts = camera.get_counts()
        emit('count_update', counts)
        emit('reset_confirmation', {'status': 'success'})


if __name__ == '__main__':
    # Initialize camera
    if initialize_camera():
        # Start background thread for count updates
        update_thread = threading.Thread(target=count_update_thread, daemon=True)
        update_thread.start()
        
        # Run Flask app
        try:
            socketio.run(app, host='0.0.0.0', port=5000, debug=False, allow_unsafe_werkzeug=True)
        except KeyboardInterrupt:
            print("\nShutting down...")
        finally:
            if camera:
                camera.stop()
    else:
        print("Failed to initialize camera. Exiting.")