import os
import uuid
import cv2
import numpy as np
from threading import Event, Lock
from flask import (
    Flask,
    render_template,
    Response,
    request,
    redirect,
    url_for,
    send_from_directory,
    session,
    jsonify,
    abort,
)
from werkzeug.utils import secure_filename
from ultralytics import YOLO

app = Flask(__name__)
app.secret_key = os.environ.get('SECRET_KEY', 'vehicle_dev_secret')
app.config['MAX_CONTENT_LENGTH'] = 200 * 1024 * 1024  # 200MB upload cap

# Load the YOLOv8 model
model = YOLO("yolo11s.pt")
names = model.model.names

# Vehicle classes to count
VEHICLE_CLASSES = {'car', 'truck', 'bus', 'motorcycle'}
ALLOWED_EXTENSIONS = {'mp4', 'mov', 'avi', 'mkv'}
UPLOAD_DIR = 'uploads'

# Track reset events per stream (webcam/video per session)
reset_events: dict[str, Event] = {}
reset_lock = Lock()


def allowed_file(filename: str) -> bool:
    return '.' in filename and filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS


def ensure_upload_dir() -> None:
    if not os.path.exists(UPLOAD_DIR):
        os.makedirs(UPLOAD_DIR)


def get_line_from_session():
    if 'counting_line' not in session:
        session['counting_line'] = {'x1': 0, 'y1': 300, 'x2': 1020, 'y2': 300}
    return session['counting_line']


def fresh_vehicle_counts() -> dict[str, int]:
    return {vehicle: 0 for vehicle in VEHICLE_CLASSES}


def get_reset_event(stream_id: str) -> Event:
    with reset_lock:
        event = reset_events.get(stream_id)
        if event is None:
            event = Event()
            reset_events[stream_id] = event
        return event


def release_reset_event(stream_id: str) -> None:
    with reset_lock:
        reset_events.pop(stream_id, None)


def get_webcam_stream_id() -> str:
    stream_id = session.get('webcam_stream_id')
    if not stream_id:
        stream_id = f'webcam-{uuid.uuid4().hex}'
        session['webcam_stream_id'] = stream_id
    return stream_id


def get_video_stream_id(filename: str) -> str:
    video_streams = session.get('video_stream_ids', {})
    stream_id = video_streams.get(filename)
    if not stream_id:
        stream_id = f'video-{uuid.uuid4().hex}'
        video_streams[filename] = stream_id
        session['video_stream_ids'] = video_streams
    return stream_id

# Helper function to check if two line segments intersect
def line_intersect(p1, p2, p3, p4):
    """
    Check if line segment p1-p2 intersects with line segment p3-p4
    Returns True if they intersect, False otherwise
    """
    x1, y1 = p1
    x2, y2 = p2
    x3, y3 = p3
    x4, y4 = p4

    denom = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4)
    if abs(denom) < 1e-10:
        return False

    t = ((x1 - x3) * (y3 - y4) - (y1 - y3) * (x3 - x4)) / denom
    u = -((x1 - x2) * (y1 - y3) - (y1 - y2) * (x1 - x3)) / denom

    return 0 <= t <= 1 and 0 <= u <= 1

def crossed_line(prev_pos, curr_pos, line_start, line_end):
    """
    Check if movement from prev_pos to curr_pos crossed the line.
    Uses orientation check - more robust for frame skipping.
    """
    # Check if the two line segments intersect
    if line_intersect(prev_pos, curr_pos, line_start, line_end):
        return True
    return False


def generate_frames(capture, line_data, stream_id: str):
    """
    Shared frame generator for webcam and uploaded videos.
    Handles detection, drawing overlays, and reset events.
    """
    track_positions = {}
    counted_ids = set()
    vehicle_count = 0
    vehicle_type_counts = fresh_vehicle_counts()
    line_start = (line_data['x1'], line_data['y1'])
    line_end = (line_data['x2'], line_data['y2'])
    frame_idx = 0
    reset_event = get_reset_event(stream_id)

    try:
        while True:
            ret, frame = capture.read()
            if not ret:
                break

            frame_idx += 1
            if frame_idx % 2 != 0:
                continue

            if reset_event.is_set():
                track_positions.clear()
                counted_ids.clear()
                vehicle_count = 0
                vehicle_type_counts = fresh_vehicle_counts()
                reset_event.clear()

            frame = cv2.resize(frame, (1020, 600))
            results = model.track(frame, persist=True)

            if results and results[0].boxes is not None and results[0].boxes.id is not None:
                boxes = results[0].boxes.xyxy.int().cpu().tolist()
                class_ids = results[0].boxes.cls.int().cpu().tolist()
                track_ids = results[0].boxes.id.int().cpu().tolist()

                for box, class_id, track_id in zip(boxes, class_ids, track_ids):
                    label_name = names[class_id]
                    x1, y1, x2, y2 = box
                    center_x = (x1 + x2) // 2
                    center_y = (y1 + y2) // 2

                    if label_name in VEHICLE_CLASSES:
                        if track_id in track_positions and track_id not in counted_ids:
                            prev_x, prev_y = track_positions[track_id]
                            cv2.line(frame, (prev_x, prev_y), (center_x, center_y), (255, 100, 0), 2)

                            if crossed_line((prev_x, prev_y), (center_x, center_y), line_start, line_end):
                                counted_ids.add(track_id)
                                vehicle_count += 1
                                vehicle_type_counts[label_name] += 1
                                cv2.circle(frame, (center_x, center_y), 25, (0, 255, 0), 5)

                        track_positions[track_id] = (center_x, center_y)

                    box_color = (0, 255, 0) if label_name in VEHICLE_CLASSES else (255, 0, 0)
                    cv2.rectangle(frame, (x1, y1), (x2, y2), box_color, 2)

                    label = f'{track_id} - {label_name}'
                    if track_id in counted_ids:
                        label += ' ✓'
                    cv2.putText(frame, label, (x1, y1 - 10), cv2.FONT_HERSHEY_SIMPLEX, 0.5, (255, 0, 255), 1)
                    cv2.circle(frame, (center_x, center_y), 3, (0, 255, 255), -1)

            cv2.line(frame, line_start, line_end, (0, 255, 255), 3, cv2.LINE_AA)
            line_length = int(np.sqrt((line_end[0] - line_start[0]) ** 2 + (line_end[1] - line_start[1]) ** 2))
            dash_length = 20
            for i in range(0, max(line_length, 1), dash_length * 2):
                t1 = i / line_length if line_length else 0
                t2 = min((i + dash_length) / line_length, 1.0) if line_length else 0
                x1_dash = int(line_start[0] + t1 * (line_end[0] - line_start[0]))
                y1_dash = int(line_start[1] + t1 * (line_end[1] - line_start[1]))
                x2_dash = int(line_start[0] + t2 * (line_end[0] - line_start[0]))
                y2_dash = int(line_start[1] + t2 * (line_end[1] - line_start[1]))
                cv2.line(frame, (x1_dash, y1_dash), (x2_dash, y2_dash), (0, 0, 0), 3)

            cv2.rectangle(frame, (10, 10), (350, 140), (0, 0, 0), -1)
            cv2.putText(frame, f'Gesamt: {vehicle_count}', (20, 35), cv2.FONT_HERSHEY_SIMPLEX, 0.7, (255, 255, 255), 2)
            cv2.putText(frame, f"Autos: {vehicle_type_counts.get('car', 0)}", (20, 65), cv2.FONT_HERSHEY_SIMPLEX, 0.6, (200, 200, 200), 1)
            cv2.putText(frame, f"LKW: {vehicle_type_counts.get('truck', 0)}", (20, 90), cv2.FONT_HERSHEY_SIMPLEX, 0.6, (200, 200, 200), 1)
            cv2.putText(frame, f"Busse: {vehicle_type_counts.get('bus', 0)}", (20, 115), cv2.FONT_HERSHEY_SIMPLEX, 0.6, (200, 200, 200), 1)
            cv2.putText(frame, f"Motorraeder: {vehicle_type_counts.get('motorcycle', 0)}", (20, 135), cv2.FONT_HERSHEY_SIMPLEX, 0.5, (200, 200, 200), 1)

            _, buffer = cv2.imencode('.jpg', frame)
            frame_bytes = buffer.tobytes()

            yield (b'--frame\r\n'
                   b'Content-Type: image/jpeg\r\n\r\n' + frame_bytes + b'\r\n')
    finally:
        capture.release()
        release_reset_event(stream_id)

@app.route('/')
def index():
    return render_template('index.html')

@app.route('/start_webcam')
def start_webcam():
    get_line_from_session()
    stream_id = get_webcam_stream_id()
    return render_template('webcam.html', stream_id=stream_id)

@app.route('/api/set_line', methods=['POST'])
def set_counting_line():
    """API endpoint to set the counting line coordinates"""
    data = request.get_json(silent=True) or {}
    try:
        session['counting_line'] = {
            'x1': int(data['x1']),
            'y1': int(data['y1']),
            'x2': int(data['x2']),
            'y2': int(data['y2'])
        }
    except (KeyError, ValueError, TypeError):
        abort(400, description='Ungültige Linienkoordinaten')
    return jsonify({'status': 'success', 'line': session['counting_line']})

@app.route('/api/get_line', methods=['GET'])
def get_counting_line():
    """API endpoint to get the current counting line coordinates"""
    return jsonify(get_line_from_session())

@app.route('/api/reset_count', methods=['POST'])
def reset_count():
    """API endpoint to reset the vehicle count for a stream"""
    data = request.get_json(silent=True) or {}
    stream_id = data.get('stream_id')
    if not stream_id:
        abort(400, description='stream_id ist erforderlich')
    valid_ids = {session.get('webcam_stream_id')}
    valid_ids.update(session.get('video_stream_ids', {}).values())
    valid_ids.discard(None)
    if stream_id not in valid_ids:
        abort(403, description='Stream gehört nicht zur aktuellen Sitzung')
    event = get_reset_event(stream_id)
    event.set()
    return jsonify({'status': 'success', 'message': 'Zähler wird zurückgesetzt'})

def detect_objects_from_webcam(line_data, stream_id):
    cap = cv2.VideoCapture(0)  # 0 for the default webcam
    if not cap.isOpened():
        cap.release()
        raise RuntimeError('Webcam konnte nicht geöffnet werden')
    return generate_frames(cap, line_data, stream_id)

@app.route('/webcam_feed')
def webcam_feed():
    line_data = get_line_from_session()
    stream_id = get_webcam_stream_id()
    try:
        generator = detect_objects_from_webcam(line_data, stream_id)
    except RuntimeError as exc:
        abort(503, description=str(exc))
    return Response(generator,
                    mimetype='multipart/x-mixed-replace; boundary=frame')

@app.route('/upload', methods=['POST'])
def upload_video():
    if 'file' not in request.files:
        abort(400, description='Keine Datei erhalten')

    file = request.files['file']
    if not file or file.filename == '':
        abort(400, description='Keine Datei ausgewählt')

    filename = secure_filename(file.filename)
    if not filename:
        abort(400, description='Ungültiger Dateiname')
    if not allowed_file(filename):
        abort(400, description='Ungültiger Dateityp')

    ensure_upload_dir()
    name, ext = os.path.splitext(filename)
    stored_filename = f"{name}_{uuid.uuid4().hex}{ext.lower()}"
    file_path = os.path.join(UPLOAD_DIR, stored_filename)
    file.save(file_path)

    return redirect(url_for('play_video', filename=stored_filename))

@app.route('/uploads/<filename>')
def play_video(filename):
    safe_filename = os.path.basename(filename)
    if safe_filename != filename:
        abort(400, description='Ungültiger Dateiname')
    file_path = os.path.join(UPLOAD_DIR, safe_filename)
    if not os.path.isfile(file_path):
        abort(404)
    get_line_from_session()
    stream_id = get_video_stream_id(safe_filename)
    return render_template('play_video.html', filename=safe_filename, stream_id=stream_id)

@app.route('/video/<path:filename>')
def send_video(filename):
    return send_from_directory(UPLOAD_DIR, filename)

def detect_objects_from_video(video_path, line_data, stream_id):
    cap = cv2.VideoCapture(video_path)
    if not cap.isOpened():
        cap.release()
        raise RuntimeError('Video konnte nicht geöffnet werden')
    return generate_frames(cap, line_data, stream_id)

@app.route('/video_feed/<filename>')
def video_feed(filename):
    safe_filename = os.path.basename(filename)
    if safe_filename != filename:
        abort(400, description='Ungültiger Dateiname')
    video_path = os.path.join(UPLOAD_DIR, safe_filename)
    if not os.path.isfile(video_path):
        abort(404)
    line_data = get_line_from_session()
    stream_id = get_video_stream_id(safe_filename)
    try:
        generator = detect_objects_from_video(video_path, line_data, stream_id)
    except RuntimeError as exc:
        abort(503, description=str(exc))
    return Response(generator,
                    mimetype='multipart/x-mixed-replace; boundary=frame')

if __name__ == '__main__':
    app.run('0.0.0.0',debug=False, port=8080)