import cv2
import easyocr
import requests
import os
import time
import threading
import re
from queue import Queue
from flask import Flask, Response
from flask_cors import CORS
from ultralytics import YOLO

# Configuration
BACKEND_URL = os.environ.get('BACKEND_URL', 'http://localhost:3000')
CAMERA_ID = 0
PROCESS_INTERVAL = 1.5  # Más reactivo
MODEL_PATH = 'best.pt'

app = Flask(__name__)
CORS(app)

# Shared state
outputFrame = None
frame_lock = threading.Lock()
latest_detections = []
detection_lock = threading.Lock()

# Cola para procesamiento OCR asíncrono
ocr_queue = Queue(maxsize=5)

def send_plate(plate_number):
    """Envía la patente detectada al backend"""
    try:
        url = f"{BACKEND_URL}/api/detect"
        requests.post(url, json={'plate_number': plate_number}, timeout=3)
        print(f"✓ Plate sent: {plate_number}")
    except Exception as e:
        print(f"✗ Error sending plate: {e}")

def validate_and_send(text):
    """Valida formato chileno y envía"""
    # Formato nuevo: XXXX-00 | Formato antiguo: XX-0000
    if re.match(r'^[A-Z]{4}\d{2}$', text) or re.match(r'^[A-Z]{2}\d{4}$', text):
        send_plate(text)
        return True
    return False

def ocr_worker(reader):
    """Hilo dedicado para OCR - no bloquea el stream"""
    while True:
        try:
            plate_img = ocr_queue.get(timeout=1)
            if plate_img is None:
                continue
            
            # Preprocesamiento para mejor OCR
            gray = cv2.cvtColor(plate_img, cv2.COLOR_BGR2GRAY)
            
            ocr_results = reader.readtext(gray, detail=0, paragraph=False, 
                                          allowlist='ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789')
            for text in ocr_results:
                clean_text = ''.join(e for e in text if e.isalnum()).upper()
                if len(clean_text) >= 6:
                    validate_and_send(clean_text)
        except:
            pass

def camera_loop():
    """Hilo principal de captura - mantiene FPS alto"""
    global outputFrame, latest_detections
    
    print("🚀 Initializing ALPR System...")
    print("📷 Loading camera...")
    
    cap = cv2.VideoCapture(CAMERA_ID)
    cap.set(cv2.CAP_PROP_FOURCC, cv2.VideoWriter_fourcc(*'MJPG'))
    cap.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
    cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 480)
    cap.set(cv2.CAP_PROP_FPS, 30)
    cap.set(cv2.CAP_PROP_BUFFERSIZE, 1)
    
    print("🧠 Loading YOLO model...")
    try:
        model = YOLO(MODEL_PATH)
    except Exception as e:
        print(f"❌ Critical Error loading model: {e}")
        return
    
    print("📝 Initializing EasyOCR...")
    reader = easyocr.Reader(['en'], gpu=False)
    
    # Iniciar worker de OCR
    ocr_thread = threading.Thread(target=ocr_worker, args=(reader,), daemon=True)
    ocr_thread.start()
    
    print("✅ System ready!")
    
    last_process_time = 0
    frame_count = 0
    
    while True:
        # Captura eficiente - solo 2 grabs
        cap.grab()
        cap.grab()
        ret, frame = cap.retrieve()
        
        if not ret:
            time.sleep(0.01)
            continue
        
        frame_count += 1
        current_time = time.time()
        
        # Procesar ALPR cada PROCESS_INTERVAL segundos
        if current_time - last_process_time > PROCESS_INTERVAL:
            last_process_time = current_time
            
            # YOLO detection - usar imgsz pequeño para velocidad
            results = model(frame, verbose=False, imgsz=320, conf=0.5)
            
            new_detections = []
            for r in results:
                for box in r.boxes:
                    x1, y1, x2, y2 = map(int, box.xyxy[0])
                    conf = float(box.conf[0])
                    new_detections.append((x1, y1, x2, y2, conf))
                    
                    # Extraer imagen de placa y enviar a cola OCR
                    plate_img = frame[y1:y2, x1:x2].copy()
                    if plate_img.size > 0 and not ocr_queue.full():
                        ocr_queue.put(plate_img)
            
            with detection_lock:
                latest_detections = new_detections
        
        # Actualizar frame para streaming (sin bloquear)
        display_frame = frame
        with detection_lock:
            for (x1, y1, x2, y2, conf) in latest_detections:
                cv2.rectangle(display_frame, (x1, y1), (x2, y2), (0, 255, 0), 2)
                cv2.putText(display_frame, f"{conf:.0%}", (x1, y1-5), 
                           cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0, 255, 0), 1)
        
        with frame_lock:
            outputFrame = display_frame

def generate():
    """Generador para streaming MJPEG"""
    global outputFrame
    while True:
        time.sleep(0.033)  # ~30 FPS para el stream
        with frame_lock:
            if outputFrame is None:
                continue
            _, encoded = cv2.imencode(".jpg", outputFrame, [cv2.IMWRITE_JPEG_QUALITY, 75])
        yield b'--frame\r\nContent-Type: image/jpeg\r\n\r\n' + encoded.tobytes() + b'\r\n'

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

@app.route("/health")
def health():
    return {"status": "ok", "service": "alpr"}

if __name__ == "__main__":
    t = threading.Thread(target=camera_loop, daemon=True)
    t.start()
    app.run(host="0.0.0.0", port=5001, debug=False, threaded=True, use_reloader=False)