import os
import time
import threading
import queue

import cv2
import numpy as np
from PIL import Image

import streamlit as st
from ultralytics import YOLO
import torch

# add_script_run_ctx peut ne pas exister selon la version de Streamlit ;
# on le rend optionnel pour éviter un crash au démarrage.
try:
    from streamlit.runtime.scriptrunner import add_script_run_ctx
except Exception:  # pragma: no cover
    def add_script_run_ctx(_t):  # fallback no-op
        return _t


# =========================
# === FONCTIONS UTILES  ===
# =========================
def draw_text_with_background(
    image,
    text,
    position,
    font=cv2.FONT_HERSHEY_SIMPLEX,
    font_scale=1,
    font_thickness=2,
    text_color=(255, 255, 255),
    bg_color=(0, 0, 0),
    padding=5,
):
    """Ajoute du texte avec un fond sur une image OpenCV."""
    text_size, _ = cv2.getTextSize(text, font, font_scale, font_thickness)
    text_width, text_height = text_size

    x, y = position
    # Sécuriser les bornes d'affichage
    tl_x = max(0, x)
    tl_y = max(0, y - text_height - padding)
    br_x = min(image.shape[1] - 1, x + text_width + padding * 2)
    br_y = min(image.shape[0] - 1, y + padding)

    cv2.rectangle(image, (tl_x, tl_y), (br_x, br_y), bg_color, -1)
    cv2.putText(
        image,
        text,
        (tl_x + padding, min(y, image.shape[0] - 1)),
        font,
        font_scale,
        text_color,
        font_thickness,
        cv2.LINE_AA,
    )


def check_camera_availability(max_idx=10):
    """Diagnostic rapide pour lister des webcams locales disponibles."""
    available = []
    for i in range(max_idx):
        cap = cv2.VideoCapture(i)
        if cap.isOpened():
            ret, _ = cap.read()
            if ret:
                available.append(i)
        cap.release()
    return available


def _alpha_fill_poly(base_img, pts, color_bgr=(0, 255, 0), alpha=0.25, thickness=2):
    """
    Dessine un polygone 'transparent' en copiant sur overlay puis en blend.
    OpenCV ne supporte pas l'alpha directement dans cv2.fillPoly.
    """
    overlay = base_img.copy()
    pts_np = np.array(pts, np.int32)

    cv2.fillPoly(overlay, [pts_np], color_bgr)
    cv2.addWeighted(overlay, alpha, base_img, 1 - alpha, 0, dst=base_img)
    cv2.polylines(base_img, [pts_np], isClosed=True, color=color_bgr, thickness=thickness)


def preview_polygons(poly1, poly2):
    """Crée une prévisualisation des polygones sur une image noire."""
    preview = np.zeros((640, 1200, 3), dtype=np.uint8)

    # Zone 1 (vert)
    if len(poly1) >= 3:
        _alpha_fill_poly(preview, poly1, (0, 200, 0), alpha=0.25)
        for i, pt in enumerate(poly1):
            cv2.circle(preview, pt, 5, (255, 255, 255), -1)
            draw_text_with_background(
                preview, f"P1-{i+1}: {pt}", (pt[0] + 10, pt[1]), font_scale=0.5, bg_color=(0, 100, 0)
            )

    # Zone 2 (rouge)
    if len(poly2) >= 3:
        _alpha_fill_poly(preview, poly2, (0, 0, 200), alpha=0.25)
        for i, pt in enumerate(poly2):
            cv2.circle(preview, pt, 5, (255, 255, 255), -1)
            draw_text_with_background(
                preview, f"P2-{i+1}: {pt}", (pt[0] + 10, pt[1]), font_scale=0.5, bg_color=(100, 0, 0)
            )

    draw_text_with_background(preview, "Zone 1 (Vert)", (10, 30), font_scale=0.7, bg_color=(0, 100, 0))
    draw_text_with_background(preview, "Zone 2 (Rouge)", (10, 60), font_scale=0.7, bg_color=(100, 0, 0))

    # Grille
    grid_spacing = 100
    grid_color = (50, 50, 50)
    for x in range(0, preview.shape[1], grid_spacing):
        cv2.line(preview, (x, 0), (x, preview.shape[0]), grid_color, 1)
        draw_text_with_background(preview, str(x), (x, 20), font_scale=0.5, bg_color=(30, 30, 30))
    for y in range(0, preview.shape[0], grid_spacing):
        cv2.line(preview, (0, y), (preview.shape[1], y), grid_color, 1)
        draw_text_with_background(preview, str(y), (5, y), font_scale=0.5, bg_color=(30, 30, 30))

    return preview


# ================================
# === CLASSE TRAITEMENT YOLOv8 ===
# ================================
class YOLOVideoProcessor:
    def __init__(self, model_path, poly1, poly2, tracker_method="bot"):
        # Device
        self.device = "cuda" if torch.cuda.is_available() else "cpu"

        # Paramètres par défaut (écrasés par l'UI ensuite)
        self.frame_skip = 2
        self.downsample_factor = 0.5
        self.img_size = 640
        self.conf_threshold = 0.35

        # Chargement modèle
        self.model = YOLO(model_path)  # 'task' n'est pas requis
        self.model.to(self.device)

        # Tracking
        self.tracker_method = tracker_method
        self.tracker_config = "botsort.yaml" if tracker_method.lower() == "bot" else "bytetrack.yaml"

        # Compteurs d'IDs uniques par zone
        self.unique_region1_ids = set()
        self.unique_region2_ids = set()

        # Polygones
        self.poly1 = poly1
        self.poly2 = poly2

        # Threads/queues
        self.stop_processing = False
        self.frame_queue = queue.Queue(maxsize=1)
        self.result_queue = queue.Queue(maxsize=1)

    @staticmethod
    def is_in_region(center, poly):
        poly_np = np.array(poly, dtype=np.int32)
        return cv2.pointPolygonTest(poly_np, center, False) >= 0

    def reset_counts(self):
        self.unique_region1_ids.clear()
        self.unique_region2_ids.clear()

    def process_frame(self, frame):
        if frame is None:
            return None

        # Downscale contrôlé
        orig_h, orig_w = frame.shape[:2]
        resized_w = orig_w
        resized_h = orig_h
        if self.downsample_factor < 1.0:
            resized_w = max(1, int(orig_w * self.downsample_factor))
            resized_h = max(1, int(orig_h * self.downsample_factor))
            resized_frame = cv2.resize(frame, (resized_w, resized_h), interpolation=cv2.INTER_AREA)
        else:
            resized_frame = frame

        # Inference + tracking
        with torch.no_grad():
            results = self.model.track(
                resized_frame,
                persist=True,
                tracker=self.tracker_config,
                conf=self.conf_threshold,
                imgsz=self.img_size,
                device=self.device,
            )

        display = frame.copy()

        # Dessiner polygones (transparent)
        _alpha_fill_poly(display, self.poly1, (0, 200, 0), alpha=0.2, thickness=2)
        _alpha_fill_poly(display, self.poly2, (0, 0, 200), alpha=0.2, thickness=2)

        # Mise à l'échelle des boxes vers la taille originale
        sx = orig_w / float(resized_w)
        sy = orig_h / float(resized_h)

        if results and len(results) > 0 and getattr(results[0], "boxes", None) is not None:
            try:
                boxes_xywh = results[0].boxes.xywh.cpu().numpy()
                # track ids peuvent être None sur la première frame
                ids_tensor = results[0].boxes.id
                track_ids = ids_tensor.int().cpu().tolist() if ids_tensor is not None else [None] * len(boxes_xywh)

                for (x, y, w, h), tid in zip(boxes_xywh, track_ids):
                    # centre + bbox rescalés
                    cx = int(x * sx)
                    cy = int(y * sy)
                    ww = int(w * sx)
                    hh = int(h * sy)

                    # Comptage par centre de la bbox
                    if tid is not None:
                        if self.is_in_region((cx, cy), self.poly1):
                            self.unique_region1_ids.add(tid)
                        if self.is_in_region((cx, cy), self.poly2):
                            self.unique_region2_ids.add(tid)

                    # Dessin bbox
                    tl = (max(0, cx - ww // 2), max(0, cy - hh // 2))
                    br = (min(display.shape[1] - 1, cx + ww // 2), min(display.shape[0] - 1, cy + hh // 2))
                    cv2.rectangle(display, tl, br, (0, 255, 0), 2)

            except Exception as e:
                # On ne casse pas l'affichage si une frame pose problème
                draw_text_with_background(display, f"Tracking error: {e}", (10, 60), bg_color=(80, 0, 0))

        # Affichage compteurs
        h, w = display.shape[:2]
        draw_text_with_background(display, f"Total Sens 1: {len(self.unique_region1_ids)}", (10, h - 50))
        draw_text_with_background(display, f"Total Sens 2: {len(self.unique_region2_ids)}", (w - 300, h - 50))

        return display

    def process_webcam_frames(self):
        """Thread de traitement : lit les frames de frame_queue, pousse résultats dans result_queue."""
        while not self.stop_processing:
            try:
                frame = self.frame_queue.get(timeout=0.5)
            except queue.Empty:
                continue

            start = time.time()
            processed = self.process_frame(frame)
            fps = 1.0 / max(1e-6, (time.time() - start))

            if processed is not None:
                draw_text_with_background(processed, f"FPS: {fps:.1f}", (10, 30))

            # Remplacer l'ancien résultat si plein
            try:
                if self.result_queue.full():
                    _ = self.result_queue.get_nowait()
                self.result_queue.put_nowait(
                    (processed, len(self.unique_region1_ids), len(self.unique_region2_ids))
                )
            except queue.Full:
                pass
            finally:
                self.frame_queue.task_done()

    def process_webcam(self, camera_id=0, display_placeholder=None, count_placeholders=None):
        """Capture en direct avec multi-threading et rendu dans Streamlit."""
        cap = None
        backends = [
            cv2.CAP_ANY,
            getattr(cv2, "CAP_DSHOW", cv2.CAP_ANY),
            getattr(cv2, "CAP_MSMF", cv2.CAP_ANY),
            getattr(cv2, "CAP_V4L2", cv2.CAP_ANY),
            getattr(cv2, "CAP_AVFOUNDATION", cv2.CAP_ANY),
        ]

        # Ouverture
        for backend in backends:
            try:
                cap = cv2.VideoCapture(camera_id, backend)
                if cap.isOpened():
                    if display_placeholder:
                        display_placeholder.success(f"✅ Webcam connectée (backend: {backend})")
                    break
            except Exception as e:
                if display_placeholder:
                    display_placeholder.warning(f"Backend {backend} échec: {e}")

        if cap is None or not cap.isOpened():
            # Dernière chance sans backend explicite
            cap = cv2.VideoCapture(camera_id)

        if not cap.isOpened():
            if display_placeholder:
                display_placeholder.error("⚠️ Impossible d'ouvrir la source vidéo.")
            return

        # Paramètres caméra (best-effort)
        try:
            cap.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
            cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 480)
            cap.set(cv2.CAP_PROP_FPS, 30)
        except Exception:
            if display_placeholder:
                display_placeholder.warning("⚠️ Impossible de régler certains paramètres caméra.")

        # Reset état session
        self.reset_counts()
        self.stop_processing = False

        # Thread de traitement
        t = threading.Thread(target=self.process_webcam_frames, daemon=True)
        try:
            add_script_run_ctx(t)
        except Exception:
            pass
        t.start()

        # Premier frame pour valider
        time.sleep(0.3)
        ok, first = cap.read()
        if not ok:
            if display_placeholder:
                display_placeholder.error("⚠️ Lecture impossible depuis la webcam (permissions ?).")
            self.stop_processing = True
            cap.release()
            t.join(timeout=1.0)
            return

        if display_placeholder is not None:
            display_placeholder.image(cv2.cvtColor(first, cv2.COLOR_BGR2RGB), channels="RGB", use_column_width=True,
                                      caption="Webcam connectée !")

        ui_update_interval = 0.03  # ~30 FPS
        last_ui = 0.0
        frame_idx = 0

        try:
            while not self.stop_processing:
                ok, frame = cap.read()
                if not ok:
                    time.sleep(0.05)
                    continue

                # Envoi au thread de traitement (skip pour alléger)
                if frame_idx % self.frame_skip == 0:
                    try:
                        if self.frame_queue.full():
                            _ = self.frame_queue.get_nowait()
                            self.frame_queue.task_done()
                        self.frame_queue.put_nowait(frame)
                    except queue.Full:
                        pass

                # Affichage si résultat dispo
                now = time.time()
                if now - last_ui >= ui_update_interval:
                    try:
                        processed, c1, c2 = self.result_queue.get_nowait()
                        if processed is not None and display_placeholder is not None:
                            rgb = cv2.cvtColor(processed, cv2.COLOR_BGR2RGB)
                            display_placeholder.image(Image.fromarray(rgb), channels="RGB", use_column_width=True)
                        if count_placeholders and len(count_placeholders) >= 2:
                            count_placeholders[0].metric("Véhicules Sens 1 (Vert)", c1)
                            count_placeholders[1].metric("Véhicules Sens 2 (Rouge)", c2)
                    except queue.Empty:
                        pass
                    last_ui = now

                frame_idx += 1
                time.sleep(0.001)

        except Exception as e:
            if display_placeholder:
                display_placeholder.error(f"Erreur boucle principale: {e}")
        finally:
            self.stop_processing = True
            cap.release()
            t.join(timeout=1.0)
            if display_placeholder:
                display_placeholder.success("✅ Flux vidéo arrêté.")


# ==========================
# === INTERFACE STREAMLIT ===
# ==========================
def main():
    st.set_page_config(
        page_title="Détecteur de Véhicules en Temps Réel",
        page_icon="🚗",
        layout="wide",
        menu_items={"About": "Détection de véhicules avec YOLOv8"},
    )

    st.title("🚗 Détection et comptage de Véhicules en Temps Réel")

    # Session state
    st.session_state.setdefault("webcam_active", False)
    st.session_state.setdefault("processor", None)
    st.session_state.setdefault("processing_thread", None)

    # Chargement du modèle
    model_path = "best.pt"
    if not os.path.exists(model_path):
        with st.spinner("📥 Téléchargement du modèle YOLO…"):
            try:
                from huggingface_hub import hf_hub_download

                model_path = hf_hub_download(
                    repo_id="ModuMLTECH/projet_comptage_avance",
                    filename="best.pt",
                )
                st.success("✅ Modèle chargé depuis Hugging Face Hub.")
            except Exception as e:
                st.error(f"❌ Erreur chargement modèle: {e}")
                st.warning("⚠️ Fallback sur un modèle YOLO public (yolov8n.pt).")
                model_path = "yolov8n.pt"

    # === SIDEBAR ===
    with st.sidebar:
        st.header("🔹 Paramètres")

        st.subheader("📍 Polygone 1 (vert)")
        poly1_input = st.text_area("Entrez 4 points (x,y) séparés par des espaces", "465,350 609,350 520,630 3,630")

        st.subheader("📍 Polygone 2 (rouge)")
        poly2_input = st.text_area("Entrez 4 points (x,y) séparés par des espaces", "678,350 815,350 1203,630 743,630")

        tracker_method = st.selectbox("Méthode de tracking", ["bot", "byte"], index=0)

        st.subheader("🚀 Optimisation")
        frame_skip = st.slider("Skip de frames", 1, 5, 2)
        downsample = st.slider("Facteur d'échelle", 0.3, 1.0, 0.5, 0.1)
        conf_threshold = st.slider("Seuil de confiance", 0.1, 0.9, 0.35, 0.05)

        st.subheader("💻 Système")
        device_info = f"GPU: {'Disponible' if torch.cuda.is_available() else 'Non disponible'}"
        if torch.cuda.is_available():
            device_info += f" ({torch.cuda.get_device_name(0)})"
        st.info(device_info)

    def parse_polygon(txt):
        try:
            pts = []
            for token in txt.replace(";", " ").split():
                x, y = token.split(",")
                pts.append((int(x), int(y)))
            return pts
        except Exception:
            return []

    poly1 = parse_polygon(poly1_input)
    poly2 = parse_polygon(poly2_input)
    valid_polygons = len(poly1) == 4 and len(poly2) == 4

    # Prévisualisation
    st.header("🖼️ Prévisualisation des masques")
    if valid_polygons:
        prev = preview_polygons(poly1, poly2)
        st.image(cv2.cvtColor(prev, cv2.COLOR_BGR2RGB), use_column_width=True, caption="Masques de détection")
        st.success("✅ Polygones valides (4 points chacun).")
    else:
        st.warning("⚠️ Définissez deux polygones valides de 4 points chacun.")

    # Section webcam
    st.header("Détection en Temps Réel avec Webcam")

    available = check_camera_availability()
    if not available:
        st.warning("⚠️ Aucune caméra locale détectée (vous pouvez tester une caméra IP).")
    else:
        st.success(f"✅ Caméras détectées: {available}")

    camera_options = {"Webcam par défaut (0)": 0}
    for i in range(1, 8):
        camera_options[f"Caméra alternative ({i})"] = i
    camera_options["Caméra IP (entrez l'URL)"] = "ip"

    selected = st.selectbox("Source vidéo", list(camera_options.keys()))
    if camera_options[selected] == "ip":
        camera_id = st.text_input("URL RTSP/HTTP", "http://adresse-ip:port/video")
    else:
        camera_id = camera_options[selected]

    display_quality = st.select_slider("Qualité d'affichage", options=["Basse", "Moyenne", "Haute"], value="Moyenne")
    # (placeholder pour gérer des resize/qualité plus tard si besoin)

    video_container = st.container()
    video_placeholder = video_container.empty()
    col1, col2 = st.columns(2)
    count_placeholders = [col1.empty(), col2.empty()]

    st.info("ℹ️ Optimisations: multi-threading, resize adaptatif, CUDA si dispo.")

    col_start, col_stop = st.columns(2)

    if col_start.button("▶️ Démarrer la détection"):
        if not valid_polygons:
            st.error("❌ Les polygones doivent avoir exactement 4 points chacun.")
        elif st.session_state.webcam_active:
            st.warning("⚠️ La webcam est déjà active.")
        else:
            video_placeholder.info("🔄 Connexion à la source vidéo…")

            processor = YOLOVideoProcessor(model_path, poly1, poly2, tracker_method)
            processor.frame_skip = frame_skip
            processor.downsample_factor = downsample
            processor.conf_threshold = conf_threshold

            st.session_state.processor = processor
            st.session_state.webcam_active = True

            thread = threading.Thread(
                target=st.session_state.processor.process_webcam,
                args=(camera_id, video_placeholder, count_placeholders),
                daemon=True,
            )
            try:
                add_script_run_ctx(thread)
            except Exception:
                pass

            try:
                thread.start()
                st.session_state.processing_thread = thread
            except Exception as e:
                st.error(f"Erreur au démarrage du thread: {e}")
                st.session_state.webcam_active = False

    if col_stop.button("⏹️ Arrêter"):
        if st.session_state.webcam_active and st.session_state.processor:
            st.session_state.processor.stop_processing = True
            st.session_state.webcam_active = False

            if st.session_state.processing_thread:
                st.session_state.processing_thread.join(timeout=2.0)
                st.session_state.processing_thread = None

            time.sleep(0.3)
            video_placeholder.empty()
            for ph in count_placeholders:
                ph.empty()
        else:
            st.warning("⚠️ Aucune détection en cours.")

if __name__ == "__main__":
    main()