import cv2
import numpy as np
import os
from typing import List, Dict, Optional

from ..config import (
    ULTRALYTICS_AVAILABLE, 
    YOLO26_MODELS, 
    COLORS,
    DEFAULT_CONF_THRESHOLD,
    DEFAULT_IOU_THRESHOLD,
)

if ULTRALYTICS_AVAILABLE:
    from ultralytics import YOLO

class YOLO26Detector:
    def __init__(self, 
                 model_size: str = "nano",
                 model_path: Optional[str] = None,
                 conf_threshold: float = DEFAULT_CONF_THRESHOLD,
                 iou_threshold: float = DEFAULT_IOU_THRESHOLD,
                 device: str = "auto"):
        self.conf_threshold = conf_threshold
        self.iou_threshold = iou_threshold
        self.device = device
        self.model = None
        
        if not ULTRALYTICS_AVAILABLE:
            raise RuntimeError("Ultralytics not installed. Run: pip install ultralytics")
        
        if model_path and os.path.exists(model_path):
            model_name = model_path
        elif model_size in YOLO26_MODELS:
            model_name = YOLO26_MODELS[model_size]
        else:
            print(f"Unknown model size '{model_size}', defaulting to 'nano'")
            model_name = YOLO26_MODELS["nano"]
        
        print(f"Loading YOLO26 model: {model_name}")
        self.model = YOLO(model_name)
        print(f"YOLO26 model loaded successfully!")
        print(f"Classes: {len(self.model.names)} | Device: {device}")
    
    def detect(self, 
               frame: np.ndarray,
               conf_threshold: Optional[float] = None,
               classes: Optional[List[int]] = None) -> List[Dict]:
        if self.model is None:
            return []
        
        conf = conf_threshold if conf_threshold is not None else self.conf_threshold
        
        results = self.model(
            frame,
            conf=conf,
            iou=self.iou_threshold,
            device=self.device if self.device != "auto" else None,
            classes=classes,
            verbose=False
        )
        
        detections = []
        for result in results:
            boxes = result.boxes
            if boxes is None:
                continue
                
            for i in range(len(boxes)):
                xyxy = boxes.xyxy[i].cpu().numpy()
                x1, y1, x2, y2 = map(int, xyxy)
                
                conf_val = float(boxes.conf[i].cpu().numpy())
                class_id = int(boxes.cls[i].cpu().numpy())
                label = self.model.names[class_id]
                
                detections.append({
                    "bbox": (x1, y1, x2, y2),
                    "label": label,
                    "confidence": conf_val,
                    "class_id": class_id
                })
        
        return detections
    
    def detect_and_track(self,
                         frame: np.ndarray,
                         conf_threshold: Optional[float] = None,
                         tracker: str = "bytetrack.yaml") -> List[Dict]:
        if self.model is None:
            return []
        
        conf = conf_threshold if conf_threshold is not None else self.conf_threshold
        
        results = self.model.track(
            frame,
            conf=conf,
            iou=self.iou_threshold,
            device=self.device if self.device != "auto" else None,
            tracker=tracker,
            persist=True,
            verbose=False
        )
        
        detections = []
        for result in results:
            boxes = result.boxes
            if boxes is None:
                continue
                
            for i in range(len(boxes)):
                xyxy = boxes.xyxy[i].cpu().numpy()
                x1, y1, x2, y2 = map(int, xyxy)
                
                conf_val = float(boxes.conf[i].cpu().numpy())
                class_id = int(boxes.cls[i].cpu().numpy())
                label = self.model.names[class_id]
                
                track_id = None
                if boxes.id is not None:
                    track_id = int(boxes.id[i].cpu().numpy())
                
                detections.append({
                    "bbox": (x1, y1, x2, y2),
                    "label": label,
                    "confidence": conf_val,
                    "class_id": class_id,
                    "track_id": track_id
                })
        
        return detections
    
    def draw_detections(self, 
                        frame: np.ndarray, 
                        detections: List[Dict],
                        show_labels: bool = True,
                        show_conf: bool = True) -> np.ndarray:
        result = frame.copy()
        
        for det in detections:
            x1, y1, x2, y2 = det["bbox"]
            label = det["label"]
            conf = det["confidence"]
            track_id = det.get("track_id")
            
            if conf > 0.7:
                color = COLORS["high_conf"]
            elif conf > 0.5:
                color = COLORS["medium_conf"]
            else:
                color = COLORS["low_conf"]
            
            cv2.rectangle(result, (x1, y1), (x2, y2), color, 2)
            
            if show_labels:
                label_parts = [label]
                if track_id is not None:
                    label_parts.append(f"ID:{track_id}")
                if show_conf:
                    label_parts.append(f"{conf:.2f}")
                label_text = " | ".join(label_parts)
                
                (text_w, text_h), baseline = cv2.getTextSize(
                    label_text, cv2.FONT_HERSHEY_SIMPLEX, 0.5, 1
                )
                cv2.rectangle(
                    result, 
                    (x1, y1 - text_h - 8), 
                    (x1 + text_w + 4, y1), 
                    color, 
                    -1
                )
                cv2.putText(
                    result, 
                    label_text, 
                    (x1 + 2, y1 - 4),
                    cv2.FONT_HERSHEY_SIMPLEX, 
                    0.5, 
                    (0, 0, 0), 
                    1
                )
        
        return result
    
    def get_class_names(self) -> Dict[int, str]:
        return self.model.names if self.model else {}