models/detection/detector.py

import logging
from PIL import Image, ImageDraw
from huggingface_hub import hf_hub_download
from ultralytics import YOLO
import os
import shutil

# Setup logger
logger = logging.getLogger(__name__)
logging.basicConfig(level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s")

# Optional: clear weights cache each time (only for dev use)
shutil.rmtree("models/detection/weights", ignore_errors=True)

class ObjectDetector:
    def __init__(self, model_key="yolov8n", device="cpu"):
        """
        Initializes an Ultralytics YOLO model using HF download path.

        Args:
            model_key (str): e.g. 'yolov8n', 'yolov8s', etc.
            device (str): 'cpu' or 'cuda'
        """
        # Optional aliasing
        alias_map = {
            "yolov8n": "yolov8n",
            "yolov8s": "yolov8s",
            "yolov8l": "yolov8l",
            "yolov11b": "yolov11b"
        }

        resolved_key = alias_map.get(model_key.lower(), model_key.lower())

        # HF repo map
        hf_map = {
            "yolov8n": ("ultralytics/yolov8", "yolov8n.pt"),
            "yolov8s": ("ultralytics/yolov8", "yolov8s.pt"),
            "yolov8l": ("ultralytics/yolov8", "yolov8l.pt"),
            "yolov11b": ("Ultralytics/YOLO11", "yolov11b.pt"),
        }

        if resolved_key not in hf_map:
            raise ValueError(f"Unsupported model key: {resolved_key}")

        repo_id, filename = hf_map[resolved_key]

        # 📥 Download from HF Hub
        weights_path = hf_hub_download(
            repo_id=repo_id,
            filename=filename,
            cache_dir="models/detection/weights",
            force_download=True  # Optional: change to False for reuse
        )

        logger.info(f"✅ Loaded YOLO model: {resolved_key} from {weights_path}")
        self.device = device
        self.model = YOLO(weights_path)

    def predict(self, image: Image.Image, conf_threshold=0.25):
        logger.info("Running object detection")
        results = self.model(image)
        detections = []
        for r in results:
            for box in r.boxes:
                detections.append({
                    "class_name": r.names[int(box.cls)],
                    "confidence": float(box.conf),
                    "bbox": box.xyxy[0].tolist()
                })
        logger.info(f"Detected {len(detections)} objects")
        return detections

    def draw(self, image: Image.Image, detections, alpha=0.5):
        overlay = image.copy()
        draw = ImageDraw.Draw(overlay)
        for det in detections:
            bbox = det["bbox"]
            label = f'{det["class_name"]} {det["confidence"]:.2f}'
            draw.rectangle(bbox, outline="red", width=2)
            draw.text((bbox[0], bbox[1]), label, fill="red")
        return Image.blend(image, overlay, alpha)