import os

from ultralytics import YOLO

# 全局变量
_yolo_model = None


model_path = os.path.join(os.path.dirname(__file__), "models", "best.pt")


def load_model():
    """加载YOLO目标检测模型"""
    global _yolo_model

    try:
        _yolo_model = YOLO(model_path)
    except Exception as e:
        print(f"YOLO model load failed: {e}")
        return False

    return True if _yolo_model else False


def detect(frame, conf_threshold=0.2):
    """YOLO目标检测、返回(是否识别到, 结果字符串)"""
    global _yolo_model

    if not _yolo_model or frame is None:
        return (False, "未初始化或无效帧")

    try:
        results = _yolo_model(frame, conf=conf_threshold)
        # 检查是否有检测结果
        has_results = len(results[0].boxes) > 0 if results else False

        if not has_results:
            return (False, "未检测到目标")

        # 构建结果字符串
        result_parts = []
        for box in results[0].boxes:
            cls = int(box.cls[0])
            conf = float(box.conf[0])
            bbox = [float(x) for x in box.xyxy[0]]
            class_name = _yolo_model.names[cls] if hasattr(_yolo_model, 'names') else f"类别{cls}"
            result_parts.append(f"{class_name} (置信度: {conf:.2f}, 边界框: {bbox})")

        result_str = "; ".join(result_parts)
        return (has_results, result_str)

    except Exception as e:
        print(f"YOLO detect error: {e}")
        return (False, f"检测错误: {str(e)}")