import torch
from transformers import DetrImageProcessor, DetrForObjectDetection
from PIL import Image
import gradio as gr
import matplotlib.pyplot as plt
import matplotlib.patches as patches
import io

# Load the processor and model
processor = DetrImageProcessor.from_pretrained('facebook/detr-resnet-101')
model = DetrForObjectDetection.from_pretrained('facebook/detr-resnet-101')

def object_detection(image, confidence_threshold):
    try:
        # Convert the input to a PIL Image object if it's not already
        if not isinstance(image, Image.Image):
            image = Image.open(io.BytesIO(image))
        
        # Preprocess the image
        inputs = processor(images=image, return_tensors="pt")

        # Perform object detection
        outputs = model(**inputs)

        # Extract bounding boxes and labels
        target_sizes = torch.tensor([image.size[::-1]])
        results = processor.post_process_object_detection(outputs, target_sizes=target_sizes, threshold=confidence_threshold)[0]

        # Plot the image with bounding boxes
        plt.figure(figsize=(16, 10))
        plt.imshow(image)
        ax = plt.gca()

        detected_objects = []
        for score, label, box in zip(results["scores"], results["labels"], results["boxes"]):
            box = [round(i, 2) for i in box.tolist()]
            xmin, ymin, xmax, ymax = box
            width, height = xmax - xmin, ymax - ymin

            ax.add_patch(plt.Rectangle((xmin, ymin), width, height, fill=False, color='red', linewidth=3))
            text = f'{model.config.id2label[label.item()]}: {round(score.item(), 3)}'
            ax.text(xmin, ymin, text, fontsize=15, bbox=dict(facecolor='yellow', alpha=0.5))
            detected_objects.append(text)

        plt.axis('off')

        # Save the plot to an image buffer
        buf = io.BytesIO()
        plt.savefig(buf, format='png')
        buf.seek(0)
        plt.close()

        # Convert buffer to an Image object
        result_image = Image.open(buf)

        # Join detected objects into a single string
        detected_objects_text = "\n".join(detected_objects)

        return result_image, detected_objects_text
    
    except Exception as e:
        return Image.new("RGB", (224, 224), color="white"), str(e)

# Define the Gradio interface
demo = gr.Interface(
    fn=object_detection,
    inputs=[gr.Image(label="Upload an Image"), gr.Slider(minimum=0.0, maximum=1.0, label="Confidence Threshold")],
    outputs=[gr.Image(label="Detected Objects"), gr.Textbox(label="Detected Objects List")],
    title="Object Detection with DETR (ResNet-101)",
    description="Upload an image and get object detection results using the DETR model with a ResNet-101 backbone."
)

# Launch the Gradio interface
if __name__ == "__main__":
    demo.launch()