import os
os.environ['PYTORCH_ENABLE_MPS_FALLBACK'] = '1'
os.environ['GRADIO_DEFAULT_LANG'] = 'en'

import gradio as gr
import torch
import cv2
import numpy as np
from PIL import Image
from typing import Tuple, List
from rfdetr.detr import RFDETRMedium

# UI Element classes
CLASSES = ['button', 'field', 'heading', 'iframe', 'image', 'label', 'link', 'text']

# Single color for all boxes (BGR format for OpenCV)
BOX_COLOR = (0, 255, 0)  # Green

# Global model variable
model = None

def load_model(model_path: str = "model.pth"):
    """Load RF-DETR model"""
    global model
    if model is None:
        print("Loading RF-DETR model...")
        model = RFDETRMedium(pretrain_weights=model_path, resolution=1600)
        print("Model loaded successfully!")
    return model

def draw_detections(
    image: np.ndarray,
    boxes: List[Tuple[int, int, int, int]],
    scores: List[float],
    classes: List[int],
    thickness: int = 3,
    font_scale: float = 0.6
) -> np.ndarray:
    """Draw detection boxes and labels on image"""
    img_with_boxes = image.copy()

    for box, score, cls_id in zip(boxes, scores, classes):
        x1, y1, x2, y2 = map(int, box)

        # Draw rectangle
        cv2.rectangle(img_with_boxes, (x1, y1), (x2, y2), BOX_COLOR, thickness)

        # Prepare label with confidence score only
        label = f"{score:.2f}"

        # Calculate label size and position
        (label_width, label_height), baseline = cv2.getTextSize(
            label, cv2.FONT_HERSHEY_SIMPLEX, font_scale, thickness=2
        )

        # Draw label background
        label_y = max(y1 - 10, label_height + 10)
        cv2.rectangle(
            img_with_boxes,
            (x1, label_y - label_height - baseline - 5),
            (x1 + label_width + 5, label_y + baseline - 5),
            BOX_COLOR,
            -1
        )

        # Draw label text
        cv2.putText(
            img_with_boxes,
            label,
            (x1 + 2, label_y - baseline - 5),
            cv2.FONT_HERSHEY_SIMPLEX,
            font_scale,
            (255, 255, 255),
            thickness=2
        )

    return img_with_boxes

@torch.inference_mode()
def detect_ui_elements(
    image: Image.Image,
    confidence_threshold: float,
    line_thickness: int
) -> Tuple[Image.Image, str]:
    """
    Detect UI elements in the uploaded image

    Args:
        image: Input PIL Image
        confidence_threshold: Minimum confidence score for detections
        line_thickness: Thickness of bounding box lines

    Returns:
        Annotated image and detection summary text
    """
    try:
        if image is None:
            return None, "Please upload an image first."

        # Load model
        model = load_model()

        # Convert PIL to numpy array (RGB)
        img_array = np.array(image)

        # Convert RGB to BGR for OpenCV
        img_bgr = cv2.cvtColor(img_array, cv2.COLOR_RGB2BGR)

        # Run detection (returns supervision Detections object)
        detections = model.predict(img_array, threshold=confidence_threshold)

        # Extract detection data
        filtered_boxes = detections.xyxy  # Bounding boxes in xyxy format
        filtered_scores = detections.confidence  # Confidence scores
        filtered_classes = detections.class_id  # Class IDs

        # Draw detections
        annotated_img = draw_detections(
            img_bgr,
            filtered_boxes.tolist(),
            filtered_scores.tolist(),
            filtered_classes.tolist(),
            thickness=line_thickness
        )

        # Convert back to RGB for display
        annotated_img_rgb = cv2.cvtColor(annotated_img, cv2.COLOR_BGR2RGB)
        annotated_pil = Image.fromarray(annotated_img_rgb)

        # Create summary text
        summary_text = f"**Total detections:** {len(filtered_boxes)}"

        return annotated_pil, summary_text

    except Exception as e:
        import traceback
        error_msg = f"**Error during detection:**\n\n```\n{str(e)}\n\n{traceback.format_exc()}\n```"
        print(error_msg)  # Also print to logs
        return None, error_msg

# Gradio interface
with gr.Blocks(title="CU-1 UI Element Detector", theme=gr.themes.Soft()) as demo:

    gr.Markdown("""
    # CU-1 UI Element Detector

    Upload a screenshot or UI mockup to automatically detect elements.
    """)

    with gr.Row():
        with gr.Column(scale=1):
            input_image = gr.Image(
                type="pil",
                label="Upload Screenshot",
                height=400,
                sources=["upload"]
            )

            with gr.Accordion("Detection Settings", open=True):
                confidence_slider = gr.Slider(
                    minimum=0.1,
                    maximum=0.9,
                    value=0.35,
                    step=0.05,
                    label="Confidence Threshold",
                    info="Higher values = fewer but more confident detections"
                )

                thickness_slider = gr.Slider(
                    minimum=1,
                    maximum=6,
                    value=2,
                    step=1,
                    label="Box Line Thickness"
                )

            detect_button = gr.Button("Detect Elements", variant="primary", size="lg")

        with gr.Column(scale=1):
            output_image = gr.Image(
                type="pil",
                label="Detected Elements",
                height=400
            )

            summary_output = gr.Markdown(label="Detection Summary")


    # Connect button
    detect_button.click(
        fn=detect_ui_elements,
        inputs=[input_image, confidence_slider, thickness_slider],
        outputs=[output_image, summary_output]
    )

# Launch
if __name__ == "__main__":
    demo.queue().launch(share=False)