app.py

# IMPORTANT: Import spaces FIRST, before any CUDA-related packages
try:
    import spaces
    HF_SPACES_GPU = True
except ImportError:
    # Create a dummy decorator if not running on Spaces
    class spaces:
        @staticmethod
        def GPU(func):
            return func
    HF_SPACES_GPU = False

import os
import json
import gc
import traceback
from typing import Optional, Tuple, Any

import torch
import gradio as gr
import supervision as sv
from PIL import Image

# Try to import optional dependencies
try:
    from transformers import (
        AutoModelForCausalLM,
        AutoTokenizer,
        AutoModelForImageTextToText,
        AutoProcessor,
        BitsAndBytesConfig,
    )
except Exception:
    AutoModelForCausalLM = None
    AutoTokenizer = None
    AutoModelForImageTextToText = None
    AutoProcessor = None
    BitsAndBytesConfig = None

# Try to import huggingface_hub for model downloading
try:
    from huggingface_hub import hf_hub_download
except ImportError:
    hf_hub_download = None

# Import RF-DETR (assumes it's in the same directory or installed)
try:
    from rfdetr import RFDETRMedium
except ImportError:
    print("Warning: RF-DETR not found. Please ensure it's properly installed.")
    RFDETRMedium = None

# ============================================================================
# Configuration for Hugging Face Spaces
# ============================================================================

class SpacesConfig:
    """Configuration optimized for Hugging Face Spaces."""

    def __init__(self):
        # Get HF token from environment
        hf_token = os.environ.get('HF_TOKEN') or os.environ.get('HUGGINGFACE_TOKEN')
        
        self.settings = {
            'results_dir': '/tmp/results',
            'checkpoint': None,
            'hf_model_repo': 'edeler/lorai',  # Hugging Face model repository
            'hf_model_filename': 'lorai.pth',
            'hf_token': hf_token,
            'resolution': 576,
            'threshold': 0.7,
            'use_llm': True,
            'llm_model_id': 'google/medgemma-4b-it',
            'llm_max_new_tokens': 200,
            'llm_temperature': 0.2,
            'llm_4bit': True,
            'enable_caching': True,
            'max_cache_size': 100,
        }

    def get(self, key: str, default: Any = None) -> Any:
        return self.settings.get(key, default)
    
    def set_hf_model_repo(self, repo_id: str, filename: str = 'lorai.pth'):
        """Set Hugging Face model repository."""
        self.settings['hf_model_repo'] = repo_id
        self.settings['hf_model_filename'] = filename

# ============================================================================
# Memory Management (simplified for Spaces)
# ============================================================================

class MemoryManager:
    """Simplified memory management for Spaces."""

    def __init__(self):
        self.memory_thresholds = {
            'gpu_warning': 0.8,
            'system_warning': 0.85,
        }

    def cleanup_memory(self, force: bool = False) -> None:
        """Perform memory cleanup."""
        try:
            gc.collect()
            if torch and torch.cuda.is_available():
                torch.cuda.empty_cache()
                torch.cuda.synchronize()
        except Exception as e:
            print(f"Memory cleanup error: {e}")

# Global memory manager
memory_manager = MemoryManager()

# ============================================================================
# Model Loading
# ============================================================================

def find_checkpoint(hf_repo: Optional[str] = None, hf_filename: str = 'lorai.pth') -> Optional[str]:
    """Find RF-DETR checkpoint in various locations or download from Hugging Face Hub."""
    
    # First check if we should download from Hugging Face
    repo_id = hf_repo or os.environ.get('HF_MODEL_REPO')
    
    if repo_id and hf_hub_download is not None:
        try:
            print(f"Downloading checkpoint from Hugging Face Hub: {repo_id}/{hf_filename}")
            checkpoint_path = hf_hub_download(
                repo_id=repo_id,
                filename=hf_filename,
                cache_dir="/tmp/hf_cache"
            )
            print(f"✓ Downloaded checkpoint to: {checkpoint_path}")
            return checkpoint_path
        except Exception as e:
            print(f"Warning: Failed to download from Hugging Face Hub: {e}")
            print("Falling back to local checkpoints...")
    
    # Fall back to local file search
    candidates = [
        "lorai.pth",  # Current directory
        "rf-detr-medium.pth",
        "/tmp/results/checkpoint_best_total.pth",
        "/tmp/results/checkpoint_best_ema.pth",
        "/tmp/results/checkpoint_best_regular.pth",
        "/tmp/results/checkpoint.pth",
    ]

    for path in candidates:
        if os.path.isfile(path):
            print(f"Found local checkpoint: {path}")
            return path
    
    return None

def load_model(checkpoint_path: str, resolution: int):
    """Load RF-DETR model."""
    if RFDETRMedium is None:
        raise RuntimeError("RF-DETR not available. Please install it properly.")

    model = RFDETRMedium(pretrain_weights=checkpoint_path, resolution=resolution)
    try:
        model.optimize_for_inference()
    except Exception:
        pass
    return model

# ============================================================================
# LLM Integration
# ============================================================================

class TextGenerator:
    """Simplified text generator for Spaces."""

    def __init__(self, model_id: str, max_tokens: int = 200, temperature: float = 0.2):
        self.model_id = model_id
        self.max_tokens = max_tokens
        self.temperature = temperature
        self.model = None
        self.tokenizer = None
        self.processor = None
        self.is_multimodal = False

    def load_model(self, hf_token: Optional[str] = None):
        """Load the LLM model."""
        if self.model is not None:
            return

        if (AutoModelForCausalLM is None and AutoModelForImageTextToText is None):
            raise RuntimeError("Transformers not available")

        # Clear memory before loading
        memory_manager.cleanup_memory()

        print(f"Loading model: {self.model_id}")

        model_kwargs = {
            "device_map": "auto",
            "low_cpu_mem_usage": True,
        }
        
        # Add token if provided
        if hf_token:
            model_kwargs["token"] = hf_token

        if torch and torch.cuda.is_available():
            model_kwargs["torch_dtype"] = torch.bfloat16

        # Use 4-bit quantization if available
        if BitsAndBytesConfig is not None:
            try:
                compute_dtype = torch.bfloat16 if torch and torch.cuda.is_available() else torch.float16
                model_kwargs["quantization_config"] = BitsAndBytesConfig(
                    load_in_4bit=True,
                    bnb_4bit_compute_dtype=compute_dtype,
                    bnb_4bit_use_double_quant=True,
                    bnb_4bit_quant_type="nf4"
                )
                model_kwargs["torch_dtype"] = compute_dtype
            except Exception:
                pass

        # Check if it's a multimodal model
        is_multimodal = "medgemma" in self.model_id.lower()

        if is_multimodal and AutoModelForImageTextToText is not None and AutoProcessor is not None:
            self.processor = AutoProcessor.from_pretrained(self.model_id, token=hf_token)
            self.model = AutoModelForImageTextToText.from_pretrained(self.model_id, **model_kwargs)
            self.is_multimodal = True
        elif AutoModelForCausalLM is not None and AutoTokenizer is not None:
            self.tokenizer = AutoTokenizer.from_pretrained(self.model_id, token=hf_token)
            self.model = AutoModelForCausalLM.from_pretrained(self.model_id, **model_kwargs)
            self.is_multimodal = False
        else:
            raise RuntimeError("Required model classes not available")

        print("✓ Model loaded successfully")

    def generate(self, text: str, image: Optional[Image.Image] = None, hf_token: Optional[str] = None) -> str:
        """Generate text using the loaded model."""
        self.load_model(hf_token)

        if self.model is None:
            return f"[Model not loaded: {text}]"

        try:
            # Create messages
            system_text = "You are a concise medical assistant. Provide a brief, clear summary of detection results. Avoid repetition and be direct. Do not give medical advice."
            user_text = f"Summarize these detection results in 3 clear sentences:\n\n{text}"

            if self.is_multimodal:
                # Multimodal model
                user_content = [{"type": "text", "text": user_text}]
                if image is not None:
                    user_content.append({"type": "image", "image": image})

                messages = [
                    {"role": "system", "content": [{"type": "text", "text": system_text}]},
                    {"role": "user", "content": user_content},
                ]

                inputs = self.processor.apply_chat_template(
                    messages,
                    add_generation_prompt=True,
                    tokenize=True,
                    return_dict=True,
                    return_tensors="pt",
                )

                if torch:
                    inputs = inputs.to(self.model.device, dtype=torch.bfloat16)

                with torch.inference_mode():
                    generation = self.model.generate(
                        **inputs,
                        max_new_tokens=self.max_tokens,
                        do_sample=self.temperature > 0,
                        temperature=max(0.01, self.temperature) if self.temperature > 0 else None,
                        use_cache=False,
                    )

                input_len = inputs["input_ids"].shape[-1]
                generation = generation[0][input_len:]
                decoded = self.processor.decode(generation, skip_special_tokens=True)
                return decoded.strip()

            else:
                # Text-only model
                messages = [
                    {"role": "system", "content": system_text},
                    {"role": "user", "content": user_text},
                ]

                inputs = self.tokenizer.apply_chat_template(
                    messages,
                    add_generation_prompt=True,
                    tokenize=True,
                    return_dict=True,
                    return_tensors="pt",
                )

                inputs = inputs.to(self.model.device)

                with torch.inference_mode():
                    generation = self.model.generate(
                        **inputs,
                        max_new_tokens=self.max_tokens,
                        do_sample=self.temperature > 0,
                        temperature=max(0.01, self.temperature) if self.temperature > 0 else None,
                        use_cache=False,
                    )

                input_len = inputs["input_ids"].shape[-1]
                generation = generation[0][input_len:]
                decoded = self.tokenizer.decode(generation, skip_special_tokens=True)
                return decoded.strip()

        except Exception as e:
            error_msg = f"[Generation error: {e}]"
            print(f"Generation error: {traceback.format_exc()}")
            return f"{error_msg}\n\n{text}"

# ============================================================================
# Application State
# ============================================================================

class AppState:
    """Application state for Spaces."""

    def __init__(self):
        self.config = SpacesConfig()
        self.model = None
        self.class_names = None
        self.text_generator = None

    def load_model(self):
        """Load the detection model."""
        if self.model is not None:
            return

        checkpoint = find_checkpoint(
            hf_repo=self.config.get('hf_model_repo'),
            hf_filename=self.config.get('hf_model_filename', 'lorai.pth')
        )
        if not checkpoint:
            hf_repo = self.config.get('hf_model_repo') or os.environ.get('HF_MODEL_REPO')
            if hf_repo:
                raise FileNotFoundError(
                    f"No RF-DETR checkpoint found. Could not download from '{hf_repo}'. "
                    "Please check the repository ID and ensure the model file exists."
                )
            else:
                raise FileNotFoundError(
                    "No RF-DETR checkpoint found. Please either:\n"
                    "1. Set HF_MODEL_REPO environment variable (e.g., 'edeler/lorai'), or\n"
                    "2. Upload lorai.pth to your Space's root directory"
                )

        print(f"Loading RF-DETR from: {checkpoint}")
        self.model = load_model(checkpoint, self.config.get('resolution'))

        # Try to load class names
        try:
            results_json = "/tmp/results/results.json"
            if os.path.isfile(results_json):
                with open(results_json, 'r') as f:
                    data = json.load(f)
                classes = []
                for split in ("valid", "test", "train"):
                    if "class_map" in data and split in data["class_map"]:
                        for item in data["class_map"][split]:
                            name = item.get("class")
                            if name and name != "all" and name not in classes:
                                classes.append(name)
                self.class_names = classes if classes else None
        except Exception:
            pass

        print("✓ RF-DETR model loaded")

    def preload_all_models(self):
        """Preload both detection and LLM models into VRAM at startup."""
        print("=" * 60)
        print("Preloading all models into VRAM...")
        print("=" * 60)
        
        # Load detection model
        print("\n[1/2] Loading RF-DETR detection model...")
        self.load_model()
        
        # Load LLM model
        if self.config.get('use_llm'):
            print("\n[2/2] Loading MedGemma LLM model...")
            try:
                model_size = "4B"  # Default to 4B model
                generator = self.get_text_generator(model_size)
                hf_token = self.config.get('hf_token')
                generator.load_model(hf_token)
                print("✓ MedGemma model loaded and ready")
            except Exception as e:
                print(f"⚠️ Warning: Could not preload LLM model: {e}")
                print("LLM will be loaded on first use instead")
        
        print("\n" + "=" * 60)
        print("✓ All models loaded and ready in VRAM!")
        print("=" * 60 + "\n")

    def get_text_generator(self, model_size: str = "4B") -> TextGenerator:
        """Get or create text generator."""
        # Determine model ID based on size selection
        model_id = 'google/medgemma-27b-it' if model_size == "27B" else 'google/medgemma-4b-it'

        # Check if we need to create a new generator for different model size
        if (self.text_generator is None or
            hasattr(self.text_generator, 'model_id') and
            self.text_generator.model_id != model_id):

            max_tokens = self.config.get('llm_max_new_tokens')
            temperature = self.config.get('llm_temperature')

            self.text_generator = TextGenerator(model_id, max_tokens, temperature)
        return self.text_generator

# ============================================================================
# UI and Inference
# ============================================================================

def create_detection_interface():
    """Create the Gradio interface."""

    # Color palette for annotations
    COLOR_PALETTE = sv.ColorPalette.from_hex([
        "#ffff00", "#ff9b00", "#ff66ff", "#3399ff", "#ff66b2",
        "#ff8080", "#b266ff", "#9999ff", "#66ffff", "#33ff99",
        "#66ff66", "#99ff00",
    ])

    @spaces.GPU
    def annotate_image(image: Image.Image, threshold: float, model_size: str = "4B") -> Tuple[Image.Image, str]:
        """Process an image and return annotated version with description."""

        if image is None:
            return None, "Please upload an image."

        try:
            # Models are preloaded at startup, but check just in case
            if app_state.model is None:
                app_state.load_model()

            # Run detection
            detections = app_state.model.predict(image, threshold=threshold)

            # Annotate image
            bbox_annotator = sv.BoxAnnotator(color=COLOR_PALETTE, thickness=2)
            label_annotator = sv.LabelAnnotator(text_scale=0.5, text_color=sv.Color.BLACK)

            labels = []
            for i in range(len(detections)):
                class_id = int(detections.class_id[i]) if detections.class_id is not None else None
                conf = float(detections.confidence[i]) if detections.confidence is not None else 0.0

                if app_state.class_names and class_id is not None:
                    if 0 <= class_id < len(app_state.class_names):
                        label_name = app_state.class_names[class_id]
                    else:
                        label_name = str(class_id)
                else:
                    label_name = str(class_id) if class_id is not None else "object"

                labels.append(f"{label_name} {conf:.2f}")

            annotated = image.copy()
            annotated = bbox_annotator.annotate(annotated, detections)
            annotated = label_annotator.annotate(annotated, detections, labels)

            # Generate description
            description = f"Found {len(detections)} detections above threshold {threshold}:\n\n"

            if len(detections) > 0:
                counts = {}
                for i in range(len(detections)):
                    class_id = int(detections.class_id[i]) if detections.class_id is not None else None
                    if app_state.class_names and class_id is not None:
                        if 0 <= class_id < len(app_state.class_names):
                            name = app_state.class_names[class_id]
                        else:
                            name = str(class_id)
                    else:
                        name = str(class_id) if class_id is not None else "object"
                    counts[name] = counts.get(name, 0) + 1

                for name, count in counts.items():
                    description += f"- {count}× {name}\n"

                # Use LLM for description if enabled
                if app_state.config.get('use_llm'):
                    try:
                        generator = app_state.get_text_generator(model_size)
                        hf_token = app_state.config.get('hf_token')
                        # Model is already preloaded, just generate
                        llm_description = generator.generate(description, image=annotated, hf_token=hf_token)
                        description = llm_description
                    except Exception as e:
                        print(f"LLM generation failed: {e}")
                        # Just use the basic description if LLM fails
                        pass
            else:
                description += "No objects detected above the confidence threshold."

            return annotated, description

        except Exception as e:
            error_msg = f"Error processing image: {str(e)}"
            print(f"Processing error: {traceback.format_exc()}")
            return None, error_msg

    # Create the interface
    with gr.Blocks(title="Medical Image Analysis", theme=gr.themes.Soft()) as demo:
        gr.Markdown("# 🏥 Medical Image Analysis")
        gr.Markdown("Upload a medical image to detect and analyze findings using AI.")
        
        # Check if HF token is available
        hf_token = app_state.config.get('hf_token')
        if not hf_token:
            gr.Markdown("⚠️ **Note:** HF_TOKEN not set. AI text generation will be disabled. Detection will still work.")
        else:
            gr.Markdown("✅ **AI-powered analysis enabled** using MedGemma 4B")

        with gr.Row():
            with gr.Column():
                input_image = gr.Image(type="pil", label="Upload Image", height=400)
                threshold_slider = gr.Slider(
                    minimum=0.1,
                    maximum=1.0,
                    value=0.7,
                    step=0.05,
                    label="Confidence Threshold",
                    info="Higher values = fewer but more confident detections"
                )

                model_size_radio = gr.Radio(
                    choices=["4B"],
                    value="4B",
                    label="MedGemma Model Size",
                    info="Using MedGemma 4B for AI-generated analysis",
                    visible=False  # Hide since only one option
                )

                analyze_btn = gr.Button("🔍 Analyze Image", variant="primary")
                
                # Example images
                gr.Examples(
                    examples=[
                        ["1.jpg"],
                        ["2.jpg"],
                        ["3.jpg"],
                    ],
                    inputs=input_image,
                    label="Example Images",
                    examples_per_page=3
                )

            with gr.Column():
                output_image = gr.Image(type="pil", label="Results", height=400)
                output_text = gr.Textbox(
                    label="Analysis Results",
                    lines=8,
                    max_lines=15,
                    show_copy_button=True
                )

        # Wire up the interface
        analyze_btn.click(
            fn=annotate_image,
            inputs=[input_image, threshold_slider, model_size_radio],
            outputs=[output_image, output_text]
        )

        # Also run when image is uploaded
        input_image.change(
            fn=annotate_image,
            inputs=[input_image, threshold_slider, model_size_radio],
            outputs=[output_image, output_text]
        )

        # Footer
        gr.Markdown("---")

    return demo

# ============================================================================
# Main Application
# ============================================================================

# Global app state
app_state = AppState()

def main():
    """Main entry point for the Spaces app."""
    print("🚀 Starting Medical Image Analysis App")

    # Ensure results directory exists
    os.makedirs(app_state.config.get('results_dir'), exist_ok=True)

    # Preload models if NOT running on HF Spaces with GPU
    # On HF Spaces, models will be loaded on first inference call (triggered by @spaces.GPU)
    if not HF_SPACES_GPU:
        print("Running locally - preloading models into VRAM...")
        try:
            app_state.preload_all_models()
        except Exception as e:
            print(f"⚠️ Warning: Failed to preload models: {e}")
            print("Models will be loaded on first use instead")
    else:
        print("Running on HF Spaces - models will load on first inference (via @spaces.GPU)")
        print("This is the recommended approach for Spaces GPU management.")

    # Create and launch the interface
    demo = create_detection_interface()

    # Launch with Spaces-optimized settings
    demo.launch(
        server_name="0.0.0.0",
        server_port=7860,
        share=False,  # Spaces handles this
        show_error=True,
        show_api=False,
    )

if __name__ == "__main__":
    main()