app.py

#!/usr/bin/env python3
"""
AR-Diffusion Chat Interface for Hugging Face Spaces
Experimental model with Quality vs Speed modes
Optimized for Zero GPU deployment with @spaces.GPU
"""

import gradio as gr
import torch
import torch.nn.functional as F
from transformers import AutoTokenizer, AutoModelForCausalLM
import random
import numpy as np
import re
import time
from typing import List, Tuple
import os
import gc
import spaces

# Global model variables for memory efficiency
tokenizer = None
model = None
device = None

class ARDiffusionGenerator:
    """Base AR-Diffusion generator with shared functionality"""
    
    def __init__(self, tokenizer, model, device):
        self.tokenizer = tokenizer
        self.model = model
        self.device = device
        self.mask_token_id = self._find_mask_token()
    
    def _find_mask_token(self) -> int:
        """Find MASK token ID"""
        for candidate in ['MASK', '<mask>', '[MASK]', '<|mask|>']:
            try:
                tokens = self.tokenizer.encode(candidate, add_special_tokens=False)
                if len(tokens) == 1:
                    return tokens[0]
            except:
                continue
        return getattr(self.tokenizer, 'unk_token_id', 50257) or 50257
    
    def create_prompt(self, instruction: str) -> str:
        """Create Alpaca-style prompt"""
        return f"""### Instruction:
{instruction}

### Response:
"""

class QualityGenerator(ARDiffusionGenerator):
    """Quality-focused AR-Diffusion generator"""
    
    def filter_logits(self, logits: torch.Tensor, top_k: int = 0, top_p: float = 1.0, 
                     temperature: float = 1.0) -> torch.Tensor:
        """Research-grade filtering with proper order"""
        original_shape = logits.shape
        if logits.dim() == 3:
            logits = logits.squeeze(0)
        elif logits.dim() == 1:
            logits = logits.unsqueeze(0)
        
        logits = logits.clone()
        
        # Temperature scaling first
        if temperature != 1.0:
            logits = logits / temperature
        
        # Top-k filtering
        if top_k > 0 and top_k < logits.size(-1):
            topk_vals, _ = torch.topk(logits, top_k, dim=-1)
            thresholds = topk_vals[:, -1].unsqueeze(-1)
            logits = torch.where(logits < thresholds, 
                               torch.full_like(logits, float("-inf")), logits)
        
        # Top-p filtering
        if top_p > 0.0 and top_p < 1.0:
            sorted_logits, sorted_indices = torch.sort(logits, descending=True, dim=-1)
            probs = torch.softmax(sorted_logits, dim=-1)
            cum_probs = probs.cumsum(dim=-1)
            
            mask = cum_probs > top_p
            mask[:, 0] = False
            
            scatter_mask = torch.zeros_like(logits, dtype=torch.bool).scatter(
                dim=-1, index=sorted_indices, src=mask)
            logits = torch.where(scatter_mask, 
                               torch.full_like(logits, float("-inf")), logits)
        
        # Restore original shape
        if len(original_shape) == 1:
            logits = logits.squeeze(0)
        elif original_shape[0] == 1 and logits.dim() == 2:
            logits = logits.unsqueeze(0)
        
        return logits
    
    def generate_start(self, prompt: str, length: int = 8) -> List[int]:
        """Generate natural start"""
        tokens = self.tokenizer(prompt, return_tensors="pt").to(self.device)
        input_ids = tokens['input_ids'][0]
        
        generated = []
        current = input_ids.clone()
        
        with torch.no_grad():
            for _ in range(length):
                outputs = self.model(input_ids=current.unsqueeze(0))
                logits = outputs.logits[0, -1]
                
                filtered_logits = self.filter_logits(
                    logits, top_k=50, top_p=0.9, temperature=0.8
                )
                
                probs = F.softmax(filtered_logits, dim=-1)
                next_token = torch.multinomial(probs, 1).item()
                
                if next_token in [self.tokenizer.eos_token_id, 128001, 13]:
                    break
                
                generated.append(next_token)
                current = torch.cat([current, torch.tensor([next_token], device=self.device)])
        
        return generated
    
    def create_sequence(self, prompt: str) -> Tuple[str, torch.Tensor]:
        """Create corrupted sequence for quality mode"""
        prompt_tokens = self.tokenizer(prompt, return_tensors="pt")['input_ids'][0]
        natural_start = self.generate_start(prompt, length=random.randint(8, 12))
        
        # Longer sequences for better quality
        prompt_length = len(prompt_tokens)
        if prompt_length > 25:
            num_masks = random.randint(35, 50)
        elif prompt_length > 15:
            num_masks = random.randint(25, 40)
        else:
            num_masks = random.randint(20, 35)
        
        sequence = (
            prompt_tokens.tolist() +
            natural_start +
            [self.mask_token_id] * num_masks +
            [13]
        )
        
        tensor = torch.tensor(sequence)
        text = self.tokenizer.decode(tensor, skip_special_tokens=False)
        return text, tensor
    
    def generate(self, prompt: str, progress_callback=None) -> Tuple[str, dict]:
        """Quality generation with progress updates and speed tracking"""
        steps = 40
        temperature = 0.7
        start_time = time.time()
        
        if progress_callback:
            progress_callback(0.1, "Creating sequence...")
        
        full_prompt = self.create_prompt(prompt)
        corrupted_text, corrupted_ids = self.create_sequence(full_prompt)
        
        if progress_callback:
            progress_callback(0.2, "Starting quality denoising...")
        
        result, stats = self._denoise_quality(corrupted_ids, steps, temperature, progress_callback)
        
        # Calculate overall stats
        total_time = time.time() - start_time
        response = self._clean_response(result)
        word_count = len(response.split())
        
        stats.update({
            'total_time': total_time,
            'word_count': word_count,
            'words_per_second': word_count / total_time if total_time > 0 else 0
        })
        
        return response, stats
    
    def _denoise_quality(self, corrupted_ids: torch.Tensor, steps: int, temperature: float, progress_callback=None) -> Tuple[str, dict]:
        """Quality denoising with progress updates and speed tracking"""
        current_ids = corrupted_ids.clone()
        total_replacements = 0
        start_time = time.time()
        
        for step in range(steps):
            if progress_callback:
                progress = 0.2 + (step / steps) * 0.7
                elapsed = time.time() - start_time
                tokens_per_sec = total_replacements / elapsed if elapsed > 0 else 0
                progress_callback(progress, f"Quality step {step+1}/{steps} | {tokens_per_sec:.1f} tok/s")
            
            mask_positions = (current_ids == self.mask_token_id).nonzero(as_tuple=True)[0]
            
            if len(mask_positions) == 0:
                break
            
            with torch.no_grad():
                outputs = self.model(input_ids=current_ids.unsqueeze(0).to(self.device))
                logits = outputs.logits[0]
                
                current_temp = max(0.4, temperature * (1 - step / steps))
                
                # Conservative replacement for quality
                if step < steps // 4:
                    max_replacements = min(1, len(mask_positions))
                elif step < steps // 2:
                    max_replacements = min(2, len(mask_positions))
                else:
                    max_replacements = min(3, len(mask_positions))
                
                sorted_positions = sorted(mask_positions.tolist())
                
                for pos in sorted_positions[:max_replacements]:
                    if pos < len(logits):
                        token_logits = logits[pos].clone()
                        
                        # Anti-repetition
                        context_start = max(0, pos - 5)
                        recent_tokens = set(current_ids[context_start:pos].tolist())
                        for recent_token in recent_tokens:
                            if recent_token < len(token_logits):
                                token_logits[recent_token] -= 8.0
                        
                        # Quality filtering
                        filtered_logits = self.filter_logits(
                            token_logits, 
                            top_k=30,
                            top_p=0.75,
                            temperature=current_temp
                        )
                        
                        probs = F.softmax(filtered_logits, dim=-1)
                        probs = torch.clamp(probs, min=1e-8, max=1.0)
                        new_token = torch.multinomial(probs, 1).item()
                        
                        # Filter unwanted tokens
                        unwanted = [self.mask_token_id, 128001, 128000]
                        if new_token in unwanted:
                            top_k_vals, top_k_indices = torch.topk(filtered_logits, 10)
                            for alternative in top_k_indices:
                                if alternative.item() not in unwanted:
                                    new_token = alternative.item()
                                    break
                        
                        current_ids[pos] = new_token
                        total_replacements += 1
        
        if progress_callback:
            elapsed = time.time() - start_time
            final_speed = total_replacements / elapsed if elapsed > 0 else 0
            progress_callback(0.95, f"Finalizing... | Final speed: {final_speed:.1f} tok/s")
        
        # Calculate final statistics
        total_time = time.time() - start_time
        stats = {
            'mode': 'Quality',
            'steps': steps,
            'tokens_replaced': total_replacements,
            'generation_time': total_time,
            'tokens_per_second': total_replacements / total_time if total_time > 0 else 0
        }
        
        result = self.tokenizer.decode(current_ids, skip_special_tokens=True)
        return result, stats
    
    def _clean_response(self, text: str) -> str:
        """Clean response for quality output"""
        if "### Response:" in text:
            response = text.split("### Response:")[-1].strip()
        else:
            response = text.strip()
        
        if not response:
            return text
        
        # Quality cleaning
        response = re.sub(r"'{2,}", "", response)
        response = re.sub(r'"{2,}', "", response)
        response = re.sub(r"\.{2,}", ".", response)
        response = re.sub(r",{2,}", ",", response)
        response = re.sub(r"\s+", " ", response)
        
        # Remove artifacts
        response = re.sub(r"\$+", "", response)
        response = re.sub(r"#+", "", response)
        response = re.sub(r"@+", "", response)
        
        response = response.strip()
        if response and not response.endswith(('.', '!', '?')):
            response += "."
        
        return response

class SpeedGenerator(ARDiffusionGenerator):
    """Speed-focused AR-Diffusion generator"""
    
    def filter_logits(self, logits: torch.Tensor, top_k: int = 15, top_p: float = 0.8, 
                     temperature: float = 1.0) -> torch.Tensor:
        """Fast logits filtering"""
        logits = logits.clone()
        
        if temperature != 1.0:
            logits = logits / temperature
        
        # Top-k filtering
        if top_k > 0 and top_k < logits.size(-1):
            topk_vals, _ = torch.topk(logits, top_k, dim=-1)
            threshold = topk_vals[-1]
            logits = torch.where(logits < threshold, torch.full_like(logits, float("-inf")), logits)
        
        # Top-p filtering
        if top_p > 0.0 and top_p < 1.0:
            sorted_logits, sorted_indices = torch.sort(logits, descending=True, dim=-1)
            probs = torch.softmax(sorted_logits, dim=-1)
            cum_probs = probs.cumsum(dim=-1)
            
            mask = cum_probs > top_p
            mask[0] = False
            
            scatter_mask = torch.zeros_like(logits, dtype=torch.bool)
            scatter_mask.scatter_(0, sorted_indices, mask)
            logits = torch.where(scatter_mask, torch.full_like(logits, float("-inf")), logits)
        
        return logits
    
    def generate_start(self, prompt: str, length: int = 6) -> List[int]:
        """Generate natural start for speed mode"""
        tokens = self.tokenizer(prompt, return_tensors="pt").to(self.device)
        input_ids = tokens['input_ids'][0]
        
        generated = []
        current = input_ids.clone()
        
        with torch.no_grad():
            for _ in range(length):
                outputs = self.model(input_ids=current.unsqueeze(0))
                logits = outputs.logits[0, -1]
                
                filtered_logits = self.filter_logits(logits, top_k=20, top_p=0.9, temperature=0.8)
                probs = F.softmax(filtered_logits, dim=-1)
                next_token = torch.multinomial(probs, 1).item()
                
                if next_token in [self.tokenizer.eos_token_id, 128001, 13]:
                    break
                
                generated.append(next_token)
                current = torch.cat([current, torch.tensor([next_token], device=self.device)])
        
        return generated
    
    def create_sequence(self, prompt: str) -> Tuple[str, torch.Tensor]:
        """Create sequence optimized for speed"""
        prompt_tokens = self.tokenizer(prompt, return_tensors="pt")['input_ids'][0]
        natural_start = self.generate_start(prompt, length=6)
        
        # Shorter sequences for speed
        prompt_words = len(prompt.split())
        if prompt_words > 8:
            num_masks = random.randint(15, 25)
        else:
            num_masks = random.randint(12, 20)
        
        sequence = (
            prompt_tokens.tolist() +
            natural_start +
            [self.mask_token_id] * num_masks +
            [13]
        )
        
        tensor = torch.tensor(sequence)
        text = self.tokenizer.decode(tensor, skip_special_tokens=False)
        return text, tensor
    
    def generate(self, prompt: str, progress_callback=None) -> Tuple[str, dict]:
        """Speed generation with progress updates and speed tracking"""
        steps = 10
        temperature = 0.8
        start_time = time.time()
        
        if progress_callback:
            progress_callback(0.1, "Creating sequence...")
        
        full_prompt = self.create_prompt(prompt)
        corrupted_text, corrupted_ids = self.create_sequence(full_prompt)
        
        if progress_callback:
            progress_callback(0.2, "Starting speed denoising...")
        
        result, stats = self._denoise_speed(corrupted_ids, steps, temperature, progress_callback)
        
        # Calculate overall stats
        total_time = time.time() - start_time
        response = self._clean_response(result)
        word_count = len(response.split())
        
        stats.update({
            'total_time': total_time,
            'word_count': word_count,
            'words_per_second': word_count / total_time if total_time > 0 else 0
        })
        
        return response, stats
    
    def _denoise_speed(self, corrupted_ids: torch.Tensor, steps: int, temperature: float, progress_callback=None) -> Tuple[str, dict]:
        """Ultra-fast denoising with progress updates and speed tracking"""
        current_ids = corrupted_ids.clone()
        total_replacements = 0
        start_time = time.time()
        
        # Use mixed precision for speed on GPU
        with torch.autocast(device_type='cuda', dtype=torch.float16, enabled=self.device.type == 'cuda'):
            for step in range(steps):
                if progress_callback:
                    progress = 0.2 + (step / steps) * 0.7
                    elapsed = time.time() - start_time
                    tokens_per_sec = total_replacements / elapsed if elapsed > 0 else 0
                    progress_callback(progress, f"Speed step {step+1}/{steps} | {tokens_per_sec:.1f} tok/s")
                
                mask_pos = (current_ids == self.mask_token_id).nonzero(as_tuple=True)[0]
                
                if len(mask_pos) == 0:
                    break
                
                with torch.no_grad():
                    outputs = self.model(input_ids=current_ids.unsqueeze(0).to(self.device))
                    logits = outputs.logits[0]
                    
                    current_temp = temperature * (0.9 + 0.2 * (step / steps))
                    
                    # Aggressive replacement for speed
                    max_replace = min(8, len(mask_pos))
                    positions = sorted(mask_pos.tolist())[:max_replace]
                    
                    for pos in positions:
                        if pos < len(logits):
                            token_logits = logits[pos].clone()
                            
                            # Light anti-repetition
                            recent_start = max(0, pos - 3)
                            recent_tokens = set(current_ids[recent_start:pos].tolist())
                            for token in recent_tokens:
                                if token < len(token_logits):
                                    token_logits[token] -= 3.0
                            
                            # Fast filtering
                            filtered_logits = self.filter_logits(
                                token_logits, top_k=12, top_p=0.85, temperature=current_temp
                            )
                            
                            probs = F.softmax(filtered_logits, dim=-1)
                            probs = torch.clamp(probs, min=1e-8, max=1.0)
                            new_token = torch.multinomial(probs, 1).item()
                            
                            # Quick filtering
                            if new_token in [self.mask_token_id, 128001, 128000]:
                                top_vals, top_indices = torch.topk(filtered_logits, 3)
                                new_token = top_indices[1].item()
                            
                            current_ids[pos] = new_token
                            total_replacements += 1
        
        if progress_callback:
            elapsed = time.time() - start_time
            final_speed = total_replacements / elapsed if elapsed > 0 else 0
            progress_callback(0.95, f"Finalizing... | Final speed: {final_speed:.1f} tok/s")
        
        # Calculate final statistics
        total_time = time.time() - start_time
        stats = {
            'mode': 'Speed',
            'steps': steps,
            'tokens_replaced': total_replacements,
            'generation_time': total_time,
            'tokens_per_second': total_replacements / total_time if total_time > 0 else 0
        }
        
        result = self.tokenizer.decode(current_ids, skip_special_tokens=True)
        return result, stats
    
    def _clean_response(self, text: str) -> str:
        """Clean response for speed output"""
        if "### Response:" in text:
            response = text.split("### Response:")[-1].strip()
        else:
            response = text.strip()
        
        if not response:
            return text
        
        # Minimal cleaning for speed
        response = re.sub(r"'{3,}", "", response)
        response = re.sub(r'"{3,}', "", response)
        response = re.sub(r"\.{3,}", ".", response)
        response = re.sub(r",{3,}", ",", response)
        response = re.sub(r"\s+", " ", response)
        
        response = response.strip()
        if response and not response.endswith(('.', '!', '?')):
            response += "."
        
        return response

@spaces.GPU
def load_model():
    """Load model with Zero GPU optimization using @spaces.GPU"""
    global tokenizer, model, device
    
    if tokenizer is not None and model is not None:
        return tokenizer, model, device
    
    try:
        # This appears to be a LoRA adapter
        adapter_path = "rootxhacker/llama-3B-diffusion-exp-fixed"
        device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
        
        print(f"Loading AR-Diffusion model on {device}...")
        
        # Load tokenizer from adapter
        tokenizer = AutoTokenizer.from_pretrained(adapter_path, trust_remote_code=True)
        if tokenizer.pad_token is None:
            tokenizer.pad_token = tokenizer.eos_token
        
        # Load the adapter model
        print("Loading adapter model...")
        model = AutoModelForCausalLM.from_pretrained(
            adapter_path,
            torch_dtype=torch.float16 if device.type == "cuda" else torch.float32,
            device_map="auto" if device.type == "cuda" else None,
            trust_remote_code=True,
            low_cpu_mem_usage=True
        )
        
        print("✅ AR-Diffusion model loaded successfully!")
        return tokenizer, model, device
        
    except Exception as e:
        print(f"❌ Error loading {adapter_path}: {e}")
        
        # Fallback to a working model for demonstration
        print("🔄 Falling back to demonstration model...")
        device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
        fallback_model = "gpt2-medium"
        
        tokenizer = AutoTokenizer.from_pretrained(fallback_model)
        if tokenizer.pad_token is None:
            tokenizer.pad_token = tokenizer.eos_token
            
        model = AutoModelForCausalLM.from_pretrained(
            fallback_model,
            torch_dtype=torch.float16 if device.type == "cuda" else torch.float32,
            device_map="auto" if device.type == "cuda" else None,
            low_cpu_mem_usage=True
        )
        
        print(f"✅ Fallback model {fallback_model} loaded successfully!")
        print("⚠️ Note: Using fallback model - AR-Diffusion features may not work as expected")
        return tokenizer, model, device

def cleanup_memory():
    """Clean up GPU memory"""
    if torch.cuda.is_available():
        torch.cuda.empty_cache()
    gc.collect()

@spaces.GPU
def chat_function(message, history, mode, progress=gr.Progress()):
    """Main chat function with @spaces.GPU decorator, progress tracking, and speed display"""
    if not message.strip():
        return history, "", ""
    
    try:
        # Load model (this will run on GPU when GPU is allocated)
        progress(0.05)
        tok, mod, dev = load_model()
        
        # Create appropriate generator
        if mode == "Quality (Slower, Better)":
            generator = QualityGenerator(tok, mod, dev)
            progress(0.1)
        else:
            generator = SpeedGenerator(tok, mod, dev)
            progress(0.1)
        
        # Generate response with progress callback
        def progress_callback(pct, status_msg):
            progress(pct)
        
        response, stats = generator.generate(message, progress_callback)
        
        progress(1.0)
        
        # Create performance info
        perf_info = f"""**⚡ Performance Stats:**
- **Mode:** {stats['mode']}
- **Generation Time:** {stats['generation_time']:.2f}s
- **Tokens Replaced:** {stats['tokens_replaced']}
- **Speed:** {stats['tokens_per_second']:.1f} tokens/sec
- **Words Generated:** {stats['word_count']} words
- **Words/Second:** {stats['words_per_second']:.1f}
- **Steps:** {stats['steps']}"""
        
        # Update history
        history.append([message, response])
        
        # Cleanup memory for Zero GPU efficiency
        cleanup_memory()
        
        return history, "", perf_info
        
    except Exception as e:
        error_msg = f"Error: {str(e)}"
        history.append([message, error_msg])
        cleanup_memory()
        return history, "", f"**❌ Error occurred during generation**"

def clear_chat():
    """Clear chat history and cleanup memory"""
    cleanup_memory()
    return [], ""

# Create Gradio interface
def create_interface():
    with gr.Blocks(
        title="AR-Diffusion Chat - Experimental Model",
        theme=gr.themes.Soft(),
        css="""
        .warning-box {
            background-color: #fff3cd;
            border: 1px solid #ffeaa7;
            border-radius: 5px;
            padding: 10px;
            margin: 10px 0;
        }
        """
    ) as interface:
        
        gr.HTML("""
        <div style="text-align: center; margin-bottom: 20px;">
            <h1>🧪 AR-Diffusion Chat Interface</h1>
            <p><strong>⚠️ EXPERIMENTAL MODEL ⚠️</strong></p>
            <p>This is an experimental AR-Diffusion model. Results may vary and the model is still under development.</p>
            <p><em>🔥 Powered by Zero GPU with @spaces.GPU</em></p>
            <p><small>Model: rootxhacker/llama-3B-diffusion-exp-fixed (LoRA Adapter)</small></p>
        </div>
        """)
        
        with gr.Row():
            with gr.Column(scale=3):
                chatbot = gr.Chatbot(
                    [],
                    elem_id="chatbot",
                    bubble_full_width=False,
                    height=500,
                    show_label=False
                )
                
                with gr.Row():
                    msg = gr.Textbox(
                        placeholder="Type your message here...",
                        show_label=False,
                        scale=9
                    )
                    send_btn = gr.Button("Send", scale=1, variant="primary")
                
                with gr.Row():
                    clear_btn = gr.Button("Clear Chat", variant="secondary")
            
            with gr.Column(scale=1):
                gr.HTML("""
                <div class="warning-box">
                    <h3>⚙️ Mode Selection</h3>
                    <p><strong>Quality Mode:</strong> Slower but more coherent responses (~40 steps)</p>
                    <p><strong>Speed Mode:</strong> Faster responses with decent quality (~10 steps)</p>
                    <p><em>🔥 GPU acceleration via @spaces.GPU</em></p>
                </div>
                """)
                
                mode = gr.Radio(
                    choices=["Quality (Slower, Better)", "Speed (Faster)"],
                    value="Quality (Slower, Better)",
                    label="Generation Mode"
                )
                
                # Performance display
                perf_display = gr.Markdown(
                    "**⚡ Performance Stats:** *Generate a message to see stats*",
                    elem_id="performance"
                )
                
                gr.HTML("""
                <div class="warning-box">
                    <h3>ℹ️ About AR-Diffusion</h3>
                    <p>This experimental model uses autoregressive diffusion for text generation, creating responses by iteratively denoising masked tokens.</p>
                    <br>
                    <p><strong>Model:</strong> LoRA adapter trained for AR-Diffusion</p>
                    <p><strong>Note:</strong> This model is experimental and may produce unexpected results. If the specific model fails to load, a fallback model will be used for demonstration.</p>
                </div>
                """)
        
        # Event handlers
        def submit_message(message, history, mode):
            return chat_function(message, history, mode)
        
        send_btn.click(
            submit_message,
            inputs=[msg, chatbot, mode],
            outputs=[chatbot, msg, perf_display]
        )
        
        msg.submit(
            submit_message,
            inputs=[msg, chatbot, mode],
            outputs=[chatbot, msg, perf_display]
        )
        
        clear_btn.click(
            clear_chat,
            outputs=[chatbot, perf_display]
        )
    
    return interface

# Launch interface
if __name__ == "__main__":
    demo = create_interface()
    demo.queue(max_size=20)  # Important for Zero GPU
    demo.launch(
        share=False,
        server_name="0.0.0.0",
        server_port=7860,
        show_error=True
    )

# Requirements.txt should include:
# torch>=2.0.0
# transformers>=4.30.0
# gradio
# numpy
# accelerate
# spaces
# peft