core/unified_model.py

"""
Intelligent Tokenizer v6.2.0 - Unified Model
Integrates encoder, decoder, and tokenizer with all GPT improvements
"""

import torch
import torch.nn as nn
import torch.nn.functional as F
from typing import Dict, List, Optional, Tuple, Union
import math

# Import our components
try:
    from .encoder import EncoderV62
    from .decoder import DecoderV62
    from .tokenizer import ByteTokenizerV62
except ImportError:
    # For standalone testing
    from encoder import EncoderV62
    from decoder import DecoderV62
    from tokenizer import ByteTokenizerV62


class IntelligentTokenizerV62(nn.Module):
    """
    Complete v6.2.0 model with progressive splitting and optimizations

    Key features:
    - 48-byte chunks (46+2 with BOS/EOS)
    - Progressive splitting: 48→1→N→M tokens
    - Multi-level cross-attention
    - KV cache optimization (8x reduction)
    - All GPT-5 improvements integrated
    """

    def __init__(self, config: Optional[Dict] = None):
        super().__init__()

        # Default configuration
        self.config = config or {}

        # Model components
        self.tokenizer = ByteTokenizerV62(config)
        self.encoder = EncoderV62(config)
        self.decoder = DecoderV62(config)

        # Training configuration
        self.compression_weight = 0.1
        self.reconstruction_weight = 0.1
        self.boundary_weight = 0.1

        # Monitoring
        self.register_buffer('training_step', torch.tensor(0))
        self.register_buffer('current_epoch', torch.tensor(0))

    def forward(self,
                input_ids: torch.Tensor = None,
                attention_mask: torch.Tensor = None,
                labels: torch.Tensor = None,
                text: str = None,
                return_loss: bool = True,
                temperature: float = 1.0) -> Dict[str, torch.Tensor]:
        """
        Unified forward pass

        Args:
            input_ids: Pre-tokenized input (optional)
            attention_mask: Attention mask (optional)
            labels: Target labels for training (optional)
            text: Raw text input (alternative to input_ids)
            return_loss: Whether to compute loss
            temperature: Temperature for Gumbel-Softmax in encoder

        Returns:
            Dictionary with model outputs
        """
        # Handle text input
        if text is not None:
            encoded = self.tokenizer.encode(text, add_special_tokens=True)
            input_ids = encoded['input_ids'].unsqueeze(0) if encoded['input_ids'].dim() == 1 else encoded['input_ids']
            attention_mask = encoded['attention_mask'].unsqueeze(0) if encoded['attention_mask'].dim() == 1 else encoded['attention_mask']

        # Handle string passed as input_ids (common mistake)
        if isinstance(input_ids, str):
            text = input_ids
            encoded = self.tokenizer.encode(text, add_special_tokens=True)
            input_ids = encoded['input_ids'].unsqueeze(0) if encoded['input_ids'].dim() == 1 else encoded['input_ids']
            attention_mask = encoded['attention_mask'].unsqueeze(0) if encoded['attention_mask'].dim() == 1 else encoded['attention_mask']

        # Ensure tensors are on the right device
        device = next(self.parameters()).device
        if input_ids is not None and torch.is_tensor(input_ids):
            input_ids = input_ids.to(device)
        if attention_mask is not None and torch.is_tensor(attention_mask):
            attention_mask = attention_mask.to(device)
        if labels is not None and torch.is_tensor(labels):
            labels = labels.to(device)

        # Encoder forward pass with temperature for Gumbel annealing
        encoder_outputs = self.encoder(
            input_ids=input_ids,
            attention_mask=attention_mask,
            temperature=temperature
        )

        # Decoder forward pass
        if labels is not None:
            # Training mode with teacher forcing (GPT suggestion: shift by 1)
            # Input: labels[:-1], Target: labels[1:]
            decoder_input = labels[:, :-1] if labels.dim() > 1 else labels[:-1]
            decoder_mask = attention_mask[:, :-1] if attention_mask is not None and attention_mask.dim() > 1 else None

            decoder_outputs = self.decoder(
                encoder_all_hidden=encoder_outputs['all_hidden_states'],
                decoder_input_ids=decoder_input,
                attention_mask=decoder_mask
            )
        else:
            # Inference mode (without teacher forcing)
            # For now, fallback to using input as labels for stable training
            # TODO: Implement proper autoregressive generation
            if return_loss and input_ids is not None:
                labels = input_ids  # Use input as both input and target
                decoder_input = labels[:, :-1] if labels.dim() > 1 else labels[:-1]
                decoder_mask = attention_mask[:, :-1] if attention_mask is not None and attention_mask.dim() > 1 else None

                decoder_outputs = self.decoder(
                    encoder_all_hidden=encoder_outputs['all_hidden_states'],
                    decoder_input_ids=decoder_input,
                    attention_mask=decoder_mask
                )
            else:
                decoder_outputs = self.decoder(
                    encoder_all_hidden=encoder_outputs['all_hidden_states'],
                    decoder_input_ids=None,
                    attention_mask=attention_mask
                )

        # Combine outputs with prefix to avoid key collision (GPT suggestion)
        outputs = {}
        for key, value in encoder_outputs.items():
            outputs[f'enc_{key}'] = value
        for key, value in decoder_outputs.items():
            outputs[f'dec_{key}'] = value

        # Compute loss if requested
        if return_loss and labels is not None:
            loss = self.compute_loss(outputs, labels, attention_mask)
            outputs['loss'] = loss

        return outputs

    def compute_loss(self,
                    outputs: Dict[str, torch.Tensor],
                    labels: torch.Tensor,
                    attention_mask: Optional[torch.Tensor] = None) -> torch.Tensor:
        """
        Compute combined loss with multiple objectives

        Components:
        1. Reconstruction loss (cross-entropy)
        2. Compression loss (encourage higher compression)
        3. Boundary loss (boundary prediction accuracy)
        """
        losses = {}

        # 1. Reconstruction loss (GPT suggestion: use shifted targets)
        if 'dec_logits' in outputs:
            logits = outputs['dec_logits']

            # Shift targets for next-token prediction
            target_labels = labels[:, 1:] if labels.dim() > 1 else labels[1:]
            target_mask = attention_mask[:, 1:] if attention_mask is not None and attention_mask.dim() > 1 else None

            # Reshape for cross-entropy
            batch_size, seq_len, vocab_size = logits.shape
            logits_flat = logits.reshape(-1, vocab_size)
            labels_flat = target_labels.reshape(-1)

            # Mask out padding (GPT suggestion: use bool mask)
            if target_mask is not None:
                mask_flat = target_mask.reshape(-1).bool()
                reconstruction_loss = F.cross_entropy(
                    logits_flat[mask_flat],
                    labels_flat[mask_flat],
                    ignore_index=self.tokenizer.PAD,
                    label_smoothing=0.1  # Added label smoothing
                )
            else:
                reconstruction_loss = F.cross_entropy(
                    logits_flat,
                    labels_flat,
                    ignore_index=self.tokenizer.PAD,
                    label_smoothing=0.1
                )

            losses['reconstruction'] = reconstruction_loss * self.reconstruction_weight

        # 2. Compression loss (GPT suggestion: use proper device tensor creation)
        if 'enc_compression_ratio' in outputs:
            # Target compression ratio (e.g., 24:1 as per config)
            target_ratio = 24.0
            current_ratio = outputs['enc_compression_ratio']

            # Create tensors on same device (GPT suggestion)
            if isinstance(current_ratio, (int, float)):
                current_ratio_tensor = labels.new_tensor(current_ratio, dtype=torch.float32)
            else:
                current_ratio_tensor = current_ratio.float()
            target_ratio_tensor = labels.new_tensor(target_ratio, dtype=torch.float32)

            # Penalize deviation from target (use smooth L1 to avoid explosion)
            compression_loss = F.smooth_l1_loss(
                current_ratio_tensor,
                target_ratio_tensor,
                beta=2.0  # Transition point from L2 to L1
            )

            losses['compression'] = compression_loss * self.compression_weight

        # 3. Boundary loss (GPT suggestion: more meaningful boundary learning)
        if 'enc_boundaries' in outputs and outputs['enc_boundaries'] is not None:
            boundary_scores = outputs['enc_boundaries']

            # Boundary sparsity + smoothness (GPT suggestion)
            # Encourage sparse but clear boundaries
            boundary_probs = torch.sigmoid(boundary_scores)

            # Sparsity loss (boundaries should be rare)
            sparsity_loss = boundary_probs.mean() * 0.1

            # Smoothness loss (adjacent boundaries should be different)
            if boundary_scores.size(1) > 1:
                diff = boundary_scores[:, 1:] - boundary_scores[:, :-1]
                smoothness_loss = (diff ** 2).mean() * 0.01
            else:
                smoothness_loss = 0.0

            boundary_loss = sparsity_loss + smoothness_loss

            losses['boundary'] = boundary_loss * self.boundary_weight

        # Combine all losses
        total_loss = sum(losses.values())

        # Store individual losses for monitoring
        self.last_losses = losses

        return total_loss

    def generate(self,
                text: str = None,
                input_ids: torch.Tensor = None,
                max_length: int = 48,
                temperature: float = 0.1,
                top_k: int = 10,
                top_p: float = 0.95) -> str:
        """
        Generate/reconstruct text

        Args:
            text: Input text to encode and reconstruct
            input_ids: Pre-encoded input
            max_length: Maximum generation length
            temperature: Sampling temperature
            top_k: Top-k sampling
            top_p: Top-p (nucleus) sampling

        Returns:
            Reconstructed/generated text
        """
        # Encode input if text is provided (GPT suggestion: handle multi-chunk properly)
        chunk_positions = None
        if text is not None:
            # Check if text needs chunking
            if len(text.encode('utf-8')) > self.tokenizer.content_size:
                encoded = self.tokenizer.encode(text, add_special_tokens=True, return_chunks=True)
                chunk_positions = encoded.get('chunk_positions', None)
            else:
                encoded = self.tokenizer.encode(text, add_special_tokens=True)

            input_ids = encoded['input_ids'].unsqueeze(0) if encoded['input_ids'].dim() == 1 else encoded['input_ids']
            attention_mask = encoded['attention_mask'].unsqueeze(0) if encoded['attention_mask'].dim() == 1 else encoded['attention_mask']
        else:
            attention_mask = (input_ids != self.tokenizer.PAD).bool()  # GPT suggestion: bool mask

        # Move to device
        device = next(self.parameters()).device
        input_ids = input_ids.to(device)
        attention_mask = attention_mask.to(device)

        # Encode
        with torch.no_grad():
            encoder_outputs = self.encoder(
                input_ids=input_ids,
                attention_mask=attention_mask
            )

            # Prepare all hidden states for decoder
            if 'all_hidden_states' in encoder_outputs:
                encoder_all_hidden = encoder_outputs['all_hidden_states']
            else:
                compressed = encoder_outputs.get('compressed', encoder_outputs.get('hidden_states'))
                encoder_all_hidden = [compressed] * 4

        # Autoregressive generation (fixed version)
        batch_size = input_ids.size(0)

        # Start with BOS token
        generated_ids = torch.full((batch_size, 1), self.tokenizer.BOS, device=device)

        for step in range(max_length - 1):
            with torch.no_grad():
                # Decode current sequence
                decoder_outputs = self.decoder(
                    encoder_all_hidden=encoder_all_hidden,
                    decoder_input_ids=generated_ids,
                    attention_mask=torch.ones_like(generated_ids),
                    use_cache=False
                )

                # Get next token prediction
                logits = decoder_outputs['logits'][:, -1, :] / temperature

                # Top-k filtering
                if top_k > 0:
                    indices_to_remove = logits < torch.topk(logits, top_k)[0][..., -1, None]
                    logits[indices_to_remove] = float('-inf')

                # Sample next token
                probs = F.softmax(logits, dim=-1)
                next_token = torch.multinomial(probs, num_samples=1)

                # Append to generated sequence
                generated_ids = torch.cat([generated_ids, next_token], dim=1)

                # Check for EOS
                if (next_token == self.tokenizer.EOS).all():
                    break

        # Decode to text (GPT suggestion: proper multi-chunk reconstruction)
        if generated_ids.dim() > 2 and chunk_positions is not None:
            # Multi-chunk output with positions
            text = self.tokenizer.reconstruct(
                generated_ids,
                positions=chunk_positions,
                overlap=self.tokenizer.chunk_overlap
            )
        elif generated_ids.dim() > 2:
            # Multi-chunk without positions (fallback)
            text = self.tokenizer.reconstruct(generated_ids)
        else:
            # Single sequence
            text = self.tokenizer.decode(generated_ids[0] if generated_ids.dim() > 1 else generated_ids)

        return text

    def compress(self, text: str) -> Dict[str, Union[torch.Tensor, float]]:
        """
        Compress text and return compression statistics

        Args:
            text: Input text to compress

        Returns:
            Dictionary with compressed representation and statistics
        """
        # Encode text
        encoded = self.tokenizer.encode(text, add_special_tokens=True)
        input_ids = encoded['input_ids'].unsqueeze(0) if encoded['input_ids'].dim() == 1 else encoded['input_ids']
        attention_mask = encoded['attention_mask'].unsqueeze(0) if encoded['attention_mask'].dim() == 1 else encoded['attention_mask']

        # Move to device
        device = next(self.parameters()).device
        input_ids = input_ids.to(device)
        attention_mask = attention_mask.to(device)

        # Get compressed representation
        with torch.no_grad():
            encoder_outputs = self.encoder(
                input_ids=input_ids,
                attention_mask=attention_mask
            )

        return {
            'compressed': encoder_outputs['compressed'],
            'num_tokens': encoder_outputs['num_tokens'],
            'compression_ratio': encoder_outputs['compression_ratio'],
            'original_bytes': len(text.encode('utf-8')),
            'compressed_size': encoder_outputs['num_tokens'] * 2  # Approximate bytes
        }

    def update_training_state(self, epoch: int, step: int = 0, reconstruction_loss: float = None):
        """
        Update training state - adaptive, not phase-based

        Args:
            epoch: Current epoch
            step: Current training step
            reconstruction_loss: Current reconstruction quality
        """
        self.current_epoch = torch.tensor(epoch)
        self.training_step = torch.tensor(step)

        # Update encoder warmup (gates only)
        self.encoder.set_warmup_step(step)

        # Adaptive weight adjustment based on performance
        if reconstruction_loss is not None:
            # If reconstruction is poor, increase its weight
            if reconstruction_loss > 1.0:
                self.reconstruction_weight = 1.0
                self.compression_weight = 0.1  # Less compression focus
            else:
                # Good reconstruction, can focus on compression
                self.reconstruction_weight = 0.5
                self.compression_weight = 0.1

            # Boundary weight stays moderate
            self.boundary_weight = 0.1

            # Let encoder know about reconstruction quality
            self.encoder.adaptive_compression_control(reconstruction_loss)
        else:
            # Default balanced weights
            self.reconstruction_weight = 0.5
            self.compression_weight = 0.1
            self.boundary_weight = 0.1

    def get_model_stats(self) -> Dict[str, float]:
        """
        Get model statistics for monitoring

        Returns:
            Dictionary with various model statistics
        """
        stats = {}

        # Encoder stats (GPT suggestion: already prefixed)
        encoder_stats = self.encoder.get_monitoring_stats()
        stats.update({f'encoder_{k}': v for k, v in encoder_stats.items()})

        # Decoder memory stats
        decoder_memory = self.decoder.get_memory_usage()
        stats.update({f'decoder_{k}': v for k, v in decoder_memory.items()})

        # Loss stats (if available) - check for tensor items
        if hasattr(self, 'last_losses'):
            for k, v in self.last_losses.items():
                if isinstance(v, torch.Tensor):
                    stats[f'loss_{k}'] = v.item() if v.numel() == 1 else v.mean().item()
                else:
                    stats[f'loss_{k}'] = float(v)

        # Training info
        stats['current_epoch'] = self.current_epoch.item()
        stats['training_step'] = self.training_step.item()

        return stats

    def save_checkpoint(self, path: str):
        """
        Save model checkpoint

        Args:
            path: Path to save checkpoint
        """
        checkpoint = {
            'model_state_dict': self.state_dict(),
            'config': self.config,
            'epoch': self.current_epoch.item(),
            'step': self.training_step.item(),
            'stats': self.get_model_stats()
        }
        torch.save(checkpoint, path)
        print(f"Checkpoint saved to {path}")

    @classmethod
    def from_checkpoint(cls, path: str, device: str = 'cuda'):
        """
        Load model from checkpoint

        Args:
            path: Path to checkpoint
            device: Device to load model on

        Returns:
            Loaded model instance
        """
        checkpoint = torch.load(path, map_location=device)

        # Create model with saved config
        model = cls(checkpoint.get('config', {}))
        model.load_state_dict(checkpoint['model_state_dict'])
        model.to(device)

        # Restore training state
        if 'epoch' in checkpoint:
            model.current_epoch = torch.tensor(checkpoint['epoch'])
        if 'step' in checkpoint:
            model.training_step = torch.tensor(checkpoint['step'])

        print(f"Model loaded from {path} (Epoch {checkpoint.get('epoch', 0)})")
        return model


if __name__ == "__main__":
    # Test unified model
    print("Testing Intelligent Tokenizer v6.2.0")

    # Create model
    model = IntelligentTokenizerV62()
    print(f"Model created with {sum(p.numel() for p in model.parameters())/1e6:.1f}M parameters")

    # Test texts
    test_texts = [
        "Hello, world!",
        "안녕하세요, 만나서 반갑습니다. 오늘 날씨가 좋네요!",
        "今天天气很好。",
    ]

    for text in test_texts:
        print(f"\nInput: {text}")

        # Compress
        compression = model.compress(text)
        print(f"  Compression ratio: {compression['compression_ratio']:.1f}:1")
        print(f"  Tokens: {compression['num_tokens']}")

        # Generate (reconstruct)
        reconstructed = model.generate(text, temperature=0.1)
        print(f"  Reconstructed: {reconstructed}")

    # Get model stats
    stats = model.get_model_stats()
    print(f"\nModel Statistics:")
    for key, value in stats.items():
        if isinstance(value, float):
            print(f"  {key}: {value:.4f}")
        else:
            print(f"  {key}: {value}")