"""
Byte Dream Utilities
Helper functions for image processing, model management, and optimization
"""

import torch
import numpy as np
from PIL import Image
from pathlib import Path
import hashlib
import json
from typing import Optional, Tuple, List


def load_image(image_path: str) -> Image.Image:
    """
    Load image from file
    
    Args:
        image_path: Path to image file
        
    Returns:
        PIL Image object
    """
    path = Path(image_path)
    
    if not path.exists():
        raise FileNotFoundError(f"Image not found: {image_path}")
    
    try:
        image = Image.open(path).convert('RGB')
        return image
    except Exception as e:
        raise IOError(f"Error loading image: {e}")


def save_image(
    image: Image.Image,
    output_path: str,
    format: str = None,
    quality: int = 95,
):
    """
    Save image to file
    
    Args:
        image: PIL Image to save
        output_path: Output file path
        format: Image format (PNG, JPEG, etc.)
        quality: JPEG quality (1-100)
    """
    path = Path(output_path)
    path.parent.mkdir(parents=True, exist_ok=True)
    
    # Auto-detect format from extension
    if format is None:
        format = path.suffix.upper().replace('.', '')
        if format == 'JPG':
            format = 'JPEG'
    
    # Save with appropriate settings
    if format == 'JPEG':
        image.save(path, format=format, quality=quality, optimize=True)
    else:
        image.save(path, format=format, optimize=True)
    
    print(f"Image saved to: {path}")


def resize_image(
    image: Image.Image,
    width: Optional[int] = None,
    height: Optional[int] = None,
    maintain_aspect: bool = True,
) -> Image.Image:
    """
    Resize image to specified dimensions
    
    Args:
        image: Input image
        width: Target width
        height: Target height
        maintain_aspect: Maintain aspect ratio
        
    Returns:
        Resized PIL Image
    """
    orig_width, orig_height = image.size
    
    if width is None and height is None:
        return image
    
    if maintain_aspect:
        if width and height:
            # Fit within bounding box
            ratio = min(width / orig_width, height / orig_height)
            new_width = int(orig_width * ratio)
            new_height = int(orig_height * ratio)
        elif width:
            ratio = width / orig_width
            new_width = width
            new_height = int(orig_height * ratio)
        else:
            ratio = height / orig_height
            new_width = int(orig_width * ratio)
            new_height = height
    else:
        new_width = width if width else orig_width
        new_height = height if height else orig_height
    
    resized = image.resize((new_width, new_height), Image.Resampling.LANCZOS)
    return resized


def center_crop(image: Image.Image, width: int, height: int) -> Image.Image:
    """
    Center crop image to specified dimensions
    
    Args:
        image: Input image
        width: Crop width
        height: Crop height
        
    Returns:
        Cropped PIL Image
    """
    orig_width, orig_height = image.size
    
    left = (orig_width - width) // 2
    top = (orig_height - height) // 2
    right = left + width
    bottom = top + height
    
    cropped = image.crop((left, top, right, bottom))
    return cropped


def image_to_tensor(image: Image.Image) -> torch.Tensor:
    """
    Convert PIL Image to PyTorch tensor
    
    Args:
        image: PIL Image
        
    Returns:
        Normalized tensor in range [-1, 1]
    """
    # Convert to numpy array
    img_array = np.array(image).astype(np.float32)
    
    # Normalize to [0, 1]
    img_array = img_array / 255.0
    
    # Normalize to [-1, 1]
    img_array = 2.0 * img_array - 1.0
    
    # Convert to tensor and rearrange to CHW format
    tensor = torch.from_numpy(img_array).permute(2, 0, 1)
    
    return tensor


def tensor_to_image(tensor: torch.Tensor) -> Image.Image:
    """
    Convert PyTorch tensor to PIL Image
    
    Args:
        tensor: Tensor in range [-1, 1], shape (B, C, H, W) or (C, H, W)
        
    Returns:
        PIL Image
    """
    # Handle batch dimension
    if tensor.dim() == 4:
        tensor = tensor[0]
    
    # Convert from CHW to HWC
    img_array = tensor.cpu().numpy().transpose(1, 2, 0)
    
    # Clip to valid range
    img_array = np.clip(img_array, -1, 1)
    
    # Convert from [-1, 1] to [0, 255]
    img_array = ((img_array + 1.0) * 127.5).round().astype(np.uint8)
    
    # Ensure RGB format
    if img_array.shape[2] == 1:
        img_array = np.repeat(img_array, 3, axis=2)
    
    image = Image.fromarray(img_array)
    return image


def generate_prompt_hash(prompt: str) -> str:
    """
    Generate unique hash for a prompt
    
    Args:
        prompt: Text prompt
        
    Returns:
        Short hash string
    """
    hash_object = hashlib.md5(prompt.encode())
    return hash_object.hexdigest()[:8]


def get_model_statistics(model: torch.nn.Module) -> dict:
    """
    Get model parameter statistics
    
    Args:
        model: PyTorch model
        
    Returns:
        Dictionary with parameter counts
    """
    total_params = sum(p.numel() for p in model.parameters())
    trainable_params = sum(p.numel() for p in model.parameters() if p.requires_grad)
    
    param_size = 0
    for param in model.parameters():
        param_size += param.numel() * param.element_size()
    
    buffer_size = 0
    for buffer in model.buffers():
        buffer_size += buffer.numel() * buffer.element_size()
    
    size_mb = (param_size + buffer_size) / 1024 ** 2
    
    stats = {
        'total_parameters': total_params,
        'trainable_parameters': trainable_params,
        'non_trainable_parameters': total_params - trainable_params,
        'model_size_mb': round(size_mb, 2),
    }
    
    return stats


def optimize_memory_usage(device: str = "cpu"):
    """
    Optimize memory usage for inference
    
    Args:
        device: Target device
    """
    import gc
    
    # Clear CUDA cache if available
    if torch.cuda.is_available():
        torch.cuda.empty_cache()
    
    # Force garbage collection
    gc.collect()
    
    # Set memory allocator for CPU
    if device == "cpu":
        # Enable memory efficient attention if available
        try:
            import os
            os.environ['KMP_DUPLICATE_LIB_OK'] = 'TRUE'
        except:
            pass
    
    print("Memory optimization applied")


def set_seed(seed: int):
    """
    Set random seed for reproducibility
    
    Args:
        seed: Random seed value
    """
    torch.manual_seed(seed)
    if torch.cuda.is_available():
        torch.cuda.manual_seed_all(seed)
    np.random.seed(seed)


def validate_prompt(prompt: str) -> Tuple[bool, str]:
    """
    Validate and sanitize prompt
    
    Args:
        prompt: Input prompt
        
    Returns:
        Tuple of (is_valid, message)
    """
    if not prompt or not prompt.strip():
        return False, "Prompt cannot be empty"
    
    if len(prompt) > 1000:
        return False, "Prompt too long (max 1000 characters)"
    
    # Check for potentially harmful content
    forbidden_terms = []
    for term in forbidden_terms:
        if term.lower() in prompt.lower():
            return False, f"Prompt contains forbidden term: {term}"
    
    return True, "Valid prompt"


def create_image_grid(
    images: List[Image.Image],
    rows: int = None,
    cols: int = None,
) -> Image.Image:
    """
    Create a grid of images
    
    Args:
        images: List of PIL Images
        rows: Number of rows
        cols: Number of columns
        
    Returns:
        Grid image
    """
    if not images:
        raise ValueError("No images provided")
    
    num_images = len(images)
    
    # Determine grid dimensions
    if rows is None and cols is None:
        cols = int(np.ceil(np.sqrt(num_images)))
        rows = int(np.ceil(num_images / cols))
    elif rows is None:
        rows = int(np.ceil(num_images / cols))
    elif cols is None:
        cols = int(np.ceil(num_images / rows))
    
    # Get image size (use first image as reference)
    width, height = images[0].size
    
    # Create grid image
    grid_width = cols * width
    grid_height = rows * height
    grid_image = Image.new('RGB', (grid_width, grid_height), color='white')
    
    # Paste images into grid
    for i, image in enumerate(images):
        row = i // cols
        col = i % cols
        x = col * width
        y = row * height
        grid_image.paste(image, (x, y))
    
    return grid_image


def get_device_info() -> dict:
    """
    Get device information
    
    Returns:
        Dictionary with device info
    """
    info = {
        'cuda_available': torch.cuda.is_available(),
        'device_count': torch.cuda.device_count() if torch.cuda.is_available() else 0,
        'cpu_cores': __import__('os').cpu_count(),
    }
    
    if torch.cuda.is_available():
        info['current_device'] = torch.cuda.current_device()
        info['device_name'] = torch.cuda.get_device_name(0)
        info['cuda_version'] = torch.version.cuda
    
    return info


class ProgressTracker:
    """Track progress of long-running operations"""
    
    def __init__(self, total: int, description: str = ""):
        self.total = total
        self.current = 0
        self.description = description
    
    def update(self, n: int = 1):
        """Update progress"""
        self.current += n
    
    def get_progress(self) -> float:
        """Get progress percentage"""
        return (self.current / self.total) * 100 if self.total > 0 else 0
    
    def __str__(self):
        percent = self.get_progress()
        bar_length = 30
        filled_length = int(bar_length * self.current // self.total)
        bar = '█' * filled_length + '-' * (bar_length - filled_length)
        return f"{self.description}: [{bar}] {percent:.1f}% ({self.current}/{self.total})"