"""Model management utilities."""
import json
import logging
import os
from typing import Dict, List, Optional

from app.config import settings
from app.services import file_manager

logger = logging.getLogger(__name__)


# Known models for Easy Real-ESRGAN
KNOWN_MODELS = {
    'RealESRGAN_x2plus': {
        'scale': 2,
        'description': '2x upscaling',
        'url': 'https://github.com/xinntao/Real-ESRGAN/releases/download/v0.2.1/RealESRGAN_x2plus.pth',
        'size_mb': 66.7,
    },
    'RealESRGAN_x3plus': {
        'scale': 3,
        'description': '3x upscaling',
        'url': 'https://github.com/xinntao/Real-ESRGAN/releases/download/v0.2.1/RealESRGAN_x3plus.pth',
        'size_mb': 101.7,
    },
    'RealESRGAN_x4plus': {
        'scale': 4,
        'description': '4x upscaling (general purpose)',
        'url': 'https://github.com/xinntao/Real-ESRGAN/releases/download/v0.1.0/RealESRGAN_x4plus.pth',
        'size_mb': 101.7,
    },
    'RealESRGAN_x4plus_anime_6B': {
        'scale': 4,
        'description': '4x upscaling (anime/art)',
        'url': 'https://github.com/xinntao/Real-ESRGAN/releases/download/v0.2.2/RealESRGAN_x4plus_anime_6B.pth',
        'size_mb': 18.9,
    },
}


def get_available_models() -> List[Dict]:
    """Get list of available models with details."""
    models = []
    
    for model_name, metadata in KNOWN_MODELS.items():
        model_path = os.path.join(settings.models_dir, f'{model_name}.pth')
        available = os.path.exists(model_path)
        
        size_mb = metadata['size_mb']
        if available:
            try:
                actual_size = os.path.getsize(model_path) / (1024 * 1024)
                size_mb = actual_size
            except OSError:
                pass
        
        models.append({
            'name': model_name,
            'scale': metadata['scale'],
            'description': metadata['description'],
            'available': available,
            'size_mb': size_mb,
            'size_bytes': int(size_mb * 1024 * 1024),
        })
    
    return models


def is_model_available(model_name: str) -> bool:
    """Check if a model is available locally."""
    model_path = os.path.join(settings.models_dir, f'{model_name}.pth')
    return os.path.exists(model_path)


def get_model_scale(model_name: str) -> Optional[int]:
    """Get upscaling factor for a model."""
    if model_name in KNOWN_MODELS:
        return KNOWN_MODELS[model_name]['scale']
    
    # Try to infer from model name
    if 'x2' in model_name.lower():
        return 2
    elif 'x3' in model_name.lower():
        return 3
    elif 'x4' in model_name.lower():
        return 4
    
    return None


async def download_model(model_name: str) -> tuple[bool, str]:
    """
    Download a model.
    
    Returns: (success, message)
    """
    if model_name not in KNOWN_MODELS:
        return False, f'Unknown model: {model_name}'

    if is_model_available(model_name):
        return True, f'Model already available: {model_name}'

    metadata = KNOWN_MODELS[model_name]
    url = metadata['url']
    model_path = os.path.join(settings.models_dir, f'{model_name}.pth')

    try:
        logger.info(f'Downloading model: {model_name} from {url}')
        
        import urllib.request
        os.makedirs(settings.models_dir, exist_ok=True)
        
        def download_progress(count, block_size, total_size):
            downloaded = count * block_size
            percent = min(downloaded * 100 / total_size, 100)
            logger.debug(f'Download progress: {percent:.1f}%')

        urllib.request.urlretrieve(url, model_path, download_progress)
        
        if os.path.exists(model_path):
            size_mb = os.path.getsize(model_path) / (1024 * 1024)
            logger.info(f'Model downloaded: {model_name} ({size_mb:.1f} MB)')
            return True, f'Model downloaded: {model_name} ({size_mb:.1f} MB)'
        else:
            return False, f'Failed to download model: {model_name}'
    
    except Exception as e:
        logger.error(f'Failed to download model {model_name}: {e}', exc_info=True)
        return False, f'Download failed: {str(e)}'


async def download_models(model_names: List[str]) -> Dict[str, tuple[bool, str]]:
    """Download multiple models."""
    results = {}
    
    for model_name in model_names:
        success, message = await download_model(model_name)
        results[model_name] = (success, message)
        logger.info(f'Download result for {model_name}: {success} - {message}')
    
    return results


def get_models_directory_info() -> Dict:
    """Get information about the models directory."""
    models_dir = settings.models_dir
    
    return {
        'path': models_dir,
        'size_mb': file_manager.get_directory_size_mb(models_dir),
        'model_count': len([f for f in os.listdir(models_dir) if f.endswith('.pth')]) 
                       if os.path.isdir(models_dir) else 0,
    }