"""
Model utilities for downloading and managing the marine species model.
"""

import os
import shutil
from pathlib import Path
from typing import Optional, Dict, Any
from huggingface_hub import hf_hub_download, list_repo_files

from app.core.config import settings
from app.core.logging import get_logger

logger = get_logger(__name__)


def download_model_from_hf(
    repo_id: str,
    model_filename: str,
    local_dir: str,
    force_download: bool = False
) -> str:
    """
    Download model from HuggingFace Hub.
    
    Args:
        repo_id: HuggingFace repository ID
        model_filename: Name of the model file
        local_dir: Local directory to save the model
        force_download: Whether to force re-download if file exists
        
    Returns:
        Path to the downloaded model file
    """
    try:
        # Create local directory if it doesn't exist
        Path(local_dir).mkdir(parents=True, exist_ok=True)
        
        local_path = Path(local_dir) / model_filename
        
        # Check if file already exists and force_download is False
        if local_path.exists() and not force_download:
            logger.info(f"Model already exists at {local_path}")
            return str(local_path)
        
        logger.info(f"Downloading {model_filename} from {repo_id}...")
        
        downloaded_path = hf_hub_download(
            repo_id=repo_id,
            filename=model_filename,
            local_dir=local_dir,
            local_dir_use_symlinks=False,
            force_download=force_download
        )
        
        logger.info(f"Model downloaded successfully to: {downloaded_path}")
        return downloaded_path
        
    except Exception as e:
        logger.error(f"Failed to download model: {str(e)}")
        raise


def list_available_files(repo_id: str) -> list:
    """
    List all available files in a HuggingFace repository.
    
    Args:
        repo_id: HuggingFace repository ID
        
    Returns:
        List of available files
    """
    try:
        files = list_repo_files(repo_id)
        return files
    except Exception as e:
        logger.error(f"Failed to list repository files: {str(e)}")
        return []


def verify_model_file(model_path: str) -> bool:
    """
    Verify that a model file exists and is valid.
    
    Args:
        model_path: Path to the model file
        
    Returns:
        True if model file is valid
    """
    try:
        path = Path(model_path)
        
        # Check if file exists
        if not path.exists():
            logger.error(f"Model file does not exist: {model_path}")
            return False
        
        # Check file size (should be > 1MB for a real model)
        file_size = path.stat().st_size
        if file_size < 1024 * 1024:  # 1MB
            logger.warning(f"Model file seems too small: {file_size} bytes")
            return False
        
        # Check file extension
        if not path.suffix.lower() in ['.pt', '.pth']:
            logger.warning(f"Unexpected model file extension: {path.suffix}")
        
        logger.info(f"Model file verified: {model_path} ({file_size / (1024*1024):.1f} MB)")
        return True
        
    except Exception as e:
        logger.error(f"Failed to verify model file: {str(e)}")
        return False


def get_model_info(model_path: str) -> Dict[str, Any]:
    """
    Get information about a model file.
    
    Args:
        model_path: Path to the model file
        
    Returns:
        Dictionary with model information
    """
    info = {
        "path": model_path,
        "exists": False,
        "size_mb": 0,
        "size_bytes": 0
    }
    
    try:
        path = Path(model_path)
        
        if path.exists():
            info["exists"] = True
            size_bytes = path.stat().st_size
            info["size_bytes"] = size_bytes
            info["size_mb"] = size_bytes / (1024 * 1024)
            info["modified_time"] = path.stat().st_mtime
        
    except Exception as e:
        logger.error(f"Failed to get model info: {str(e)}")
    
    return info


def cleanup_model_cache(cache_dir: Optional[str] = None) -> None:
    """
    Clean up model cache directory.
    
    Args:
        cache_dir: Cache directory to clean (uses default if None)
    """
    try:
        if cache_dir is None:
            cache_dir = Path.home() / ".cache" / "huggingface"
        
        cache_path = Path(cache_dir)
        
        if cache_path.exists():
            logger.info(f"Cleaning up cache directory: {cache_path}")
            shutil.rmtree(cache_path)
            logger.info("Cache cleanup completed")
        else:
            logger.info("Cache directory does not exist")
            
    except Exception as e:
        logger.error(f"Failed to cleanup cache: {str(e)}")


def setup_model_directory() -> str:
    """
    Setup the model directory and ensure it exists.
    
    Returns:
        Path to the model directory
    """
    model_dir = Path(settings.MODEL_PATH).parent
    model_dir.mkdir(parents=True, exist_ok=True)
    
    logger.info(f"Model directory setup: {model_dir}")
    return str(model_dir)


if __name__ == "__main__":
    # Command line utility for model management
    import argparse
    
    parser = argparse.ArgumentParser(description="Model management utility")
    parser.add_argument("--download", action="store_true", help="Download model from HuggingFace")
    parser.add_argument("--verify", action="store_true", help="Verify model file")
    parser.add_argument("--info", action="store_true", help="Show model information")
    parser.add_argument("--list-files", action="store_true", help="List available files in HF repo")
    parser.add_argument("--cleanup-cache", action="store_true", help="Cleanup model cache")
    parser.add_argument("--force", action="store_true", help="Force download even if file exists")
    
    args = parser.parse_args()
    
    if args.download:
        setup_model_directory()
        download_model_from_hf(
            repo_id=settings.HUGGINGFACE_REPO,
            model_filename=f"{settings.MODEL_NAME}.pt",
            local_dir=str(Path(settings.MODEL_PATH).parent),
            force_download=args.force
        )
    
    if args.verify:
        is_valid = verify_model_file(settings.MODEL_PATH)
        print(f"Model valid: {is_valid}")
    
    if args.info:
        info = get_model_info(settings.MODEL_PATH)
        print(f"Model info: {info}")
    
    if args.list_files:
        files = list_available_files(settings.HUGGINGFACE_REPO)
        print(f"Available files in {settings.HUGGINGFACE_REPO}:")
        for file in files:
            print(f"  - {file}")
    
    if args.cleanup_cache:
        cleanup_model_cache()