"""
Utility functions for the PawPrint Flyer Generator.
"""

import os
from pathlib import Path
from PIL import Image


def validate_inputs(animal_photo, animal_name, species):
    """
    Validate user inputs before processing.
    
    Args:
        animal_photo: PIL Image or None
        animal_name: str
        species: str
        
    Returns:
        str: Error message if validation fails, None if all OK
    """
    if animal_photo is None:
        return "⚠️ Please upload an animal photo to continue."
    
    if not animal_name or animal_name.strip() == "":
        return "⚠️ Please enter the animal's name."
    
    if not species or species not in ["Dog", "Cat"]:
        return "⚠️ Please select a species (Dog or Cat)."
    
    return None


def get_background_options():
    """
    Get available background images from the assets folder.
    
    Returns:
        dict: Mapping of display names to file paths
    """
    backgrounds_dir = Path(__file__).parent.parent / "assets" / "backgrounds"
    
    if not backgrounds_dir.exists():
        return {}
    
    background_files = {
        "Cozy Living Room": "cozy_living_room.jpg",
        "Home with Yard": "home_yard.jpg",
        "Beach Shore": "beach_shore.jpg",
        "Autumn Cottage": "autumn_cottage.jpg",
        "Lavender Field": "lavender_field.jpg",
    }
    
    result = {}
    for name, filename in background_files.items():
        path = backgrounds_dir / filename
        if path.exists():
            result[name] = str(path)
    
    return result


def resize_image(image, target_size, maintain_aspect=True):
    """
    Resize an image to target size.
    
    Args:
        image: PIL Image
        target_size: tuple of (width, height)
        maintain_aspect: bool, whether to maintain aspect ratio
        
    Returns:
        PIL Image: Resized image
    """
    if maintain_aspect:
        image.thumbnail(target_size, Image.Resampling.LANCZOS)
        return image
    else:
        return image.resize(target_size, Image.Resampling.LANCZOS)


def ensure_rgb(image):
    """
    Convert image to RGB mode if needed.
    
    Args:
        image: PIL Image
        
    Returns:
        PIL Image in RGB mode
    """
    if image.mode == 'RGBA':
        # Create a white background
        background = Image.new('RGB', image.size, (255, 255, 255))
        background.paste(image, mask=image.split()[3])  # Use alpha channel as mask
        return background
    elif image.mode != 'RGB':
        return image.convert('RGB')
    return image