#!/usr/bin/env python3

# Copyright 2025 The Helium Authors
# You can use, redistribute, and/or modify this source code under
# the terms of the GPL-3.0 license that can be found in the LICENSE file.
"""
Generates scaled resources for Helium branding
"""

import os
import sys

from pathlib import Path
from PIL import Image


def scale_image(input_file, size, output_path):
    """
    Scales the square image to provided size and saves it
    """
    img = Image.open(input_file)

    if size is not None:
        img.thumbnail((size, size))

    # make sure output path exists
    os.makedirs(output_path.parent, exist_ok=True)

    img.save(output_path, optimize=True)


def generate_resources(resource_list, resource_dir):
    """
    Parses the resource list and generates resources
    for each valid line
    """
    with open(resource_list, 'r', encoding='utf-8') as file:
        for line_number, line in enumerate(file, start=1):
            line = line.strip()
            if not line or line.startswith('#'):
                continue

            line_parts = line.split()

            input_file = resource_dir / line_parts[0]
            size = None
            output_file = None

            if len(line_parts) == 2:
                output_file = resource_dir / line_parts[1]
            elif len(line_parts) == 3:
                size = int(line_parts[1])
                output_file = resource_dir / line_parts[2]
            else:
                raise ValueError(f"Line {line_number} in the resource file is invalid.")

            scale_image(input_file, size, output_file)
            size_str = "undefined" if size is None else f"{size}x{size}"
            print(f"Created {output_file} (size {size_str})")


def main():
    """CLI entrypoint"""
    if len(sys.argv) != 3:
        print(
            "Usage: python3 generate_resources.py " \
            "<generate_resources.txt> <resources_dir>"
        )
        sys.exit(1)

    resource_list = sys.argv[1]
    resource_dir = Path(sys.argv[2])

    generate_resources(resource_list, resource_dir)


if __name__ == "__main__":
    main()