#!/usr/bin/env python3
"""
Combine two SVG files vertically (top over bottom) with centering and spacing.
Useful for combining separated logo elements for 3D printing.
"""

import argparse
import xml.etree.ElementTree as ET
from pathlib import Path


def load_svg(svg_path: Path):
    """Load SVG and extract its dimensions and content"""
    tree = ET.parse(svg_path)
    root = tree.getroot()

    # Get dimensions from viewBox or width/height attributes
    viewbox = root.get('viewBox')
    if viewbox:
        parts = viewbox.split()
        x, y, width, height = map(float, parts)
    else:
        width = float(root.get('width', 0))
        height = float(root.get('height', 0))
        x, y = 0, 0

    return {
        'root': root,
        'width': width,
        'height': height,
        'viewbox_x': x,
        'viewbox_y': y
    }


def combine_svgs_vertical(top_svg_path: Path, bottom_svg_path: Path, output_path: Path,
                         spacing: float = 20, margin: float = 10):
    """
    Combine two SVGs vertically with the top one centered above the bottom one.

    Args:
        top_svg_path: Path to top SVG (e.g., icon)
        bottom_svg_path: Path to bottom SVG (e.g., text)
        output_path: Path for output combined SVG
        spacing: Vertical space between top and bottom elements (default: 20)
        margin: Margin around the entire composition (default: 10)
    """
    # Load both SVGs
    top_svg = load_svg(top_svg_path)
    bottom_svg = load_svg(bottom_svg_path)

    # Calculate combined dimensions
    max_width = max(top_svg['width'], bottom_svg['width'])
    combined_height = top_svg['height'] + spacing + bottom_svg['height']

    # Add margins
    canvas_width = max_width + (2 * margin)
    canvas_height = combined_height + (2 * margin)

    # Calculate centering offsets
    top_x_offset = margin + (max_width - top_svg['width']) / 2
    top_y_offset = margin

    bottom_x_offset = margin + (max_width - bottom_svg['width']) / 2
    bottom_y_offset = margin + top_svg['height'] + spacing

    # Create new SVG root
    combined = ET.Element('svg', {
        'xmlns': 'http://www.w3.org/2000/svg',
        'width': str(canvas_width),
        'height': str(canvas_height),
        'viewBox': f'0 0 {canvas_width} {canvas_height}'
    })

    # Add comment for clarity
    comment = ET.Comment(f' Combined: {top_svg_path.name} (top) + {bottom_svg_path.name} (bottom) ')
    combined.append(comment)

    # Create group for top SVG with transform
    top_group = ET.SubElement(combined, 'g', {
        'id': 'top',
        'transform': f'translate({top_x_offset}, {top_y_offset})'
    })

    # Copy all elements from top SVG
    for child in top_svg['root']:
        if child.tag != '{http://www.w3.org/2000/svg}metadata':
            top_group.append(child)

    # Create group for bottom SVG with transform
    bottom_group = ET.SubElement(combined, 'g', {
        'id': 'bottom',
        'transform': f'translate({bottom_x_offset}, {bottom_y_offset})'
    })

    # Copy all elements from bottom SVG
    for child in bottom_svg['root']:
        if child.tag != '{http://www.w3.org/2000/svg}metadata':
            bottom_group.append(child)

    # Write output
    tree = ET.ElementTree(combined)
    ET.indent(tree, space='  ')
    tree.write(output_path, encoding='utf-8', xml_declaration=True)

    print(f"Created {output_path}")
    print(f"  Top ({top_svg_path.name}): {top_svg['width']:.0f}x{top_svg['height']:.0f} at ({top_x_offset:.1f}, {top_y_offset:.1f})")
    print(f"  Bottom ({bottom_svg_path.name}): {bottom_svg['width']:.0f}x{bottom_svg['height']:.0f} at ({bottom_x_offset:.1f}, {bottom_y_offset:.1f})")
    print(f"  Canvas: {canvas_width:.0f}x{canvas_height:.0f}")
    print(f"  Spacing: {spacing:.0f}, Margin: {margin:.0f}")


def main():
    parser = argparse.ArgumentParser(
        description='Combine two SVG files vertically with centering and spacing'
    )
    parser.add_argument('top', help='Top SVG file (e.g., icon)')
    parser.add_argument('bottom', help='Bottom SVG file (e.g., text)')
    parser.add_argument('output', help='Output SVG file')
    parser.add_argument('--spacing', '-s', type=float, default=20,
                       help='Vertical spacing between elements (default: 20)')
    parser.add_argument('--margin', '-m', type=float, default=10,
                       help='Margin around entire composition (default: 10)')

    args = parser.parse_args()

    top_path = Path(args.top)
    bottom_path = Path(args.bottom)
    output_path = Path(args.output)

    if not top_path.exists():
        print(f"ERROR: Top SVG file not found: {top_path}")
        return 1

    if not bottom_path.exists():
        print(f"ERROR: Bottom SVG file not found: {bottom_path}")
        return 1

    combine_svgs_vertical(top_path, bottom_path, output_path, args.spacing, args.margin)

    return 0


if __name__ == '__main__':
    exit(main())