#!/usr/bin/env python3
"""为 MusicXML 钢琴谱添加花括号分组。"""
import sys
import xml.etree.ElementTree as ET

if len(sys.argv) < 2:
    print('Usage: python add_brace.py input.musicxml [output.musicxml]')
    sys.exit(1)

input_file = sys.argv[1]
output_file = sys.argv[2] if len(sys.argv) > 2 else input_file.replace('.musicxml', '_braced.musicxml')

ET.register_namespace('m', 'http://www.musescore.org/ns/mscore')
ET.register_namespace('xlink', 'http://www.w3.org/1999/xlink')

tree = ET.parse(input_file)
root = tree.getroot()
part_list = root.find('part-list')

if part_list is None:
    print('Error: no <part-list> found in file')
    sys.exit(1)

# 添加花括号分组（插在 part-list 最前面）
group_start = ET.Element('part-group')
group_start.set('number', '1')
group_start.set('type', 'start')
ET.SubElement(group_start, 'group-symbol').text = 'brace'
ET.SubElement(group_start, 'group-barline').text = 'bracket'
ET.SubElement(group_start, 'group-time')
part_list.insert(0, group_start)

# 每个 score-part 加 <group>1</group>
for sp in part_list.findall('score-part'):
    g = ET.SubElement(sp, 'group')
    g.text = '1'

# 结束分组
part_list.append(ET.Element('part-group', number='1', type='stop'))

try:
    ET.indent(root)
except AttributeError:
    pass

tree.write(output_file, encoding='UTF-8', xml_declaration=True)
print(f'Added brace grouping')
print(f'Output: {output_file}')