#!/usr/bin/env python3
#
# Write out a modified version of a .abc file with just the data
# to print the first line of the music only.
#

import argparse
import pathlib
import sys

def process(inf):
    continued = False
    print("X:1")
    for line in inf:
        line = line.strip()
        # If it is empty or starts "%", ignore it.
        if len(line) == 0 or line[0] == "%":
            continue

        # Is it a header line? I.e. does it start LETTER (or +) COLON?
        # If so, output only ones we need.
        start = line[:2]
        if len(start) > 1 and start[1] == ":" and (start[0].isalpha() or start[0] == '+'):
            if start[0] in ["M", "K", "L"]:
                print(line)
        # Output line. If the line ends with a continuation, carry
        # on outputting lines, otherwise stop.
        else:
            print(line)
            if line[-1] != "\\":
                break

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Write minimal version of ABC input file with just the first line of music.")
    parser.add_argument('input', type=argparse.FileType('r'),
                        help='input ABC file')
    args = parser.parse_args()

    path = pathlib.Path(args.input.name)
    with path.open() as f:
        process(f)
    sys.exit(0)