import os

formatted_lines = []
if os.path.exists('musiclist.txt'):
    with open('musiclist.txt', 'r') as file:
        lines = file.readlines()
        for line in lines:
            formatted_lines.append(line.split(' --- ')[0])

while True:
    first_part = input('Enter the artist and song title: ')
    if first_part == '':
        print('You must enter an artist and song title')
        continue
    if first_part in formatted_lines:
        print('This song is already in the list')
        continue
    provider = input('Enter the provider: ')
    if provider == '':
        print('You must enter a provider')
        continue
    url = input('Enter the source URL: ')
    if url == '':
        print('You must enter a source URL')
        continue
    if (provider == 'YT') and (url.split('?v=')[0] == 'https://www.youtube.com/watch'):
        urlid = url.split('?v=')[1]
        with open('musiclist.txt', 'a') as file:
            file.write(f'{first_part} --- {urlid} --- {provider}\n')
    elif (provider == 'YTM') and (url.split('?v=')[0] == 'https://music.youtube.com/watch'):
        urlid = url.split('?v=')[1]
        with open('musiclist.txt', 'a') as file:
            file.write(f'{first_part} --- {urlid} --- {provider}\n')
    else:
        print('Invalid source URL')
        continue