mailgen.py

import click
import re
import string
import sre_yield

# Usage examples:
# {name}\.{lname}
# [a-z]{lname}
# {lname}\.[a-z]{2}
# ...

@click.command()
@click.option('-f', '--format', type=str, default=None, help='String format')
@click.option('-ff', '--formats', type=click.File('r'), default=None, help='Strings formats (file)')
@click.option('-n', '--names', default=None, type=click.File('r'))
@click.option('-s', '--surnames', default=None, type=click.File('r'))
@click.option('-o', '--output', required=True, type=click.Path(exists=False), help='Output file')
def cli(format, formats, names, surnames, output):
    formats_list = []
    if format is not None:
        formats_list.append(format)
    elif formats is not None:
        formats_list.extend(formats.read().split('\n'))
    else:
        print('[!] Specify -f\\--format or -ff\\--formats')
        return
    
    for format in formats_list:
        if '{name}' in format:
            names_list = [re.escape(i) for i in names.read().split('\n') if i != '']
            names_regex = '(' + '|'.join(names_list) + ')'
            format = format.replace('{name}', names_regex)

        if '{lname}' in format:
            surnames_list = [re.escape(i) for i in surnames.read().split('\n') if i != '']
            surnames_regex = '(' + '|'.join(surnames_list) + ')'
            format = format.replace('{lname}', surnames_regex)

        with open(output, 'w') as f:
            for i in sre_yield.AllStrings(format):
                f.write(i + '\n')

if __name__ == '__main__':
    cli()