#!/usr/bin/python
"""Utility to generate character statistics about a number of source files"""

# Copyright Abel Sinkovics (abel@sinkovics.hu) 2016.
# Distributed under the Boost Software License, Version 1.0.
#    (See accompanying file LICENSE_1_0.txt or copy at
#          http://www.boost.org/LICENSE_1_0.txt)

import argparse
import os


def count_characters(root, out):
    """Count the occurrances of the different characters in the files"""
    if os.path.isfile(root):
        with open(root, 'rb') as in_f:
            for line in in_f:
                for char in line:
                    if char not in out:
                        out[char] = 0
                    out[char] = out[char] + 1
    elif os.path.isdir(root):
        for filename in os.listdir(root):
            count_characters(os.path.join(root, filename), out)


def generate_statistics(root):
    """Generate the statistics from all files in root (recursively)"""
    out = dict()
    count_characters(root, out)
    return out


def main():
    """The main function of the script"""
    desc = 'Generate character statistics from a source tree'
    parser = argparse.ArgumentParser(description=desc)
    parser.add_argument(
        '--src',
        dest='src',
        required=True,
        help='The root of the source tree'
    )
    parser.add_argument(
        '--out',
        dest='out',
        default='chars.py',
        help='The output filename'
    )

    args = parser.parse_args()

    stats = generate_statistics(args.src)
    with open(args.out, 'wb') as out_f:
        out_f.write('CHARS={0}\n'.format(stats))


if __name__ == '__main__':
    main()