Count lines in files

## count-lines
#!/bin/python
"""
This utility allows you to count the number of lines in files

by default just .py files, but accepts command-line arguments.
This utility does miss files and folders beginning with '.'
so don't use them!

usage: {script} {path} [extensions] [exclude]

based on: https://stackoverflow.com/questions/38543709/count-lines-of-code-in-directory-using-python#answer-46329364

## Changelog

### 1.0

#### additions

- extensions cli argument
- exclude cli argument
- __main__ so can be run standalone

#### fixes

- python2 utf8 files

#### changes

- omits dot-file fs-entries
- renamed thing to fsentry everywhere

"""

import os
import io
import sys

def countlines(start, lines=0, header=True, begin_start=None, exts=None, exclude_begin=None):
    if exts is None:
        exts = ['.py']

    if exclude_begin is None:
        exclude_begin = []

    if header:
        print('{:>10} |{:>10} | {:<20}'.format('ADDED', 'TOTAL', 'FILE'))
        print('{:->11}|{:->11}|{:->20}'.format('', '', ''))

    for fsentry in os.listdir(start):
        fsentry = os.path.join(start, fsentry)

        if os.path.isfile(fsentry):
            ext_match = False
            for ext in exts:
                if fsentry.endswith(ext):
                    ext_match = True

            if ext_match:
                with io.open(fsentry, encoding='utf-8') as f:
                    newlines = f.readlines()
                    newlines = len(newlines)
                    lines += newlines

                    if begin_start is not None:
                        reldir_of_fsentry = '.' + fsentry.replace(begin_start, '')
                    else:
                        reldir_of_fsentry = '.' + fsentry.replace(start, '')

                    print('{:>10} |{:>10} | {:<20}'.format(
                            newlines, lines, reldir_of_fsentry))

    for fsentry in os.listdir(start):
        fsentry = os.path.join(start, fsentry)
        basename = os.path.basename(fsentry)
        excluded = False

        for exclusion in exclude_begin:
            if basename.startswith(exclusion):
                excluded = True

        if os.path.isdir(fsentry) and not basename.startswith('.') and not excluded:
            lines = countlines(
                fsentry,
                lines,
                header=False,
                begin_start=start,
                exts=exts,
                exclude_begin=exclude_begin)

    return lines


if __name__ == '__main__':
    if len(sys.argv) < 2:
        print("Must supply path")
        exit(1)

    exts=None
    if len(sys.argv) > 2:
        exts=sys.argv[2].split(',')

    exclude=None
    if len(sys.argv) > 3:
        exclude = sys.argv[3].split(',')

    if not os.path.exists(sys.argv[1]):
        print("Must supply valid path")
        exit(2)

    total = countlines(sys.argv[1], exts=exts, exclude_begin=exclude)
    print("{}".format(total))