bump_copyright

#!/usr/bin/env python

"""\
Update LICENSE (copyright year) and copy it to file headers.
"""

import sys
import os
import re
import argparse
from datetime import datetime


DIR = os.path.dirname(os.path.abspath(__file__))
LICENSE = os.path.join(DIR, "LICENSE")
HDR_START = "#%L"
HDR_END = "#L%"
CURRENT_YEAR = datetime.now().strftime("%Y")


def update_license(year):
    with open(LICENSE) as f:
        content = f.read()
    new_content = re.sub(r"-(\d{4})", "-%s" % year, content)
    with open(LICENSE, "w") as f:
        f.write(new_content)
    return new_content


def add_comments(txt):
    new_lines = []
    for line in txt.strip().splitlines():
        line = line.strip()
        new_lines.append("# {}".format(line) if line else "#")
    return "\n".join(new_lines) + "\n"


def update_hdr(new_txt, path):
    with open(path) as f:
        content = f.read()
        start = content.find(HDR_START)
        end = content.find(HDR_END)
        if start > 0 and end > 0:
            new_txt = add_comments(new_txt)
            new_content = "%s%s\n%s# %s" % (
                content[:start], HDR_START, new_txt, content[end:]
            )
            with open(path, "w") as f:
                f.write(new_content)


def update_headers(new_txt):
    for d, subdirs, fnames in os.walk(DIR):
        for fn in fnames:
            if fn.endswith(".py"):
                update_hdr(new_txt, os.path.join(d, fn))


def year(s):
    if not re.match(r"\d{4}", s):
        raise argparse.ArgumentTypeError("year must be in YYYY format")
    return s


def make_parser():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("-y", "--year", metavar="YYYY", type=year,
                        default=CURRENT_YEAR, help="end copyright year")
    return parser


def main(argv):
    parser = make_parser()
    args = parser.parse_args(argv[1:])
    new_txt = update_license(args.year)
    update_headers(new_txt)


if __name__ == "__main__":
    main(sys.argv)