r"""
:Author:    Franz Glasner
:Copyright: (c) 2020-2022 Franz Glasner.
            All rights reserved.
:License:   BSD 3-Clause "New" or "Revised" License.
            See :ref:`LICENSE <license>` for details.
            If you cannot find LICENSE see
            <https://opensource.org/licenses/BSD-3-Clause>
:ID:        @(#) $HGid$

"""

from __future__ import print_function, absolute_import

from . import (__version__, __revision__, __date__)

import argparse
import io
import sys


def main(argv=None):
    aparser = argparse.ArgumentParser(
        description="Python implementation of dos2unix",
        fromfile_prefix_chars='@')
    aparser.add_argument(
        "--version", "-V", action="version",
        version="%s (rv:%s)" % (__version__, __revision__))
    aparser.add_argument(
        "--keepdate", "-k", action="store_true",
        help="Keep the date stamp of output file same as input file.")
    aparser.add_argument(
        "--oldfile", "-o", action="store_false", dest="newfile", default=False,
        help="Old file mode. Convert the file and write output to it."
             " The program defaults to run in this mode."
             " Wildcard names may be used. ")
    aparser.add_argument(
        "--newfile", "-n", action="store_true", dest="newfile", default=False,
        help="New file mode. Convert the infile and write output to outfile."
             " File names must be given in pairs and wildcard names should"
             " NOT be used or you WILL lose your files.")
    aparser.add_argument(
        "--quiet", "-q", action="store_true",
        help="Quiet mode. Suppress all warning and messages.")

    aparser.add_argument(
        "files", nargs="+", metavar="FILE")

    opts = aparser.parse_args(args=argv)

    if opts.keepdate:
        raise NotImplementedError("--keepdate, -k")

    return dos2unix(opts)


def gen_opts(files=[], newfile=False, keepdate=False, quiet=True):
    if keepdate:
        raise NotImplementedError("--keepdate, -k")

    if newfile and (len(files) % 2):
        raise ValueError("need pairs of files")

    opts = argparse.Namespace(files=files,
                              newfile=newfile,
                              keepdate=keepdate,
                              quiet=quiet)
    return opts


def dos2unix(opts):
    if opts.newfile:
        return _convert_copy(opts)
    else:
        return _convert_inplace(opts)


def _convert_inplace(opts):
    lines = []
    for filename in opts.files:
        with io.open(filename, "rt", encoding="iso-8859-1") as source:
            for line in source:
                lines.append(line.encode("iso-8859-1"))
        with open(filename, "wb") as dest:
            for line in lines:
                dest.write(line)


def _convert_copy(opts):
    if len(opts.files) % 2:
        print("ERROR: need pairs of files", file=sys.stderr)
        return 64  # :manpage:`sysexits(3)` EX_USAGE
    idx = 0
    while idx < len(opts.files):
        with io.open(opts.files[idx], "rt", encoding="iso-8859-1") as source:
            with open(opts.files[idx+1], "wb") as dest:
                for line in source:
                    dest.write(line.encode("iso-8859-1"))
        idx += 2


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