Sort files the way python's sorted() function sorts

pysort.py

#!/usr/bin/env python3
"""pysort
=========

Sort files in pythonic order
"""
# Copyright 2020 Stephen Whitlock
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
__author__ = "Stephen Whitlock"
__maintainer__ = "Stephen Whitlock"
__email__ = "[email protected]"
__version__ = "1.0.0"
__copyright__ = "2020, Stephen Whitlock"
__license__ = "MIT"
import hashlib
import sys
import os
import argparse


class Parser(argparse.ArgumentParser):
    """Parse the chosen path for this module and test that it is
    valid.
    """

    def __init__(self):
        super().__init__(prog=f"\u001b[0;36;40mpysort\u001b[0;0m",)
        self._add_arguments()
        self._args = self.parse_args()
        self.path = self._args.path
        self.dedupe = self._args.dedupe
        self._exit_invalid()

    def _add_arguments(self):
        self.add_argument(
            "path",
            metavar="PATH",
            action="store",
            help="path to the file you wish to sort",
        )
        self.add_argument(
            "-d",
            "--dedupe",
            action="store_true",
            help="remove duplicates from file"
        )

    def _exit_invalid(self):
        if not os.path.isfile(self.path):
            print(f"`{self.path}' is not a file", file=sys.stderr)
            if not os.path.exists(self.path):
                print(f"`{self.path}' does not exist", file=sys.stderr)
            sys.exit(1)


class MaxSizeList(list):
    def __init__(self, maxlen):
        super().__init__()
        self._maxlen = maxlen

    def append(self, element):
        self.__delitem__(slice(0, len(self) == self._maxlen))
        super(MaxSizeList, self).append(element)


class HashCap:
    def __init__(self, path):
        self.path = path
        self.snapshot = MaxSizeList(maxlen=2)

    def hash_file(self):
        """Open the files and inspect it to get its hash. Return the
        hash as a string
        """
        with open(self.path, "rb") as lines:
            md5_hash = hashlib.md5(lines.read())
            self.snapshot.append(md5_hash.hexdigest())

    def compare(self):
        """Compare two hashes in the ``snapshot`` list.

        :return:        Boolean: True for both match, False if they
                        don't.
        """
        return self.snapshot[0] == self.snapshot[1]


class TextIO:
    """Input / output for the selected path."""

    def __init__(self, path):
        self.path = path
        self.lines = []

    def read_file(self):
        """read files into buffer."""
        with open(self.path) as file:
            fin = file.read()
            self.lines.extend(fin.splitlines())

    def sort(self):
        """Sort the list of lines from file."""
        self.lines = sorted(self.lines)

    def write(self):
        """write buffer back to file."""
        with open(self.path, "w") as file:
            for line in self.lines:
                file.write(f"{line}\n")

    def deduplicate(self):
        newlines = []
        for line in self.lines:
            if line not in newlines:
                newlines.append(line)
        self.lines = newlines


def announce_sort(path, match):
    """Announce whether a file needed to be sorted or not.

    :param path:    Path to the file to sort.
    :param match:   Boolean: True for both match, False if they don't.
    """
    if match:
        print(f"`{path}' already sorted")
    else:
        print(f"sorted `{path}'")


def announce_dedupe(path, match):
    """Announce whether a file needed to be deduplicated or not.

    :param path:    Path to the file to sort.
    :param match:   Boolean: True for both match, False if they don't.
    """
    if match:
        print(f"no duplicates found in `{path}'")
    else:
        print(f"deduplicated `{path}'")


def main():
    """where it's at"""
    parser = Parser()
    path = parser.path
    file = TextIO(path)
    hashcap = HashCap(path)

    hashcap.hash_file()
    file.read_file()
    file.sort()
    file.write()
    hashcap.hash_file()

    match = hashcap.compare()

    announce_sort(path, match)

    if parser.dedupe:
        file.deduplicate()
        file.write()
        hashcap.hash_file()

        match = hashcap.compare()

        announce_dedupe(path, match)


if __name__ == "__main__":
    main()