#!/usr/bin/python

# The MIT License (MIT)
#
# Copyright (c) 2026 pacman64
#
# 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.


from itertools import islice
from sys import argv, exit, stderr, stdin, stdout
from time import sleep


info = '''
teletype [options...] [files...]

Simulate the cadence of old-fashioned teletype machines, by slowing down
the output of ASCII/UTF-8 symbols from the inputs given.

All options can start with either a single or a double leading dash:

    -h, -help    show this help message
'''


def run_teletype(src):
    'Emit data runes with a delay for each symbol.'

    prev = '\n'

    for line in src:
        # ignore trailing LF/CRLF from lines
        line = line.rstrip('\r\n').rstrip('\n')

        # emit runes with a delay, which is the whole point of this script;
        # the exception is ANSI-style runs of bytes, which are emitted all
        # together
        ansi = False
        for e in list(line):
            # an escape byte marks the start of an ANSI-style sequence
            if e == '\x1b':
                ansi = True

            if not ansi:
                # delay each visible item's appeareance by 15 ms
                sleep(0.015)

            # an `m` means the end of an ANSI-style sequence, even if there
            # wasn't one preceding it
            if e == 'm':
                ansi = False

            # emit the item, ensuring it shows right away
            stdout.write(e)
            stdout.flush()

        # time-bunch line-feeds together, by waiting only before the first
        # one in its run of line-feed bytes
        if prev != '':
            # wait for 750 ms before ending the line(s)
            sleep(0.75)
        prev = line

        # ensure a line-feed ends each line, even the last one
        stdout.write('\n')
        stdout.flush()


try:
    # handle the help option, if given
    if len(argv) > 1 and argv[1] in ('-h', '--h', '-help', '--help'):
        print(info.strip())
        exit(0)

    # ignore leading end-of-options `--`, if present
    skip = 2 if len(argv) > 1 and argv[1] == '--' else 1

    # handle all named inputs, in the order given
    for name in islice(argv, skip, None):
        with open(name, encoding='utf-8') as inp:
            run_teletype(inp)

    # read from stdin, if no named inputs were given
    if len(argv) - skip < 1:
        run_teletype(stdin)
except BrokenPipeError:
    # quit quietly, instead of showing a confusing error message
    stderr.close()
except KeyboardInterrupt:
    exit(2)
except Exception as e:
    # chances are, func `open` failed because some file given doesn't exist
    print(str(e), file=stderr)
    exit(1)