#!/usr/bin/python3

# The MIT License (MIT)
#
# Copyright © 2024 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.


info = '''
tb [options...] [python expression] [filepath/URI...]

This is the MINImal version of the Transform Bytes tool.
'''


from sys import argv, exit, stderr, stdin, stdout
from typing import Generator


# no args or a leading help-option arg means show the help message and quit
help_opts = ('-h', '--h', '-help', '--help')
if len(argv) < 2 or (len(argv) == 2 and argv[1] in help_opts):
    print(info.strip(), file=stderr)
    exit(0)


class Skip:
    pass


skip = Skip()


def recover(attempt, fallback = None):
    try:
        return attempt()
    except Exception as e:
        if callable(fallback):
            return fallback(e)
        return fallback

recovered = recover
rescue = recover
rescued = recover


no_input_opts = (
    '=', '-n', '--n', '-nil', '--nil', '-none', '--none', '-null', '--null',
)

args = argv[1:]
load_input = True
expression = None

# handle all other leading options; the explicit help options are
# handled earlier in the script
while len(args) > 0:
    if args[0] in no_input_opts:
        load_input = False
        args = args[1:]
        continue
    break

if len(args) > 0:
    expression = args[0]
    args = args[1:]

if expression is None:
    print(info.strip(), file=stderr)
    exit(0)


def make_open_read(open):
    'Restrict the file-open func to a read-only-binary file-open func.'
    def open_readonly(name):
        return open(name, mode='rb')
    return open_readonly

def seems_url(s):
    protocols = ('https://', 'http://', 'file://', 'ftp://', 'data:')
    return any(s.startswith(p) for p in protocols)


def tobytes(x):
    if isinstance(x, bytes):
        return x
    if isinstance(x, (bool, int)):
        return bytes(int(x))
    if isinstance(x, float):
        return bytes(str(x), encoding='utf-8')
    if isinstance(x, str):
        return bytes(x, encoding='utf-8')
    return bytes(x)

def tointorbytes(x):
    return x if isinstance(x, int) else tobytes(x)


open_read = make_open_read(open)
open = open_read

exec = None


def adapt_result(x, default):
    if x is True:
        return default
    if x is False:
        return None

    if isinstance(x, Skip):
        return None

    if callable(x):
        return x(default)
    return x


def emit_result(w, x):
    if x is None:
        return

    if isinstance(x, (list, tuple, range, Generator)):
        for e in x:
            w.write(tobytes(e))
        return

    w.write(tobytes(x))


def eval_expr(expr, using):
    global v, val, value, d, dat, data
    # offer several aliases for the variable with the input bytes
    v = val = value = d = dat = data = using
    return adapt_result(eval(expr), using)


import functools
import itertools
import math
import random
import statistics
import string
import time


try:
    if not expression or expression == '.':
        expression = 'data'
    expression = compile(expression, expression, 'eval')

    got_stdin = False
    all_stdin = None
    dashes = args.count('-')

    if any(seems_url(name) for name in args):
        from urllib.request import urlopen

    data = None

    if load_input:
        for name in args:
            if name == '-':
                if dashes > 1:
                    if not got_stdin:
                        all_stdin = stdin.buffer.read()
                        got_stdin = True
                    data = all_stdin
                else:
                    data = stdin.buffer.read()
            elif seems_url(name):
                with urlopen(name) as inp:
                    data = inp.read()
            else:
                with open_read(name) as inp:
                    data = inp.read()

            emit_result(stdout.buffer, eval_expr(expression, data))

        if len(args) == 0:
            data = stdin.buffer.read()
            emit_result(stdout.buffer, eval_expr(expression, data))
    else:
        emit_result(stdout.buffer, eval(expression))
except BrokenPipeError:
    # quit quietly, instead of showing a confusing error message
    stderr.close()
except KeyboardInterrupt:
    exit(2)
except Exception as e:
    s = str(e)
    s = s if s else '<generic exception>'
    print(f'\x1b[31m{s}\x1b[0m', file=stderr)
    exit(1)