#!/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 = '''
tbp [options...] [python expression] [files/URIs...]


Transform Bytes with Python runs a python expression on each whole-input,
read as a bytes-type value.

The expression can use either `v`, `value`, `d`, or `data` for the current
input.

Input-sources can be either files or web-URIs. When not given any explicit
named sources, the standard input is used. It's even possible to reuse the
standard input using multiple single dashes (-) in the order needed: stdin
is only read once in this case, and kept for later reuse.

When the expression results in None, the current input is ignored. When the
expression results in a boolean, this determines whether the whole input is
copied/appended back to the standard output, or ignored.
'''


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


if len(argv) < 2:
    print(info.strip(), file=stderr)
    exit(0)
if len(argv) == 2 and argv[1] in ('-h', '--h', '-help', '--help'):
    print(info.strip())
    exit(0)


class Skip:
    pass


skip = Skip()


def cond(*args):
    if len(args) == 0:
        return None

    for i, e in enumerate(args):
        if i % 2 == 0 and i < len(args) - 1 and e:
            return args[i + 1]

    return args[-1] if len(args) % 2 == 1 else None


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

catch = rescue
catched = rescue
caught = rescue
recover = rescue
recovered = rescue
rescued = rescue


def wait(seconds, result):
    t = (int, float)
    if (not isinstance(seconds, t)) and isinstance(result, t):
        seconds, result = result, seconds
    sleep(seconds)
    return result

delay = wait


no_input_opts = (
    '=', '-n', '--n', '-nil', '--nil', '-none', '--none', '-null', '--null',
)
string_opts = ('-s', '--s', '-str', '--str', '-string', '--string')
more_modules_opts = ('-mm', '--mm', '-more', '--more')

args = argv[1:]
load_input = True
string_input = False
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

    if args[0] in more_modules_opts:
        import functools
        import itertools
        import json
        import math
        import random
        import statistics
        import string
        import time
        args = args[1:]
        continue

    if args[0] in string_opts:
        string_input = True
        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_read(name):
        return open(name, mode='rb')
    return open_read


def fail(msg, code = 1):
    print(f'\x1b[31m{str(msg)}\x1b[0m', file=stderr)
    exit(code)


def message(msg, result = None):
    print(msg, file=stderr)
    return result

msg = message


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


def tobytes(x):
    if isinstance(x, (bytearray, 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)


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, int):
        w.write(tobytes(x))
        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)


cr = '\r' if string_input else b'\r'
crlf = '\r\n' if string_input else b'\r\n'
dquo = '"' if string_input else b'"'
dquote = '"' if string_input else b'"'
empty = '' if string_input else b''
lcurly = '{' if string_input else b'{'
lf = '\n' if string_input else b'\n'
rcurly = '}' if string_input else b'}'
s = '' if string_input else b''
squo = '\'' if string_input else b'\''
squote = '\'' if string_input else b'\''
utf8bom = '\xef\xbb\xbf' if string_input else b'\xef\xbb\xbf'

nil = None
none = None
null = None

exec = None
open = make_open_read(open)

modules_opts = (
    '-m', '--m', '-mod', '--mod', '-module', '--module',
    '-modules', '--modules',
)
more_modules_opts = ('-mm', '--mm', '-more', '--more')

while len(args) > 0:
    if args[0] in no_input_opts:
        no_input = True
        args = args[1:]
        continue

    if args[0] in modules_opts:
        try:
            if len(args) < 2:
                msg = 'a module name or a comma-separated list of modules'
                raise Exception('expected ' + msg)

            g = globals()
            from importlib import import_module
            for e in args[1].split(','):
                g[e] = import_module(e)

            g = None
            import_module = None
            args = args[2:]
        except Exception as e:
            fail(e, 1)

        continue

    if args[0] in more_modules_opts:
        import functools, itertools, json, math, random, statistics, string, time
        args = args[1:]
        continue

    break


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

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

    data = None

    if not load_input:
        emit_result(stdout.buffer, eval_expr(expression, None))
        exit(0)

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

    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()

            if string_input:
                data = str(data, encoding='utf-8')
        elif seemsurl(name):
            with urlopen(name) as inp:
                data = inp.read()
        else:
            with open(name) as inp:
                data = inp.read()

        if string_input and not isinstance(data, str):
            data = str(data, encoding='utf-8')
        emit_result(stdout.buffer, eval_expr(expression, data))

    if len(args) == 0:
        data = stdin.buffer.read()
        if string_input and not isinstance(data, str):
            data = str(data, encoding='utf-8')
        emit_result(stdout.buffer, eval_expr(expression, data))
except BrokenPipeError:
    # quit quietly, instead of showing a confusing error message
    stderr.close()
    exit(0)
except KeyboardInterrupt:
    # stderr.close()
    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)