Zephyr Breeze, a Ponyvania cheater

zephyr_breeze.py

#!/usr/bin/env python3

'Zephyr Breeze, a Ponyvania cheater.'
# This program is in the public domain.
# It's tested on the Windows build of Ponyvania v2.0.2.
# Call it with the option `--help` for usage.

import re, subprocess
from pathlib import Path
from tempfile import TemporaryDirectory


replacers = dict(

    disable_save_crypt = dict(
        help = 'Disable encryption (and decryption) of `ponySaveFile1`, `ponySaveFile2`, etc. You can then edit your saves easily in a text editor. Before using this replacer, back up your saves, and decrypt each save file by loading it and copying `saveFile.ini`.',
        f = lambda x: re.sub(
            r'fast_file_key_crypt\(([^,]+), ([^,]+),.+',
            r'if (file_exists(\2)) {file_delete(\2)} file_copy(\1, \2)',
            x),
        scripts = [
            'gml_Object_obj_creationMenu_Create_0',
            'gml_Object_obj_loadGame_Create_0',
            'gml_Object_obj_loadGame_Step_0',
            'gml_Script_script_loadSettings',
            'gml_Script_script_saveSettings']),

    auto_pda = dict(
        help = 'Enable the effect of the PDA (Peekaboo + Dowsing Stick + Eye of Decay) regardless of which accessory you have equipped.',
        f = lambda x:
            re.sub(r'\S+ == "PDA"', 'true', x),
        scripts = [
            'gml_Object_obj_player_Step_0',
            'gml_Object_obj_settings_Draw_0',
            'gml_Object_obj_spawnBlueChest_Step_0',
            'gml_Object_obj_spawnStash_Step_0']),

    print_drop_rates = dict(
        help = 'Print the drop rates of items to the console when you kill a monster.',
        f = lambda x: re.sub(
            r'\{\s+(if \(random\(100\) < (.+)\))',
            r'{show_debug_message("Drop rate: 1 in " + string(100 / (\2))); \1',
            x),
        scripts = [
            'gml_Script_script_dropRates']),

    super_paw = dict(
        help = 'Massively increase the luck bonus from the Black Cat Paw.',
        f = lambda x: re.sub(
            r'(if \(argument0 == "Black Cat Paw"\)\s+return )\d+;',
            lambda m: m.group(1) + '900;',
            x),
        scripts = [
            'gml_Script_script_weaponLCK']),

    force_changelings = dict(
        help = "Force a changeling to spawn in any room of Canterlot that allows one. (You probably only want to keep this replacer on while you're hunting changelings.)",
        f = lambda x:
            re.sub(r'\bspawnAnyway == 1\b', 'true', x),
        scripts = [
            'gml_Object_obj_spawnEnemy_Step_0']))


def replace_datadotwin(umc_path, code_dir, data_target_path, data_orig_path, **kwargs):
    # Get the replacers to use.
    rs = [r for (name, r) in replacers.items() if kwargs[name]]
    # Get the code of each script to be replaced.
    scripts = {
        name: (code_dir / (name + '.gml')).read_text()
        for name in sorted({name
            for replacer in rs
            for name in replacer['scripts']})}
    # Process the replacers.
    for replacer in rs:
        for name in replacer['scripts']:
             scripts[name] = replacer['f'](scripts[name])
    with TemporaryDirectory() as td:
        td = Path(td)
        # Write out the new scripts into their own files.
        for name, code in scripts.items():
            (td / (name + '.gml')).write_text(code)
        # Uncomment the next line to look at the generated files.
        #print("Look in this directory to see the new code:"); print(td); import time; time.sleep(1000000)
        # Invoke UndertaleModTool.
        subprocess.run(cwd = td, check = True, args = map(str, [
            umc_path,
            'replace', data_orig_path,
            '-o', data_target_path,
            '-c', *(f'{name}=./{name}.gml' for name in scripts)]))


def main():
    import argparse

    p = argparse.ArgumentParser(description = __doc__)
    p.add_argument('umc_path',
        help = "The path to UndertaleModTool's `UndertaleModCli`",
        type = Path)
    p.add_argument('code_dir',
        help = 'The `CodeEntries` directory produced by `UndertaleModCli dump data.win -c UMT_DUMP_ALL`',
        type = Path)
    p.add_argument('data_target_path',
        help = "Ponyvania's `data.win` file to overwrite",
        type = Path)
    p.add_argument('data_orig_path',
        help = "A backup you've made of the original `data.win`",
        type = Path)

    g = p.add_argument_group('replacers')
    for name, d in replacers.items():
        g.add_argument('--' + name.replace('_', '-'),
           help = d['help'],
           action = 'store_true')

    replace_datadotwin(**vars(p.parse_args()))

if __name__ == '__main__':
    main()