diff options
| -rw-r--r-- | bot/exts/evergreen/fun.py | 101 | ||||
| -rw-r--r-- | bot/resources/evergreen/caesar_info.json | 4 |
2 files changed, 103 insertions, 2 deletions
diff --git a/bot/exts/evergreen/fun.py b/bot/exts/evergreen/fun.py index b0240c45..2f575c1c 100644 --- a/bot/exts/evergreen/fun.py +++ b/bot/exts/evergreen/fun.py @@ -1,14 +1,16 @@ import functools +import json import logging import random -from typing import Callable, Tuple, Union +from pathlib import Path +from typing import Callable, Iterable, Tuple, Union from discord import Embed, Message from discord.ext import commands from discord.ext.commands import Bot, Cog, Context, MessageConverter from bot import utils -from bot.constants import Emojis +from bot.constants import Colours, Emojis log = logging.getLogger(__name__) @@ -26,12 +28,35 @@ UWU_WORDS = { } +def caesar_cipher(text: str, offset: int) -> Iterable[str]: + """ + Implements a lazy Caesar Cipher algorithm. + + Encrypts a `text` given a specific integer `offset`. The sign + of the `offset` dictates the direction in which it shifts to, + with a negative value shifting to the left, and a positive + value shifting to the right. + """ + for char in text: + if not char.isascii() or not char.isalpha() or char.isspace(): + yield char + continue + + case_start = 65 if char.isupper() else 97 + true_offset = (ord(char) - case_start + offset) % 26 + + yield chr(case_start + true_offset) + + class Fun(Cog): """A collection of general commands for fun.""" def __init__(self, bot: Bot) -> None: self.bot = bot + with Path("bot/resources/evergreen/caesar_info.json").open("r", encoding="UTF-8") as f: + self._caesar_cipher_embed = json.load(f) + @commands.command() async def roll(self, ctx: Context, num_rolls: int = 1) -> None: """Outputs a number of random dice emotes (up to 6).""" @@ -79,6 +104,78 @@ class Fun(Cog): converted_text = f">>> {converted_text.lstrip('> ')}" await ctx.send(content=converted_text, embed=embed) + @commands.group(name="caesarcipher", aliases=("caesar", "cc",)) + async def caesarcipher_group(self, ctx: Context) -> None: + """ + Translates a message using the Caesar Cipher. + + See `decrypt`, `encrypt`, and `info` subcommands. + """ + if ctx.invoked_subcommand is None: + await ctx.invoke(self.bot.get_command("help"), "caesarcipher") + + @caesarcipher_group.command(name="info") + async def caesarcipher_info(self, ctx: Context) -> None: + """Information about the Caesar Cipher.""" + embed = Embed.from_dict(self._caesar_cipher_embed) + embed.colour = Colours.dark_green + + await ctx.send(embed=embed) + + @staticmethod + async def _caesar_cipher(ctx: Context, offset: int, msg: str, left_shift: bool = False) -> None: + """ + Given a positive integer `offset`, translates and sends the given `msg`. + + Performs a right shift by default unless `left_shift` is specified as `True`. + + Also accepts a valid Discord Message ID or link. + """ + if offset < 0: + await ctx.send(":no_entry: Cannot use a negative offset.") + return + + if left_shift: + offset = -offset + + def conversion_func(text: str) -> str: + """Encrypts the given string using the Caesar Cipher.""" + return "".join(caesar_cipher(text, offset)) + + text, embed = await Fun._get_text_and_embed(ctx, msg) + + if embed is not None: + embed = Fun._convert_embed(conversion_func, embed) + + converted_text = conversion_func(text) + + if converted_text: + converted_text = f">>> {converted_text.lstrip('> ')}" + + await ctx.send(content=converted_text, embed=embed) + + @caesarcipher_group.command(name="encrypt", aliases=("rightshift", "rshift", "enc",)) + async def caesarcipher_encrypt(self, ctx: Context, offset: int, *, msg: str) -> None: + """ + Given a positive integer `offset`, encrypt the given `msg`. + + Performs a right shift of the letters in the message. + + Also accepts a valid Discord Message ID or link. + """ + await self._caesar_cipher(ctx, offset, msg, left_shift=False) + + @caesarcipher_group.command(name="decrypt", aliases=("leftshift", "lshift", "dec",)) + async def caesarcipher_decrypt(self, ctx: Context, offset: int, *, msg: str) -> None: + """ + Given a positive integer `offset`, decrypt the given `msg`. + + Performs a left shift of the letters in the message. + + Also accepts a valid Discord Message ID or link. + """ + await self._caesar_cipher(ctx, offset, msg, left_shift=True) + @staticmethod async def _get_text_and_embed(ctx: Context, text: str) -> Tuple[str, Union[Embed, None]]: """ diff --git a/bot/resources/evergreen/caesar_info.json b/bot/resources/evergreen/caesar_info.json new file mode 100644 index 00000000..8229c4f3 --- /dev/null +++ b/bot/resources/evergreen/caesar_info.json @@ -0,0 +1,4 @@ +{ + "title": "Caesar Cipher", + "description": "**Information**\nThe Caesar Cipher, named after the Roman General Julius Caesar, is one of the simplest and most widely known encryption techniques. It is a type of substitution cipher in which each letter in the plaintext is replaced by a letter given a specific position offset in the alphabet, with the letters wrapping around both sides.\n\n**Examples**\n1) `Hello World` <=> `Khoor Zruog` where letters are shifted forwards by `3`.\n2) `Julius Caesar` <=> `Yjaxjh Rpthpg` where letters are shifted backwards by `11`." +} |