Hrochobot/hrochobot/cogs/messages.py

import discord
from discord.ext import commands
from discord.utils import get
import hrochobot.utils.data as data

MESSAGES_JSON = "messages"

def as_reply(message: str):
    return "\n".join(map(lambda x: f"> {x}", message.split('\n')))

class Messages(commands.Cog):
    def __init__(self, bot):
        self.bot = bot

    @discord.message_command()
    async def forward(self, ctx, message: discord.Message):
        messages_json = data.load_guild_data(ctx.guild.id, MESSAGES_JSON)
        if "forward_channel" not in messages_json:
            return await ctx.respond(f"Forwarding channel not set.", ephemeral=True)
        
        forward_channel = get(ctx.guild.channels, id=messages_json["forward_channel"])
        header_text = f"{ctx.author.mention} forwarded:\n{message.author.mention} wrote in {message.channel.mention}:\n"
        await forward_channel.send(f"{header_text}{as_reply(message.clean_content)}")
        return await ctx.respond("Message successfully forwarded.", ephemeral=True)

    @discord.slash_command(description="Sets channel for forwarding.")
    @discord.option("channel", discord.TextChannel, description="Channel for forwarding.")
    @discord.default_permissions(administrator=True)
    async def set_forward_channel(self, ctx, channel: discord.TextChannel):
        messages_json = data.load_guild_data(ctx.guild.id, MESSAGES_JSON)
        messages_json["forward_channel"] = channel.id
        data.dump_guild_data(ctx.guild.id, MESSAGES_JSON, messages_json)
        return await ctx.respond(f"Forwarding channel set to {channel.mention}.\n" + \
                                 "Remember to set permissions for forwarding.", ephemeral=True)

def setup(bot):
    bot.add_cog(Messages(bot))