"""Plugin: encode and decode strings (base64, hex, URL, ROT13)."""

from __future__ import annotations

import base64
import urllib.parse

from derp.plugin import command

_ROT13 = str.maketrans(
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
    "NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm",
)

_ENCODERS: dict[str, tuple[str, callable]] = {
    "b64": ("Base64", lambda t: base64.b64encode(t.encode()).decode()),
    "hex": ("Hex", lambda t: t.encode().hex()),
    "url": ("URL", lambda t: urllib.parse.quote(t, safe="")),
    "rot13": ("ROT13", lambda t: t.translate(_ROT13)),
}

_DECODERS: dict[str, tuple[str, callable]] = {
    "b64": ("Base64", lambda t: base64.b64decode(t).decode("utf-8", errors="replace")),
    "hex": ("Hex", lambda t: bytes.fromhex(t).decode("utf-8", errors="replace")),
    "url": ("URL", lambda t: urllib.parse.unquote(t)),
    "rot13": ("ROT13", lambda t: t.translate(_ROT13)),
}

_FORMATS = ", ".join(_ENCODERS)


@command("encode", help=f"Encode text: !encode <{_FORMATS}> <text>")
async def cmd_encode(bot, message):
    """Encode text in the specified format."""
    parts = message.text.split(None, 2)
    if len(parts) < 3:
        await bot.reply(message, f"Usage: !encode <{_FORMATS}> <text>")
        return

    fmt = parts[1].lower()
    text = parts[2]

    entry = _ENCODERS.get(fmt)
    if entry is None:
        await bot.reply(message, f"Unknown format: {fmt} (valid: {_FORMATS})")
        return

    try:
        result = entry[1](text)
        await bot.reply(message, result)
    except Exception as exc:
        await bot.reply(message, f"Encode error: {exc}")


@command("decode", help=f"Decode text: !decode <{_FORMATS}> <text>")
async def cmd_decode(bot, message):
    """Decode text from the specified format."""
    parts = message.text.split(None, 2)
    if len(parts) < 3:
        await bot.reply(message, f"Usage: !decode <{_FORMATS}> <text>")
        return

    fmt = parts[1].lower()
    text = parts[2]

    entry = _DECODERS.get(fmt)
    if entry is None:
        await bot.reply(message, f"Unknown format: {fmt} (valid: {_FORMATS})")
        return

    try:
        result = entry[1](text)
        await bot.reply(message, result)
    except Exception as exc:
        await bot.reply(message, f"Decode error: {exc}")