import contextlib
import logging
import re
from collections.abc import Callable

from discord import Embed, Message
from discord.ext import commands
from discord.ext.commands import Context, MessageConverter

log = logging.getLogger(__name__)


def sub_clyde(username: str | None) -> str | None:
    """
    Replace "e"/"E" in any "clyde" in `username` with a Cyrillic "е"/"Е" and return the new string.

    Discord disallows "clyde" anywhere in the username for webhooks. It will return a 400.
    Return None only if `username` is None.
    """  # noqa: RUF002
    def replace_e(match: re.Match) -> str:
        char = "е" if match[2] == "e" else "Е"  # noqa: RUF001
        return match[1] + char

    if username:
        return re.sub(r"(clyd)(e)", replace_e, username, flags=re.I)
    return username  # Empty string or None


async def get_discord_message(ctx: Context, text: str) -> Message | str:
    """
    Attempts to convert a given `text` to a discord Message object and return it.

    Conversion will succeed if given a discord Message ID or link.
    Returns `text` if the conversion fails.
    """
    with contextlib.suppress(commands.BadArgument):
        text = await MessageConverter().convert(ctx, text)
    return text


async def get_text_and_embed(ctx: Context, text: str) -> tuple[str, Embed | None]:
    """
    Attempts to extract the text and embed from a possible link to a discord Message.

    Does not retrieve the text and embed from the Message if it is in a channel the user does
    not have read permissions in.

    Returns a tuple of:
        str: If `text` is a valid discord Message, the contents of the message, else `text`.
        Optional[Embed]: The embed if found in the valid Message, else None
    """
    embed: Embed | None = None

    msg = await get_discord_message(ctx, text)
    # Ensure the user has read permissions for the channel the message is in
    if isinstance(msg, Message):
        permissions = msg.channel.permissions_for(ctx.author)
        if permissions.read_messages:
            text = msg.clean_content
            # Take first embed because we can't send multiple embeds
            if msg.embeds:
                embed = msg.embeds[0]

    return text, embed


def convert_embed(func: Callable[[str, ], str], embed: Embed) -> Embed:
    """
    Converts the text in an embed using a given conversion function, then return the embed.

    Only modifies the following fields: title, description, footer, fields
    """
    embed_dict = embed.to_dict()

    embed_dict["title"] = func(embed_dict.get("title", ""))
    embed_dict["description"] = func(embed_dict.get("description", ""))

    if "footer" in embed_dict:
        embed_dict["footer"]["text"] = func(embed_dict["footer"].get("text", ""))

    if "fields" in embed_dict:
        for field in embed_dict["fields"]:
            field["name"] = func(field.get("name", ""))
            field["value"] = func(field.get("value", ""))

    return Embed.from_dict(embed_dict)