import traceback
from typing import Optional

import discord
from discord.ext import commands

from didier.utils.discord.constants import Limits
from didier.utils.types.string import abbreviate

__all__ = ["create_error_embed"]


def _get_traceback(exception: Exception) -> str:
    """Get a proper representation of the exception"""
    tb = traceback.format_exception(type(exception), exception, exception.__traceback__)
    error_string = ""
    for line in tb:
        # Don't add endless tracebacks
        if line.strip().startswith("The above exception was the direct cause of"):
            break

        # Escape Discord Markdown formatting
        error_string += line
        if line.strip():
            error_string += "\n"

    return abbreviate(error_string, Limits.EMBED_FIELD_VALUE_LENGTH - 8)


def create_error_embed(ctx: Optional[commands.Context], exception: Exception) -> discord.Embed:
    """Create an embed for the traceback of an exception"""
    message = str(exception)

    # Wrap the traceback in a codeblock for readability
    description = _get_traceback(exception).strip()
    description = f"```\n{description}\n```"

    embed = discord.Embed(title="Error", colour=discord.Colour.red())

    if ctx is not None:
        if ctx.guild is None or isinstance(ctx.channel, discord.DMChannel):
            origin = "DM"
        else:
            origin = f"<#{ctx.channel.id}> ({ctx.guild.name})"

        invocation = f"{ctx.author.display_name} in {origin}"

        if ctx.interaction is not None and ctx.interaction.command is not None:
            command = ctx.interaction.command.name
        else:
            command = ctx.message.content or "N/A"

        embed.add_field(name="Command", value=command, inline=True)
        embed.add_field(name="Context", value=invocation, inline=True)

    if message:
        embed.add_field(name="Exception", value=message, inline=False)

    embed.add_field(name="Traceback", value=description, inline=False)

    return embed