"""
This example implements Matrix bot that can execute some commands.

It uses environment variables to specify authorization data. Use Ctrl+C to stop
the bot.
"""

import asyncio
import time
import html
import os
import traceback
import logging

from mab import *

from _environment import check_environment

async def on_help_command(ctx: EventContext) -> None:
    """!help"""
    HELP_MESSAGE = (
        "<strong>Here is the list of the commands:</strong><br>"
        "<ul>"
        "<li><code>!help</code> - this help message</li>"
        "<li><code>!time</code> - get UNIX timestamp</li>"
        "<li><code>!raise</code> - raise <code>RuntimeError()</code></li>"
        "<li><code>!assert</code> - perform <code>assert</code> that will fail</li>"
        "<li><code>!mul A B [C] [D]...</code> - multiply A, B... and so on</li>"
        "<li><code>!args arg1 [arg2] ... [arg5]</code> - command that takes 1..5 arguments</li>"
        "</ul>"
    )
    await ctx.bot.send_text(ctx.room, HELP_MESSAGE)

async def on_time_command(ctx: EventContext) -> None:
    """!time"""
    await ctx.bot.send_text(
        ctx.room,
        f"Current UNIX timestamp is <strong>{int(time.time())}</strong>"
    )

async def on_raise_command(ctx: EventContext) -> None:
    """!raise"""
    await ctx.bot.send_text(
        ctx.room,
        "<strong>Executing <code>raise RuntimeError()</code>...</strong>"
    )
    raise RuntimeError()

async def on_assert_command(ctx: EventContext) -> None:
    """!assert"""
    await ctx.bot.send_text(
        ctx.room,
        "<strong>Executing <code>assert False</code>...</strong>"
    )
    assert False

async def on_mul_command(ctx: EventContext) -> None:
    """!mul"""
    try:
        numbers = [float(v) for v in ctx[CTX_CMD_ARGS]]
        v = numbers[0]
        for n in numbers[1:]:
            v *= n
        response = " * ".join(html.escape("%.2f" % n) for n in numbers)
        response += f" = <strong>{html.escape(str(v))}<strong>"
        await ctx.bot.send_text(ctx.room, response)
    except Exception as e:
        await ctx.bot.send_text(ctx.room, f"Could not process the command: {e}")

async def on_args_command(ctx: EventContext) -> None:
    """!args"""
    try:
        response = (
            f"Prefix: <code>{ctx[CTX_CMD_PREFIX]}</code><br>"
            f"Verb: <code>{ctx[CTX_CMD_VERB]}</code><br>"
            f"Arguments: <code>{len(ctx[CTX_CMD_ARGS])}</code><br>"
            f"Arguments are:<br><ol>"
        )
        for arg in ctx[CTX_CMD_ARGS]:
            response += f"<li><code>{html.escape(arg)}</code></li>"
        response += "</ol>"
        await ctx.bot.send_text(
            ctx.room,
            response
        )
    except:
        await ctx.bot.send_text(
            ctx.room,
            f"Could not process the command: {traceback.format_exc()}"
        )

async def invalid_usage(ctx: EventContext) -> None:
    """This callback is called when the bot used incorrectly."""
    await ctx.bot.send_text(ctx.room, "Use <code>!help</code>")


async def main() -> None:
    """Application entry point"""
    logging.basicConfig(level=logging.INFO)
    logging.getLogger("nio").setLevel(logging.CRITICAL+1)
    check_environment()

    config = MatrixBotConfig(
        matrix_homeserver_url=os.environ["MATRIX_HOMESERVER"],
        matrix_username_localpart=os.environ["MATRIX_USERNAME"],
        storage_directory="session_storage"
    )
    bot = MatrixBot(config)

    COMMANDS = {
        on_help_command: BodyCommandFilter(["help", "?"]),
        on_time_command: BodyCommandFilter("time"),
        on_raise_command: BodyCommandFilter("raise"),
        on_assert_command: BodyCommandFilter("assert"),
        on_mul_command: BodyCommandFilter("mul", min_args=2),
        on_args_command: BodyCommandFilter("args", min_args=1, max_args=5),
    }
    for callback, filter in COMMANDS.items():
        f = ~SenderIsBotFilter() & filter
        bot.add_callback(f, callback)
    bot.add_callback(~SenderIsBotFilter() & NewMessageFilter(), invalid_usage)

    # run until Ctrl+C
    try:
        await bot.run()
    except asyncio.CancelledError:
        pass

if __name__ == "__main__":
    asyncio.run(main())