from base64 import b64encode
from dataclasses import dataclass
from irctokens import StatefulDecoder, build
from typing import Optional
import trio

@dataclass
class Config:
    host: str
    nick: str
    password: str
    port: int = 6667
    leader: str = ','
    user: str = 'columbo'
    channels: Optional[list[str]] = None
    realname: str = 'columbo-irc_client v0.1'
    current_nick: Optional[str] = None
    encoding: str = 'utf-8'

async def _sender(stream, config, inbox):
    def prepare(line):
        print(f'>{line}')
        return f'{line.format()}\r\n'.encode(config.encoding)
    config.current_nick = config.nick
    preamble = [
        ('CAP', ['REQ', 'sasl']),
        ('USER', [config.user, '0', '*', config.realname]),
        ('NICK', [config.nick]),
    ]
    for args in preamble:
        await stream.send_all(prepare(build(*args)))
    async with inbox:
        async for line in inbox:
            await stream.send_all(prepare(line))

async def _handle(config, channel, outbox, line):
    print(f'<{line}')
    if line.command == 'PING':
        await outbox.send(build('PONG', [line.params[0]]))
    elif line.command == 'CAP':
        if line.params[1] == 'ACK' and line.params[2] == 'sasl':
            await outbox.send(build('AUTHENTICATE', ['PLAIN']))
    elif line.command == 'AUTHENTICATE':
        if line.params[0] == '+':
            creds = b64encode(f'\0{config.nick}\0{config.password}'.encode(config.encoding)).decode()
            await outbox.send(build('AUTHENTICATE', [creds]))
    elif line.command == '900': # RPL_LOGGEDIN
        await outbox.send(build('CAP', ['END']))
    elif line.command == '001': # RPL_WELCOME
        config.current_nick = line.params[0]
        if config.channels:
            for channel in config.channels:
                await outbox.send(build('JOIN', [channel]))
    elif line.command == 'PRIVMSG':
        await channel.send(((outbox, config), line))

async def _receiver(stream, config, channel, outbox):
    decoder = StatefulDecoder()
    async with channel, outbox:
        async for data in stream:
            for line in decoder.push(data):
                await _handle(config, channel, outbox, line)

async def connect(config, channel):
    stream = await trio.open_tcp_stream(config.host, config.port)
    outbox_send, outbox_recv = trio.open_memory_channel(0)
    async with stream:
        async with trio.open_nursery() as nursery:
            nursery.start_soon(_sender, stream, config, outbox_recv)
            nursery.start_soon(_receiver, stream, config, channel, outbox_send)