from dataclasses import dataclass, field
from datetime import datetime
from typing import Dict, Optional

from paircd.client import Client
from paircd.channel import Channel
from paircd.reply import QUIT


@dataclass
class Server:
    clients_by_nick: Dict[str, Client] = field(default_factory=dict)
    channels_by_name: Dict[str, Channel] = field(default_factory=dict)
    create_time: datetime = field(default_factory=datetime.utcnow)

    def add_client(self, client: Client) -> None:
        self.clients_by_nick[client.nickname] = client

    def get_channel_by_name(self, name: str, create: bool = True) -> Optional[Channel]:
        if name not in self.channels_by_name and create:
            self.channels_by_name[name] = Channel(name=name)
        return self.channels_by_name.get(name)

    def get_client_by_name(self, name: str) -> Optional[Client]:
        return self.clients_by_nick.get(name)

    def remove_client_by_name(self, name: str) -> None:
        del self.clients_by_nick[name]

    def rename_client(self, name: str, new_name: str) -> None:
        if name not in self.clients_by_nick:
            raise KeyError(f"No client on server with nick {name}")
        if new_name in self.clients_by_nick:
            raise KeyError(f"Client already exists with nick {new_name}")
        self.clients_by_nick[new_name] = self.clients_by_nick[name]
        del self.clients_by_nick[name]

    async def disconnect_client(self, nick: str, quit_msg: str) -> None:
        client = self.clients_by_nick[nick]

        if client.closed:
            return

        client.log(f"is quitting: {quit_msg}")
        msg = QUIT(quit_msg, prefix=client.id())
        for client in self.clients_by_nick.values():
            if client.nickname == nick:
                continue
            client.write_message(msg)

        for channel_name in client.channels:
            channel = self.get_channel_by_name(channel_name, create=False)
            if channel is None:
                continue
            channel.remove_client_by_nick(client.nickname)
            if channel.get_channel_size() == 0:
                del self.channels_by_name[channel_name]

        self.remove_client_by_name(client.nickname)
        await client.close()