import { useEffect, useMemo, useState } from 'react';
import { useServerStore } from '../stores/server.ts';
import { useChannelStore } from '../stores/channel.ts';
import { VoiceChannel } from './VoiceChannel.tsx';
import { CreateChannelModal } from './CreateChannelModal.tsx';

export function ChannelList() {
  const activeServerId = useServerStore((state) => state.activeServerId);
  const servers = useServerStore((state) => state.servers);
  const channelsByServer = useChannelStore((state) => state.channelsByServer);
  const fetchChannels = useChannelStore((state) => state.fetchChannels);
  const activeChannelId = useChannelStore((state) => state.activeChannelId);
  const setActiveChannel = useChannelStore((state) => state.setActiveChannel);
  const [showCreate, setShowCreate] = useState(false);

  useEffect(() => {
    if (activeServerId) {
      fetchChannels(activeServerId);
    }
  }, [activeServerId, fetchChannels]);

  const channels = useMemo(() => {
    return activeServerId ? channelsByServer[activeServerId] || [] : [];
  }, [activeServerId, channelsByServer]);

  const activeServer = useMemo(() => {
    if (!activeServerId) return null;
    return servers.find((s) => s.id === activeServerId) || null;
  }, [servers, activeServerId]);

  const categories = useMemo(() => {
    const map = new Map<string, typeof channels>();
    for (const channel of channels) {
      const category = channel.category || 'TEXT CHANNELS';
      const list = map.get(category) || [];
      list.push(channel);
      map.set(category, list);
    }
    for (const list of map.values()) {
      list.sort((a, b) => a.position - b.position);
    }
    return Array.from(map.entries());
  }, [channels]);

  return (
    <div className="h-full w-56 bg-gb-bg-s border-r border-gb-bg-t flex flex-col">
      <div className="terminal-border border-t-0 border-x-0 px-3 py-2 text-gb-fg truncate flex items-center justify-between">
        <span>{activeServerId ? `[SERVER ${activeServer?.name ?? activeServerId}]` : '[NO SERVER]'}</span>
        {activeServerId && (
          <button
            onClick={() => setShowCreate(true)}
            className="terminal-button text-xs"
            title="Create channel"
          >
            [+]
          </button>
        )}
      </div>
      <div className="flex-1 overflow-y-auto p-2 font-mono text-sm">
        {categories.length === 0 && (
          <p className="text-gb-fg-f">[no channels]</p>
        )}
        {categories.map(([category, list]) => (
          <div key={category} className="mb-3">
            <div className="text-gb-fg-t text-xs uppercase mb-1">{category}</div>
            <div className="text-gb-fg-f text-xs mb-1">---</div>
            {list.map((channel) =>
              channel.type === 'voice' ? (
                <VoiceChannel
                  key={channel.id}
                  channelId={channel.id}
                  channelName={channel.name}
                />
              ) : (
                <button
                  key={channel.id}
                  onClick={() => setActiveChannel(channel.id)}
                  className={`w-full text-left px-2 py-1 rounded-sm flex items-center gap-2 ${
                    channel.id === activeChannelId ? 'terminal-active' : 'hover:bg-gb-bg-t text-gb-fg-s'
                  }`}
                >
                  <span className="text-gb-fg-f">#</span>
                  <span className="truncate">{channel.name}</span>
                </button>
              )
            )}
          </div>
        ))}
      </div>
      {showCreate && activeServerId && (
        <CreateChannelModal serverId={activeServerId} onClose={() => setShowCreate(false)} />
      )}
    </div>
  );
}