import { useState, type FormEvent } from 'react';
import { useChannels } from '../hooks/use-channels';
import type { ChannelVisibility } from '../types';

/** Browse + join discoverable channels, and create a new one. Shown in the main pane. */
export function ChannelBrowser({ onJoined }: { onJoined?: (threadId: string) => void }) {
  const { browsable, loading, error, join, create } = useChannels();
  const [name, setName] = useState('');
  const [topic, setTopic] = useState('');
  const [visibility, setVisibility] = useState<ChannelVisibility>('public');
  const [busy, setBusy] = useState(false);

  async function submitCreate(e: FormEvent): Promise<void> {
    e.preventDefault();
    const n = name.trim();
    if (!n || busy) return;
    setBusy(true);
    try {
      const threadId = await create({ name: n, ...(topic.trim() ? { topic: topic.trim() } : {}), visibility });
      setName('');
      setTopic('');
      onJoined?.(threadId);
    } catch {
      // surfaced via the hook's error
    } finally {
      setBusy(false);
    }
  }

  async function doJoin(threadId: string): Promise<void> {
    await join(threadId);
    onJoined?.(threadId);
  }

  return (
    <div className="miu-browser">
      <div className="miu-browser-head">Channels</div>

      <form className="miu-channel-create" onSubmit={submitCreate}>
        <input
          className="miu-input"
          value={name}
          onChange={(e) => setName(e.target.value)}
          placeholder="New channel name"
          aria-label="Channel name"
        />
        <input
          className="miu-input"
          value={topic}
          onChange={(e) => setTopic(e.target.value)}
          placeholder="Topic (optional)"
          aria-label="Channel topic"
        />
        <div className="miu-channel-vis">
          <label>
            <input type="radio" name="miu-vis" checked={visibility === 'public'} onChange={() => setVisibility('public')} /> Public
          </label>
          <label>
            <input type="radio" name="miu-vis" checked={visibility === 'private'} onChange={() => setVisibility('private')} /> Private
          </label>
        </div>
        <button type="submit" className="miu-send" disabled={!name.trim() || busy}>
          Create
        </button>
      </form>

      <div className="miu-browser-list">
        {loading && browsable.length === 0 ? <div className="miu-empty">Loading…</div> : null}
        {error ? <div className="miu-empty miu-error">{error}</div> : null}
        {!loading && browsable.length === 0 ? <div className="miu-empty">No channels yet — create one above.</div> : null}
        {browsable.map((c) => (
          <div key={c.threadId} className="miu-browser-row">
            <span className="miu-channel-glyph" aria-hidden="true">{c.visibility === 'private' ? '🔒' : '#'}</span>
            <span className="miu-browser-main">
              <span className="miu-browser-name">{c.name}</span>
              {c.topic ? <span className="miu-browser-topic">{c.topic}</span> : null}
              <span className="miu-browser-meta">
                {c.memberCount} member{c.memberCount === 1 ? '' : 's'}
              </span>
            </span>
            {c.joined ? (
              <span className="miu-browser-joined">Joined</span>
            ) : (
              <button type="button" className="miu-join" onClick={() => void doJoin(c.threadId)}>
                Join
              </button>
            )}
          </div>
        ))}
      </div>
    </div>
  );
}