import { useCallback, useMemo, useState } from 'react';
import { useTranslation } from 'react-i18next';
import { useParams } from 'react-router';

import type { Message } from '@/api/messages';
import { ChatView } from '@/components/chat/ChatView';
import { PinsPanel } from '@/components/chat/PinsPanel';
import { SearchPanel } from '@/components/chat/SearchPanel';
import { useAuthorDirectory } from '@/components/chat/useAuthorDirectory';
import { Card } from '@/components/ui/primitives';
import { canManageMessages, canSendMessages } from '@/lib/identity';
import { useMessagesStore } from '@/stores/messages';
import { useSessionStore } from '@/stores/session';

/**
 * Область контента комнаты: для текстовых комнат — чат (лента, поиск, пины),
 * для голосовых сохраняется заглушка до следующих фаз.
 */
export default function GuildView() {
  const { t } = useTranslation();
  const params = useParams<{ guildId?: string; channelId?: string }>();
  const guild = useSessionStore((state) =>
    params.guildId === undefined
      ? null
      : (state.guilds.find((item) => item.id === params.guildId) ?? null),
  );
  const sessionUser = useSessionStore((state) => state.user);
  const channel = guild?.channels.find((item) => item.id === params.channelId) ?? null;
  const channelId = channel?.id ?? null;

  const [searchOpen, setSearchOpen] = useState(false);
  const [pinsOpen, setPinsOpen] = useState(false);
  const [jump, setJump] = useState<{ id: string; token: number } | null>(null);

  const messages = useMessagesStore((state) =>
    channelId === null ? undefined : state.channels[channelId]?.messages,
  );
  const pins = useMessagesStore((state) =>
    channelId === null ? undefined : state.channels[channelId]?.pins,
  );
  const pinsLoaded = useMessagesStore(
    (state) => channelId !== null && state.channels[channelId]?.pinsLoaded === true,
  );

  // Справочник авторов для поиска и пинов: id берём из загруженной ленты.
  const authorIds = useMemo(
    () =>
      (messages ?? [])
        .map((message: Message) => message.author_id)
        .filter((id): id is string => id !== undefined),
    [messages],
  );
  const authors = useAuthorDirectory(guild?.id ?? null, authorIds);

  const onJumpHandled = useCallback(() => setJump(null), []);
  const goToMessage = useCallback((id: string) => {
    setJump({ id, token: Date.now() });
  }, []);

  if (params.channelId === undefined || channel === null) {
    return (
      <section id="app-content" className="absolute inset-0 flex items-center justify-center p-6">
        <Card className="max-w-md text-center">
          <h2 className="text-lg font-semibold">{t('channels.noSelection.title')}</h2>
          <p className="mt-2 text-sm text-fg-muted">{t('channels.noSelection.body')}</p>
        </Card>
      </section>
    );
  }

  const isVoice = channel.type === 'voice';
  const permissions = guild?.my_permissions ?? [];
  const isAdmin = sessionUser?.is_instance_admin === true;
  const canPin = canManageMessages(permissions, isAdmin) && canSendMessages(permissions, isAdmin);
  // Счётчик пинов: пока панель не открывали, ориентируемся на загруженную ленту.
  const pinCount = pinsLoaded
    ? (pins?.length ?? 0)
    : (messages ?? []).filter((message: Message) => message.pinned).length;

  return (
    <section id="app-content" className="absolute inset-0 flex flex-col">
      <header className="flex items-center gap-2 border-b border-border/40 px-4 py-3">
        <span aria-hidden="true" className="text-fg-muted">
          {isVoice ? '🔊' : '#'}
        </span>
        <h2 className="text-sm font-semibold">{channel.name}</h2>
        {channel.slowmode_seconds === undefined || channel.slowmode_seconds === 0 ? null : (
          <span className="text-xs text-fg-muted">
            {t('channels.slowmode', { seconds: channel.slowmode_seconds })}
          </span>
        )}
        {isVoice ? null : (
          <div className="ml-auto flex items-center gap-1">
            <button
              type="button"
              aria-label={t('chat.search.open')}
              title={t('chat.search.open')}
              aria-expanded={searchOpen}
              className="rounded-[var(--radius-sm)] px-1.5 text-base leading-none text-fg-muted transition-[color,background-color,transform] duration-[var(--duration-fast)] hover:bg-surface-3 hover:text-fg active:scale-95"
              onClick={() => setSearchOpen((open) => !open)}
            >
              🔍
            </button>
            <button
              type="button"
              aria-label={t('chat.pins.open')}
              title={t('chat.pins.open')}
              className="flex items-center gap-1 rounded-[var(--radius-sm)] px-1.5 text-base leading-none text-fg-muted transition-[color,background-color,transform] duration-[var(--duration-fast)] hover:bg-surface-3 hover:text-fg active:scale-95"
              onClick={() => setPinsOpen(true)}
            >
              📌
              {pinCount === 0 ? null : <span className="text-xs font-medium">{pinCount}</span>}
            </button>
          </div>
        )}
      </header>

      {isVoice ? (
        <div className="flex flex-1 items-center justify-center p-6">
          <Card className="max-w-md text-center">
            <h3 className="text-lg font-semibold">{t('channels.voicePlaceholder.title')}</h3>
            <p className="mt-2 text-sm text-fg-muted">
              {t('channels.voicePlaceholder.body', { name: channel.name })}
            </p>
          </Card>
        </div>
      ) : (
        <>
          <SearchPanel
            channelId={channel.id}
            open={searchOpen}
            onClose={() => setSearchOpen(false)}
            authors={authors}
            onJump={goToMessage}
          />
          <ChatView
            key={channel.id}
            channel={channel}
            guildId={guild?.id ?? null}
            jumpTo={jump}
            onJumpHandled={onJumpHandled}
          />
          <PinsPanel
            channelId={channel.id}
            channelName={channel.name}
            open={pinsOpen}
            onClose={() => setPinsOpen(false)}
            authors={authors}
            canManageMessages={canPin}
            onJump={(id) => {
              setPinsOpen(false);
              goToMessage(id);
            }}
          />
        </>
      )}
    </section>
  );
}