import { createGroup } from '@chat-app/shared/chat';
import { extractErrorCode } from '@chat-app/shared/i18n';
import { useMemo, useState } from 'react';
import { useTranslation } from 'react-i18next';
import { useNavigate } from 'react-router-dom';

import { useFriendshipsContext } from '../context/FriendshipsContext';
import { supabase } from '../lib/supabase';
import { AlertIcon, CheckCircleIcon, SpinnerIcon, UsersIcon } from './icons';
import { Modal } from './Modal';

interface Props {
  open: boolean;
  onClose: () => void;
}

export function CreateGroupDialog({ open, onClose }: Props) {
  const { t } = useTranslation(['app', 'errors']);
  const navigate = useNavigate();
  const { friendships } = useFriendshipsContext();
  const acceptedFriends = useMemo(
    () => friendships.filter((f) => f.status === 'accepted').map((f) => f.peer),
    [friendships],
  );

  const [name, setName] = useState('');
  const [selected, setSelected] = useState<Set<string>>(new Set());
  const [busy, setBusy] = useState(false);
  const [error, setError] = useState<string | null>(null);

  function toggle(userId: string) {
    setSelected((prev) => {
      const next = new Set(prev);
      if (next.has(userId)) next.delete(userId);
      else next.add(userId);
      return next;
    });
  }

  async function handleSubmit(e: React.FormEvent) {
    e.preventDefault();
    if (busy || name.trim().length === 0) return;
    setBusy(true);
    setError(null);
    try {
      const id = await createGroup({
        client: supabase,
        name,
        memberUserIds: Array.from(selected),
      });
      onClose();
      setName('');
      setSelected(new Set());
      navigate('/chats/' + id);
    } catch (err: unknown) {
      const code = extractErrorCode(err);
      setError(
        code
          ? t('errors:' + code, { defaultValue: t('errors:generic') })
          : err instanceof Error
            ? err.message
            : t('errors:generic'),
      );
    } finally {
      setBusy(false);
    }
  }

  return (
    <Modal open={open} onClose={onClose} title={t('app:group.create_title')}>
      <form onSubmit={handleSubmit} className="space-y-4">
        <div className="space-y-1.5">
          <label className="block text-xs font-medium uppercase tracking-wide text-neutral-400">
            {t('app:group.create_name_label')}
          </label>
          <input
            type="text"
            required
            maxLength={64}
            autoFocus
            value={name}
            onChange={(e) => setName(e.target.value)}
            placeholder={t('app:group.create_name_placeholder')}
            className="w-full rounded-lg border border-white/10 bg-ink-800 px-3 py-2.5 text-sm text-white placeholder-neutral-500 transition focus:border-brand-400 focus:outline-none focus:ring-2 focus:ring-brand-500/40"
          />
        </div>

        <div className="space-y-2">
          <label className="block text-xs font-medium uppercase tracking-wide text-neutral-400">
            {t('app:group.create_members_label')}{' '}
            <span className="text-neutral-500">({selected.size})</span>
          </label>
          {acceptedFriends.length === 0 ? (
            <div className="flex items-center gap-3 rounded-lg border border-white/5 bg-ink-800/60 p-4 text-xs text-neutral-400">
              <UsersIcon className="h-4 w-4" />
              <span>{t('app:group.create_members_empty')}</span>
            </div>
          ) : (
            <ul className="max-h-72 space-y-1 overflow-y-auto rounded-lg border border-white/5 bg-ink-800/40 p-1">
              {acceptedFriends.map((f) => {
                const active = selected.has(f.userId);
                const letter =
                  (f.displayName ?? f.username ?? '?').trim().charAt(0).toUpperCase() || '?';
                return (
                  <li key={f.userId}>
                    <button
                      type="button"
                      onClick={() => toggle(f.userId)}
                      aria-pressed={active}
                      className={
                        'flex w-full cursor-pointer items-center gap-3 rounded-lg px-3 py-2 text-left transition focus:outline-none focus-visible:ring-2 focus-visible:ring-brand-400/40 ' +
                        (active ? 'bg-brand-500/15 ring-1 ring-brand-400/30' : 'hover:bg-white/5')
                      }
                    >
                      <div className="flex h-8 w-8 shrink-0 items-center justify-center rounded-full bg-brand-500/30 text-xs font-semibold text-white ring-1 ring-brand-400/30">
                        {letter}
                      </div>
                      <div className="min-w-0 flex-1">
                        <p className="truncate text-sm text-white">{f.displayName}</p>
                        <p className="truncate text-xs text-neutral-500">@{f.username}</p>
                      </div>
                      {active && <CheckCircleIcon className="h-4 w-4 text-brand-300" />}
                    </button>
                  </li>
                );
              })}
            </ul>
          )}
        </div>

        {error && (
          <div
            role="alert"
            className="flex items-start gap-3 rounded-lg border border-rose-500/20 bg-rose-500/10 p-3 text-sm text-rose-100"
          >
            <AlertIcon className="mt-0.5 h-5 w-5 shrink-0 text-rose-400" />
            <p className="min-w-0 flex-1 break-words">{error}</p>
          </div>
        )}

        <button
          type="submit"
          disabled={busy || name.trim().length === 0}
          className="inline-flex w-full cursor-pointer items-center justify-center gap-2 rounded-lg bg-gradient-to-br from-brand-400 to-brand-600 px-4 py-2.5 text-sm font-semibold text-white shadow-glow transition hover:from-brand-300 hover:to-brand-500 focus:outline-none focus-visible:ring-2 focus-visible:ring-brand-400/60 disabled:cursor-not-allowed disabled:opacity-60"
        >
          {busy && <SpinnerIcon className="h-4 w-4" />}
          <span>{t(busy ? 'app:group.create_cta_loading' : 'app:group.create_cta')}</span>
        </button>
      </form>
    </Modal>
  );
}