import type { QuotaLineView, QuotaSubject, QuotaSubjectView } from '@dorfteich/shared';
import { useState } from 'react';
import { useTranslation } from 'react-i18next';

import { ApiError, apiDelete, apiGet, apiPut } from '../lib/api';

/**
 * Site-Admin quota override management (issue #58): look up a user or pond, see
 * every quota's effective value on the ladder, and set or clear a per-subject
 * override — which the QuotaService picks up at the next consumption check. The
 * usage column flags subjects currently over their effective limit.
 */
export function QuotaManager(): React.JSX.Element {
  const { t } = useTranslation('quotas');
  const [type, setType] = useState<QuotaSubject>('user');
  const [q, setQ] = useState('');
  const [subject, setSubject] = useState<QuotaSubjectView | null>(null);
  const [drafts, setDrafts] = useState<Record<string, string>>({});
  const [error, setError] = useState<string | null>(null);

  const apply = (view: QuotaSubjectView): void => {
    setSubject(view);
    setDrafts(
      Object.fromEntries(
        view.lines.map((l) => [l.key, l.override === null ? '' : String(l.override)]),
      ),
    );
  };

  const find = async (): Promise<void> => {
    setError(null);
    setSubject(null);
    try {
      const hit = await apiGet<{ id: string }>(
        `/admin/quotas/lookup?type=${type}&q=${encodeURIComponent(q.trim())}`,
      );
      apply(await apiGet<QuotaSubjectView>(`/admin/quotas/${type}/${hit.id}`));
    } catch (err) {
      setError(err instanceof ApiError && err.status === 404 ? t('overrides.notFound') : 'error');
    }
  };

  const set = async (key: string): Promise<void> => {
    if (!subject) return;
    const value = Number(drafts[key]);
    if (!Number.isFinite(value) || value < 0) return;
    apply(
      await apiPut<QuotaSubjectView>(`/admin/quotas/${subject.type}/${subject.id}/${key}`, {
        value,
      }),
    );
  };

  const clear = async (key: string): Promise<void> => {
    if (!subject) return;
    apply(await apiDelete<QuotaSubjectView>(`/admin/quotas/${subject.type}/${subject.id}/${key}`));
  };

  return (
    <section className="settings-section quota-manager">
      <h2>{t('overrides.title')}</h2>
      <div className="quota-manager__lookup">
        <select
          className="quota-manager__type"
          value={type}
          aria-label={t('overrides.typeLabel')}
          onChange={(e) => setType(e.target.value as QuotaSubject)}
        >
          <option value="user">{t('overrides.user')}</option>
          <option value="pond">{t('overrides.pond')}</option>
        </select>
        <input
          className="quota-manager__query"
          value={q}
          placeholder={t('overrides.query')}
          onChange={(e) => setQ(e.target.value)}
          onKeyDown={(e) => e.key === 'Enter' && void find()}
        />
        <button type="button" className="button" onClick={() => void find()}>
          {t('overrides.find')}
        </button>
      </div>
      {error && (
        <p className="form-banner form-banner--error" role="alert">
          {error === 'error' ? t('overrides.notFound') : error}
        </p>
      )}

      {subject && (
        <>
          <p className="quota-manager__subject">{subject.label}</p>
          <table className="table quota-manager__table">
            <thead>
              <tr>
                <th>{t('overrides.key')}</th>
                <th>{t('overrides.default')}</th>
                <th>{t('overrides.override')}</th>
                <th>{t('overrides.effective')}</th>
                <th>{t('overrides.usage')}</th>
              </tr>
            </thead>
            <tbody>
              {subject.lines.map((line) => (
                <QuotaRow
                  key={line.key}
                  line={line}
                  draft={drafts[line.key] ?? ''}
                  onDraft={(v) => setDrafts((d) => ({ ...d, [line.key]: v }))}
                  onSet={() => void set(line.key)}
                  onClear={() => void clear(line.key)}
                />
              ))}
            </tbody>
          </table>
        </>
      )}
    </section>
  );
}

function QuotaRow({
  line,
  draft,
  onDraft,
  onSet,
  onClear,
}: {
  line: QuotaLineView;
  draft: string;
  onDraft: (v: string) => void;
  onSet: () => void;
  onClear: () => void;
}): React.JSX.Element {
  const { t } = useTranslation('quotas');
  const overQuota = line.usage !== null && line.usage > line.effective;
  return (
    <tr className={`quota-row${overQuota ? ' quota-row--over' : ''}`} data-key={line.key}>
      <td>{t(`keys.${line.key}`)}</td>
      <td>{line.instanceDefault}</td>
      <td className="quota-row__override">
        <input
          type="number"
          min={0}
          className="quota-row__input"
          value={draft}
          onChange={(e) => onDraft(e.target.value)}
        />
        <button type="button" className="linklike" onClick={onSet}>
          {t('overrides.set')}
        </button>
        {line.override !== null && (
          <button type="button" className="linklike" onClick={onClear}>
            {t('overrides.clear')}
          </button>
        )}
      </td>
      <td className="quota-row__effective">{line.effective}</td>
      <td className="quota-row__usage">
        {line.usage ?? '—'}
        {overQuota && <span className="quota-row__flag"> · {t('overrides.overQuota')}</span>}
      </td>
    </tr>
  );
}