import type {
  AuditEntryView,
  AuditListView,
  JobTriggerOutcome,
  JobTriggerResult,
  StorageOverviewView,
  SystemJobView,
} from '@dorfteich/shared';
import { keepPreviousData, useQuery } from '@tanstack/react-query';
import { useState } from 'react';
import { useTranslation } from 'react-i18next';
import { Link } from 'react-router-dom';

import { SettingsLayout } from '../components/SettingsLayout';
import { formatBytes } from '../files/file-format';
import { apiGet, apiPost } from '../lib/api';
import { BackupSection } from './AdminBackupSection';

import { useDocumentTitle } from '../lib/use-document-title';
/**
 * Site-Admin "System" panel (issue #86): maintenance jobs with a manual
 * trigger, the backup card fed by the sidecar's status.json, the audit-log
 * viewer, and the per-pond storage top list — the operator's single glance
 * for instance health (operations.md).
 */
export function AdminSystemPage(): React.JSX.Element {
  const { t } = useTranslation('system');
  useDocumentTitle(t('title'));
  return (
    <>
      <h1>{t('title')}</h1>
      <p>
        <Link to="/admin">← {t('backLink')}</Link>
      </p>
      <SettingsLayout>
        <JobsSection />
        <BackupSection />
        <AuditViewer />
        <StorageSection />
      </SettingsLayout>
    </>
  );
}

function cadenceParts(seconds: number): {
  unit: 'days' | 'hours' | 'minutes' | 'seconds';
  count: number;
} {
  if (seconds % 86_400 === 0) return { unit: 'days', count: seconds / 86_400 };
  if (seconds % 3_600 === 0) return { unit: 'hours', count: seconds / 3_600 };
  if (seconds % 60 === 0) return { unit: 'minutes', count: seconds / 60 };
  return { unit: 'seconds', count: seconds };
}

function durationLabel(ms: number): string {
  if (ms < 1000) return `${ms} ms`;
  return `${(ms / 1000).toFixed(ms < 10_000 ? 1 : 0)} s`;
}

function JobsSection(): React.JSX.Element {
  const { t } = useTranslation('system');
  const [notice, setNotice] = useState<{ job: string; outcome: JobTriggerOutcome } | null>(null);
  const [pending, setPending] = useState<string | null>(null);

  const query = useQuery({
    queryKey: ['admin', 'system', 'jobs'],
    queryFn: () => apiGet<SystemJobView[]>('/admin/system/jobs'),
  });

  const trigger = async (name: string): Promise<void> => {
    setPending(name);
    setNotice(null);
    try {
      const result = await apiPost<JobTriggerResult>(`/admin/system/jobs/${name}/run`, {});
      setNotice({ job: name, outcome: result.outcome });
    } finally {
      setPending(null);
      await query.refetch();
    }
  };

  return (
    <section className="settings-section">
      <h2>{t('jobs.title')}</h2>
      {notice && (
        <p role="status" className="system-jobs__notice">
          {t(`jobs.triggered.${notice.outcome}`)}
        </p>
      )}
      <table className="table system-jobs__table">
        <thead>
          <tr>
            <th>{t('jobs.columns.job')}</th>
            <th>{t('jobs.columns.cadence')}</th>
            <th>{t('jobs.columns.lastRun')}</th>
            <th>{t('jobs.columns.duration')}</th>
            <th>{t('jobs.columns.outcome')}</th>
            <th>{t('jobs.columns.actions')}</th>
          </tr>
        </thead>
        <tbody>
          {(query.data ?? []).map((job) => (
            <tr key={job.name}>
              <td>
                {t(`jobs.names.${job.name}`, { defaultValue: job.name })}
                {!job.registered && (
                  <span className="system-badge system-badge--warn">{t('jobs.unregistered')}</span>
                )}
              </td>
              <td>
                {(() => {
                  const { unit, count } = cadenceParts(job.cadenceSeconds);
                  return t(`jobs.cadence.${unit}`, { count });
                })()}
              </td>
              <td>{job.lastRunAt ? new Date(job.lastRunAt).toLocaleString() : '—'}</td>
              <td>{job.lastDurationMs !== null ? durationLabel(job.lastDurationMs) : '—'}</td>
              <td>
                <JobOutcome job={job} />
              </td>
              <td>
                {job.registered && (
                  <button
                    type="button"
                    className="button"
                    disabled={pending !== null || job.status === 'RUNNING'}
                    onClick={() => void trigger(job.name)}
                  >
                    {pending === job.name ? t('jobs.runPending') : t('jobs.run')}
                  </button>
                )}
              </td>
            </tr>
          ))}
        </tbody>
      </table>
    </section>
  );
}

function JobOutcome({ job }: { job: SystemJobView }): React.JSX.Element {
  const { t } = useTranslation('system');
  if (job.status === 'RUNNING')
    return <span className="system-badge">{t('jobs.outcome.running')}</span>;
  if (job.status === 'FAILED')
    return (
      <span className="system-badge system-badge--error" title={job.lastError ?? undefined}>
        {t('jobs.outcome.failed')}
      </span>
    );
  if (!job.lastRunAt) return <span className="system-badge">{t('jobs.outcome.never')}</span>;
  return <span className="system-badge system-badge--ok">{t('jobs.outcome.ok')}</span>;
}

interface AuditFilter {
  actor: string;
  action: string;
  from: string;
  to: string;
}

const EMPTY_FILTER: AuditFilter = { actor: '', action: '', from: '', to: '' };

function AuditViewer(): React.JSX.Element {
  const { t } = useTranslation('system');
  const [draft, setDraft] = useState<AuditFilter>(EMPTY_FILTER);
  const [filter, setFilter] = useState<AuditFilter>(EMPTY_FILTER);
  const [page, setPage] = useState(1);

  const query = useQuery({
    queryKey: ['admin', 'system', 'audit', filter, page],
    queryFn: () => {
      const params = new URLSearchParams({ page: String(page) });
      if (filter.actor) params.set('actor', filter.actor);
      if (filter.action) params.set('action', filter.action);
      if (filter.from) params.set('from', new Date(filter.from).toISOString());
      if (filter.to) params.set('to', new Date(filter.to).toISOString());
      return apiGet<AuditListView>(`/admin/system/audit?${params.toString()}`);
    },
    placeholderData: keepPreviousData,
  });

  const data = query.data;

  return (
    <section className="settings-section system-audit">
      <h2>{t('audit.title')}</h2>
      <form
        className="system-audit__filters"
        onSubmit={(e) => {
          e.preventDefault();
          setPage(1);
          setFilter(draft);
        }}
      >
        <input
          type="text"
          value={draft.actor}
          placeholder={t('audit.filters.actor')}
          aria-label={t('audit.filters.actor')}
          onChange={(e) => setDraft({ ...draft, actor: e.target.value })}
        />
        <select
          value={draft.action}
          aria-label={t('audit.filters.action')}
          onChange={(e) => setDraft({ ...draft, action: e.target.value })}
        >
          <option value="">{t('audit.filters.actionAny')}</option>
          {KNOWN_ACTIONS.map((action) => (
            <option key={action} value={action}>
              {t(`audit.actions.${action}`, { defaultValue: action })}
            </option>
          ))}
        </select>
        <input
          type="datetime-local"
          value={draft.from}
          aria-label={t('audit.filters.from')}
          onChange={(e) => setDraft({ ...draft, from: e.target.value })}
        />
        <input
          type="datetime-local"
          value={draft.to}
          aria-label={t('audit.filters.to')}
          onChange={(e) => setDraft({ ...draft, to: e.target.value })}
        />
        <button type="submit" className="button">
          {t('audit.filters.apply')}
        </button>
      </form>

      {data && data.entries.length === 0 && <p>{t('audit.empty')}</p>}
      {data && data.entries.length > 0 && (
        <table className="table system-audit__table">
          <thead>
            <tr>
              <th>{t('audit.columns.time')}</th>
              <th>{t('audit.columns.actor')}</th>
              <th>{t('audit.columns.action')}</th>
              <th>{t('audit.columns.target')}</th>
              <th>{t('audit.columns.details')}</th>
            </tr>
          </thead>
          <tbody>
            {data.entries.map((entry) => (
              <AuditRow key={entry.id} entry={entry} />
            ))}
          </tbody>
        </table>
      )}
      {data && (
        <div className="system-audit__pager">
          <button
            type="button"
            className="button"
            disabled={page <= 1}
            onClick={() => setPage((p) => p - 1)}
          >
            {t('audit.previous')}
          </button>
          <span>
            {t('audit.pager', { page: data.page, pageCount: data.pageCount, total: data.total })}
          </span>
          <button
            type="button"
            className="button"
            disabled={page >= data.pageCount}
            onClick={() => setPage((p) => p + 1)}
          >
            {t('audit.next')}
          </button>
        </div>
      )}
    </section>
  );
}

const KNOWN_ACTIONS = [
  'grant.created',
  'grant.deleted',
  'member.added',
  'member.role_changed',
  'member.removed',
  'user.disabled_set',
  'user.verification_resent',
  'user.deleted',
  'user.site_admin_set',
  'user.pseudonymized',
  'quota.override_set',
  'quota.override_cleared',
  'plugin.installed',
  'plugin.mode_set',
  'plugin.uninstalled',
  'plugin.pond_toggled',
  'settings.changed',
  'setup.preseeded',
  'setup.admin_created',
  'setup.smtp_stored',
  'setup.completed',
  'auth.signup',
  'auth.email_verified',
  'auth.login_failed',
  'auth.login_succeeded',
  'auth.password_reset',
  'job.triggered',
  'backup.settings_changed',
  'backup.run_triggered',
  'backup.restore_requested',
  'api.token_created',
  'api.token_revoked',
  'api.write',
];

function AuditRow({ entry }: { entry: AuditEntryView }): React.JSX.Element {
  const { t } = useTranslation('system');
  return (
    <tr>
      <td>{new Date(entry.at).toLocaleString()}</td>
      <td>{entry.actor ? entry.actor.displayName : t('audit.systemActor')}</td>
      <td>{t(`audit.actions.${entry.action}`, { defaultValue: entry.action })}</td>
      <td>
        {entry.targetType && (
          <code>
            {entry.targetType}:{entry.targetId}
          </code>
        )}
      </td>
      <td>{entry.details && <code>{JSON.stringify(entry.details)}</code>}</td>
    </tr>
  );
}

function StorageSection(): React.JSX.Element {
  const { t } = useTranslation('system');
  const query = useQuery({
    queryKey: ['admin', 'system', 'storage'],
    queryFn: () => apiGet<StorageOverviewView>('/admin/system/storage'),
  });
  const view = query.data;
  if (!view) return <></>;

  return (
    <section className="settings-section system-storage">
      <h2>{t('storage.title')}</h2>
      <p>{t('storage.total', { total: formatBytes(view.totalBytes) })}</p>
      {view.ponds.length === 0 && <p>{t('storage.empty')}</p>}
      {view.ponds.length > 0 && (
        <table className="table system-storage__table">
          <thead>
            <tr>
              <th>{t('storage.columns.pond')}</th>
              <th>{t('storage.columns.type')}</th>
              <th>{t('storage.columns.used')}</th>
            </tr>
          </thead>
          <tbody>
            {view.ponds.map((pond) => (
              <tr key={pond.pondId}>
                <td>
                  <Link to={`/p/${pond.slug}`}>{pond.name}</Link>
                </td>
                <td>{t(`storage.types.${pond.type}`)}</td>
                <td>{formatBytes(pond.storageBytesUsed)}</td>
              </tr>
            ))}
          </tbody>
        </table>
      )}
    </section>
  );
}