import { useState } from 'react';
import { useNavigate } from 'react-router';
import { useTranslation } from 'react-i18next';
import { Window, Card, Button, SegmentedControl, Callout } from '@olly/modern-sk';
import { TrackRow } from '../../components/track/TrackRow';
import { LoadingSkeleton } from '../../components/common/LoadingSkeleton';
import { EmptyState } from '../../components/common/EmptyState';
import { ErrorState } from '../../components/common/ErrorState';
import { usePermissions } from '../../hooks/usePermissions';
import { useIsOffline } from '../../hooks/useConnectionStatus';
import {
  useGetDuplicatesQuery,
  useGetBrokenFilesQuery,
  useGetMissingMetadataQuery,
  useRunCleanupMutation,
} from '../../api/endpoints/storage';

const PAGE_SIZE = 50;
type Tab = 'duplicates' | 'broken' | 'missing';

/** `/storage/maintenance` — A6 maintenance: duplicates, broken files, missing
 * metadata, and orphan cleanup. */
export function StorageMaintenancePage() {
  const { t } = useTranslation();
  const offline = useIsOffline();
  const [tab, setTab] = useState<Tab>('duplicates');

  return (
    <div style={{ padding: '1.5rem', maxWidth: 1100, margin: '0 auto' }}>
      <Window title={t('pages.storageMaintenance')}>
        <p style={{ color: 'var(--color-text-2)', marginTop: 0 }}>
          {t('storage.maintenance.subtitle')}
        </p>

        {offline && (
          <Callout variant="info">{t('common.offlineBanner')}</Callout>
        )}

        <CleanupSection />

        <div style={{ margin: '1.25rem 0' }}>
          <SegmentedControl
            value={tab}
            onValueChange={(v) => setTab(v as Tab)}
            items={[
              { value: 'duplicates', label: t('storage.maintenance.tabs.duplicates') },
              { value: 'broken', label: t('storage.maintenance.tabs.broken') },
              { value: 'missing', label: t('storage.maintenance.tabs.missing') },
            ]}
          />
        </div>

        {/* Only the active tab is mounted, so only its query fires. */}
        {tab === 'duplicates' && <DuplicatesTab />}
        {tab === 'broken' && (
          <TrackListTab useQuery={useGetBrokenFilesQuery} emptyKey="broken" />
        )}
        {tab === 'missing' && (
          <TrackListTab useQuery={useGetMissingMetadataQuery} emptyKey="missing" />
        )}
      </Window>
    </div>
  );
}

/** Orphan-file cleanup — admin only (enqueues a worker job). */
function CleanupSection() {
  const { t } = useTranslation();
  const { isAdmin } = usePermissions();
  const [runCleanup, { isLoading }] = useRunCleanupMutation();
  const [done, setDone] = useState(false);

  if (!isAdmin) return null;

  const handle = async () => {
    setDone(false);
    await runCleanup().unwrap();
    setDone(true);
  };

  return (
    <Card
      style={{
        padding: '1rem 1.25rem',
        display: 'flex',
        alignItems: 'center',
        gap: '1rem',
      }}
    >
      <div style={{ flex: 1 }}>
        <div style={{ fontWeight: 600 }}>
          {t('storage.maintenance.cleanup.title')}
        </div>
        <div style={{ fontSize: '0.8125rem', color: 'var(--color-text-3)' }}>
          {t('storage.maintenance.cleanup.description')}
        </div>
      </div>
      {done && (
        <span style={{ fontSize: '0.8125rem', color: 'var(--color-accent)' }}>
          {t('storage.maintenance.cleanup.enqueued')}
        </span>
      )}
      <Button variant="ember" disabled={isLoading} onClick={() => void handle()}>
        {t('storage.maintenance.cleanup.button')}
      </Button>
    </Card>
  );
}

/** Duplicate groups (tracks sharing an acoustic fingerprint). */
function DuplicatesTab() {
  const { t } = useTranslation();
  const navigate = useNavigate();
  const { data, isLoading, isError, refetch } = useGetDuplicatesQuery();

  if (isLoading) return <LoadingSkeleton rows={5} height={56} />;
  if (isError) return <ErrorState onRetry={refetch} />;
  if (!data || data.length === 0) {
    return (
      <EmptyState icon="✓" title={t('storage.maintenance.duplicates.empty')} />
    );
  }

  return (
    <div style={{ display: 'flex', flexDirection: 'column', gap: '1rem' }}>
      {data.map((group) => (
        <Card key={group.fingerprint} style={{ padding: '0.75rem 1rem' }}>
          <div
            style={{
              fontSize: '0.8125rem',
              color: 'var(--color-text-3)',
              marginBottom: '0.5rem',
            }}
          >
            {t('storage.maintenance.duplicates.groupTitle', {
              count: group.tracks.length,
            })}
          </div>
          {group.tracks.map((track) => (
            <TrackRow
              key={track.id}
              track={track}
              showAlbum
              onEditMetadata={(tr) => void navigate(`/tracks/${tr.id}/metadata`)}
            />
          ))}
        </Card>
      ))}
    </div>
  );
}

/** A paginated track list backed by a maintenance query (broken / missing). */
function TrackListTab({
  useQuery,
  emptyKey,
}: {
  useQuery:
    | typeof useGetBrokenFilesQuery
    | typeof useGetMissingMetadataQuery;
  emptyKey: 'broken' | 'missing';
}) {
  const { t } = useTranslation();
  const navigate = useNavigate();
  const [offset, setOffset] = useState(0);
  const { data, isLoading, isError, refetch } = useQuery({
    limit: PAGE_SIZE,
    offset,
  });

  if (isLoading) return <LoadingSkeleton rows={6} height={56} />;
  if (isError) return <ErrorState onRetry={refetch} />;
  if (!data || data.items.length === 0) {
    return (
      <EmptyState
        icon="✓"
        title={t(`storage.maintenance.${emptyKey}.empty`)}
      />
    );
  }

  const from = offset + 1;
  const to = offset + data.items.length;
  // Broken files map to the `failed` metadata bucket; missing → `pending`.
  const batchStatus = emptyKey === 'broken' ? 'failed' : 'pending';

  return (
    <div style={{ display: 'flex', flexDirection: 'column', gap: '0.25rem' }}>
      <div style={{ display: 'flex', justifyContent: 'flex-end', marginBottom: '0.5rem' }}>
        <Button
          variant="ghost"
          size="sm"
          onClick={() => void navigate(`/metadata/batch?status=${batchStatus}`)}
        >
          {t('storage.maintenance.editBatch')}
        </Button>
      </div>
      {data.items.map((track) => (
        <TrackRow
          key={track.id}
          track={track}
          showAlbum
          onEditMetadata={(tr) => void navigate(`/tracks/${tr.id}/metadata`)}
        />
      ))}
      {(offset > 0 || data.hasMore) && (
        <div
          style={{
            display: 'flex',
            alignItems: 'center',
            justifyContent: 'flex-end',
            gap: '0.75rem',
            marginTop: '0.75rem',
          }}
        >
          <span style={{ fontSize: '0.8125rem', color: 'var(--color-text-3)' }}>
            {t('storage.maintenance.pagination', {
              from,
              to,
              total: data.total,
            })}
          </span>
          <Button
            variant="ghost"
            size="sm"
            disabled={offset === 0}
            onClick={() => setOffset(Math.max(0, offset - PAGE_SIZE))}
          >
            {t('storage.maintenance.prev')}
          </Button>
          <Button
            variant="ghost"
            size="sm"
            disabled={!data.hasMore}
            onClick={() => setOffset(offset + PAGE_SIZE)}
          >
            {t('storage.maintenance.next')}
          </Button>
        </div>
      )}
    </div>
  );
}