import React, { useState, useMemo } from 'react';
import { useTranslation } from 'react-i18next';
import { ColumnDef } from '@tanstack/react-table';
import { useAuditLog, AuditLogEntry } from '@/api/hooks';
import { DataGrid } from '@/components/shared/DataGrid';
import { Card } from '@/components/ui/Card';
import { Input } from '@/components/ui/Input';
import { Button } from '@/components/ui/Button';
import { EmptyState } from '@/components/ui/EmptyState';
import { Badge } from '@/components/ui/Badge';

export function AuditLogPage() {
  const { t } = useTranslation();

  const [page, setPage] = useState(1);
  const [pageSize] = useState(25);
  const [filterUser, setFilterUser] = useState('');
  const [filterAction, setFilterAction] = useState('');
  const [filterEntity, setFilterEntity] = useState('');
  const [filterDateFrom, setFilterDateFrom] = useState('');
  const [filterDateTo, setFilterDateTo] = useState('');

  const filters = useMemo(
    () => ({
      user: filterUser || undefined,
      action: filterAction || undefined,
      entity: filterEntity || undefined,
      dateFrom: filterDateFrom || undefined,
      dateTo: filterDateTo || undefined,
    }),
    [filterUser, filterAction, filterEntity, filterDateFrom, filterDateTo]
  );

  const { data, isLoading, isError } = useAuditLog(page, pageSize, filters);

  const columns = useMemo<ColumnDef<AuditLogEntry, any>[]>(
    () => [
      {
        accessorKey: 'timestamp',
        header: t('auditLog.timestamp'),
        cell: (info) => {
          const val = info.getValue();
          if (!val) return '—';
          const date = new Date(val);
          return date.toLocaleString('de-DE');
        },
      },
      {
        accessorKey: 'user',
        header: t('auditLog.user'),
        cell: (info) => info.getValue() || '—',
      },
      {
        accessorKey: 'action',
        header: t('auditLog.action'),
        cell: (info) =>
          info.getValue() ? <Badge variant="primary">{info.getValue()}</Badge> : '—',
      },
      {
        accessorKey: 'entity',
        header: t('auditLog.entity'),
        cell: (info) => info.getValue() || '—',
      },
      {
        accessorKey: 'entity_id',
        header: t('auditLog.entityId'),
        cell: (info) => info.getValue() || '—',
      },
      {
        accessorKey: 'details',
        header: t('auditLog.details'),
        cell: (info) => {
          const val = info.getValue();
          if (!val) return '—';
          return <span className="text-sm text-secondary-600 truncate">{val}</span>;
        },
      },
    ],
    [t]
  );

  const handleResetFilters = () => {
    setFilterUser('');
    setFilterAction('');
    setFilterEntity('');
    setFilterDateFrom('');
    setFilterDateTo('');
    setPage(1);
  };

  const hasFilters = filterUser || filterAction || filterEntity || filterDateFrom || filterDateTo;

  if (isError) {
    return (
      <div className="p-6 max-w-7xl mx-auto" data-testid="audit-log-page">
        <h1 className="text-2xl font-bold text-secondary-900 mb-6">{t('auditLog.title')}</h1>
        <EmptyState
          title={t('auditLog.notAvailable')}
          description={t('auditLog.empty')}
        />
      </div>
    );
  }

  const entries = data?.items ?? [];
  const total = data?.total ?? 0;

  return (
    <div className="p-6 max-w-7xl mx-auto" data-testid="audit-log-page">
      <h1 className="text-2xl font-bold text-secondary-900 mb-6">{t('auditLog.title')}</h1>

      <Card title={t('common.filter')} className="mb-4">
        <div className="grid grid-cols-1 md:grid-cols-3 lg:grid-cols-5 gap-3">
          <Input
            label={t('auditLog.user')}
            value={filterUser}
            onChange={(e) => setFilterUser(e.target.value)}
            placeholder="anna.schmidt"
          />
          <Input
            label={t('auditLog.action')}
            value={filterAction}
            onChange={(e) => setFilterAction(e.target.value)}
            placeholder="create, update, delete"
          />
          <Input
            label={t('auditLog.entity')}
            value={filterEntity}
            onChange={(e) => setFilterEntity(e.target.value)}
            placeholder="company, contact"
          />
          <Input
            label={t('auditLog.dateFrom')}
            type="date"
            value={filterDateFrom}
            onChange={(e) => setFilterDateFrom(e.target.value)}
          />
          <Input
            label={t('auditLog.dateTo')}
            type="date"
            value={filterDateTo}
            onChange={(e) => setFilterDateTo(e.target.value)}
          />
        </div>
        {hasFilters && (
          <div className="mt-3 flex justify-end">
            <Button variant="ghost" size="sm" onClick={handleResetFilters}>
              {t('common.reset')}
            </Button>
          </div>
        )}
      </Card>

      <DataGrid
        columns={columns}
        data={entries}
        total={total}
        page={page}
        pageSize={pageSize}
        onPageChange={setPage}
        loading={isLoading}
        emptyMessage={t('auditLog.empty')}
        testId="audit-log-grid"
      />
    </div>
  );
}
