'use client';

import type { AdminAuditDto, AdminAuditQuery } from '@impuestos/contracts';
import { useQuery } from '@tanstack/react-query';
import { useState, type FormEvent } from 'react';
import { Button } from '@/components/ui/button';
import { EmptyState } from '@/components/ui/empty-state';
import { Input } from '@/components/ui/input';
import { Skeleton } from '@/components/ui/skeleton';
import { Table, Td, Th, Tr } from '@/components/ui/table';
import { useT } from '@/i18n/t';
import { api } from '@/lib/api';

const EMPTY: AdminAuditQuery = {};

/**
 * Flow H: read only, filterable, exportable. The action is shown as the code it is stored
 * as rather than a translated phrase: it is the same token the filter takes, and an
 * operator searching a log wants to match what they see.
 */
export function AuditScreen() {
  const t = useT();
  const [draft, setDraft] = useState<Record<string, string>>({});
  const [filters, setFilters] = useState<AdminAuditQuery>(EMPTY);
  const [pages, setPages] = useState<AdminAuditDto[]>([]);
  const [cursor, setCursor] = useState<string | undefined>(undefined);

  const audit = useQuery({
    queryKey: ['admin', 'audit', filters, cursor],
    queryFn: ({ signal }) => api.listAudit({ ...filters, ...(cursor ? { cursor } : {}) }, signal),
  });

  // Pages accumulate, so "show more" appends rather than replacing what is on screen.
  const rows = cursor ? [...pages, ...(audit.data?.items ?? [])] : (audit.data?.items ?? []);

  function apply(event: FormEvent) {
    event.preventDefault();
    setPages([]);
    setCursor(undefined);
    setFilters(clean(draft));
  }

  function clear() {
    setDraft({});
    setPages([]);
    setCursor(undefined);
    setFilters(EMPTY);
  }

  return (
    <div className="space-y-5">
      <div className="flex flex-wrap items-center justify-between gap-3">
        <h1 className="text-xl font-semibold tracking-tight">{t('admin.audit.title')}</h1>
        <a
          href={api.auditCsvUrl(filters)}
          className="text-sm text-accent-700 hover:underline"
          download
        >
          {t('admin.audit.export')}
        </a>
      </div>

      <form onSubmit={apply} className="flex flex-wrap items-end gap-3">
        {(
          [
            ['actor', 'admin.audit.filterActor', 'text'],
            ['action', 'admin.audit.filterAction', 'text'],
            ['subject', 'admin.audit.filterSubject', 'text'],
            ['from', 'admin.audit.filterFrom', 'date'],
            ['to', 'admin.audit.filterTo', 'date'],
          ] as const
        ).map(([key, label, type]) => (
          <div key={key} className="space-y-1">
            <label htmlFor={`audit-${key}`} className="block text-xs font-medium">
              {t(label)}
            </label>
            <Input
              id={`audit-${key}`}
              type={type}
              value={draft[key] ?? ''}
              onChange={(event) => setDraft({ ...draft, [key]: event.target.value })}
              className="h-9 w-44 rounded-lg text-sm"
              autoComplete="off"
            />
          </div>
        ))}
        {/* Grouped, so the two buttons wrap together rather than one at a time. */}
        <div className="flex gap-2">
          <Button type="submit" className="h-9 rounded-lg">
            {t('admin.audit.apply')}
          </Button>
          <Button type="button" variant="ghost" className="h-9 rounded-lg" onClick={clear}>
            {t('admin.audit.clear')}
          </Button>
        </div>
      </form>

      {audit.data ? (
        <p className="text-xs text-[var(--text-muted)]">
          {t('admin.audit.total', { count: audit.data.total })}
        </p>
      ) : null}

      {audit.isPending && rows.length === 0 ? <Skeleton name="admin-user-row" count={6} /> : null}

      {audit.isError ? (
        <div className="space-y-3">
          <p role="alert" className="text-sm">
            {t('common.error.generic')}
          </p>
          <Button type="button" className="h-9 rounded-lg" onClick={() => void audit.refetch()}>
            {t('common.retry')}
          </Button>
        </div>
      ) : null}

      {audit.data && rows.length === 0 ? <EmptyState title={t('admin.audit.empty')} /> : null}

      {rows.length > 0 ? (
        <Table>
          <thead>
            <tr>
              <Th>{t('admin.audit.col.when')}</Th>
              <Th>{t('admin.audit.col.actor')}</Th>
              <Th>{t('admin.audit.col.action')}</Th>
              <Th>{t('admin.audit.col.subject')}</Th>
              <Th>{t('admin.audit.col.resource')}</Th>
              <Th>{t('admin.audit.col.ip')}</Th>
            </tr>
          </thead>
          <tbody>
            {rows.map((row) => (
              <Tr key={row.id}>
                <Td className="tnum whitespace-nowrap">
                  {row.createdAt.slice(0, 16).replace('T', ' ')}
                </Td>
                <Td className="whitespace-nowrap">{row.actorEmail ?? row.actorUserId}</Td>
                <Td className="whitespace-nowrap font-medium">{row.action}</Td>
                <Td className="whitespace-nowrap">{row.subjectEmail ?? t('common.none')}</Td>
                <Td className="max-w-64 truncate" title={row.resource}>
                  {row.resource}
                </Td>
                <Td className="tnum whitespace-nowrap">{row.ip ?? t('common.none')}</Td>
              </Tr>
            ))}
          </tbody>
        </Table>
      ) : null}

      {audit.data?.cursor ? (
        <Button
          type="button"
          variant="secondary"
          className="h-9 rounded-lg"
          onClick={() => {
            setPages(rows);
            setCursor(audit.data.cursor);
          }}
        >
          {t('common.loadMore')}
        </Button>
      ) : null}
    </div>
  );
}

function clean(draft: Record<string, string>): AdminAuditQuery {
  const out: Record<string, string> = {};
  for (const [key, value] of Object.entries(draft)) {
    if (value.trim().length > 0) out[key] = value.trim();
  }
  return out as AdminAuditQuery;
}