import React from 'react';
import { useQuery } from '@tanstack/react-query';
import {
  Activity, AlertTriangle, Cpu, Database, Layers, RefreshCw, Settings2, ListTree,
} from 'lucide-react';
import { adminApi } from '../../api/client';
import { ProgressBar } from '../../components/ProgressBar';

interface ActiveTask { name: string; id: string; args: string; started_ago_s: number | null }
interface Worker { name: string; concurrency: number | null; reserved: number; active: ActiveTask[] }
interface Run {
  id: number; source_id: number; status: string; stage: string; target: number;
  fetched: number; processed: number; added: number; duplicates: number;
  skipped: number; failed: number; error: string | null; percent: number;
  started_at: string; heartbeat_at: string | null;
}

interface DebugData {
  generated_at: string;
  celery: { workers: Worker[]; error?: string };
  queues: Record<string, { messages: number; unacked: number; consumers: number }> | { error: string };
  corpus: {
    documents: number; documents_embedded: number; documents_without_embedding: number;
    fingerprints_estimate: number; elasticsearch_documents: number | null;
  };
  sources: {
    by_status: Record<string, number>;
    active_runs: Run[];
    stale_run_ids: number[];
    recent_problem_runs: Run[];
  };
  tasks_24h: Record<string, number>;
  recent_failed_tasks: { public_id: string; type: string; error: string; created_at: string }[];
  config: Record<string, string>;
}

const STAGE_LABELS: Record<string, string> = {
  queued: 'в очереди', fetch: 'выборка', index: 'индексация', finished: 'завершено',
};

function fmtNum(n: number | null | undefined): string {
  return n == null ? '—' : n.toLocaleString('ru-RU');
}

export function Debug() {
  const { data, isFetching, error } = useQuery({
    queryKey: ['admin-debug'],
    queryFn: () => adminApi.debug().then((r) => r.data as DebugData),
    refetchInterval: 5000,
  });

  if (error) {
    return <div className="text-red-600 text-sm">Не удалось получить срез состояния: {String(error)}</div>;
  }
  if (!data) {
    return <div className="text-gray-400 text-sm">Сбор данных…</div>;
  }

  const queuesErr = 'error' in data.queues ? (data.queues as { error: string }).error : null;
  const queues = queuesErr ? {} : (data.queues as Record<string, { messages: number; unacked: number; consumers: number }>);
  const embedPercent = data.corpus.documents
    ? (data.corpus.documents_embedded / data.corpus.documents) * 100
    : 0;

  return (
    <div className="space-y-6">
      <div className="flex items-center justify-between">
        <h1 className="text-2xl font-bold text-gray-900 flex items-center gap-2">
          Отладка
          {isFetching && <RefreshCw className="w-4 h-4 text-gray-300 animate-spin" />}
        </h1>
        <span className="text-xs text-gray-400">срез от {new Date(data.generated_at).toLocaleTimeString('ru-RU')}</span>
      </div>

      {/* Активные прогоны заливки */}
      <Card icon={Layers} title={`Заливка источников — активных прогонов: ${data.sources.active_runs.length}`}>
        {data.sources.stale_run_ids.length > 0 && (
          <div className="mb-3 flex items-start gap-2 text-sm text-amber-700 bg-amber-50 border border-amber-100 rounded-lg p-3">
            <AlertTriangle className="w-4 h-4 mt-0.5 shrink-0" />
            <span>
              Прогоны без признаков жизни больше 10 минут: {data.sources.stale_run_ids.join(', ')}.
              Обычно это упавший или перезапущенный worker-indexer — проверьте его логи и очередь queue.index.
            </span>
          </div>
        )}
        {data.sources.active_runs.length ? (
          <div className="space-y-3">
            {data.sources.active_runs.map((r) => (
              <div key={r.id} className="flex items-center gap-4">
                <div className="w-40 shrink-0 text-sm text-gray-600 truncate">
                  #{r.id} · источник {r.source_id}
                </div>
                <ProgressBar
                  percent={r.percent}
                  status={r.status}
                  label={`${STAGE_LABELS[r.stage] || r.stage} · получено ${r.fetched}/${r.target} · +${r.added}`}
                />
              </div>
            ))}
          </div>
        ) : (
          <p className="text-sm text-gray-400">Сейчас ничего не заливается.</p>
        )}
        <div className="mt-3 flex flex-wrap gap-2">
          {Object.entries(data.sources.by_status).map(([s, c]) => (
            <span key={s} className="px-3 py-1 bg-gray-100 rounded-lg text-sm text-gray-700">{s}: <b>{c}</b></span>
          ))}
        </div>
      </Card>

      {/* Воркеры */}
      <Card icon={Cpu} title="Воркеры Celery">
        {data.celery.error && <p className="text-sm text-red-600 mb-2">{data.celery.error}</p>}
        {data.celery.workers.length ? (
          <div className="space-y-4">
            {data.celery.workers.map((w) => (
              <div key={w.name}>
                <div className="flex items-baseline justify-between mb-1">
                  <span className="font-medium text-gray-800 text-sm">{w.name}</span>
                  <span className="text-xs text-gray-500">
                    параллельно: {w.concurrency ?? '—'} · в работе: {w.active.length} · зарезервировано: {w.reserved}
                  </span>
                </div>
                {w.active.length ? (
                  <div className="border border-gray-100 rounded-lg divide-y divide-gray-50 text-xs font-mono">
                    {w.active.map((t) => (
                      <div key={t.id} className="px-3 py-1.5 flex gap-3">
                        <span className="text-gray-400 tabular-nums shrink-0">
                          {t.started_ago_s != null ? `${t.started_ago_s}с` : '—'}
                        </span>
                        <span className="text-gray-800 shrink-0">{t.name}</span>
                        <span className="text-gray-400 truncate">{t.args}</span>
                      </div>
                    ))}
                  </div>
                ) : <p className="text-xs text-gray-400">простаивает</p>}
              </div>
            ))}
          </div>
        ) : <p className="text-sm text-gray-400">Воркеры не отвечают на ping.</p>}
      </Card>

      {/* Очереди */}
      <Card icon={Activity} title="Очереди RabbitMQ">
        {queuesErr ? (
          <p className="text-sm text-red-600">{queuesErr}</p>
        ) : (
          <table className="w-full text-sm">
            <thead className="text-gray-500 text-left">
              <tr><th className="py-1">Очередь</th><th className="py-1">Ждут</th><th className="py-1">В работе</th><th className="py-1">Потребителей</th></tr>
            </thead>
            <tbody className="divide-y divide-gray-50">
              {Object.entries(queues).map(([name, q]) => (
                <tr key={name}>
                  <td className="py-1.5 text-gray-800">{name}</td>
                  <td className="py-1.5 text-gray-600 tabular-nums">{fmtNum(q.messages)}</td>
                  <td className="py-1.5 text-gray-600 tabular-nums">{fmtNum(q.unacked)}</td>
                  <td className={`py-1.5 tabular-nums ${q.consumers ? 'text-gray-600' : 'text-red-600'}`}>{q.consumers}</td>
                </tr>
              ))}
            </tbody>
          </table>
        )}
      </Card>

      {/* Корпус */}
      <Card icon={Database} title="Корпус сравнения">
        <div className="grid grid-cols-2 lg:grid-cols-4 gap-4 mb-4">
          <Metric label="Документов" value={fmtNum(data.corpus.documents)} />
          <Metric label="С эмбеддингом" value={fmtNum(data.corpus.documents_embedded)} />
          <Metric label="Отпечатков (оценка)" value={fmtNum(data.corpus.fingerprints_estimate)} />
          <Metric label="В Elasticsearch" value={fmtNum(data.corpus.elasticsearch_documents)} />
        </div>
        <ProgressBar
          percent={embedPercent}
          status={data.corpus.documents_without_embedding > 0 ? 'partial' : 'done'}
          label={`покрытие эмбеддингами (L3): без вектора ${fmtNum(data.corpus.documents_without_embedding)} документов`}
        />
      </Card>

      {/* Проблемные прогоны */}
      {data.sources.recent_problem_runs.length > 0 && (
        <Card icon={AlertTriangle} title="Последние проблемные прогоны">
          <div className="space-y-2 text-sm">
            {data.sources.recent_problem_runs.map((r) => (
              <div key={r.id} className="flex flex-wrap items-baseline gap-x-3 gap-y-1 border-b border-gray-50 pb-2 last:border-0">
                <span className="text-gray-800">#{r.id}</span>
                <span className="text-gray-500">источник {r.source_id}</span>
                <span className={r.status === 'error' ? 'text-red-600' : 'text-amber-600'}>{r.status}</span>
                <span className="text-gray-500">
                  получено {r.fetched}/{r.target}, добавлено {r.added}, ошибок {r.failed}
                </span>
                {r.error && <span className="w-full text-xs font-mono text-red-600 break-all">{r.error}</span>}
              </div>
            ))}
          </div>
        </Card>
      )}

      {/* Задачи пользователей */}
      <Card icon={ListTree} title="Проверки за 24 часа">
        <div className="flex flex-wrap gap-2 mb-3">
          {Object.entries(data.tasks_24h).map(([s, c]) => (
            <span key={s} className="px-3 py-1 bg-gray-100 rounded-lg text-sm text-gray-700">{s}: <b>{c}</b></span>
          ))}
          {!Object.keys(data.tasks_24h).length && <span className="text-sm text-gray-400">задач не было</span>}
        </div>
        {data.recent_failed_tasks.length > 0 && (
          <div className="text-xs space-y-1">
            <div className="text-gray-500 mb-1">Последние упавшие:</div>
            {data.recent_failed_tasks.map((t) => (
              <div key={t.public_id} className="flex gap-3">
                <span className="text-gray-400 shrink-0">{new Date(t.created_at).toLocaleString('ru-RU')}</span>
                <span className="text-gray-700 shrink-0">{t.type}</span>
                <span className="text-red-600 font-mono truncate">{t.error || '—'}</span>
              </div>
            ))}
          </div>
        )}
      </Card>

      {/* Конфигурация */}
      <Card icon={Settings2} title="Конфигурация бэкендов">
        <div className="grid grid-cols-2 lg:grid-cols-3 gap-x-6 gap-y-2 text-sm">
          {Object.entries(data.config).map(([k, v]) => (
            <div key={k} className="flex justify-between gap-3 border-b border-gray-50 py-1">
              <span className="text-gray-500">{k}</span>
              <span className="text-gray-800 font-mono truncate" title={v}>{v}</span>
            </div>
          ))}
        </div>
      </Card>
    </div>
  );
}

function Card({ icon: Icon, title, children }: { icon: React.ElementType; title: string; children: React.ReactNode }) {
  return (
    <div className="bg-white rounded-xl border border-gray-100 p-5">
      <h2 className="font-semibold text-gray-800 mb-4 flex items-center gap-2">
        <Icon className="w-4 h-4 text-gray-400" /> {title}
      </h2>
      {children}
    </div>
  );
}

function Metric({ label, value }: { label: string; value: string }) {
  return (
    <div>
      <div className="text-xl font-bold text-gray-900 tabular-nums">{value}</div>
      <div className="text-xs text-gray-500">{label}</div>
    </div>
  );
}