import { useState, useEffect, useCallback, useRef } from 'react';
import api from './lib/api.js';
import PageHeader from './components/PageHeader.jsx';
import {
  IconClockPlay,
  IconSettings,
  IconTerminal2,
  IconPlayerPlay,
  IconRefresh,
} from '@tabler/icons-react';

const POLL_LOGS_MS = 2500;
const INTERVAL_MIN = 1;
const INTERVAL_MAX = 1440;
const LOG_LINES_MIN = 100;
const LOG_LINES_MAX = 2000;

export default function NetworkMapSchedulerPage() {
  const [settings, setSettings] = useState({
    enabled: false,
    intervalMinutes: 5,
    runPing: true,
    runSpeedTest: true,
    logMaxLines: 500,
  });
  const [nextRunAt, setNextRunAt] = useState(null);
  const [logs, setLogs] = useState([]);
  const [loading, setLoading] = useState(true);
  const [saving, setSaving] = useState(false);
  const [running, setRunning] = useState(false);
  const [error, setError] = useState(null);
  const logEndRef = useRef(null);
  const logContainerRef = useRef(null);
  const [autoScroll, setAutoScroll] = useState(true);

  const fetchSettings = useCallback(async (abortSignal) => {
    try {
      const opts = abortSignal ? { signal: abortSignal } : {};
      const { data } = await api.get('/scheduler/network-map/settings', opts);
      setSettings({
        enabled: Boolean(data.enabled),
        intervalMinutes: Math.max(INTERVAL_MIN, Math.min(INTERVAL_MAX, Number(data.intervalMinutes) || 5)),
        runPing: data.runPing !== false,
        runSpeedTest: data.runSpeedTest !== false,
        logMaxLines: Math.max(LOG_LINES_MIN, Math.min(LOG_LINES_MAX, Number(data.logMaxLines) || 500)),
      });
      setNextRunAt(typeof data.nextRunAt === 'number' ? data.nextRunAt : null);
    } catch (e) {
      if (e?.name === 'CanceledError' || e?.name === 'AbortError' || e?.code === 'ERR_CANCELED') return;
      setError(e?.response?.data?.message || e?.message || 'Не удалось загрузить настройки');
    }
  }, []);

  const fetchLogs = useCallback(async () => {
    try {
      const { data } = await api.get('/scheduler/network-map/logs');
      setLogs(Array.isArray(data?.lines) ? data.lines : []);
    } catch (_) {
      // не показываем ошибку при опросе логов
    }
  }, []);

  useEffect(() => {
    const controller = new AbortController();
    (async () => {
      setLoading(true);
      await fetchSettings(controller.signal);
      setLoading(false);
    })();
    return () => controller.abort();
  }, [fetchSettings]);

  useEffect(() => {
    fetchLogs();
    const t = setInterval(fetchLogs, POLL_LOGS_MS);
    return () => clearInterval(t);
  }, [fetchLogs]);

  useEffect(() => {
    if (!settings.enabled || !nextRunAt) return;
    const t = setInterval(fetchSettings, 60 * 1000);
    return () => clearInterval(t);
  }, [settings.enabled, nextRunAt, fetchSettings]);

  useEffect(() => {
    if (autoScroll && logEndRef.current) {
      logEndRef.current.scrollIntoView({ behavior: 'smooth' });
    }
  }, [logs, autoScroll]);

  const handleSave = async () => {
    setSaving(true);
    setError(null);
    try {
      await api.patch('/scheduler/network-map/settings', {
        networkMapSchedulerEnabled: settings.enabled,
        networkMapSchedulerIntervalMinutes: settings.intervalMinutes,
        networkMapSchedulerRunPing: settings.runPing,
        networkMapSchedulerRunSpeedTest: settings.runSpeedTest,
        networkMapSchedulerLogMaxLines: settings.logMaxLines,
      });
      await fetchSettings();
    } catch (e) {
      setError(e?.response?.data?.message || e?.message || 'Не удалось сохранить');
    } finally {
      setSaving(false);
    }
  };

  const handleRunNow = async () => {
    setRunning(true);
    setError(null);
    try {
      await api.post('/scheduler/network-map/run-now');
      setTimeout(fetchLogs, 500);
    } catch (e) {
      setError(e?.response?.data?.message || e?.message || 'Не удалось запустить');
    } finally {
      setRunning(false);
    }
  };

  if (loading) {
    return (
      <div>
        <PageHeader
          title="Планировщик карты сети"
          icon={<IconClockPlay size={24} />}
          meta="Пинг и замер скорости между серверами по расписанию"
        />
        <div className="text-center py-5 text-muted">Загрузка настроек…</div>
      </div>
    );
  }

  return (
    <div>
      <PageHeader
        title="Планировщик карты сети"
        icon={<IconClockPlay size={24} />}
        meta="Пинг и замер скорости между серверами по расписанию; кеш ускоряет загрузку карты сети."
        actions={
          <div className="btn-list">
            <button
              type="button"
              className="btn btn-primary"
              onClick={handleRunNow}
              disabled={running}
            >
              <IconPlayerPlay className={running ? 'spin me-2' : 'me-2'} size={18} />
              {running ? 'Запуск…' : 'Запустить сейчас'}
            </button>
          </div>
        }
      />

      {error && (
        <div className="alert alert-danger alert-dismissible fade show mb-3" role="alert">
          {error}
          <button type="button" className="btn-close" aria-label="Закрыть" onClick={() => setError(null)} />
        </div>
      )}

      <div className="row row-deck row-cards g-3">
        <div className="col-12 col-lg-5">
          <div className="card">
            <div className="card-header">
              <h3 className="card-title d-flex align-items-center">
                <IconSettings className="me-2" size={20} />
                Настройки
              </h3>
              <div className="card-actions">
                <button
                  type="button"
                  className="btn btn-primary btn-sm"
                  onClick={handleSave}
                  disabled={saving}
                >
                  {saving ? 'Сохранение…' : 'Сохранить'}
                </button>
              </div>
            </div>
            <div className="card-body">
              <div className="mb-3">
                <label className="form-check form-switch">
                  <input
                    className="form-check-input"
                    type="checkbox"
                    checked={settings.enabled}
                    onChange={(e) => setSettings((s) => ({ ...s, enabled: e.target.checked }))}
                  />
                  <span className="form-check-label">Включить планировщик</span>
                </label>
                <div className="form-hint">Периодически обновлять пинг и скорость по связям из «Сетевые настройки»</div>
                {settings.enabled && nextRunAt != null && (
                  <div className="mt-2 text-muted small">
                    Следующий запуск: {new Date(nextRunAt).toLocaleString('ru-RU', { dateStyle: 'short', timeStyle: 'medium' })}
                  </div>
                )}
              </div>

              <div className="mb-3">
                <label className="form-label">Интервал (минут)</label>
                <input
                  type="number"
                  className="form-control"
                  min={INTERVAL_MIN}
                  max={INTERVAL_MAX}
                  value={settings.intervalMinutes}
                  onChange={(e) =>
                    setSettings((s) => ({
                      ...s,
                      intervalMinutes: Math.max(INTERVAL_MIN, Math.min(INTERVAL_MAX, parseInt(e.target.value, 10) || INTERVAL_MIN)),
                    }))
                  }
                />
                <div className="form-hint">От 1 до 1440 (сутки). По умолчанию 5 мин.</div>
              </div>

              <div className="mb-3">
                <label className="form-label">Задачи</label>
                <div>
                  <label className="form-check form-switch me-3">
                    <input
                      className="form-check-input"
                      type="checkbox"
                      checked={settings.runPing}
                      onChange={(e) => setSettings((s) => ({ ...s, runPing: e.target.checked }))}
                    />
                    <span className="form-check-label">Пинг</span>
                  </label>
                  <label className="form-check form-switch">
                    <input
                      className="form-check-input"
                      type="checkbox"
                      checked={settings.runSpeedTest}
                      onChange={(e) => setSettings((s) => ({ ...s, runSpeedTest: e.target.checked }))}
                    />
                    <span className="form-check-label">Замер скорости</span>
                  </label>
                </div>
              </div>

              <div className="mb-0">
                <label className="form-label">Строк в логе</label>
                <input
                  type="number"
                  className="form-control"
                  min={LOG_LINES_MIN}
                  max={LOG_LINES_MAX}
                  value={settings.logMaxLines}
                  onChange={(e) =>
                    setSettings((s) => ({
                      ...s,
                      logMaxLines: Math.max(LOG_LINES_MIN, Math.min(LOG_LINES_MAX, parseInt(e.target.value, 10) || 500)),
                    }))
                  }
                />
                <div className="form-hint">Кольцевой буфер: от 100 до 2000 строк.</div>
              </div>
            </div>
          </div>
        </div>

        <div className="col-12 col-lg-7">
          <div className="card flex-fill">
            <div className="card-header d-flex align-items-center">
              <h3 className="card-title d-flex align-items-center mb-0">
                <IconTerminal2 className="me-2" size={20} />
                Логи
              </h3>
              <div className="card-actions ms-auto">
                <label className="form-check form-switch form-check-inline mb-0 me-2">
                  <input
                    className="form-check-input"
                    type="checkbox"
                    checked={autoScroll}
                    onChange={(e) => setAutoScroll(e.target.checked)}
                  />
                  <span className="form-check-label small">Автопрокрутка</span>
                </label>
                <button
                  type="button"
                  className="btn btn-outline-secondary btn-sm"
                  onClick={fetchLogs}
                  aria-label="Обновить логи"
                >
                  <IconRefresh size={16} />
                </button>
              </div>
            </div>
            <div
              ref={logContainerRef}
              className="card-body p-0"
              style={{ minHeight: 320 }}
            >
              <pre
                className="mb-0 p-3 bg-dark text-light rounded-0 rounded-bottom"
                style={{
                  fontSize: 12,
                  fontFamily: 'ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace',
                  maxHeight: 420,
                  overflow: 'auto',
                  whiteSpace: 'pre-wrap',
                  wordBreak: 'break-word',
                }}
              >
                {logs.length === 0 ? (
                  <span className="text-muted">Логов пока нет. Включите планировщик и нажмите «Запустить сейчас» или дождитесь следующего запуска.</span>
                ) : (
                  logs.map((line, i) => (
                    <span key={i} style={{ display: 'block' }}>
                      {line}
                    </span>
                  ))
                )}
                <span ref={logEndRef} />
              </pre>
            </div>
          </div>
        </div>
      </div>
    </div>
  );
}