/**
 * 워크스페이스 slot0 보조지표 — 알림 미니 차트가 메인 차트 인스턴스 스타일과 맞추도록
 */
import type { IndicatorConfig } from '../types';
import { loadWorkspace } from './backendApi';

let cached: IndicatorConfig[] | null = null;
let loadPromise: Promise<IndicatorConfig[]> | null = null;
let loadedSessionKey: number | null = null;

export function invalidateWorkspaceChartIndicatorsCache(): void {
  cached = null;
  loadPromise = null;
  loadedSessionKey = null;
}

export function ensureWorkspaceChartIndicators(sessionKey = 0): Promise<IndicatorConfig[]> {
  if (cached !== null && loadedSessionKey === sessionKey) {
    return Promise.resolve(cached);
  }
  if (loadedSessionKey !== sessionKey) {
    cached = null;
    loadPromise = null;
  }
  if (!loadPromise) {
    loadPromise = loadWorkspace()
      .then(ws => {
        const slot0 = (Array.isArray(ws?.slots) ? ws.slots[0] : null) as
          | { indicators?: IndicatorConfig[] }
          | null;
        cached = Array.isArray(slot0?.indicators) ? slot0!.indicators! : [];
        loadedSessionKey = sessionKey;
        loadPromise = null;
        return cached;
      })
      .catch(() => {
        cached = [];
        loadedSessionKey = sessionKey;
        loadPromise = null;
        return [];
      });
  }
  return loadPromise;
}

export function getWorkspaceChartIndicatorsCache(): IndicatorConfig[] | null {
  return cached;
}