import type { RangeMileageResult } from './cache.js';

const MANUAL_SNAPSHOT_TTL_MS = 60 * 1000;

interface ManualSnapshot {
  result: RangeMileageResult;
  updatedAt: string;
  expiresAt: number;
}

let snapshot: ManualSnapshot | null = null;

export function storeManualMonitoringSnapshot(
  result: RangeMileageResult,
  now = Date.now(),
): ManualSnapshot {
  snapshot = {
    result,
    updatedAt: new Date(now).toISOString(),
    expiresAt: now + MANUAL_SNAPSHOT_TTL_MS,
  };
  return snapshot;
}

export function getManualMonitoringSnapshot(
  start: string,
  end: string,
  now = Date.now(),
): ManualSnapshot | null {
  if (!snapshot || snapshot.expiresAt <= now) {
    snapshot = null;
    return null;
  }
  if (snapshot.result.start !== start || snapshot.result.end !== end) return null;
  return snapshot;
}

export function clearManualMonitoringSnapshot(): void {
  snapshot = null;
}