interface SchedulerSnapshot {
  initializedAt: number;
  phase: "idle" | "running" | "paused";
  queueDepth: number;
  currentTaskId: string | null;
  lastSseEventAt: number | null;
  lastHeartbeatAt: number | null;
  lastPullAt: number | null;
  lastAccountsSyncAt: number | null;
  lastTaskStartedAt: number | null;
  lastTaskFinishedAt: number | null;
  nextHeartbeatAt: number | null;
  nextPullAt: number | null;
  lastError: string | null;
}

const schedulerState: SchedulerSnapshot = {
  initializedAt: 0,
  phase: "idle",
  queueDepth: 0,
  currentTaskId: null,
  lastSseEventAt: null,
  lastHeartbeatAt: null,
  lastPullAt: null,
  lastAccountsSyncAt: null,
  lastTaskStartedAt: null,
  lastTaskFinishedAt: null,
  nextHeartbeatAt: null,
  nextPullAt: null,
  lastError: null,
};

export function initScheduler(): void {
  schedulerState.initializedAt = schedulerState.initializedAt || Date.now();
}

export function setSchedulerPhase(phase: SchedulerSnapshot["phase"]): void {
  schedulerState.phase = phase;
}

export function setSchedulerQueueDepth(queueDepth: number): void {
  schedulerState.queueDepth = Math.max(0, queueDepth);
}

export function setSchedulerCurrentTask(taskId: string | null): void {
  schedulerState.currentTaskId = taskId;
  if (taskId) {
    schedulerState.lastTaskStartedAt = Date.now();
  }
}

export function noteSchedulerTaskFinished(): void {
  schedulerState.lastTaskFinishedAt = Date.now();
}

export function noteSchedulerSseEvent(): void {
  schedulerState.lastSseEventAt = Date.now();
}

export function noteSchedulerHeartbeat(): void {
  schedulerState.lastHeartbeatAt = Date.now();
}

export function noteSchedulerPull(): void {
  schedulerState.lastPullAt = Date.now();
}

export function noteSchedulerAccountsSync(): void {
  schedulerState.lastAccountsSyncAt = Date.now();
}

export function setSchedulerNextHeartbeat(timestamp: number | null): void {
  schedulerState.nextHeartbeatAt = timestamp;
}

export function setSchedulerNextPull(timestamp: number | null): void {
  schedulerState.nextPullAt = timestamp;
}

export function setSchedulerError(message: string | null): void {
  schedulerState.lastError = message;
}

export function getSchedulerState(): SchedulerSnapshot {
  return { ...schedulerState };
}