Persisting state for incrementing counter

type CPersistedCounter = {
  lastValue: number,
  updatedAt: number
}

export class IncrementingCounter {
  private resourcePath: string;
  private maxId: number;

  constructor(resourcePath: string, maxId: number) {
    this.resourcePath = resourcePath;
    this.maxId = maxId;
  }

  async getNextId(): Promise<number> {
    let currentState: CPersistedCounter;
    try {
      currentState = await wmill.getResource(this.resourcePath);
    } catch {
      // If the resource doesn't exist, throw an error
      throw new Error(`Resource ${this.resourcePath} not found in workspace`);
    }

    const newId = (currentState.lastValue + 1) % this.maxId;
    const newState: CPersistedCounter = {
      updatedAt: Date.now(),
      lastValue: newId,
    };

    // Save the updated state to the Windmill resource - do not need to await because it can proceed in background
    wmill.setResource(newState, this.resourcePath);

    return newId;
  }
}