Class AppStateMachine

packages/core/src/app/stateMachine.ts:38–94

 * Throws ZRUI_INVALID_STATE on illegal transition attempts.
 */
export class AppStateMachine {
  private state0: AppRuntimeState = "Created";

  get state(): AppRuntimeState {
    return this.state0;
  }

  /** Assert current state is one of allowed states; throw with detail on violation. */
  assertOneOf(allowed: readonly AppRuntimeState[], detail: string): void {
    for (const s of allowed) {
      if (this.state0 === s) return;
    }
    invalidState(detail);
  }

  /** Transition to Running; valid from Created or Stopped. */
  toRunning(): void {
    if (this.state0 === "Created" || this.state0 === "Stopped") {
      this.state0 = "Running";
      return;
    }
    invalidState(`cannot transition ${this.state0} -> Running`);
  }

  /** Transition to Stopped; valid only from Running. */
  toStopped(): void {
    if (this.state0 === "Running") {
      this.state0 = "Stopped";
      return;
    }
    invalidState(`cannot transition ${this.state0} -> Stopped`);
  }

  /** Transition to Faulted; valid only from Running. */
  toFaulted(): void {
    if (this.state0 === "Running") {
      this.state0 = "Faulted";
      return;
    }
    invalidState(`cannot transition ${this.state0} -> Faulted`);
  }

  /** Transition to Disposed; valid from any state. Idempotent if already Disposed. */
  dispose(): void {
    if (this.state0 === "Disposed") return;
    if (
      this.state0 === "Faulted" ||
      this.state0 === "Created" ||
      this.state0 === "Running" ||
      this.state0 === "Stopped"
    ) {
      this.state0 = "Disposed";
      return;
    }
    invalidState(`cannot transition ${this.state0} -> Disposed`);
  }
}