import ConfigUpdateListener from "../config/ConfigUpdateListener";
import ConfigManager from "../config/ConfigManager";
import BufferManagerWorker from "./BufferManagerWorker";
import ApiBufferKey from "./ApiBufferKey";
import NoOpBufferManagerWorker from "./NoOpBufferManagerWorker";
import AgentConfig from "../common/data/AgentConfig";

abstract class AbstractBufferManager implements ConfigUpdateListener {
  private readonly configManager: ConfigManager;
  private readonly dummyWorker: BufferManagerWorker<ApiBufferKey>;
  private worker: BufferManagerWorker<ApiBufferKey> | null;
  protected constructor(configManager: ConfigManager) {
    this.configManager = configManager;
    this.dummyWorker = new NoOpBufferManagerWorker();
    this.worker = this.dummyWorker;
  }
  abstract createWorker(
    agentConfig: AgentConfig
  ): BufferManagerWorker<ApiBufferKey>;

  onErroneousConfigUpdate(): void {
    if (this.worker) {
      let oldBuffer: BufferManagerWorker<ApiBufferKey> = this.worker;
      this.worker = this.dummyWorker;
      oldBuffer.shutdown();
    }
  }

  onSuccessfulConfigUpdate(agentConfig: AgentConfig): void {
    if (!this.worker) return;
    if (!this.worker.getOperatingConfig()) return;
    // @ts-ignore
    if (this.isRefreshNeeded(this.worker.getOperatingConfig(), agentConfig)) {
      let oldBufferManagerWorker: BufferManagerWorker<ApiBufferKey> =
        this.worker;
      this.worker = this.createWorker(agentConfig);
      oldBufferManagerWorker.shutdown();
    }
  }

  init(): boolean {
    return this.configManager.subscribeToUpdates(this);
  }
  shutdown(): boolean {
    if (this.worker) {
      this.worker.shutdown();
      this.worker = null;
    }
    return true;
  }
  private isRefreshNeeded(
    olderConfig: AgentConfig,
    newConfig: AgentConfig
  ): boolean {
    if (
      newConfig.getTimestamp().getTime() === 0 &&
      olderConfig.getTimestamp().getTime() === 0
    ) {
      return false;
    }
    return (
      newConfig.getTimestamp().getTime() > olderConfig.getTimestamp().getTime()
    );
  }
  getWorker(): BufferManagerWorker<ApiBufferKey> | null {
    return this.worker;
  }
}

export default AbstractBufferManager;