import EventListener from "../../../event-listener";
import { DocumentChanges } from "../../../render-plugin/document-changes-listener";
import Context from "../context-detection";

import State from "./state";


class QueuedState extends State {
  private timer: ReturnType<typeof setTimeout> | null = null;
  private readonly prefix: string;
  private readonly suffix: string;


  private constructor(
    context: EventListener,
    prefix: string,
    suffix: string
  ) {
    super(context);
    this.prefix = prefix;
    this.suffix = suffix;
  }

  static createAndStartTimer(
    context: EventListener,
    prefix: string,
    suffix: string
  ): QueuedState {
    const state = new QueuedState(context, prefix, suffix);
    state.startTimer();
    context.setContext(Context.getContext(prefix, suffix));
    return state;
  }

  handleCancelKeyPressed(): boolean {
    this.cancelTimer();
    this.context.transitionToIdleState();
    return true;
  }

  async handleDocumentChange(
    documentChanges: DocumentChanges
  ): Promise<void> {
    if (
      documentChanges.isDocInFocus() &&
      documentChanges.isTextAdded() &&
      this.context.containsTriggerCharacters(documentChanges)
    ) {
      this.cancelTimer();
      this.context.transitionToQueuedState(documentChanges.getPrefix(), documentChanges.getSuffix());
      return
    }
    if (
      (documentChanges.hasCursorMoved() ||
        documentChanges.hasUserTyped() ||
        documentChanges.hasUserDeleted() ||
        documentChanges.isTextAdded() ||
        !documentChanges.isDocInFocus())
    ) {
      this.cancelTimer();
      this.context.transitionToIdleState();
    }
  }

  startTimer(): void {
    this.cancelTimer();
    this.timer = setTimeout(() => {
      this.context.transitionToPredictingState(this.prefix, this.suffix);
    }, this.context.settings.delay);
  }

  private cancelTimer(): void {
    if (this.timer !== null) {
      clearTimeout(this.timer);
      this.timer = null;
    }
  }

  getStatusBarText(): string {
    return `Queued (${this.context.settings.delay} ms)`;
  }
}

export default QueuedState;