/**
 * Makes it possible to jump to a slide by entering its
 * slide number or id.
 */
export default class JumpToSlide {
  constructor(Reveal) {
    this.Reveal = Reveal;

    this.onInput = this.onInput.bind(this);
    this.onBlur = this.onBlur.bind(this);
    this.onKeyDown = this.onKeyDown.bind(this);
  }

  render() {
    this.element = document.createElement("div");
    this.element.className = "jump-to-slide";

    this.jumpInput = document.createElement("input");
    this.jumpInput.type = "text";
    this.jumpInput.className = "jump-to-slide-input";
    this.jumpInput.placeholder = "Jump to slide";
    this.jumpInput.addEventListener("input", this.onInput);
    this.jumpInput.addEventListener("keydown", this.onKeyDown);
    this.jumpInput.addEventListener("blur", this.onBlur);

    this.element.appendChild(this.jumpInput);
  }

  show() {
    this.indicesOnShow = this.Reveal.getIndices();

    this.Reveal.getRevealElement().appendChild(this.element);
    this.jumpInput.focus();
  }

  hide() {
    if (this.isVisible()) {
      this.element.remove();
      this.jumpInput.value = "";

      clearTimeout(this.jumpTimeout);
      delete this.jumpTimeout;
    }
  }

  isVisible() {
    return !!this.element.parentNode;
  }

  /**
   * Parses the current input and jumps to the given slide.
   */
  jump() {
    clearTimeout(this.jumpTimeout);
    delete this.jumpTimeout;

    const query = this.jumpInput.value.trim("");
    let indices = this.Reveal.location.getIndicesFromHash(query, {
      oneBasedIndex: true,
    });

    // If no valid index was found and the input query is a
    // string, fall back on a simple search
    if (!indices && /\S+/i.test(query) && query.length > 1) {
      indices = this.search(query);
    }

    if (indices && query !== "") {
      this.Reveal.slide(indices.h, indices.v, indices.f);
      return true;
    } else {
      this.Reveal.slide(
        this.indicesOnShow.h,
        this.indicesOnShow.v,
        this.indicesOnShow.f
      );
      return false;
    }
  }

  jumpAfter(delay) {
    clearTimeout(this.jumpTimeout);
    this.jumpTimeout = setTimeout(() => this.jump(), delay);
  }

  /**
   * A lofi search that looks for the given query in all
   * of our slides and returns the first match.
   */
  search(query) {
    const regex = new RegExp("\\b" + query.trim() + "\\b", "i");

    const slide = this.Reveal.getSlides().find((slide) => {
      return regex.test(slide.innerText);
    });

    if (slide) {
      return this.Reveal.getIndices(slide);
    } else {
      return null;
    }
  }

  /**
   * Reverts back to the slide we were on when jump to slide was
   * invoked.
   */
  cancel() {
    this.Reveal.slide(
      this.indicesOnShow.h,
      this.indicesOnShow.v,
      this.indicesOnShow.f
    );
    this.hide();
  }

  confirm() {
    this.jump();
    this.hide();
  }

  destroy() {
    this.jumpInput.removeEventListener("input", this.onInput);
    this.jumpInput.removeEventListener("keydown", this.onKeyDown);
    this.jumpInput.removeEventListener("blur", this.onBlur);

    this.element.remove();
  }

  onKeyDown(event) {
    if (event.keyCode === 13) {
      this.confirm();
    } else if (event.keyCode === 27) {
      this.cancel();

      event.stopImmediatePropagation();
    }
  }

  onInput(event) {
    this.jumpAfter(200);
  }

  onBlur() {
    setTimeout(() => this.hide(), 1);
  }
}