class BBTreeviewNode {
  constructor(treeview) {
    const a = this;

    a.Treeview = treeview;

    a.ID = null;
    a.Node = null;

    a.Container = null;
    a.Label = null;
    a.Value = null;

    a.Name = "";
    a.Hint = "";

    a.ParentID = null;
    a.IsChecked = false;
    a.Highlighted = false;
    a.Tag = null;

    a.initialiseComponents();
  }


  initialiseComponents() {
    const a = this;
  }


  get IsChecked() {
    const a = this;

    if (!a.Treeview.Options.ShowCheckbox) {
      return false;
    }

    return a.Node.classList.contains("x");
  }

  set IsChecked(value) {
    const a = this;

    a.setCheckbox(a.Node, value);

    // Update children
    a.Node.querySelectorAll("li").forEach(function(e) {
      a.setCheckbox(e, value);
    });

    // Update parent state
    let parentNode = a.ParentNode;
    if (parentNode == null) {
      return;
    }

    // Handle pull-ups
    if (a.Treeview.Options.EnablePullUp) {
      while (true) {
        const parentChecked = (parentNode.querySelectorAll("li.x").length > 0);

        a.setCheckbox(parentNode, parentChecked);

        parentNode = a.Treeview.getNode(parentNode);
        parentNode = parentNode.GetParentNode();

        if (parentNode == null) {
          break;
        }
      }
    } else {
      let uncheckedCount = 0;

      parentNode.querySelectorAll("li").forEach(function(e) {
        if (e.classList.contains("x")) {
          return;
        }

        uncheckedCount++;
      });

      a.setCheckbox(parentNode, (uncheckedCount <= 0));
    }
  }

  get IsExpanded() {
    const a = this;

    if (a.Node.classList.contains("e")) {
      return true;
    }

    if (a.Node.classList.contains("c")) {
      return false;
    }

    return null;
  }

  get IsHighlighted() {
    const a = this;

    return (a.Container.classList.contains("highlighted"));
  }

  get Tag() {
    const a = this;

    let tag = a.Node.getAttribute("data-bbtv-tag");
    if (a.Treeview.isNullOrWhitespace(tag)) {
      return null;
    }

    return JSON.parse(decodeURIComponent(tag));
  }

  get ParentNodeID() {
    const a = this;

    const parentNode = a.ParentNode;
    if (parentNode == null) {
      return null;
    }

    return parentNode.getAttribute("data-bbtv-id");
  }

  get ParentNode() {
    const a = this;

    return a.parentsUntilTagName(a.Node, "li");
  }


  Load(node) {
    const a = this;

    a.ID = node.getAttribute("data-bbtv-id");
    a.Node = node;

    a.Container = node.querySelectorAll("div.li")[0];
    a.Label = node.querySelectorAll("span")[0];
    a.Value = node.getAttribute("data-bbtv-value");

    a.Name = a.Label.textContent;
    a.Hint = a.Label.getAttribute("title");

    a.ParentID = a.ParentNodeID;
    a.IsChecked = a.IsChecked;
    a.Highlighted = a.IsHighlighted;
    a.Tag = a.Tag;

    a.initialiseComponents_Events();
  }

  Collapse() {
    const a = this;

    if (a.Node.classList.contains("e")) {
      a.Node.classList.remove("e");
      a.Node.classList.add("c");
    }

    a.GetChildNodes().forEach(function(e) {
      e.classList.add("hidden");
    });
  }

  Expand() {
    const a = this;

    if (a.Node.classList.contains("c")) {
      a.Node.classList.remove("c");
      a.Node.classList.add("e");
    }

    a.GetChildNodes().forEach(function(e) {
      e.classList.remove("hidden");
    });
  }

  GetCheckbox() {
    const a = this;

    if (!a.Treeview.Options.ShowCheckbox) {
      return null;
    }

    const checkboxes = a.Node.querySelectorAll("div.icon.checkbox");
    if (typeof(checkboxes) == "undefined") {
      return null;
    }

    return checkboxes[0];
  }

  GetChildNode() {
    const a = this;

    let result = a.Node.querySelectorAll("ul");
    if (result.length <= 0) {
      return null;
    }

    return result[0];
  }

  GetChildNodes() {
    const a = this;

    const childNode = a.GetChildNode();
    if (childNode == null) {
      return [];
    }

    let nodes = childNode.querySelectorAll("li");
    if (nodes.length <= 0) {
      return [];
    }

    let result = [];
    nodes.forEach(function(e) {
      if (typeof(e.parentNode) == "undefined") {
        return;
      }

      if (e.parentNode != childNode) {
        return;
      }

      result.push(e);
    });

    return result;
  }

  Remove() {
    const a = this;

    if (a.ParentNode != null) {
      if (a.ParentNode.classList.contains("e")) {
        a.ParentNode.classList.remove("e");
      }

      if (a.ParentNode.classList.contains("c")) {
        a.ParentNode.classList.remove("c");
      }
    }

    a.Node.parentNode.removeChild(a.Node);
  }

  Toggle() {
    const a = this;

    switch (a.IsExpanded) {
      case true:
        a.Collapse();
        break;
      case false:
        a.Expand();
        break;
      default: break;
    }
  }


  initialiseComponents_Events() {
    const a = this;

    // collapsible icon behaviour
    a.Node.addEventListener("click", function(e){
      e.stopPropagation();
      e.preventDefault();

      if (!a.isTag(e.target, "li")) {
        return;
      }

      if ((e.offsetX < 0) || (e.offsetX > 16) || (e.offsetY < 0) || (e.offsetY > 16)) {
        return;
      }

      const myNode = a.Treeview.getNode(e.target);
      if (myNode == null) {
        return;
      }

      myNode.Toggle();
    });

    // collapsible label behaviour
    a.Container.addEventListener("dblclick", function(e){
      e.stopPropagation();
      e.preventDefault();

      const myNode = a.Treeview.getNode(e.target);
      if (myNode == null) {
        return;
      }

      myNode.Toggle();
    });

    // checkbox behaviour
    if (a.Treeview.Options.ShowCheckbox) {
      a.GetCheckbox().addEventListener("mousedown", function(e){
        e.stopPropagation();
        e.preventDefault();

        a.IsChecked = !a.IsChecked;
      });

      a.GetCheckbox().addEventListener("click", function(e){
        e.stopPropagation();
        e.preventDefault();

        // do nothing
      });

      a.GetCheckbox().addEventListener("dblclick", function(e){
        e.stopPropagation();
        e.preventDefault();

        // do nothing
      });
    }

    // highlighting
    a.Container.addEventListener("mousedown", function(e){
      e.stopPropagation();
      e.preventDefault();

      const myNode = a.Treeview.getNode(e.target);
      if (myNode == null) {
        return;
      }

      a.Treeview.Container.querySelectorAll("div.highlighted").forEach(function(e) {
        e.classList.remove("highlighted");
      });

      // Don't show selection
      if (!a.Treeview.Options.ShowSelection) {
        return;
      }

      myNode.Container.classList.add("highlighted");
    });

    a.invalidateCollapsible();
  }

  invalidateCollapsible() {
    const a = this;

    // Invalidate state
    if (a.ParentNode == null) {
      return;
    }

    if (a.ParentNode.classList.contains("c")) {
      a.Node.classList.add("hidden");
    } else if (a.ParentNode.classList.contains("e")) {
      a.Node.classList.remove("hidden");
    } else {
      a.ParentNode.classList.add("e");
      a.Node.classList.remove("hidden");
    }
  }

  isTag = function(el, tagName) {
    return (el.tagName.toLowerCase() == tagName);
  }

  parentsUntilTagName(el, tagName) {
    const a = this;

    let node = el;

    while (true) {
      if (typeof(node.parentNode) == "undefined") {
        break;
      }

      node = node.parentNode;

      if (typeof(node) == "undefined") {
        break;
      }

      if (a.isTag(node, "ul")) {
        if (node.classList.contains("bbtreeview")) {
          return null;
        }
      }

      if (a.isTag(node, tagName)) {
        break;
      }
    }

    return node;
  }

  setCheckbox(el, value) {
    if (value) {
      if (!el.classList.contains("x")) {
        el.classList.add("x");
      }
    } else {
      if (el.classList.contains("x")) {
        el.classList.remove("x");
      }
    }
  }

}