const Tree = require('js-tree');
const proto = Tree.prototype;

proto.updateNodesPosition = function() {
  let top = 1;
  let left = 1;
  const root = this.getIndex(1);
  const self = this;

  root.top = top++;
  root.left = left++;

  if (root.children && root.children.length) {
    walk(root.children, root, left, root.node.collapsed);
  }

  function walk(children, parent, left, collapsed) {
    let height = 1;
    children.forEach(id => {
      const node = self.getIndex(id);
      if (collapsed) {
        node.top = null;
        node.left = null;
      } else {
        node.top = top++;
        node.left = left;
      }

      if (node.children && node.children.length) {
        height += walk(
          node.children,
          node,
          left + 1,
          collapsed || node.node.collapsed
        );
      } else {
        node.height = 1;
        height += 1;
      }
    });

    if (parent.node.collapsed) parent.height = 1;
    else parent.height = height;
    return parent.height;
  }
};

proto.move = function(fromId, toId, placement) {
  if (fromId === toId || toId === 1) return;

  const obj = this.remove(fromId);
  let index = null;

  if (placement === 'before') index = this.insertBefore(obj, toId);
  else if (placement === 'after') index = this.insertAfter(obj, toId);
  else if (placement === 'prepend') index = this.prepend(obj, toId);
  else if (placement === 'append') index = this.append(obj, toId);

  // todo: perf
  this.updateNodesPosition();
  return index;
};

proto.getNodeByTop = function(top) {
  const indexes = this.indexes;
  for (const id in indexes) {
    if (indexes.hasOwnProperty(id)) {
      if (indexes[id].top === top) return indexes[id];
    }
  }
};

module.exports = Tree;