/**
* Basic Node of BTree. 
* Keep reference to their children and values.
* Keep a reference to the parent and tree.
*/
export class BTreeNode {
  constructor(isLeaf) {
    /**
     * @type {number[]} list of values in the node
    */
    this.values = [];
    /**
     * @type {boolean} is a leaf
    */
    this.leaf = isLeaf;
    /**
     * @type {BTreeNode[]}
    */
    this.children = [];
    /**
     * Reference to the tree its belong.
     * @type {BTree}
     */
    this.tree = null;
    /**
     * Reference to the parent Node
     * @type {BTreeNode}
    */
    this.parent = null;
  }

  /**
   * Number of values
   * @returns {number}
   */
  get n() {
    return this.values.length;
  }

  /**
   * Add value
   * @param {number} value 
   * @param {number} pos 
   */
  addValue(value) {
    if (!value) {
      return;
    }
    let pos = 0;
    while (pos < this.n && this.values[pos] < value) {
      pos++;
    }
    this.values.splice(pos, 0, value);
  }

  /**
   * Delete value and return it
   * @param {number} pos position
   * @return {number}
   */
  removeValue(pos) {
    if (pos >= this.n) {
      return null;
    }
    return this.values.splice(pos, 1)[0];
  }

  /**
   * Add child node at position pos
   * @param {BTreeNode} node 
   * @param {number} pos 
   */
  addChild(node, pos) {
    this.children.splice(pos, 0, node);
    node.parent = this;
  }
  /**
   * Remove node from position and return it
   * @param {number} pos 
   * @return {BTreeNode}
   */
  removeChild(pos) {
    return this.children.splice(pos, 1)[0];
  }
}