function Node (graph, id, data) {
  this.id = id
  this._ = data
  this._graph = graph
  this._graph.addVertex(id, this)
  Object.defineProperty(this, 'right', {
    get: function () {
      return this._getChildNode(1)
    },
    set: function (node) {
      this._graph.setEdge(1, this.id, 1, node.id)
    },
    enumerable: true,
    configurable: true
  })
  Object.defineProperty(this, 'left', {
    get: function () {
      return this._getChildNode(0)
    },
    set: function (node) {
      this._graph.setEdge(1, this.id, 0, node.id)
    },
    enumerable: true,
    configurable: true
  })
}

Node.prototype._getChildNode = function (index) {
  const vertex = this._graph.getVertex(this.id)
  const edge = vertex.edges.outgoing[index]
  const target = edge && edge.target
  return target && this._graph.getVertex(target)._ || null
}

Node.prototype.destroy = function () {
  const vertex = this._graph.getVertex(this.id)
  return this._graph.removeVertex(vertex)
}

module.exports = Node