var _ = require('lodash');
var update = require('react-addons-update');
var RecursiveIterator = require('recursive-iterator');

function Tree(srcState) {
  this._keyCount = 0;
  this._state = srcState || {};
}

var p = Tree.prototype;

p.get = function(pathArr) {
  var obj = this._state;
  for(var i = 0, len = pathArr.length; i < len; ++i) {
    obj = obj[pathArr[i]];
    if(!obj) throw new Error('Unexistant tree path: "'+pathArr.join('.')+'"');
  }
  return obj;
};

p.update = function(pathArr, updateCommands) {
  var updateQuery = this._createUpdateQueryForPath(pathArr, updateCommands);
  this._state = update(this._state, updateQuery);
  return this;
};

p.del = function(pathArr) {
  var prop = pathArr[pathArr.length-1];
  var parentPath = pathArr.slice(0, -1);
  this.update(parentPath, {
    "$apply": function(item) {
      delete item[prop];
      return item;
    }
  });
  return this;
};

p.find = function(obj) {
  var iterator = this._getStateIterator();
  for(var item = iterator.next(); !item.done; item = iterator.next()) {
    var state = item.value;
    if(state.node === obj) {
      return state;
    }
  }
};

p.getState = function() {
  return this._state;
};

p.toJSON = function() {
  return this._state;
};


p._getStateIterator = function() {
  var iterator = new RecursiveIterator(this._state);
  return iterator;
};

p._createUpdateQueryForPath = function(pathArr, updateCommands) {
  var cursor, query = {};
  cursor = query;
  for(var i = 0, len = pathArr.length; i < len-1; ++i) {
    cursor = cursor[pathArr[i]] = {};
  }
  cursor[pathArr[pathArr.length-1]] = updateCommands;
  return query;
};

module.exports = Tree;