'use strict';

import {Type} from '../type';
import ast =require("../yamlAST");

var _toString = Object.prototype.toString;

function resolveYamlPairs(data) {
  if (null === data) {
    return true;
  }
  if(data.kind != ast.Kind.SEQ){
    return false;
  }

  var index, length, pair, keys, result,
      object = data.items;

  for (index = 0, length = object.length; index < length; index += 1) {
    pair = object[index];

    if ('[object Object]' !== _toString.call(pair)) {
      return false;
    }

    if (!Array.isArray(pair.mappings)) {
      return false;
    }

    if (1 !== pair.mappings.length) {
      return false;
    }
  }

  return true;
}

function constructYamlPairs(data) {
  if (null === data || !Array.isArray(data.items)) {
    return [];
  }

  let index, length, keys, result,
      object = data.items;

  result = ast.newItems();
  result.parent = data.parent;
  result.startPosition = data.startPosition;
  result.endPosition = data.endPosition;

  for (index = 0, length = object.length; index < length; index += 1) {
    let pair = object[index];

    let mapping = pair.mappings[0];
    
    let pairSeq = ast.newItems();
    pairSeq.parent = result;
    pairSeq.startPosition = mapping.key.startPosition
    pairSeq.endPosition = mapping.value.startPosition
    mapping.key.parent = pairSeq;
    mapping.value.parent = pairSeq;
    pairSeq.items = [mapping.key,mapping.value];
    
    result.items.push(pairSeq);
  }

  return result;
}

export = new Type('tag:yaml.org,2002:pairs', {
  kind: 'sequence',
  resolve: resolveYamlPairs,
  construct: constructYamlPairs
});