'use strict';
                        
                        var envVar = require('../environment-variables');
                        
                        /**
                         * @class  CiTravis
                         * @module  AutodocsCi
                         */
                        
                        /**
                         * Initialisation step for Travis
                         *
                         * Used to check/ set any Travis environment variables
                         *
                         * @method init
                         * @for  CiTravis
                         */
                        function environmentVariablesTravis() {
                          /**
                           * Used to set value of `REPO_SLUG`
                           *
                           * @property TRAVIS_REPO_SLUG
                           * @type String (Environment Variable)
                           * @default None - throws when not set
                           */
                          envVar.require('TRAVIS_REPO_SLUG');
                          process.env.REPO_SLUG = process.env.TRAVIS_REPO_SLUG;
                        
                          /**
                           * @property TRAVIS_PULL_REQUEST
                           * @type String (Environment Variable)
                           * @default None - throws when not set
                           */
                          envVar.require('TRAVIS_PULL_REQUEST');
                        
                          /**
                           * @property TRAVIS_BRANCH
                           * @type String (Environment Variable)
                           * @default None - throws when not set
                           */
                          envVar.require('TRAVIS_BRANCH');
                        
                          /**
                           * @property TRAVIS_BUILD_NUMBER
                           * @type String (Environment Variable)
                           * @default None - throws when not set
                           */
                          envVar.require('TRAVIS_BUILD_NUMBER');
                        
                          /**
                           * @property TRAVIS_JOB_NUMBER
                           * @type String (Environment Variable)
                           * @default None - throws when not set
                           */
                          envVar.require('TRAVIS_JOB_NUMBER');
                        }
                        
                        /**
                         * Based on the Travis environment variables,
                         * determines whether to trigger generation and publishing of documentation.
                         *
                         * If `FLAG_PUBLISH_ON_RELEASE` is `true`,
                         * then will trigger if Travis says that a tag was pushed.
                         *
                         * Otherwise, it will trigger when a branch is pushed,
                         * if Travis says that this **is not** a pull request,
                         * and the branch being pushed matches `DOCUMENT_BRANCH`.
                         *
                         * Both cases also require that the correct build index for the current job
                         * matches `DOCUMENT_JOB_INDEX`.
                         * This is to ensure that documentation is only published once per successful build.
                         *
                         * @method shouldRun
                         * @return {Boolean} `true` when documentation should be generated and published
                         */
                        function testShouldPublishTravis() {
                          var correctBuildIndex =
                            (process.env.TRAVIS_BUILD_NUMBER+'.'+process.env.DOCUMENT_JOB_INDEX ===
                              process.env.TRAVIS_JOB_NUMBER);
                          if (!correctBuildIndex) {
                            return false;
                          }
                          else if (process.env.FLAG_PUBLISH_ON_RELEASE === 'true') {
                            /**
                             * @property TRAVIS_TAG
                             * @type String (Environment Variable)
                             * @default None
                             */
                            return (envVar.exists('TRAVIS_TAG'));
                          }
                          else {
                            return (
                              process.env.TRAVIS_PULL_REQUEST === 'false' &&
                              process.env.TRAVIS_BRANCH === process.env.DOCUMENT_BRANCH);
                          }
                        }
                        
                        module.exports = {
                          init: environmentVariablesTravis,
                          shouldRun: testShouldPublishTravis,
                        };