Model Controller

model.js

'use strict'

/** USAGE **

HTML requires script:
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>

Attempts to load /config/mysite.json
Provides get/set methods using string paths

var siteName = "mysite"

PoziAPI()
  .initalise(siteName)
  .then(function () {
    Model()
      .debugconsole()

    Model()
      .set("config.someobject", {"foo": "bar"})

    var someobject = Model()
      .get("config.someobject")

  .catch(function (err) {
    debug("!!! ERROR !!! Initalising error occured: ", err)
  })      
*/

/**
 * Global model object.
 * ALWAYS access via Model Adapter functions.
 * NEVER reference, read or update this object directly.
 */
var __GModelInternal = {} // ALWAYS access via Model Adapter functions.

/**
 * Manages the model.
 * Loads the siteconfig.
 * Contains accessor functions to read and manipulate the model.
 * May contain persistant functions in future, e.g. Read/Write from localstorage, etc.
 */
function Model() {

  // Adapters
  var adapters = {
    'initalise': function (sitename) {
      return initalise(sitename)
    },
    'get': function (path) {
      return get(path)
    },
    'set': function (path, value) {
      return set(path, value)
    },
    'debugconsole': function () {
      return debugconsole()
    }

  }

  /**
   * Load Site Data and initalise class.
   * See API.js for param details.
   *
   * @param {string} sitename
   *
   */
  var initalise = function (sitename) {
    return new Promise(function (resolve, reject) {
      if (__GModelInternal.loaded) {
        debug("Site already initalised: ", sitename)
        return resolve()
      }

      addUrlParametersToModel()
      if (!sitename) {
        // Check if sitename was in url
        sitename = _.get(__GModelInternal, "url.site")
        if (!sitename) {
          // Check again if sitename was in url
          return reject("Model initalise was unable to determine sitename!")
        }
      }

      getSiteConfigFromServer(sitename, resolve, reject) // Consider this could save/load from localstorage.
    })
  }

  /**
   * Get url parameters from url as json object
   *
   * Uses lodash
   * @returns {json} url parameters
   *
   */
  var addUrlParametersToModel = function () {
    // Remove the '?' at the start of the string and split out each assignment
    var urlParamsSearch = _.chain(location.search.slice(1)
        .split('&'))
      // Split each array item into [key, value]
      // ignore empty string if search is empty
      .map(function (item) {
        if (item) return item.split('=');
      })
      // Remove undefined in the case the search is empty
      .compact()
      // returns an object composed from key-value pairs.
      .fromPairs()
      // Return the value of the chain operation
      .value()

    // Remove the '#' at the start of the string and split out each assignment
    var urlParamsHash = _.chain(location.hash.slice(1)
        .split('&'))
      // Split each array item into [key, value]
      // ignore empty string if search is empty
      .map(function (item) {
        if (item) return item.split('=');
      })
      // Remove undefined in the case the search is empty
      .compact()
      // Returns an object composed from key-value pairs.
      .fromPairs()
      // Return the value of the chain operation
      .value()

    var urlParams = _.merge(urlParamsSearch, urlParamsHash)

    _.set(__GModelInternal, "url", urlParams)
  }

  /**
   * Get siteconfig from server
   *
   * https://lodash.com/docs/4.17.4#get
   * @param {string} url a value siteconfig url
   * @returns {json} siteconfig
   *
   */
  var getSiteConfigFromServer = function (sitename, resolve, reject) {
    var url = "/config/" + sitename + ".json"
    debug("Get site data from site config:" + url)

    $.ajax({
      dataType: 'json',
      url: url,
      error: reject,
      success: function (sc) {
        _.set(__GModelInternal, "config", sc)
        if (!__GModelInternal || !__GModelInternal.config.title) {
          return reject("Invalid config file for site: " + sitename)
        }
        __GModelInternal.loaded = true
        setDefaultData(sitename)

        // debug(__GModelInternal)
        return resolve()
      }
    })
  }

  /**
   * Query the site config.
   *
   * https://lodash.com/docs/4.17.4#get
   * @param {string} path
   * @returns {object}
   *
   */
  var get = function (path) {
    if (!__GModelInternal.loaded) {
      debug("!!! ERROR !!! Model get called before initalise. Debug info: Model path requested: ", path)
      return null
    }
    var value = _.get(__GModelInternal, path, null)
    if (!value) {
      debug("Model path not found", path)
    }
    return value
  }

  /**
   * Set site config value
   *
   * https://lodash.com/docs/4.17.4#set
   * @param {path} string
   * @param {object} object
   * @returns {object}
   *
   */
  var set = function (path, value) {
    if (!__GModelInternal.loaded) {
      debug("!!! ERROR !!! Model set called before initalise. Debug info: Model path requested: ", path)
      return null
    }
    return _.set(__GModelInternal, path, value) // Lodash function
  }

  /**
   * Set a default value if it doesnt exist in the config.
   *
   * https://lodash.com/docs/4.17.4#set
   * @param {string} path
   * @param {object} value
   *
   */
  var setDefault = function (path, value) {
    if (!get(path, value)) {
      debug("Model path " + path + " setting default to", value)
      return set(path, value)
    } else {
      // Default value already set.
    }
  }

  /**
   * Output the current site config for debugging.
   */
  var debugconsole = function () {
    debug("Model object: ", __GModelInternal)
  }

  /**
   * If no value exists in the config then set a default value.
   *
   * @param {string} sitename
   *
   */
  var setDefaultData = function (sitename) {
    setDefault("sitename", sitename)
  }

  // Return adapters (must be at end of adapter)
  return adapters

}
// End A (Adapter)