// Copyright IBM Corp. 2014,2016. All Rights Reserved.
  // Node module: loopback
  // This file is licensed under the MIT License.
  // License text available at https://opensource.org/licenses/MIT
  
  var assert = require('assert');
  var utils = require('../../lib/utils');
  
  /*!
   * Application management functions
   */
  
  var crypto = require('crypto');
  
  function generateKey(hmacKey, algorithm, encoding) {
    hmacKey = hmacKey || 'loopback';
    algorithm = algorithm || 'sha1';
    encoding = encoding || 'hex';
    var hmac = crypto.createHmac(algorithm, hmacKey);
    var buf = crypto.randomBytes(32);
    hmac.update(buf);
    var key = hmac.digest(encoding);
    return key;
  }
  
  /**
   * Manage client applications and organize their users.
   *
   * @property {String} id  Generated ID.
   * @property {String} name Name; required.
   * @property {String} description Text description
   * @property {String} icon String Icon image URL.
   * @property {String} owner User ID of the developer who registers the application.
   * @property {String} email E-mail address
   * @property {Boolean} emailVerified Whether the e-mail is verified.
   * @property {String} url OAuth 2.0  application URL.
   * @property {String}[] callbackUrls The OAuth 2.0 code/token callback URL.
   * @property {String} status Status of the application; Either `production`, `sandbox` (default), or `disabled`.
   * @property {Date} created Date Application object was created.  Default: current date.
   * @property {Date} modified Date Application object was modified.  Default: current date.
   *
   * @property {Object} pushSettings.apns APNS configuration, see the options
   *   below and also
   *   https://github.com/argon/node-apn/blob/master/doc/apn.markdown
   * @property {Boolean} pushSettings.apns.production Whether to use production Apple Push Notification Service (APNS) servers to send push notifications.
   * If true, uses `gateway.push.apple.com:2195` and `feedback.push.apple.com:2196`.
   * If false, uses `gateway.sandbox.push.apple.com:2195` and `feedback.sandbox.push.apple.com:2196`
   * @property {String} pushSettings.apns.certData The certificate data loaded from the cert.pem file (APNS).
   * @property {String} pushSettings.apns.keyData The key data loaded from the key.pem file (APNS).
   * @property {String} pushSettings.apns.pushOptions.gateway (APNS).
   * @property {Number} pushSettings.apns.pushOptions.port (APNS).
   * @property {String} pushSettings.apns.feedbackOptions.gateway  (APNS).
   * @property {Number} pushSettings.apns.feedbackOptions.port (APNS).
   * @property {Boolean} pushSettings.apns.feedbackOptions.batchFeedback (APNS).
   * @property {Number} pushSettings.apns.feedbackOptions.interval (APNS).
   * @property {String} pushSettings.gcm.serverApiKey: Google Cloud Messaging API key.
   *
   * @property {Boolean} authenticationEnabled
   * @property {Boolean} anonymousAllowed
   * @property {Array} authenticationSchemes List of authentication schemes
   *  (see below).
   * @property {String} authenticationSchemes.scheme Scheme name.
   *   Supported values: `local`, `facebook`, `google`,
   *   `twitter`, `linkedin`, `github`.
   * @property {Object} authenticationSchemes.credential
   *   Scheme-specific credentials.
   *
   * @class Application
   * @inherits {PersistedModel}
   */
  
  module.exports = function(Application) {
  
    // Workaround for https://github.com/strongloop/loopback/issues/292
    Application.definition.rawProperties.created.default =
    Application.definition.properties.created.default = function() {
      return new Date();
    };
  
    // Workaround for https://github.com/strongloop/loopback/issues/292
    Application.definition.rawProperties.modified.default =
    Application.definition.properties.modified.default = function() {
      return new Date();
    };
  
    /*!
     * A hook to generate keys before creation
     * @param next
     */
    Application.observe('before save', function(ctx, next) {
      if (!ctx.instance) {
        // Partial update - don't generate new keys
        // NOTE(bajtos) This also means that an atomic updateOrCreate
        // will not generate keys when a new record is creatd
        return next();
      }
  
      var app = ctx.instance;
      app.created = app.modified = new Date();
      if (!app.id) {
        app.id = generateKey('id', 'md5');
      }
      app.clientKey = generateKey('client');
      app.javaScriptKey = generateKey('javaScript');
      app.restApiKey = generateKey('restApi');
      app.windowsKey = generateKey('windows');
      app.masterKey = generateKey('master');
      next();
    });
  
    /**
     * Register a new application
     * @param {String} owner Owner's user ID.
     * @param {String} name  Name of the application
     * @param {Object} options  Other options
     * @param {Function} callback  Callback function
     */
    Application.register = function(owner, name, options, cb) {
      assert(owner, 'owner is required');
      assert(name, 'name is required');
  
      if (typeof options === 'function' && !cb) {
        cb = options;
        options = {};
      }
      cb = cb || utils.createPromiseCallback();
  
      var props = {owner: owner, name: name};
      for (var p in options) {
        if (!(p in props)) {
          props[p] = options[p];
        }
      }
      this.create(props, cb);
      return cb.promise;
    };
  
    /**
     * Reset keys for the application instance
     * @callback {Function} callback
     * @param {Error} err
     */
    Application.prototype.resetKeys = function(cb) {
      this.clientKey = generateKey('client');
      this.javaScriptKey = generateKey('javaScript');
      this.restApiKey = generateKey('restApi');
      this.windowsKey = generateKey('windows');
      this.masterKey = generateKey('master');
      this.modified = new Date();
      this.save(cb);
    };
  
    /**
     * Reset keys for a given application by the appId
     * @param {Any} appId
     * @callback {Function} callback
     * @param {Error} err
     */
    Application.resetKeys = function(appId, cb) {
      cb = cb || utils.createPromiseCallback();
      this.findById(appId, function(err, app) {
        if (err) {
          if (cb) cb(err, app);
          return;
        }
        app.resetKeys(cb);
      });
      return cb.promise;
    };
  
    /**
     * Authenticate the application id and key.
     *
     * @param {Any} appId
     * @param {String} key
     * @callback {Function} callback
     * @param {Error} err
     * @param {String} matched The matching key; one of:
     * - clientKey
     * - javaScriptKey
     * - restApiKey
     * - windowsKey
     * - masterKey
     *
     */
    Application.authenticate = function(appId, key, cb) {
      cb = cb || utils.createPromiseCallback();
  
      this.findById(appId, function(err, app) {
        if (err || !app) {
          cb(err, null);
          return cb.promise;
        }
        var result = null;
        var keyNames = ['clientKey', 'javaScriptKey', 'restApiKey', 'windowsKey', 'masterKey'];
        for (var i = 0; i < keyNames.length; i++) {
          if (app[keyNames[i]] === key) {
            result = {
              application: app,
              keyType: keyNames[i]
            };
            break;
          }
        }
        cb(null, result);
      });
      return cb.promise;
    };
  };