/* global Promise, Provisioning, MessageDB */

(function(exports) {
  'use strict';

  /**
   * Default constructor, use it to copy objects. To parse objects from XML use
   * the factory function from()
   *
   * @param {Object} [obj] An object from which to copy the fields.
   */
  function ParsedMessage(obj) {
    if (obj) {
      for (var key in obj) {
        this[key] = obj[key];
      }
    }
  }

  ParsedMessage.prototype = {
    /**
     * Constructor, this is for internal use only
     */
    constructor: ParsedMessage,

    /**
     * Creates an untyped object from a typed one
     *
     * @return {Object} An untyped representation of this object.
     */
    toJSON: function pm_toJSON() {
      var obj = {
        type: this.type,
        sender: this.sender,
        serviceId: this.serviceId,
        timestamp: this.timestamp
      };

      if (this.href) {
        obj.href = this.href;
      }

      if (this.id) {
        obj.id = this.id;
      }

      if (this.created) {
        obj.created = this.created;
      }

      if (this.expires) {
        obj.expires = this.expires;
      }

      if (this.text) {
        obj.text = this.text;
      }

      if (this.action) {
        obj.action = this.action;
      }

      if (this.provisioning) {
        obj.provisioning = this.provisioning;
      }

      return obj;
    },

    /**
     * Saves the message in the database.  Returns a promise that resolves
     * to a string describing the status of the message: 'new' if the message
     * was new, 'updated' if the message updated an existing message or
     * 'discarded' if the message was discarded.
     *
     * @return {Object} A promise for this operation.
     */
    save: function pm_save() {
      var self = this;
      var json_message = this.toJSON();

      return MessageDB.put(json_message).then(function(status) {
        if (status === 'updated') {
          // In case the message was updated we must update the original too.
          self.timestamp = json_message.timestamp;
        }

        return Promise.resolve(status);
      });
    },

    /**
     * Returns true if the message has already expired
     */
    isExpired: function pm_isExpired() {
      return (this.expires && (this.expires < Date.now())) || false;
    },

    /**
     * Gets the message unique identifier
     *
     * @returns {String} An identifier for this message
     */
    getUniqueId: function pm_getUniqueId() {
      return this.timestamp;
    }
  };

  /**
   * Parse a message and returns an object holding its fields. The returned
   * object will contain the following fields:
   * - type: the content type of the message, either 'text/vnd.wap.si' or
   *         'text/vnd.wap.sl'
   * - sender: the sender of this message, a MSISDN
   * - timestamp: a timestamp taken when parsing the object
   * - href: optional for SI messages, required for SL, a URL to be displayed
   * - id: optional for SI messages, a pseudo-unique ID for the message
   * - created: optional for SI messages, creation time of this message
   * - expires: optional for SI messages, expiration time of this message
   * - action: optional for SI/SL message, action to be executed
   * - provisioning: only for CP messages, CP related object
   * - text: optional, text to be displayed
   *
   * @param {Object} message A WAP Push message as delivered by the system.
   * @param {Object} timestamp A timestamp for the message reception time.
   *
   * @return {Object} An object holding the contents of the WAP message as
   *                  separate fields.
   */
  ParsedMessage.from = function pm_from(message, timestamp) {
    var parser = new DOMParser();
    var doc = parser.parseFromString(message.content, 'text/xml');
    var obj = new ParsedMessage();

    // We don't check for errors as the message has already been validated

    obj.type = message.contentType;
    obj.sender = message.sender;
    obj.serviceId = message.serviceId;
    obj.timestamp = timestamp.toString();

    if (message.contentType === 'text/vnd.wap.si') {
      // SI message
      var indicationNode = doc.querySelector('indication');

      // 'href' attribute, optional, string
      if (indicationNode.hasAttribute('href')) {
        obj.href = indicationNode.getAttribute('href');
      }

      obj.text = indicationNode.textContent;

      // 'created' attribute, optional, date in ISO 8601 format
      if (indicationNode.hasAttribute('created')) {
        var date = new Date(indicationNode.getAttribute('created'));

        obj.created = date.getTime();
      }

      // 'si-expires' attribute, optional, date in ISO 8601 format
      if (indicationNode.hasAttribute('si-expires')) {
        var expiresDate = new Date(indicationNode.getAttribute('si-expires'));

        obj.expires = expiresDate.getTime();
      }

      /* 'action' attribute, optional, string, defaults to 'signal-medium' when
       * not present in the incoming message, see WAP-167 7.2 */
      if (indicationNode.hasAttribute('action')) {
        obj.action = indicationNode.getAttribute('action');
      } else {
        obj.action = 'signal-medium';
      }

      // 'si-id' attribute, optional, string
      if (indicationNode.hasAttribute('si-id')) {
        obj.id = indicationNode.getAttribute('si-id');
      } else if (obj.action === 'delete') {
        /* If the message has a 'delete' action but no 'si-id' field than it's
         * malformed and should be immediately discarded, see WAP-167 6.2 */
        return null;
      } else if (obj.href) {
        /* If the 'si-id' attribute is not specified then its value is
         * considered to be the same as the value of the 'href' attribute,
         * see WAP-167 5.2.1 */
        obj.id = obj.href;
      }
    } else if (message.contentType === 'text/vnd.wap.sl') {
      // SL message
      var slNode = doc.querySelector('sl');

      // 'href' attribute, always present
      obj.href = slNode.getAttribute('href');

      /* 'action' attribute, optional, string, defaults to 'execute-low' when
       * not present in the incoming message, see WAP-168 5.2 */
      if (slNode.hasAttribute('action')) {
        obj.action = slNode.getAttribute('action');
      } else {
        obj.action = 'execute-low';
      }
    } else if (message.contentType === 'text/vnd.wap.connectivity-xml') {
      // Client provisioning (CP) message
      obj.provisioning = Provisioning.fromMessage(message);

      // Security information is mandatory for the application. The application
      // must discard any message with no security information.
      if (!obj.provisioning.authInfo) {
        return null;
      }

      var authInfo = obj.provisioning.authInfo;
      // Let's discard any message that was not successfully authenticated by
      // gecko.
      if (authInfo.checked && !authInfo.pass) {
        return null;
      }

      obj.text = 'cp-message-received';
    } else {
      return null;
    }

    return obj;
  };

  /**
   * Loads the message corresponding to the specified timestamp from the
   * database. Returns a promise that resolves to the message. If the message
   * is not present the promise will be rejected.
   *
   * @param {Number} timestamp The timestamp of the message we want to
   *        retrieve.
   *
   * @returns {Object} A promise for this operation.
   */
  ParsedMessage.load = function pm_load(timestamp) {
    return MessageDB.retrieve(timestamp).then(function(message) {
      return new ParsedMessage(message);
    });
  };

  exports.ParsedMessage = ParsedMessage;
})(window);