window.SharedApi = (function ($) {
  "use strict";

  var api = {};

  api.safeAjax = function (ajaxOptions) {
    var deferredAjax = $.Deferred();

    if (!window.shell || !shell.getTokenDeferred) {
      deferredAjax.reject({
        responseText: "Power Pages shell token API is not available on this page."
      });
      return deferredAjax.promise();
    }

    shell.getTokenDeferred()
      .done(function (token) {
        ajaxOptions.headers = ajaxOptions.headers || {};
        ajaxOptions.headers["__RequestVerificationToken"] = token;

        $.ajax(ajaxOptions)
          .done(function (data, textStatus, jqXHR) {
            deferredAjax.resolve(data, textStatus, jqXHR);
          })
          .fail(function (jqXHR, textStatus, errorThrown) {
            deferredAjax.reject(jqXHR, textStatus, errorThrown);
          });
      })
      .fail(function () {
        deferredAjax.reject({
          responseText: "Could not obtain Power Pages verification token."
        });
      });

    return deferredAjax.promise();
  };

  api.get = function (url, options) {
    return api.safeAjax($.extend(true, {
      type: "GET",
      url: url,
      contentType: "application/json"
    }, options || {}));
  };

  api.post = function (url, payload, options) {
    return api.safeAjax($.extend(true, {
      type: "POST",
      url: url,
      contentType: "application/json",
      data: JSON.stringify(payload || {})
    }, options || {}));
  };

  api.patch = function (url, payload, options) {
    return api.safeAjax($.extend(true, {
      type: "PATCH",
      url: url,
      contentType: "application/json",
      data: JSON.stringify(payload || {})
    }, options || {}));
  };

  api.del = function (url, options) {
    return api.safeAjax($.extend(true, {
      type: "DELETE",
      url: url
    }, options || {}));
  };

  return api;
})(jQuery);