sap.ui.define([
	"sap/ui/core/util/MockServer",
	"sap/ui/model/json/JSONModel",
	"sap/base/Log"
], function (MockServer, JSONModel, Log) {
	"use strict";

	var oMockServer,
		_sAppPath = "sap/ui/demo/orderbrowser/",
		_sJsonFilesPath = _sAppPath + "localService/mockdata";

	var oMockServerInterface = {

		/**
		 * Initializes the mock server asynchronously.
		 * You can configure the delay with the URL parameter "serverDelay".
		 * The local mock data in this folder is returned instead of the real data for testing.
		 * @protected
		 * @returns{Promise} a promise that is resolved when the mock server has been started
		 */
		init : function (oOptionsParameter) {
			var oOptions = oOptionsParameter || {};

			return new Promise(function(fnResolve) {
				var sManifestUrl = sap.ui.require.toUrl(_sAppPath + "manifest.json"),
					oManifestModel = new JSONModel(sManifestUrl);

				oManifestModel.attachRequestCompleted(function ()  {
					var oUriParameters = new URLSearchParams(window.location.search),
						// parse manifest for local metadata URI
						sJsonFilesUrl = sap.ui.require.toUrl(_sJsonFilesPath),
						oMainDataSource = oManifestModel.getProperty("/sap.app/dataSources/mainService"),
						sMetadataUrl = sap.ui.require.toUrl(_sAppPath + oMainDataSource.settings.localUri),
						// ensure there is a trailing slash
						sMockServerUrl = /.*\/$/.test(oMainDataSource.uri) ? oMainDataSource.uri : oMainDataSource.uri + "/";

					// create a mock server instance or stop the existing one to reinitialize
					if (!oMockServer) {
						oMockServer = new MockServer({
							rootUri: sMockServerUrl
						});
					} else {
						oMockServer.stop();
					}

					// configure mock server with the given options or a default delay of 0.5s
					MockServer.config({
						autoRespond : true,
						autoRespondAfter : (oOptions.delay || oUriParameters.get("serverDelay") || 500)
					});

					// simulate all requests using mock data
					oMockServer.simulate(sMetadataUrl, {
						sMockdataBaseUrl : sJsonFilesUrl,
						bGenerateMissingMockData : true
					});

					var aRequests = oMockServer.getRequests();

					// compose an error response for requesti
					var fnResponse = function (iErrCode, sMessage, aRequest) {
						aRequest.response = function(oXhr){
							oXhr.respond(iErrCode, {"Content-Type": "text/plain;charset=utf-8"}, sMessage);
						};
					};

					// simulate metadata errors
					if (oOptions.metadataError || oUriParameters.get("metadataError")) {
						aRequests.forEach(function (aEntry) {
							if (aEntry.path.toString().indexOf("$metadata") > -1) {
								fnResponse(500, "metadata Error", aEntry);
							}
						});
					}

					// simulate request errors
					var sErrorParam = oOptions.errorType || oUriParameters.get("errorType"),
						iErrorCode = sErrorParam === "badRequest" ? 400 : 500;
					if (sErrorParam) {
						aRequests.forEach(function (aEntry) {
							fnResponse(iErrorCode, sErrorParam, aEntry);
						});
					}

					// custom mock behaviour may be added here

					// set requests and start the server
					oMockServer.setRequests(aRequests);
					oMockServer.start();

					Log.info("Running the app with mock data");
					fnResolve();
				});

				oManifestModel.attachRequestFailed(function () {
					Log.error("Failed to load application manifest");
					fnResolve();
				});
			});
		},

		/**
		 * @public returns the mockserver of the app, should be used in integration tests
		 * @returns {sap.ui.core.util.MockServer} the mockserver instance
		 */
		getMockServer : function () {
			return oMockServer;
		}
	};

	return oMockServerInterface;
});