Error messages for generating schedules

autoscheduler/frontend/src/components/SchedulingPage/CourseSelectColumn/CourseSelectCard/ExpandedCourseCard/BasicSelect/BasicOptionRow.tsx

@@ -4,6 +4,7 @@ import { useDispatch, useSelector } from 'react-redux';
 import { RootState } from '../../../../../../redux/reducer';
 import { updateCourseCard } from '../../../../../../redux/actions/courseCards';
 import * as styles from './BasicSelect.css';
+import { SectionFilter } from '../../../../../../types/CourseCardOptions';
 
 interface BasicOptionRowProps {
     id: number;
@@ -37,9 +38,9 @@ const BasicOptionRow: React.FC<BasicOptionRowProps> = ({ id, value, label }) =>
             dispatch(updateCourseCard(id, { [value]: evt.target.value as string }));
           }}
         >
-          <MenuItem value="no_preference">No Preference</MenuItem>
-          <MenuItem value="exclude">Exclude</MenuItem>
-          <MenuItem value="only">Only</MenuItem>
+          <MenuItem value={SectionFilter.NO_PREFERENCE}>No Preference</MenuItem>
+          <MenuItem value={SectionFilter.EXCLUDE}>Exclude</MenuItem>
+          <MenuItem value={SectionFilter.ONLY}>Only</MenuItem>
         </Select>
       </td>
     </tr>

autoscheduler/frontend/src/redux/actions/courseCards.ts

@@ -1,6 +1,7 @@
 import { ThunkAction } from 'redux-thunk';
 import {
   CourseCardOptions, SectionSelected, CustomizationLevel, SerializedCourseCardOptions,
+  SectionFilter,
 } from '../../types/CourseCardOptions';
 import {
   AddCourseAction, ADD_COURSE_CARD, RemoveCourseAction, REMOVE_COURSE_CARD, UpdateCourseAction,
@@ -17,9 +18,9 @@ function createEmptyCourseCard(): CourseCardOptions {
     course: '',
     customizationLevel: CustomizationLevel.BASIC,
     sections: [],
-    web: 'no_preference',
-    honors: 'exclude',
-    asynchronous: 'no_preference',
+    web: SectionFilter.NO_PREFERENCE,
+    honors: SectionFilter.EXCLUDE,
+    asynchronous: SectionFilter.NO_PREFERENCE,
     collapsed: false,
   };
 }
@@ -192,12 +193,20 @@ async function fetchCourseCardFrom(
       const hasHonors = sections.some((section) => section.section.honors);
       const hasWeb = sections.some((section) => section.section.web);
       const hasAsynchronous = sections.some((section) => section.section.asynchronous);
+      // Update honors and web based on whether the old selection is still possible
+      const honors = hasHonors ? courseCard.honors : SectionFilter.NO_PREFERENCE;
+      const web = hasWeb ? courseCard.web : SectionFilter.NO_PREFERENCE;
+      const asynchronous = hasAsynchronous ? courseCard.asynchronous : SectionFilter.NO_PREFERENCE;
+
       return {
         ...courseCard,
         sections,
         hasHonors,
         hasWeb,
         hasAsynchronous,
+        honors,
+        web,
+        asynchronous,
       };
     })
     .catch(() => undefined);

autoscheduler/frontend/src/redux/actions/schedules.ts

@@ -12,6 +12,7 @@ import { CustomizationLevel } from '../../types/CourseCardOptions';
 import { parseAllMeetings } from './courseCards';
 import { SelectScheduleAction } from '../reducers/selectedSchedule';
 import selectSchedule from './selectedSchedule';
+import { GenerateSchedulesResponse } from '../../types/APIResponses';
 
 export function addSchedule(meetings: Meeting[]): AddScheduleAction {
   return {
@@ -56,6 +57,10 @@ export function renameSchedule(index: number, name: string): RenameScheduleActio
   };
 }
 
+export const errorGeneratingSchedulesMessage = 'There was an error generating schedules, please try again.';
+
+// Fetches scheduler/generate. If something goes wrong or no schedules can be generated,
+// throws an error with a message indicating what happened.
 export function generateSchedules(includeFull: boolean):
 ThunkAction<Promise<void>, RootState, undefined, ReplaceSchedulesAction | SelectScheduleAction> {
   return async (dispatch, getState): Promise<void> => {
@@ -114,13 +119,24 @@ ThunkAction<Promise<void>, RootState, undefined, ReplaceSchedulesAction | Select
         courses,
         availabilities,
       }),
-    }).then(
-      (res) => res.json(),
-    ).then(
-      (generatedSchedules: any[][]) => generatedSchedules.map(parseAllMeetings),
-    ).then(
-      checkIfEmpty,
-    )
+    })
+      .then((res) => res.json())
+      .catch(() => {
+        // If something went wrong generating schedules, catch the error here before
+        // handling messages from no schedules being generated.
+        throw new Error(errorGeneratingSchedulesMessage);
+      })
+      .then((json) => {
+        const { schedules, message }: GenerateSchedulesResponse = json;
+        if (message) throw new Error(message);
+        if (!schedules?.length) {
+          throw new Error(errorGeneratingSchedulesMessage);
+        }
+        return schedules.map(parseAllMeetings);
+      })
+      .then(
+        checkIfEmpty,
+      )
       .then((schedules: Meeting[][]) => {
         dispatch(replaceSchedules(schedules));
         dispatch(selectSchedule(0));

autoscheduler/frontend/src/redux/reducers/courseCards.ts

@@ -2,7 +2,9 @@
  * Stores all course cards that the user uses to select courses to include
  * in generated schedules
  */
-import { CourseCardOptions, CourseCardArray, CustomizationLevel } from '../../types/CourseCardOptions';
+import {
+  CourseCardOptions, CourseCardArray, CustomizationLevel, SectionFilter,
+} from '../../types/CourseCardOptions';
 
 // action type strings
 export const ADD_COURSE_CARD = 'ADD_COURSE_CARD';
@@ -38,9 +40,9 @@ const initialCourseCardArray: CourseCardArray = {
   0: {
     course: '',
     customizationLevel: CustomizationLevel.BASIC,
-    web: 'no_preference',
-    honors: 'exclude',
-    asynchronous: 'no_preference',
+    web: SectionFilter.NO_PREFERENCE,
+    honors: SectionFilter.EXCLUDE,
+    asynchronous: SectionFilter.NO_PREFERENCE,
     sections: [],
     loading: true,
     collapsed: false,

autoscheduler/frontend/src/tests/redux/CourseCards.test.ts

@@ -16,7 +16,9 @@ import Meeting, { MeetingType } from '../../types/Meeting';
 import Section from '../../types/Section';
 import Instructor from '../../types/Instructor';
 import Grades from '../../types/Grades';
-import { CustomizationLevel, CourseCardArray, SerializedCourseCardOptions } from '../../types/CourseCardOptions';
+import {
+  CustomizationLevel, CourseCardArray, SerializedCourseCardOptions, SectionFilter,
+} from '../../types/CourseCardOptions';
 
 // The input from the backend use snake_case, so disable camelcase errors for this file
 /* eslint-disable @typescript-eslint/camelcase */
@@ -323,9 +325,9 @@ describe('Course Cards Redux', () => {
         0: {
           course: '',
           customizationLevel: CustomizationLevel.BASIC,
-          web: 'no_preference',
-          honors: 'exclude',
-          asynchronous: 'no_preference',
+          web: SectionFilter.NO_PREFERENCE,
+          honors: SectionFilter.EXCLUDE,
+          asynchronous: SectionFilter.NO_PREFERENCE,
           sections: [],
         },
       };
@@ -349,19 +351,19 @@ describe('Course Cards Redux', () => {
         0: {
           course: 'MATH 151',
           customizationLevel: CustomizationLevel.BASIC,
-          web: 'no_preference',
-          honors: 'exclude',
-          asynchronous: 'no_preference',
+          web: SectionFilter.NO_PREFERENCE,
+          honors: SectionFilter.EXCLUDE,
+          asynchronous: SectionFilter.NO_PREFERENCE,
         },
         numCardsCreated: 1,
       };
       const courseCards = [
         {
           course: 'MATH 151',
           customizationLevel: CustomizationLevel.BASIC,
-          web: 'no_preference',
-          honors: 'exclude',
-          asynchronous: 'no_preference',
+          web: SectionFilter.NO_PREFERENCE,
+          honors: SectionFilter.EXCLUDE,
+          asynchronous: SectionFilter.NO_PREFERENCE,
         },
       ];
       fetchMock.mockImplementationOnce(testFetch);

autoscheduler/frontend/src/tests/testData.ts

@@ -1,5 +1,7 @@
 /* eslint-disable @typescript-eslint/camelcase */
 
+import { GenerateSchedulesResponse } from '../types/APIResponses';
+
 /**
  * Mocks the fetch call made to the API to retrieve all sections of a given course. Should return
  * 3 sections with 5 meetings total for CSCE classes and 1 section with 1 meeting total for MATH
@@ -247,8 +249,12 @@ export async function mockFetchSchedulerGenerate(): Promise<Response> {
     }],
   };
 
-  return new Response(JSON.stringify([
-    [testSection1, testSection2],
-    [testSection1, testSection3],
-  ]));
+  const response: GenerateSchedulesResponse = {
+    schedules: [
+      [testSection1, testSection2],
+      [testSection1, testSection3],
+    ],
+    message: '',
+  };
+  return new Response(JSON.stringify(response));
 }

autoscheduler/frontend/src/tests/ui/ConfigureCard.test.tsx

@@ -11,8 +11,10 @@ import thunk from 'redux-thunk';
 import ConfigureCard from '../../components/SchedulingPage/ConfigureCard/ConfigureCard';
 import autoSchedulerReducer from '../../redux/reducer';
 import { updateCourseCard } from '../../redux/actions/courseCards';
-import { CustomizationLevel, SectionSelected } from '../../types/CourseCardOptions';
+import { CustomizationLevel, SectionFilter, SectionSelected } from '../../types/CourseCardOptions';
 import testFetch from '../testData';
+import { GenerateSchedulesResponse } from '../../types/APIResponses';
+import { errorGeneratingSchedulesMessage } from '../../redux/actions/schedules';
 
 describe('ConfigureCard component', () => {
   beforeEach(fetchMock.mockReset);
@@ -153,8 +155,8 @@ describe('ConfigureCard component', () => {
 
       // assert
       // no_preference is the default value
-      expect(web).toEqual('no_preference');
-      expect(honors).toEqual('no_preference');
+      expect(web).toEqual(SectionFilter.NO_PREFERENCE);
+      expect(honors).toEqual(SectionFilter.NO_PREFERENCE);
     });
 
     test('Does not send sections when "BASIC" customization level is selected', () => {
@@ -216,7 +218,7 @@ describe('ConfigureCard component', () => {
 
       // act
       fireEvent.click(getByText('Generate Schedules'));
-      const errorMessage = await findByText('No schedules found. Try widening your criteria.');
+      const errorMessage = await findByText(errorGeneratingSchedulesMessage);
 
       // assert
       expect(errorMessage).toBeInTheDocument();
@@ -233,7 +235,11 @@ describe('ConfigureCard component', () => {
         </Provider>,
       );
 
-      fetchMock.mockResponseOnce(JSON.stringify([[], []]));
+      const mockedResponse: GenerateSchedulesResponse = {
+        schedules: [[], []],
+        message: '',
+      };
+      fetchMock.mockResponseOnce(JSON.stringify(mockedResponse));
 
       // act
       fireEvent.click(queryByText('Generate Schedules'));

autoscheduler/frontend/src/types/APIResponses.ts

@@ -0,0 +1,6 @@
+// Module containing type definitions for API responses
+
+export interface GenerateSchedulesResponse {
+  schedules: any[][];
+  message: string;
+}

autoscheduler/frontend/src/types/CourseCardOptions.ts

@@ -6,6 +6,12 @@ export enum CustomizationLevel {
   BASIC, SECTION
 }
 
+export enum SectionFilter {
+  NO_PREFERENCE = 'no_preference',
+  EXCLUDE = 'exclude',
+  ONLY = 'only',
+}
+
 /**
  * Represents a section, its meetings, and whether or not the section
  * is curently selected