Change representation of lesson configs from classNo to lesson indices

website/api/optimiser/_constants/constants.go

@@ -46,3 +46,6 @@ var GAP_PENALTY_THRESHOLD = 120 // 2 hours in minutes
 var GAP_PENALTY_RATE = 100.0
 var LUNCH_REQUIRED_TIME = 60 // 1 hour in minutes
 var CONSECUTIVE_HOURS_PENALTY_RATE = 100
+
+// This is used by [nusmods_link.SerializeLessonIndices] to serialize the result of optimiser into a timetable share link to return to the client
+var MODULE_CODE_SEPARATOR = ";"

website/api/optimiser/_models/models.go

@@ -6,6 +6,10 @@ import (
 	"strings"
 )
 
+type LessonType = string
+type ClassNo = string
+type LessonIndex = int
+
 type OptimiserRequest struct {
 	Modules             []string `json:"modules"`             // Format: ["CS1010S", "CS2030S"]
 	Recordings          []string `json:"recordings"`          // Format: ["CS1010S Lecture", "CS2030S Laboratory"]
@@ -27,14 +31,14 @@ type TimetableState struct {
 }
 
 type ModuleSlot struct {
-	ClassNo     string      `json:"classNo"`
+	ClassNo     ClassNo     `json:"classNo"`
 	Day         string      `json:"day"`
 	EndTime     string      `json:"endTime"`
 	LessonType  string      `json:"lessonType"`
 	StartTime   string      `json:"startTime"`
 	Venue       string      `json:"venue"`
 	Coordinates Coordinates `json:"coordinates"`
-	Weeks       any       `json:"weeks"`
+	Weeks       any         `json:"weeks"`
 
 	// Parsed fields
 	StartMin    int    // Minutes from 00:00 (e.g., 540 for 09:00)
@@ -43,6 +47,7 @@ type ModuleSlot struct {
 	LessonKey   string // "MODULE|LessonType"
 	WeeksSet    map[int]bool
 	WeeksString string
+	LessonIndex LessonIndex
 }
 
 // ParseModuleSlotFields parses and populates the parsed fields in ModuleSlot for faster computation

website/api/optimiser/_modules/modules.go

@@ -44,6 +44,9 @@ func GetAllModuleSlots(optimiserRequest models.OptimiserRequest) (map[string]map
 		var moduleTimetable []models.ModuleSlot
 		for _, semester := range moduleData.SemesterData {
 			if semester.Semester == optimiserRequest.AcadSem {
+				for lessonIndex := range semester.Timetable {
+					semester.Timetable[lessonIndex].LessonIndex = lessonIndex
+				}
 				moduleTimetable = semester.Timetable
 				break
 			}

website/api/optimiser/_solver/nusmods_link.go

@@ -9,8 +9,8 @@ import (
 )
 
 // Parses the assignments into a map of module codes to lesson types to class numbers
-func CreateConfig(assignments map[string]string) map[string]map[string]string {
-	config := make(map[string]map[string]string)
+func CreateConfig(assignments map[string]string, lessonToSlots map[string][][]models.ModuleSlot) map[string]map[string][]models.LessonIndex {
+	config := make(map[string]map[string][]models.LessonIndex)
 
 	for lessonKey, classNo := range assignments {
 		// Parse lesson key: "MODULE|LESSONTYPE"
@@ -23,39 +23,55 @@ func CreateConfig(assignments map[string]string) map[string]map[string]string {
 
 		// Initialize module config if not exists
 		if config[moduleCode] == nil {
-			config[moduleCode] = make(map[string]string)
+			config[moduleCode] = make(map[string][]models.LessonIndex)
 		}
 
 		// Add lesson type and class number to config
-		config[moduleCode][lessonType] = classNo
+		for _, lessonsWithClassNo := range lessonToSlots[lessonKey] {
+			if lessonsWithClassNo[0].ClassNo != classNo {
+				continue
+			}
+
+			for _, lesson := range lessonsWithClassNo {
+				config[moduleCode][lessonType] = append(config[moduleCode][lessonType], lesson.LessonIndex)
+			}
+			break
+		}
 	}
 
 	return config
 }
 
+// Serializes an array of lesson indices into the format used in timetable share links
+//
+// Returns "1, 2, 3" with input [1, 2, 3]
+func SerializeLessonIndices(lessonIndex []models.LessonIndex) string {
+	return strings.Trim(strings.Join(strings.Fields(fmt.Sprint(lessonIndex)), ","), "[]")
+}
+
 // Constructs the URL
-func SerializeConfig(config map[string]map[string]string) string {
+func SerializeConfig(config map[string]map[string][]models.LessonIndex) string {
 	var moduleParams []string
 
 	for moduleCode, lessons := range config {
 		var lessonParams []string
-		for lessonType, classNo := range lessons {
+		for lessonType, lessonIndex := range lessons {
 			// Get abbreviation for lesson type
 			abbrev := constants.LessonTypeAbbrev[strings.ToUpper(lessonType)]
 
-			lessonParams = append(lessonParams, fmt.Sprintf("%s:%s", abbrev, classNo))
+			lessonParams = append(lessonParams, fmt.Sprintf("%s:%s", abbrev, "("+SerializeLessonIndices(lessonIndex)+")"))
 		}
 		if len(lessonParams) > 0 {
-			moduleParams = append(moduleParams, fmt.Sprintf("%s=%s", moduleCode, strings.Join(lessonParams, ",")))
+			moduleParams = append(moduleParams, fmt.Sprintf("%s=%s", moduleCode, strings.Join(lessonParams, constants.MODULE_CODE_SEPARATOR)))
 		}
 	}
 
 	return strings.Join(moduleParams, "&")
 }
 
 // GenerateNUSModsShareableLink creates a shareable NUSMods link from the assignments
-func GenerateNUSModsShareableLink(assignments map[string]string, req models.OptimiserRequest) string {
-	config := CreateConfig(assignments)
+func GenerateNUSModsShareableLink(assignments map[string]string, lessonToSlots map[string][][]models.ModuleSlot, req models.OptimiserRequest) string {
+	config := CreateConfig(assignments, lessonToSlots)
 	serializedConfig := SerializeConfig(config)
 
 	semesterPath := ""

website/api/optimiser/_solver/solver.go

@@ -383,7 +383,7 @@ func Solve(w http.ResponseWriter, req models.OptimiserRequest) {
 	})
 
 	best := BeamSearch(lessons, lessonToSlots, 2500, 100, recordings, req)
-	shareableLink := GenerateNUSModsShareableLink(best.Assignments, req)
+	shareableLink := GenerateNUSModsShareableLink(best.Assignments, lessonToSlots, req)
 	response := SolveResponse{
 		TimetableState: best,
 		ShareableLink:  shareableLink,

website/src/__mocks__/lessons-array.json

@@ -8,7 +8,8 @@
   "venue": "LT26",
   "moduleCode": "CS1010S",
   "title": "Programming Methodology",
-  "colorIndex": 0
+  "colorIndex": 0,
+  "lessonIndex": 0
 }, {
   "classNo": "1",
   "lessonType": "Recitation",
@@ -19,7 +20,8 @@
   "venue": "VCRm",
   "moduleCode": "CS1010S",
   "title": "Programming Methodology",
-  "colorIndex": 0
+  "colorIndex": 0,
+  "lessonIndex": 1
 }, {
   "classNo": "1",
   "lessonType": "Recitation",
@@ -30,7 +32,8 @@
   "venue": "VCRm",
   "moduleCode": "CS1010S",
   "title": "Programming Methodology",
-  "colorIndex": 0
+  "colorIndex": 0,
+  "lessonIndex": 2
 }, {
   "classNo": "2",
   "lessonType": "Tutorial",
@@ -41,7 +44,8 @@
   "venue": "COM1-0203",
   "moduleCode": "CS1010S",
   "title": "Programming Methodology",
-  "colorIndex": 0
+  "colorIndex": 0,
+  "lessonIndex": 3
 }, {
   "classNo": "2",
   "lessonType": "Tutorial",
@@ -52,7 +56,8 @@
   "venue": "COM1-0216",
   "moduleCode": "CS1010S",
   "title": "Programming Methodology",
-  "colorIndex": 0
+  "colorIndex": 0,
+  "lessonIndex": 4
 }, {
   "classNo": "1",
   "lessonType": "Lecture",
@@ -63,5 +68,6 @@
   "venue": "VCRm",
   "moduleCode": "CS3216",
   "title": "Application Development on Evolving Platforms",
-  "colorIndex": 1
+  "colorIndex": 1,
+  "lessonIndex": 5
 }]