Refactor scheduleAdaptiveNextDueDate function for improved readability and fix bug, Add New Tests for it

1 files changed, 18 insertions, 12 deletions

diff --git a/internal/chore/scheduler.go b/internal/chore/scheduler.go
index 5413447..cec120d 100644
--- a/internal/chore/scheduler.go
+++ b/internal/chore/scheduler.go
@@ -3,6 +3,7 @@ package chore
 import (
 	"encoding/json"
 	"fmt"
+	"math"
 	"math/rand"
 	"strings"
 	"time"
@@ -141,11 +142,15 @@ func scheduleNextDueDate(chore *chModel.Chore, completedDate time.Time) (*time.T
 	return &nextDueDate, nil
 
 }
-
 func scheduleAdaptiveNextDueDate(chore *chModel.Chore, completedDate time.Time, history []*chModel.ChoreHistory) (*time.Time, error) {
-	//  will generate due date base on history and the different between the completed date and the due date
-	// the more recent the higher weight
-	if len(history) <= 1 {
+
+	history = append([]*chModel.ChoreHistory{
+		{
+			CompletedAt: &completedDate,
+		},
+	}, history...)
+
+	if len(history) < 2 {
 		if chore.NextDueDate != nil {
 			diff := completedDate.UTC().Sub(chore.NextDueDate.UTC())
 			nextDueDate := completedDate.UTC().Add(diff)
@@ -153,22 +158,23 @@ func scheduleAdaptiveNextDueDate(chore *chModel.Chore, completedDate time.Time,
 		}
 		return nil, nil
 	}
-	var weight float64
+
+	var totalDelay float64
 	var totalWeight float64
-	var nextDueDate time.Time
+	decayFactor := 0.5 // Adjust this value to control the decay rate
+
 	for i := 0; i < len(history)-1; i++ {
 		delay := history[i].CompletedAt.UTC().Sub(history[i+1].CompletedAt.UTC()).Seconds()
-		weight = delay * float64(len(history)-i)
+		weight := math.Pow(decayFactor, float64(i))
+		totalDelay += delay * weight
 		totalWeight += weight
 	}
-	// calculate the average delay
-	averageDelay := totalWeight / float64(len(history)-1)
-	// calculate the difference between the completed date and the due date
-	nextDueDate = completedDate.UTC().Add(time.Duration(averageDelay) * time.Second)
+
+	averageDelay := totalDelay / totalWeight
+	nextDueDate := completedDate.UTC().Add(time.Duration(averageDelay) * time.Second)
 
 	return &nextDueDate, nil
 }
-
 func RemoveAssigneeAndReassign(chore *chModel.Chore, userID int) {
 	for i, assignee := range chore.Assignees {
 		if assignee.UserID == userID {