Add history entry and fix bug when completing task (#54)

The reward wasn't properly being distributed to all users

Reviewed-on: #54

backend/api_test.go

@@ -567,7 +567,8 @@ func TestCompleteTask(t *testing.T) {
 
 	// Verify the task is marked as completed
 	e.GET("/task/" + strconv.Itoa(taskId)).Expect().Status(404)
-	// Verify the allowances are updated
+
+	// Verify the allowances are updated for user 1
 	allowances := e.GET("/user/1/allowance").Expect().Status(200).JSON().Array()
 	allowances.Length().IsEqual(3)
 	allowances.Value(0).Object().Value("id").Number().IsEqual(0)
@@ -576,6 +577,21 @@ func TestCompleteTask(t *testing.T) {
 	allowances.Value(1).Object().Value("progress").Number().IsEqual(50)
 	allowances.Value(2).Object().Value("id").Number().IsEqual(2)
 	allowances.Value(2).Object().Value("progress").Number().IsEqual(25)
+
+	// And also for user 2
+	allowances = e.GET("/user/2/allowance").Expect().Status(200).JSON().Array()
+	allowances.Length().IsEqual(1)
+	allowances.Value(0).Object().Value("id").Number().IsEqual(0)
+	allowances.Value(0).Object().Value("progress").Number().IsEqual(101)
+
+	for userId := 1; userId <= 2; userId++ {
+		userIdStr := strconv.Itoa(userId)
+		// Ensure the history got updated
+		history := e.GET("/user/" + userIdStr + "/history").Expect().Status(200).JSON().Array()
+		history.Length().IsEqual(1)
+		history.Value(0).Object().Value("allowance").Number().IsEqual(101)
+		history.Value(0).Object().Value("timestamp").String().AsDateTime().InRange(getDelta(time.Now(), 2.0))
+	}
 }
 
 func getDelta(base time.Time, delta float64) (time.Time, time.Time) {

backend/db.go

@@ -341,10 +341,22 @@ func (db *Db) CompleteTask(taskId int) error {
 			return err
 		}
 
+		// Add the history entry
+		err = tx.Query("insert into history (user_id, timestamp, amount) values (?, ?, ?)").
+			Bind(userId, time.Now().Unix(), reward).
+			Exec()
+		if err != nil {
+			return err
+		}
+
+		// Calculate the sums of all weights
 		var sumOfWeights float64
 		err = tx.Query("select sum(weight) from allowances where user_id = ? and weight > 0").Bind(userId).ScanSingle(&sumOfWeights)
 		sumOfWeights += userWeight
 
+		remainingReward := reward
+
+		// Distribute the reward to the allowances
 		for allowanceRow := range tx.Query("select id, weight from allowances where user_id = ? and weight > 0").Bind(userId).Range(&err) {
 			var allowanceId int
 			var allowanceWeight float64
@@ -354,19 +366,19 @@ func (db *Db) CompleteTask(taskId int) error {
 			}
 
 			// Calculate the amount to add to the allowance
-			amount := int((allowanceWeight / sumOfWeights) * float64(reward))
+			amount := int((allowanceWeight / sumOfWeights) * float64(remainingReward))
 			sumOfWeights -= allowanceWeight
 			err = tx.Query("update allowances set balance = balance + ? where id = ? and user_id = ?").
 				Bind(amount, allowanceId, userId).Exec()
 			if err != nil {
 				return err
 			}
-			reward -= amount
+			remainingReward -= amount
 		}
 
 		// Add the remaining reward to the user
 		err = tx.Query("update users set balance = balance + ? where id = ?").
-			Bind(reward, userId).Exec()
+			Bind(remainingReward, userId).Exec()
 		if err != nil {
 			return err
 		}