Add delete goal endpoint (#27)

Closes #18

Reviewed-on: #27

backend/api_test.go

@@ -1,11 +1,16 @@
 package main
 
 import (
+	"strconv"
 	"testing"
 
 	"github.com/gavv/httpexpect/v2"
 )
 
+const (
+	TestGoalName = "Test Goal"
+)
+
 func startServer(t *testing.T) *httpexpect.Expect {
 	config := ServerConfig{
 		Datasource: ":memory:",
@@ -63,7 +68,7 @@ func TestCreateUserGoal(t *testing.T) {
 
 	// Create a new goal
 	requestBody := map[string]interface{}{
-		"name":   "Test Goal",
+		"name":   TestGoalName,
 		"target": 5000,
 		"weight": 10,
 	}
@@ -88,7 +93,7 @@ func TestCreateUserGoal(t *testing.T) {
 
 	goal := goals.Value(0).Object()
 	goal.Value("id").IsEqual(goalId)
-	goal.Value("name").IsEqual("Test Goal")
+	goal.Value("name").IsEqual(TestGoalName)
 	goal.Value("target").IsEqual(5000)
 	goal.Value("weight").IsEqual(10)
 	goal.Value("progress").IsEqual(0)
@@ -98,7 +103,7 @@ func TestCreateUserGoalNoUser(t *testing.T) {
 	e := startServer(t)
 
 	requestBody := map[string]interface{}{
-		"name":   "Test Goal",
+		"name":   TestGoalName,
 		"target": 5000,
 		"weight": 10,
 	}
@@ -139,7 +144,7 @@ func TestCreateUserGoalBadId(t *testing.T) {
 	e := startServer(t)
 
 	requestBody := map[string]interface{}{
-		"name":   "Test Goal",
+		"name":   TestGoalName,
 		"target": 5000,
 		"weight": 10,
 	}
@@ -149,3 +154,54 @@ func TestCreateUserGoalBadId(t *testing.T) {
 		Expect().
 		Status(400)
 }
+
+func TestDeleteUserGoal(t *testing.T) {
+	e := startServer(t)
+
+	// Create a new goal to delete
+	createRequest := map[string]interface{}{
+		"name":   TestGoalName,
+		"target": 1000,
+		"weight": 5,
+	}
+	response := e.POST("/user/1/goals").
+		WithJSON(createRequest).
+		Expect().
+		Status(201).
+		JSON().Object()
+
+	goalId := response.Value("id").Number().Raw()
+
+	// Delete the goal
+	e.DELETE("/user/1/goal/" + strconv.Itoa(int(goalId))).
+		Expect().
+		Status(200).
+		JSON().Object().Value("message").IsEqual("Goal deleted successfully")
+
+	// Verify the goal no longer exists
+	goals := e.GET("/user/1/goals").
+		Expect().
+		Status(200).
+		JSON().Array()
+	goals.Length().IsEqual(0)
+}
+
+func TestDeleteUserGoalNotFound(t *testing.T) {
+	e := startServer(t)
+
+	// Attempt to delete a non-existent goal
+	e.DELETE("/user/1/goal/999").
+		Expect().
+		Status(404).
+		JSON().Object().Value("error").IsEqual("Goal not found")
+}
+
+func TestDeleteUserGoalInvalidId(t *testing.T) {
+	e := startServer(t)
+
+	// Attempt to delete a goal with an invalid ID
+	e.DELETE("/user/1/goal/invalid-id").
+		Expect().
+		Status(400).
+		JSON().Object().Value("error").IsEqual("Invalid goal ID")
+}

backend/db.go

@@ -128,3 +128,25 @@ func (db *Db) CreateGoal(userId int, goal *CreateGoalRequest) (int, error) {
 
 	return lastId, nil
 }
+
+func (db *Db) DeleteGoal(userId int, goalId int) error {
+	// Check if the goal exists for the user
+	count := 0
+	err := db.db.Query("select count(*) from goals where id = ? and user_id = ?").
+		Bind(goalId, userId).ScanSingle(&count)
+	if err != nil {
+		return err
+	}
+	if count == 0 {
+		return errors.New("goal not found")
+	}
+
+	// Delete the goal
+	err = db.db.Query("delete from goals where id = ? and user_id = ?").
+		Bind(goalId, userId).Exec()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

backend/main.go

@@ -16,6 +16,13 @@ import (
 var migrations embed.FS
 var db *Db
 
+const (
+	ErrInternalServerError = "Internal Server Error"
+	ErrInvalidUserID       = "Invalid user ID"
+	ErrUserNotFound        = "User not found"
+	ErrCheckingUserExist   = "Error checking user existence: %v"
+)
+
 // ServerConfig holds configuration for the server.
 type ServerConfig struct {
 	// The datasource to the SQLite database.
@@ -34,7 +41,7 @@ func getUsers(c *gin.Context) {
 	users, err := db.GetUsers()
 	if err != nil {
 		log.Printf("Error getting users: %v", err)
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "Internal Server Error"})
+		c.JSON(http.StatusInternalServerError, gin.H{"error": ErrInternalServerError})
 		return
 	}
 	c.IndentedJSON(http.StatusOK, users)
@@ -44,19 +51,19 @@ func getUser(c *gin.Context) {
 	userIdStr := c.Param("userId")
 	userId, err := strconv.Atoi(userIdStr)
 	if err != nil {
-		log.Printf("Invalid user ID: %v", err)
+		log.Printf(ErrInvalidUserID+": %v", err)
-		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid user ID"})
+		c.JSON(http.StatusBadRequest, gin.H{"error": ErrInvalidUserID})
 		return
 	}
 
 	user, err := db.GetUser(userId)
 	if err != nil {
 		log.Printf("Error getting user: %v", err)
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "Internal Server Error"})
+		c.JSON(http.StatusInternalServerError, gin.H{"error": ErrInternalServerError})
 		return
 	}
 	if user == nil {
-		c.JSON(http.StatusNotFound, gin.H{"error": "User not found"})
+		c.JSON(http.StatusNotFound, gin.H{"error": ErrUserNotFound})
 		return
 	}
 
@@ -67,27 +74,27 @@ func getUserGoals(c *gin.Context) {
 	userIdStr := c.Param("userId")
 	userId, err := strconv.Atoi(userIdStr)
 	if err != nil {
-		log.Printf("Invalid user ID: %v", err)
+		log.Printf(ErrInvalidUserID+": %v", err)
-		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid user ID"})
+		c.JSON(http.StatusBadRequest, gin.H{"error": ErrInvalidUserID})
 		return
 	}
 
 	exists, err := db.UserExists(userId)
 	if err != nil {
-		log.Printf("Error checking user existence: %v", err)
+		log.Printf(ErrCheckingUserExist, err)
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "Internal Server Error"})
+		c.JSON(http.StatusInternalServerError, gin.H{"error": ErrInternalServerError})
 		return
 	}
 	if !exists {
-		log.Printf("Error checking user existence: %v", err)
+		log.Printf(ErrCheckingUserExist, err)
-		c.JSON(http.StatusNotFound, gin.H{"error": "User not found"})
+		c.JSON(http.StatusNotFound, gin.H{"error": ErrUserNotFound})
 		return
 	}
 
 	goals, err := db.GetUserGoals(userId)
 	if err != nil {
 		log.Printf("Error getting user goals: %v", err)
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "Internal Server Error"})
+		c.JSON(http.StatusInternalServerError, gin.H{"error": ErrInternalServerError})
 		return
 	}
 	c.IndentedJSON(http.StatusOK, goals)
@@ -97,8 +104,8 @@ func createUserGoal(c *gin.Context) {
 	userIdStr := c.Param("userId")
 	userId, err := strconv.Atoi(userIdStr)
 	if err != nil {
-		log.Printf("Invalid user ID: %v", err)
+		log.Printf(ErrInvalidUserID+": %v", err)
-		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid user ID"})
+		c.JSON(http.StatusBadRequest, gin.H{"error": ErrInvalidUserID})
 		return
 	}
 
@@ -121,7 +128,7 @@ func createUserGoal(c *gin.Context) {
 	if err != nil {
 		log.Printf("Error creating goal: %v", err)
 		if err.Error() == "user does not exist" {
-			c.JSON(http.StatusNotFound, gin.H{"error": "User not found"})
+			c.JSON(http.StatusNotFound, gin.H{"error": ErrUserNotFound})
 		} else {
 			c.JSON(http.StatusBadRequest, gin.H{"error": "Could not create goal"})
 		}
@@ -133,6 +140,49 @@ func createUserGoal(c *gin.Context) {
 	c.IndentedJSON(http.StatusCreated, response)
 }
 
+func deleteUserGoal(c *gin.Context) {
+	userIdStr := c.Param("userId")
+	goalIdStr := c.Param("goalId")
+
+	userId, err := strconv.Atoi(userIdStr)
+	if err != nil {
+		log.Printf(ErrInvalidUserID+": %v", err)
+		c.JSON(http.StatusBadRequest, gin.H{"error": ErrInvalidUserID})
+		return
+	}
+
+	goalId, err := strconv.Atoi(goalIdStr)
+	if err != nil {
+		log.Printf("Invalid goal ID: %v", err)
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid goal ID"})
+		return
+	}
+
+	exists, err := db.UserExists(userId)
+	if err != nil {
+		log.Printf(ErrCheckingUserExist, err)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": ErrInternalServerError})
+		return
+	}
+	if !exists {
+		c.JSON(http.StatusNotFound, gin.H{"error": ErrUserNotFound})
+		return
+	}
+
+	err = db.DeleteGoal(userId, goalId)
+	if err != nil {
+		if err.Error() == "goal not found" {
+			c.JSON(http.StatusNotFound, gin.H{"error": "Goal not found"})
+		} else {
+			log.Printf("Error deleting goal: %v", err)
+			c.JSON(http.StatusInternalServerError, gin.H{"error": ErrInternalServerError})
+		}
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"message": "Goal deleted successfully"})
+}
+
 /*
 *
 Initialises the database, and then starts the server.
@@ -147,6 +197,7 @@ func start(ctx context.Context, config *ServerConfig) {
 	router.GET("/api/user/:userId", getUser)
 	router.GET("/api/user/:userId/goals", getUserGoals)
 	router.POST("/api/user/:userId/goals", createUserGoal)
+	router.DELETE("/api/user/:userId/goal/:goalId", deleteUserGoal)
 
 	srv := &http.Server{
 		Addr:    ":" + config.Port,