Add POST /user/{userId}/goals (#26)

Closes #4

Reviewed-on: #26

backend/main.go

@@ -4,11 +4,12 @@ import (
 	"context"
 	"embed"
 	"errors"
-	"github.com/gin-gonic/gin"
 	"log"
 	"net/http"
 	"os"
 	"strconv"
+
+	"github.com/gin-gonic/gin"
 )
 
 //go:embed migrations/*.sql
@@ -92,6 +93,46 @@ func getUserGoals(c *gin.Context) {
 	c.IndentedJSON(http.StatusOK, goals)
 }
 
+func createUserGoal(c *gin.Context) {
+	userIdStr := c.Param("userId")
+	userId, err := strconv.Atoi(userIdStr)
+	if err != nil {
+		log.Printf("Invalid user ID: %v", err)
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid user ID"})
+		return
+	}
+
+	// Parse request body
+	var goalRequest CreateGoalRequest
+	if err := c.ShouldBindJSON(&goalRequest); err != nil {
+		log.Printf("Error parsing request body: %v", err)
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request body"})
+		return
+	}
+
+	// Validate request
+	if goalRequest.Name == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Goal name cannot be empty"})
+		return
+	}
+
+	// Create goal in database
+	goalId, err := db.CreateGoal(userId, &goalRequest)
+	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"})
+		} else {
+			c.JSON(http.StatusBadRequest, gin.H{"error": "Could not create goal"})
+		}
+		return
+	}
+
+	// Return created goal ID
+	response := CreateGoalResponse{ID: goalId}
+	c.IndentedJSON(http.StatusCreated, response)
+}
+
 /*
 *
 Initialises the database, and then starts the server.
@@ -105,6 +146,7 @@ func start(ctx context.Context, config *ServerConfig) {
 	router.GET("/api/users", getUsers)
 	router.GET("/api/user/:userId", getUser)
 	router.GET("/api/user/:userId/goals", getUserGoals)
+	router.POST("/api/user/:userId/goals", createUserGoal)
 
 	srv := &http.Server{
 		Addr:    ":" + config.Port,