first commit, i i have no idea what i have done

server/internal/handlers/users.go

@@ -0,0 +1,98 @@
+package handlers
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+	"gorm.io/gorm"
+
+	"smoop-api/internal/crypto"
+	"smoop-api/internal/dto"
+	"smoop-api/internal/models"
+)
+
+type UsersHandler struct {
+	db *gorm.DB
+}
+
+func NewUsersHandler(db *gorm.DB) *UsersHandler { return &UsersHandler{db: db} }
+
+func (h *UsersHandler) Profile(c *gin.Context) {
+	claims := MustClaims(c)
+	uid := ClaimUserID(claims)
+
+	var u models.User
+	if err := h.db.First(&u, uid).Error; err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "user not found"})
+		return
+	}
+	c.JSON(http.StatusOK, dto.MapUser(u))
+}
+
+func (h *UsersHandler) SetRole(c *gin.Context) {
+	idStr := c.Param("id")
+	uid, _ := strconv.Atoi(idStr)
+
+	var u models.User
+	if err := h.db.First(&u, uid).Error; err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "user not found"})
+		return
+	}
+	var req dto.UserRoleDto
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+	u.Role = req.Role
+	if err := h.db.Save(&u).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "save failed"})
+		return
+	}
+	c.JSON(http.StatusCreated, dto.MapUser(u))
+}
+
+func (h *UsersHandler) List(c *gin.Context) {
+	var users []models.User
+	if err := h.db.Order("id asc").Find(&users).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "query failed"})
+		return
+	}
+	out := make([]dto.UserDto, 0, len(users))
+	for _, u := range users {
+		out = append(out, dto.MapUser(u))
+	}
+	c.JSON(http.StatusOK, out)
+}
+
+// POST /users/create (admin) — create user with given role
+func (h *UsersHandler) Create(c *gin.Context) {
+	var req dto.CreateUserDto
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+	role := models.Role(strings.ToLower(req.Role))
+	if role != models.RoleAdmin && role != models.RoleUser {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid role"})
+		return
+	}
+	hash, err := crypto.Hash(req.Password, crypto.DefaultArgon2)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "hash error"})
+		return
+	}
+	u := models.User{Username: req.Username, Password: hash, Role: role}
+	if err := h.db.Create(&u).Error; err != nil {
+		// hint duplicate username
+		e := strings.ToLower(err.Error())
+		if strings.Contains(e, "duplicate") || strings.Contains(e, "unique") || strings.Contains(e, "exists") {
+			c.JSON(http.StatusBadRequest, gin.H{"error": "username already exists"})
+			return
+		}
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "create failed"})
+		return
+	}
+	c.JSON(http.StatusCreated, dto.MapUser(u))
+}