feat(user): add user modification API and handler

implement user modification functionality including:
- new endpoint /userMgr/modify
- database update function DBUpdateUser
- request/response structures
- handler with proper authentication and validation
- updated API documentation
- marked as completed in README checklist

userAct.go

@@ -25,6 +25,12 @@ type CreateUserRequest struct {
 }
 
 type ModifyUserRequest struct {
+	UserID int `json:"userID"`
+	Username string `json:"username"`
+	Passwd   string `json:"passwd"`
+}
+
+type ModifyUserTypeRequest struct {
 	UserID int `json:"userID"`
 	Type   string `json:"newType"`
 }
@@ -315,11 +321,10 @@ func CreateUserHandler(w http.ResponseWriter, r *http.Request) {
 	postLog.Info(fmt.Sprintf("[CreateUserHandler] User \"%s\" created successfully with ID: %d", req.Username, userID))
 }
 
-func ModifyUserTypeHandler (w http.ResponseWriter, r *http.Request) {
-	_, err := Auth(w, r, http.MethodPost, "superuser")
+func ModifyUserHandler (w http.ResponseWriter, r *http.Request) {
+	_, err := Auth(w, r, http.MethodPost, "user", "admin", "superuser")
 	if err != nil {
-		SendErrorResponse(w, http.StatusUnauthorized, err.Error())
-		postLog.Warning(fmt.Sprintf("[ModifyUserHandler] Auth failed: %v", err))
+		SendErrorResponse(w, http.StatusUnauthorized, fmt.Sprintf("Auth failed: %v", err))
 		return
 	}
 
@@ -338,23 +343,68 @@ func ModifyUserTypeHandler (w http.ResponseWriter, r *http.Request) {
 		postLog.Warning(fmt.Sprintf("[ModifyUserHandler] Invalid request format: %v", err))
 		return
 	}
+
 	if req.UserID == 0 {
 		SendErrorResponse(w, http.StatusBadRequest, "UserID is required")
 		postLog.Warning("[ModifyUserHandler] ModifyUser failed: UserID is empty")
 		return
 	}
+
+	if req.Username == "" {
+		SendErrorResponse(w, http.StatusBadRequest, "Username is required")
+		postLog.Warning("[ModifyUserHandler] ModifyUser failed: username is empty")
+		return
+	}
+
+	if err := DBUpdateUser(req.UserID, req.Username, req.Passwd); err != nil {
+		SendErrorResponse(w, http.StatusInternalServerError, err.Error())
+		postLog.Error(fmt.Sprintf("[ModifyUserHandler] Failed to update user [%d]: %v", req.UserID, err))
+		return
+	}
+	SendSuccessResponse(w, "User updated successfully", nil)
+	postLog.Info(fmt.Sprintf("[ModifyUserHandler] User [%d]%s updated successfully to: %s", req.UserID, GetUsernameByID(req.UserID), req.Username))
+}
+
+func ModifyUserTypeHandler (w http.ResponseWriter, r *http.Request) {
+	_, err := Auth(w, r, http.MethodPost, "superuser")
+	if err != nil {
+		SendErrorResponse(w, http.StatusUnauthorized, err.Error())
+		postLog.Warning(fmt.Sprintf("[ModifyUserTypeHandler] Auth failed: %v", err))
+		return
+	}
+
+	body, err := io.ReadAll(r.Body)
+	if err != nil {
+		SendErrorResponse(w, http.StatusBadRequest, "Failed to read request body")
+		postLog.Warning(fmt.Sprintf("[ModifyUserTypeHandler] Failed to read request body: %v", err))
+		return
+	}
+	defer r.Body.Close()
+
+	var req ModifyUserTypeRequest
+
+	if err := json.Unmarshal(body, &req); err != nil {
+		SendErrorResponse(w, http.StatusBadRequest, "Invalid request format")
+		postLog.Warning(fmt.Sprintf("[ModifyUserTypeHandler] Invalid request format: %v", err))
+		return
+	}
+	if req.UserID == 0 {
+		SendErrorResponse(w, http.StatusBadRequest, "UserID is required")
+		postLog.Warning("[ModifyUserTypeHandler] ModifyUserType failed: UserID is empty")
+		return
+	}
 	if req.Type != "admin" && req.Type != "visitor" && req.Type != "superuser" {
 		SendErrorResponse(w, http.StatusBadRequest, "Invalid type: must be 'admin' or 'visitor' or 'superuser'")
-		postLog.Warning(fmt.Sprintf("[ModifyUserHandler] ModifyUser failed: invalid type: %s", req.Type))
+		postLog.Warning(fmt.Sprintf("[ModifyUserTypeHandler] ModifyUserType failed: invalid type: %s", req.Type))
 		return
 	}
 	if err := DBUpdateUserType(req.UserID, req.Type); err != nil {
 		SendErrorResponse(w, http.StatusInternalServerError, err.Error())
-		postLog.Error(fmt.Sprintf("[ModifyUserHandler] Failed to update user type [%d]: %v", req.UserID, err))
+		postLog.Error(fmt.Sprintf("[ModifyUserTypeHandler] Failed to update user type [%d]: %v", req.UserID, err))
 		return
 	}
 	SendSuccessResponse(w, "User type updated successfully", nil)
-	postLog.Info(fmt.Sprintf("[ModifyUserHandler] User [%d]%s type updated successfully to: %s", req.UserID, GetUsernameByID(req.UserID), req.Type))
+	postLog.Info(fmt.Sprintf("[ModifyUserTypeHandler] User [%d]%s type updated successfully to: %s", req.UserID, GetUsernameByID(req.UserID), req.Type))
 }
 
 func RemoveUserHandler(w http.ResponseWriter, r *http.Request) {