feat: enhance user management and pagination features #518

- Updated GetAllUsers function to return total user count along with paginated results, improving data handling in user retrieval.
- Modified GetAllUsers API endpoint to accept page size as a parameter, allowing for dynamic pagination.
- Enhanced UsersTable component to support customizable page sizes and improved pagination logic.
- Added error handling for empty username and password in AddUser component.
- Updated LogsTable component to display pagination information in a user-friendly format.

model/user.go

@@ -81,9 +81,38 @@ func GetMaxUserId() int {
 	return user.Id
 }
 
-func GetAllUsers(startIdx int, num int) (users []*User, err error) {
-	err = DB.Unscoped().Order("id desc").Limit(num).Offset(startIdx).Omit("password").Find(&users).Error
-	return users, err
+func GetAllUsers(startIdx int, num int) (users []*User, total int64, err error) {
+	// Start transaction
+	tx := DB.Begin()
+	if tx.Error != nil {
+		return nil, 0, tx.Error
+	}
+	defer func() {
+		if r := recover(); r != nil {
+			tx.Rollback()
+		}
+	}()
+
+	// Get total count within transaction
+	err = tx.Unscoped().Model(&User{}).Count(&total).Error
+	if err != nil {
+		tx.Rollback()
+		return nil, 0, err
+	}
+
+	// Get paginated users within same transaction
+	err = tx.Unscoped().Order("id desc").Limit(num).Offset(startIdx).Omit("password").Find(&users).Error
+	if err != nil {
+		tx.Rollback()
+		return nil, 0, err
+	}
+
+	// Commit transaction
+	if err = tx.Commit().Error; err != nil {
+		return nil, 0, err
+	}
+
+	return users, total, nil
 }
 
 func SearchUsers(keyword string, group string) ([]*User, error) {