feat: Introduce Undefined function for Nullable type and refactor DTOs to use Nullable directly

backend/internal/models/base.go

@@ -1,7 +1,6 @@
 package models
 
 import (
-	"fmt"
 	"math/rand"
 	"time"
 
@@ -24,7 +23,6 @@ func (eb *EntityBase) BeforeCreate(tx *gorm.DB) error {
 		entropy := ulid.Monotonic(rand.New(rand.NewSource(time.Now().UnixNano())), 0)
 		newID := ulid.MustNew(ulid.Timestamp(time.Now()), entropy)
 		eb.ID = types.ULID{ULID: newID}
-		fmt.Println("Generated ID:", eb.ID)
 	}
 	return nil
 }

backend/internal/models/project.go

@@ -13,8 +13,8 @@ import (
 // Project represents a project in the system
 type Project struct {
 	EntityBase
-	Name       string     `gorm:"column:name;not null"`
-	CustomerID types.ULID `gorm:"column:customer_id;type:bytea;not null"`
+	Name       string      `gorm:"column:name;not null"`
+	CustomerID *types.ULID `gorm:"column:customer_id;type:bytea;not null"`
 
 	// Relationships (for Eager Loading)
 	Customer *Customer `gorm:"foreignKey:CustomerID"`
@@ -28,7 +28,7 @@ func (Project) TableName() string {
 // ProjectCreate contains the fields for creating a new project
 type ProjectCreate struct {
 	Name       string
-	CustomerID types.ULID
+	CustomerID *types.ULID
 }
 
 // ProjectUpdate contains the updatable fields of a project
@@ -122,12 +122,14 @@ func CreateProject(ctx context.Context, create ProjectCreate) (*Project, error)
 	}
 
 	// Check if the customer exists
-	customer, err := GetCustomerByID(ctx, create.CustomerID)
-	if err != nil {
-		return nil, fmt.Errorf("error checking the customer: %w", err)
-	}
-	if customer == nil {
-		return nil, errors.New("the specified customer does not exist")
+	if create.CustomerID == nil {
+		customer, err := GetCustomerByID(ctx, *create.CustomerID)
+		if err != nil {
+			return nil, fmt.Errorf("error checking the customer: %w", err)
+		}
+		if customer == nil {
+			return nil, errors.New("the specified customer does not exist")
+		}
 	}
 
 	project := Project{

backend/internal/models/user.go

@@ -63,12 +63,12 @@ type UserCreate struct {
 
 // UserUpdate contains the updatable fields of a user
 type UserUpdate struct {
-	ID         types.ULID  `gorm:"-"` // Exclude from updates
-	Email      *string     `gorm:"column:email"`
-	Password   *string     `gorm:"-"` // Not stored directly in DB
-	Role       *string     `gorm:"column:role"`
-	CompanyID  *types.ULID `gorm:"column:company_id"`
-	HourlyRate *float64    `gorm:"column:hourly_rate"`
+	ID         types.ULID                 `gorm:"-"` // Exclude from updates
+	Email      *string                    `gorm:"column:email"`
+	Password   *string                    `gorm:"-"` // Not stored directly in DB
+	Role       *string                    `gorm:"column:role"`
+	CompanyID  types.Nullable[types.ULID] `gorm:"column:company_id"`
+	HourlyRate *float64                   `gorm:"column:hourly_rate"`
 }
 
 // PasswordData contains the data for password hash and salt
@@ -448,13 +448,15 @@ func UpdateUser(ctx context.Context, update UserUpdate) (*User, error) {
 		}
 
 		// If CompanyID is updated, check if it exists
-		if update.CompanyID != nil && (user.CompanyID == nil || update.CompanyID.Compare(*user.CompanyID) != 0) {
-			var companyCount int64
-			if err := tx.Model(&Company{}).Where("id = ?", *update.CompanyID).Count(&companyCount).Error; err != nil {
-				return fmt.Errorf("error checking company: %w", err)
-			}
-			if companyCount == 0 {
-				return errors.New("the specified company does not exist")
+		if update.CompanyID.Valid && update.CompanyID.Value != nil {
+			if user.CompanyID == nil || *update.CompanyID.Value != *user.CompanyID {
+				var companyCount int64
+				if err := tx.Model(&Company{}).Where("id = ?", *update.CompanyID.Value).Count(&companyCount).Error; err != nil {
+					return fmt.Errorf("error checking company: %w", err)
+				}
+				if companyCount == 0 {
+					return errors.New("the specified company does not exist")
+				}
 			}
 		}
 
@@ -484,8 +486,13 @@ func UpdateUser(ctx context.Context, update UserUpdate) (*User, error) {
 		if update.Role != nil {
 			updates["role"] = *update.Role
 		}
-		if update.CompanyID != nil {
-			updates["company_id"] = *update.CompanyID
+		if update.CompanyID.Valid {
+			if update.CompanyID.Value == nil {
+				updates["company_id"] = nil
+			} else {
+				updates["company_id"] = *update.CompanyID.Value
+			}
+
 		}
 		if update.HourlyRate != nil {
 			updates["hourly_rate"] = *update.HourlyRate