refac: fixed, better, smarter, correct dependency injection

api/dependecyInjection.go

@@ -1,15 +1,42 @@
 package api
 
 import (
+	"GoCMS/adapters/secondary/gateways"
 	"GoCMS/adapters/secondary/gateways/models"
 	"GoCMS/useCases"
+	"fmt"
+	"os"
+	"path/filepath"
+	"reflect"
+	"runtime"
+
 	"github.com/glebarez/sqlite"
 	"go.uber.org/dig"
 	"gorm.io/gorm"
-	"os"
-	"path/filepath"
 )
 
+type UseCaseDefinition struct {
+	Constructor interface{}
+	FieldName   string
+}
+
+var useCaseDefinitions = []UseCaseDefinition{
+	{useCases.NewCreatePostUseCase, "CreatePostUseCase"},
+	{useCases.NewGetPostUseCase, "GetPostUseCase"},
+	{useCases.NewListPostsUseCase, "ListPostsUseCase"},
+	{useCases.NewUpdatePostUseCase, "UpdatePostUseCase"},
+	{useCases.NewDeletePostUseCase, "DeletePostUseCase"},
+	{useCases.NewGetUserUseCase, "GetUserUseCase"},
+	{useCases.NewCreateUserUseCase, "CreateUserUseCase"},
+	{useCases.NewUpdateUserUseCase, "UpdateUserUseCase"},
+	{useCases.NewDeleteUserUseCase, "DeleteUserUseCase"},
+	{useCases.NewListUsersUseCase, "ListUsersUseCase"},
+	{useCases.NewGetPageUseCase, "GetPageUseCase"},
+	{useCases.NewSendMailUseCase, "SendMailUseCase"},
+	{useCases.NewCreateImageUseCase, "CreateImageUseCase"},
+	{useCases.NewDeleteImageUseCase, "DeleteImageUseCase"},
+}
+
 type UseCases struct {
 	CreatePostUseCase  *useCases.CreatePostUseCase
 	GetPostUseCase     *useCases.GetPostUseCase
@@ -45,29 +72,60 @@ func InitContainer() {
 	digContainer := dig.New()
 
 	database := getDb()
-	_ = database.AutoMigrate(&models.Post{}, &models.User{})
-	_ = digContainer.Provide(func() *gorm.DB { return database })
+	if err := database.AutoMigrate(&models.Post{}, &models.User{}); err != nil {
+		panic("Failed to migrate database: " + err.Error())
+	}
 
-	_ = digContainer.Provide(func(db *gorm.DB) *UseCases {
-		return &UseCases{
-			CreatePostUseCase:  useCases.NewCreatePostUseCase(db),
-			GetPostUseCase:     useCases.NewGetPostUseCase(db),
-			ListPostsUseCase:   useCases.NewListPostsUseCase(db),
-			UpdatePostUseCase:  useCases.NewUpdatePostUseCase(db),
-			DeletePostUseCase:  useCases.NewDeletePostUseCase(db),
-			GetUserUseCase:     useCases.NewGetUserUseCase(db),
-			CreateUserUseCase:  useCases.NewCreateUserUseCase(db),
-			UpdateUserUseCase:  useCases.NewUpdateUserUseCase(db),
-			DeleteUserUseCase:  useCases.NewDeleteUserUseCase(db),
-			ListUsersUseCase:   useCases.NewListUsersUseCase(db),
-			GetPageUseCase:     useCases.NewGetPageUseCase(),
-			SendMailUseCase:    useCases.NewSendMailUseCase(),
-			CreateImageUseCase: useCases.NewCreateImageUseCase(db),
-			DeleteImageUseCase: useCases.NewDeleteImageUseCase(db),
+	if err := digContainer.Provide(func() *gorm.DB { return database }); err != nil {
+		panic("Failed to provide database: " + err.Error())
+	}
+
+	provideRepositories(digContainer)
+
+	for _, def := range useCaseDefinitions {
+		if err := digContainer.Provide(def.Constructor); err != nil {
+			funcName := runtime.FuncForPC(reflect.ValueOf(def.Constructor).Pointer()).Name()
+			panic(fmt.Sprintf("Failed to provide %s: %v", funcName, err))
 		}
-	})
-	err := digContainer.Invoke(func(useCases *UseCases) { Container = useCases })
-	if err != nil {
+	}
+
+	if err := digContainer.Provide(func(values ...any) *UseCases {
+		container := &UseCases{}
+		containerValue := reflect.ValueOf(container).Elem()
+
+		for i, value := range values {
+			fieldName := useCaseDefinitions[i].FieldName
+			field := containerValue.FieldByName(fieldName)
+			if field.IsValid() && field.CanSet() {
+				field.Set(reflect.ValueOf(value))
+			} else {
+				panic(fmt.Sprintf("Failed to set field %s", fieldName))
+			}
+		}
+
+		return container
+	}, dig.As(new(*UseCases))); err != nil {
+		panic("Failed to provide container constructor: " + err.Error())
+	}
+
+	if err := digContainer.Invoke(func(useCases *UseCases) { Container = useCases }); err != nil {
 		panic("Unable to invoke container: " + err.Error())
 	}
 }
+
+func provideRepositories(container *dig.Container) {
+	repositories := []any{
+		gateways.NewPostRepository,
+		gateways.NewUserRepository,
+		gateways.NewImageRepository,
+		gateways.NewMailRepository,
+		gateways.NewPageRepository,
+	}
+
+	for _, repo := range repositories {
+		if err := container.Provide(repo); err != nil {
+			funcName := runtime.FuncForPC(reflect.ValueOf(repo).Pointer()).Name()
+			panic(fmt.Sprintf("Failed to provide repository %s: %v", funcName, err))
+		}
+	}
+}