feat: services: crus, migrations

internal/services/default_data.go

@@ -0,0 +1,36 @@
+package services
+
+import (
+	"app/internal/dialogs"
+	"fmt"
+)
+
+func InsertDefaultData() {
+	insertPosts()
+}
+
+func InsertDefaultEntityData[T any](service Service[T], entities []T) {
+	for _, item := range entities {
+		createdItem, err := service.Create(item)
+		if err != nil {
+			dialogs.ErrorDialog("Ошибка при вставке данных по умолчанию", fmt.Sprintf("Произошла ошибка при вставке значения %#v: %s", createdItem, err))
+		}
+	}
+}
+
+func insertPosts() {
+	InsertDefaultEntityData(&PostService{}, []Post{
+		{
+			Id:   1,
+			Text: "Жителям Кузбасса запретили болеть.",
+		},
+		{
+			Id:   2,
+			Text: "⚡️⚡️⚡️Дома будут летать.",
+		},
+		{
+			Id:   3,
+			Text: "В Кузбассе начали строить дома выше, чтобы жители были ближе к богу и солнцу.",
+		},
+	})
+}

internal/services/migrator.go

@@ -0,0 +1,116 @@
+package services
+
+import (
+	"app/internal/database"
+	"app/internal/models"
+	"context"
+	"crypto/sha256"
+	"fmt"
+	"github.com/wailsapp/wails/v3/pkg/application"
+	"io"
+	"log/slog"
+	"os"
+)
+
+type Migrator struct{}
+
+var MigratorService = application.NewService(&Migrator{})
+
+var db = database.GetInstance()
+
+func CalculateFileSha256Checksum(filePath string) (string, error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return "", err
+	}
+	defer file.Close()
+
+	hasher := sha256.New()
+
+	if _, err := io.Copy(hasher, file); err != nil {
+		return "", err
+	}
+
+	return fmt.Sprintf("%x", hasher.Sum(nil)), nil
+}
+
+func dropDatabase() error {
+	_ = database.Shutdown()
+	if _, err := os.Stat(database.Path); err == nil {
+		err := os.Remove(database.Path)
+		if err != nil {
+
+			return err
+		}
+	}
+	return nil
+}
+
+func createDatabase(entities ...any) error {
+	// Close current connections and create new database
+	err := dropDatabase()
+	if err != nil {
+		return err
+	}
+
+	db = database.GetInstance()
+
+	err = db.AutoMigrate(entities...)
+	if err != nil {
+		return err
+	}
+
+	InsertDefaultData()
+	return nil
+}
+
+func Migrate(entities ...any) error {
+	hashBeforeMigration, err := CalculateFileSha256Checksum(database.Path)
+
+	slog.Info("Calculating hash...")
+
+	if err != nil {
+		return err
+	}
+
+	slog.Info("Apply migrations")
+	err = db.AutoMigrate(entities...)
+
+	if err != nil {
+		slog.Info("Error occurred while migrations: %s. Recreate database...", err)
+		if err = createDatabase(entities...); err != nil {
+			slog.Error("Error occurred again: %s. Panic!", err)
+			return err
+		}
+	} else {
+		slog.Info("Calculating hash after migrations...")
+		var hashAfterMigration string
+		hashAfterMigration, err = CalculateFileSha256Checksum(database.Path)
+		if err != nil {
+			slog.Error("Failed to calc hash: %s", err)
+			return err
+		}
+
+		if hashAfterMigration != hashBeforeMigration {
+			slog.Info("Hashes before and after migrations are different. Recreate database...")
+			err = createDatabase(entities...)
+			if err != nil {
+				slog.Error("Failed to create new database: %s", err)
+				return err
+			}
+		}
+	}
+	slog.Info("Migrations proceeded")
+	return nil
+}
+
+func (migrator *Migrator) OnStartup(ctx context.Context, options application.ServiceOptions) error {
+	return Migrate(models.Entities...)
+}
+
+func (migrator *Migrator) OnShutdown() {
+	err := database.Shutdown()
+	if err != nil {
+		panic(err)
+	}
+}

internal/services/post_service_crud.go

@@ -4,7 +4,6 @@ import (
 	"app/internal/dal"
 	"app/internal/models"
 	"errors"
-
 	"gorm.io/gen/field"
 	"gorm.io/gorm"
 )

internal/services/service.go

@@ -0,0 +1,10 @@
+package services
+
+type Service[T any] interface {
+	GetAll() ([]*T, error)
+	GetById(id uint) (*T, error)
+	Create(item T) (T, error)
+	Update(item T) (T, error)
+	Delete(item T) (T, error)
+	Count() (int64, error)
+}

internal/services/services.go

@@ -0,0 +1,7 @@
+package services
+
+import "github.com/wailsapp/wails/v3/pkg/application"
+
+var ExportedServices = []application.Service{
+	application.NewService(&PostService{}),
+}