feat: Add register command for auto-generating model registry

.gitignore

@@ -9,4 +9,5 @@ main.go.txt
 ast_dump.go.txt
 .zed
 gorm-schema
+gorm-schema.exe
 test.log

README.md

@@ -62,6 +62,7 @@ func main() {
     }
 
     rootCmd.AddCommand(
+        commands.RegisterCmd(),
         commands.InitCmd(),
         commands.CreateCmd(),
         commands.GenerateCmd(),
@@ -78,9 +79,17 @@ func main() {
 }
 ```
 
-### 4. Create your model registry
 
-Create `models/models_registry.go` in your project:
+### 4. Generate your model registry
+
+Use the register command to automatically scan your models directory (e.g., models/) and generate a models_registry.go file.
+
+
+```bash
+go run cmd/migration/main.go register [path/to/models]
+```
+
+This command creates a standard Go file that you can review and even edit if needed. It will look something like this:
 
 ```go
 package models
@@ -97,6 +106,7 @@ var ModelTypeRegistry = map[string]interface{}{
 
 ```bash
 go run cmd/migration/main.go init
+go run cmd/migration/main.go register [path/to/models]
 go run cmd/migration/main.go generate init_db
 go run cmd/migration/main.go up
 ```

cmd/gorm-schema/main.go

@@ -7,9 +7,9 @@ import (
 	"github.com/joho/godotenv"
 	"github.com/spf13/cobra"
 
-	"github.com/beesaferoot/gorm-schema/migration/commands"
-	"github.com/beesaferoot/gorm-schema/migration"
 	"github.com/beesaferoot/gorm-schema/example/models"
+	"github.com/beesaferoot/gorm-schema/migration"
+	"github.com/beesaferoot/gorm-schema/migration/commands"
 )
 
 type MyModelRegistry struct{}
@@ -31,6 +31,7 @@ func main() {
 	}
 
 	rootCmd.AddCommand(
+		commands.RegisterCmd(),
 		commands.InitCmd(),
 		commands.CreateCmd(),
 		commands.GenerateCmd(),

example/models/models_registry.go

@@ -1,11 +1,11 @@
 package models
 
 var ModelTypeRegistry = map[string]interface{}{
-	"Apartment": Apartment{},
+	"Apartment":             Apartment{},
 	"ApartmentBookingPrice": ApartmentBookingPrice{},
-	"ApartmentContract": ApartmentContract{},
-	"ApartmentHighlight": ApartmentHighlight{},
-	"Estate": Estate{},
-	"Tenant": Tenant{},
-	"User": User{},
-}	
+	"ApartmentContract":     ApartmentContract{},
+	"ApartmentHighlight":    ApartmentHighlight{},
+	"Estate":                Estate{},
+	"Tenant":                Tenant{},
+	"User":                  User{},
+}

example/user-project/cmd/migration/main.go

@@ -1,13 +1,12 @@
 package main
 
 import (
-
 	"github.com/beesaferoot/gorm-schema/example/user-project/models" // User's models package - CHANGE THIS
 	"github.com/beesaferoot/gorm-schema/migration"
 	"github.com/beesaferoot/gorm-schema/migration/commands"
 
-	"github.com/spf13/cobra"
 	"github.com/joho/godotenv"
+	"github.com/spf13/cobra"
 )
 
 // Simple registry implementation
@@ -29,6 +28,7 @@ func main() {
 	}
 
 	rootCmd.AddCommand(
+		commands.RegisterCmd(),
 		commands.InitCmd(),
 		commands.CreateCmd(),
 		commands.GenerateCmd(),

migration/commands/register.go

@@ -0,0 +1,38 @@
+package commands
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+func RegisterCmd() *cobra.Command {
+	return &cobra.Command{
+		Use:   "register [path]",
+		Short: "Generates model registry file",
+		Long:  `Scans the given path for Go files containing GORM models (structs embedding gorm.Model) and generates a models_registry.go file. If no path is provided, it defaults to the 'models' directory.`,
+		Args:  cobra.MaximumNArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+
+			var pathToValidate string
+			if len(args) > 0 {
+				pathToValidate = args[0]
+			}
+
+			validatedPath, err := validateModelPath(pathToValidate)
+			if err != nil {
+				return fmt.Errorf("failed to validate model path: %w", err)
+			}
+
+			//create model_register.go file:
+			ModelRegistry, err := createModelRegisterFile(validatedPath)
+			if err != nil {
+				return fmt.Errorf("failed to create model registry file: %w", err)
+			}
+
+			fmt.Printf("Successfully generated model registry: %s\n", ModelRegistry)
+			return nil
+
+		},
+	}
+}

migration/commands/utils.go

@@ -6,6 +6,10 @@ import (
 	"path/filepath"
 	"strings"
 
+	"go/ast"
+	"go/parser"
+	"go/token"
+
 	"gorm.io/driver/postgres"
 	"gorm.io/gorm"
 
@@ -67,3 +71,124 @@ func getMigrationLoader() (*file.MigrationLoader, error) {
 	}
 	return file.NewMigrationLoader(getMigrationsDir(), template), nil
 }
+
+func validateModelPath(path string) (string, error) {
+	if path == "" {
+		path = "models"
+	}
+
+	cleanpath := filepath.Clean(path)
+
+	absPath, err := filepath.Abs(cleanpath)
+	if err != nil {
+		return "", fmt.Errorf("invalid model path: %w", err)
+	}
+
+	wd, err := os.Getwd()
+	if err != nil {
+		return "", fmt.Errorf("failed to get working directory: %w", err)
+	}
+
+	if !strings.HasPrefix(absPath, wd) {
+		return "", fmt.Errorf("model path must be within working directory")
+	}
+
+	return absPath, nil
+}
+
+func createModelRegisterFile(dirPath string) (string, error) {
+	filePath := filepath.Join(dirPath, "models_registry.go")
+
+	packageName := filepath.Base(dirPath)
+	allModels, err := getModels(dirPath)
+
+	if err != nil {
+		return "", err
+	}
+
+	content := fmt.Sprintf(`package %s
+
+var ModelTypeRegistry = map[string]interface{}{
+	%s
+}	`, packageName, allModels)
+
+	if err := os.WriteFile(filePath, []byte(content), 0644); err != nil {
+		return "", fmt.Errorf("failed to create model registry file: %w", err)
+	}
+
+	return filePath, nil
+}
+
+func getModels(dirPath string) (string, error) {
+	var allModels []string
+
+	files, err := os.ReadDir(dirPath)
+	if err != nil {
+		return "", fmt.Errorf("failed to read directory: %w", err)
+	}
+
+	for _, file := range files {
+		if file.IsDir() || !strings.HasSuffix(file.Name(), ".go") || file.Name() == "models_registry.go" {
+			continue
+		}
+		filePath := filepath.Join(dirPath, file.Name())
+		modelNames, err := modelPerser(filePath)
+
+		if err != nil {
+			fmt.Printf("Warning: could not parse models from %s: %v\n", file.Name(), err)
+			continue
+		}
+		allModels = append(allModels, modelNames...)
+	}
+
+	var contentBuilder strings.Builder
+	for _, name := range allModels {
+		contentBuilder.WriteString(fmt.Sprintf("\t\"%s\": %s{},\n", name, name))
+	}
+	return contentBuilder.String(), nil
+}
+
+func modelPerser(file string) ([]string, error) {
+	var modelNames []string
+
+	fset := token.NewFileSet()
+
+	node, err := parser.ParseFile(fset, file, nil, 0)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse file: %w", err)
+	}
+
+	ast.Inspect(node, func(n ast.Node) bool {
+		genDecl, ok := n.(*ast.GenDecl)
+
+		if !ok || genDecl.Tok != token.TYPE {
+			return true
+		}
+
+		for _, spec := range genDecl.Specs {
+			typeSpec, ok := spec.(*ast.TypeSpec)
+
+			if !ok {
+				continue
+			}
+
+			structType, ok := typeSpec.Type.(*ast.StructType)
+			if !ok {
+				continue
+			}
+
+			for _, field := range structType.Fields.List {
+				if len(field.Names) == 0 {
+					if selfExpr, ok := field.Type.(*ast.SelectorExpr); ok {
+						if indent, ok := selfExpr.X.(*ast.Ident); ok && indent.Name == "gorm" && selfExpr.Sel.Name == "Model" {
+							modelNames = append(modelNames, typeSpec.Name.Name)
+							break
+						}
+					}
+				}
+			}
+		}
+		return true
+	})
+	return modelNames, nil
+}

tests/migration/commands_test.go

@@ -13,6 +13,13 @@ import (
 	"github.com/beesaferoot/gorm-schema/migration/commands"
 )
 
+func TestRegisterCmd(t *testing.T) {
+	cmd := commands.RegisterCmd()
+	assert.Equal(t, "register [path]", cmd.Use)
+	assert.Equal(t, "Generates model registry file", cmd.Short)
+	assert.Equal(t, `Scans the given path for Go files containing GORM models (structs embedding gorm.Model) and generates a models_registry.go file. If no path is provided, it defaults to the 'models' directory.`, cmd.Long)
+}
+
 func TestInitCmd(t *testing.T) {
 	cmd := commands.InitCmd()
 	assert.Equal(t, "init", cmd.Use)