feat: skeleton

internal/writer.go

@@ -0,0 +1,151 @@
+package internal
+
+import (
+	"errors"
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/printer"
+	"go/token"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"golang.org/x/tools/go/ast/astutil"
+)
+
+func ImplementServiceStruct(entityName string, file *ast.File, reimplement bool) {
+	serviceName := entityName + "Service"
+	isServiceStructDeclarated := false
+	var insertPos int
+
+	for i, decl := range file.Decls {
+		genDecl, ok := decl.(*ast.GenDecl)
+		if !ok {
+			continue
+		}
+		if genDecl.Tok == token.IMPORT {
+			insertPos = i + 1
+			continue
+		}
+		if genDecl.Tok != token.TYPE {
+			continue
+		}
+
+		for _, spec := range genDecl.Specs {
+			typeSpec, ok := spec.(*ast.TypeSpec)
+			if !ok {
+				continue
+			}
+			if _, ok := typeSpec.Type.(*ast.StructType); ok {
+				if typeSpec.Name != nil && typeSpec.Name.Name == serviceName {
+					isServiceStructDeclarated = true
+				}
+			}
+
+		}
+	}
+
+	if isServiceStructDeclarated && !reimplement {
+		return
+	}
+
+	serviceStruct := &ast.GenDecl{
+		Tok: token.TYPE,
+		Specs: []ast.Spec{
+			&ast.TypeSpec{
+				Name: ast.NewIdent(serviceName),
+				Type: &ast.StructType{
+					Fields: &ast.FieldList{},
+				},
+			},
+		},
+	}
+
+	file.Decls = append(file.Decls[:insertPos], append([]ast.Decl{serviceStruct}, file.Decls[insertPos:]...)...)
+}
+
+func importExists(fset *token.FileSet, file *ast.File, importPath string) bool {
+	for _, group := range astutil.Imports(fset, file) {
+		for _, imp := range group {
+			if imp.Name == nil && imp.Path.Value == `"`+importPath+`"` {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+func MaintainImports(fileSet *token.FileSet, file *ast.File) error {
+	for _, importPath := range ServiceImports {
+		if !importExists(fileSet, file, importPath) {
+			if !astutil.AddImport(fileSet, file, importPath) {
+				err := fmt.Sprintf("%s: Failed to add import: %s", fileSet.Position(file.Pos()), importPath)
+				return errors.New(err)
+			}
+		}
+	}
+	return nil
+}
+
+func ImplementMethods(structName string, methodName string, template string, node ast.Node) {
+
+}
+
+func CreateServiceFileIfNotExists(filePath string) error {
+	if _, err := os.Stat(filePath); err != nil {
+		// file wasn't created
+		f, err := os.Create(filePath)
+		if err != nil {
+			log.Fatalf("Failed to create file: %s", filePath)
+			return err
+		}
+
+		_, err = f.Write([]byte("package services\n"))
+		if err != nil {
+			log.Fatalf("Failed to write file: %s", filePath)
+			return err
+		}
+
+		defer f.Close()
+	}
+	return nil
+}
+
+func ImplementService(mainPkgPath string, modelName string, reimplement bool) error {
+	serviceRelativePath := fmt.Sprintf("services/%s.go", strings.ToLower(modelName))
+	filePath := filepath.Join(mainPkgPath, serviceRelativePath)
+
+	err := CreateServiceFileIfNotExists(filePath)
+	if err != nil {
+		return err
+	}
+
+	fset := token.NewFileSet()
+	serviceFile, err := parser.ParseFile(fset, filePath, nil, parser.ParseComments)
+	if err != nil {
+		log.Fatalf("Parsing error: %s: %v", mainPkgPath, err)
+		return err
+	}
+
+	err = MaintainImports(fset, serviceFile)
+	if err != nil {
+		return err
+	}
+	ImplementServiceStruct(modelName, serviceFile, reimplement)
+
+	file, err := os.Create(filePath)
+	if err != nil {
+		log.Fatalf("Error occured to open `%s` service file: %v", modelName, err)
+		return err
+	}
+
+	err = printer.Fprint(file, fset, serviceFile)
+	if err != nil {
+		log.Fatalf("Error occurred to writing changes in `%s` service file: %v", modelName, err)
+		return err
+	}
+
+	return nil
+}