From c84503fe283ed02368db0dbc236f2f0a866ff422 Mon Sep 17 00:00:00 2001
From: Mukesh Kumar Chaudhary <mukezhz@gmail.com>
Date: Sun, 14 Apr 2024 10:18:57 +0545
Subject: [PATCH 1/2] feat: add feature to generate the fx config by reading
 the comment

---
 cmd/generate_fx_module.go   |  23 +++++++
 cmd/run_project.go          |   1 +
 pkg/utility/fx_generator.go | 134 ++++++++++++++++++++++++++++++++++++
 3 files changed, 158 insertions(+)
 create mode 100644 cmd/generate_fx_module.go
 create mode 100644 pkg/utility/fx_generator.go

diff --git a/cmd/generate_fx_module.go b/cmd/generate_fx_module.go
new file mode 100644
index 0000000..ec119c3
--- /dev/null
+++ b/cmd/generate_fx_module.go
@@ -0,0 +1,23 @@
+package cmd
+
+import (
+	"github.com/mukezhz/geng/pkg/utility"
+	"github.com/spf13/cobra"
+)
+
+var generateFxCmd = &cobra.Command{
+	Use:   "fx",
+	Short: "Generate the fx configuration file for the project",
+	Long: `
+Generate a module by reading comments from the source code.
+Example: 
+  geng fx
+
+	`,
+	Args: cobra.MaximumNArgs(2),
+	Run:  generateFx,
+}
+
+func generateFx(_ *cobra.Command, _ []string) {
+	utility.GenerateFxModule()
+}
diff --git a/cmd/run_project.go b/cmd/run_project.go
index e5a88cf..524bbd2 100644
--- a/cmd/run_project.go
+++ b/cmd/run_project.go
@@ -28,4 +28,5 @@ func init() {
 	rootCmd.AddCommand(runProjectCmd)
 	rootCmd.AddCommand(addInfrastructureCmd)
 	rootCmd.AddCommand(addServiceCmd)
+	rootCmd.AddCommand(generateFxCmd)
 }
diff --git a/pkg/utility/fx_generator.go b/pkg/utility/fx_generator.go
new file mode 100644
index 0000000..87c20e5
--- /dev/null
+++ b/pkg/utility/fx_generator.go
@@ -0,0 +1,134 @@
+package utility
+
+import (
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"os"
+	"path/filepath"
+	"strings"
+	"text/template"
+
+	"golang.org/x/text/cases"
+	"golang.org/x/text/language"
+)
+
+func GenerateFxModule() {
+	fset := token.NewFileSet()
+	root := "./"
+	moduleMap := make(map[string][]string)
+
+	err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			return nil
+		}
+		if !strings.HasSuffix(info.Name(), ".go") {
+			return nil
+		}
+
+		file, err := parser.ParseFile(fset, path, nil, parser.ParseComments)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Failed to parse file %s: %v\n", path, err)
+			return err
+		}
+
+		processedFile := processFile(file)
+		if len(processedFile) != 0 {
+			moduleMap[filepath.Dir(path)] = append(moduleMap[filepath.Dir(path)], processedFile...)
+		}
+
+		return nil
+	})
+	generateFile(moduleMap)
+
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error walking through the directory: %v\n", err)
+		os.Exit(1)
+	}
+}
+
+func processFile(file *ast.File) []string {
+	providers := make([]string, 0)
+	ast.Inspect(file, func(n ast.Node) bool {
+		fn, ok := n.(*ast.FuncDecl)
+		if !ok || fn.Doc == nil {
+			return true
+		}
+
+		var provide bool
+		var asInterface string
+
+		for _, comment := range fn.Doc.List {
+			if strings.Contains(comment.Text, "@fxProvide") {
+				provide = true
+			}
+			if strings.HasPrefix(comment.Text, "// @fxAs ") {
+				parts := strings.SplitN(comment.Text, " ", 3)
+				if len(parts) > 2 {
+					asInterface = strings.TrimSpace(parts[2])
+				}
+			}
+		}
+
+		if provide {
+			if asInterface != "" {
+				providers = append(providers, fmt.Sprintf("fx.Provide(fx.Annotate(%s, fx.As(new(%s)))),", fn.Name.Name, asInterface))
+			} else {
+				providers = append(providers, fmt.Sprintf("fx.Provide(%s),", fn.Name.Name))
+			}
+		}
+		return true
+	})
+	return providers
+}
+
+type Module struct {
+	PackageName string
+	ModuleName  string
+	Name        string
+	Providers   []string
+}
+
+const templateText = `package {{.PackageName}}
+
+import "go.uber.org/fx"
+
+// This file is generated by geng. DO NOT EDIT.
+
+var {{.ModuleName}} = fx.Module("{{.Name}}",
+{{- range .Providers}}
+    {{.}}
+{{- end}}
+)
+`
+
+func generateFile(dependencies map[string][]string) {
+	tmpl, err := template.New("module").Parse(templateText)
+	if err != nil {
+		panic(err)
+	}
+
+	for k, v := range dependencies {
+		module := Module{
+			PackageName: filepath.Base(k),
+			Name:        filepath.Base(k),
+			ModuleName:  cases.Title(language.English).String(filepath.Base(k)),
+			Providers:   v,
+		}
+		filePath := filepath.Join(k, "module.go")
+		file, err := os.Create(filePath)
+		if err != nil {
+			panic(err)
+		}
+		defer file.Close()
+
+		err = tmpl.Execute(file, module)
+		if err != nil {
+			panic(err)
+		}
+	}
+}

From 9f84b1581879c86f0b95c5d9cc6665495b3f309c Mon Sep 17 00:00:00 2001
From: Mukesh Kumar Chaudhary <mukezhz@gmail.com>
Date: Sun, 14 Apr 2024 10:27:04 +0545
Subject: [PATCH 2/2] refactor: add message after code run

---
 pkg/utility/fx_generator.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkg/utility/fx_generator.go b/pkg/utility/fx_generator.go
index 87c20e5..4a07821 100644
--- a/pkg/utility/fx_generator.go
+++ b/pkg/utility/fx_generator.go
@@ -98,6 +98,8 @@ const templateText = `package {{.PackageName}}
 import "go.uber.org/fx"
 
 // This file is generated by geng. DO NOT EDIT.
+// File generated at: {{.Timestamp}}
+// File will be overwritten when running geng again.
 
 var {{.ModuleName}} = fx.Module("{{.Name}}",
 {{- range .Providers}}
@@ -131,4 +133,6 @@ func generateFile(dependencies map[string][]string) {
 			panic(err)
 		}
 	}
+	count := len(dependencies)
+	fmt.Printf("Generated %d module files\n", count)
 }