feat: actually print file from ast

internal/imports/formatter.go

@@ -1,10 +1,12 @@
 package imports
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"go/ast"
 	"go/parser"
+	"go/printer"
 	"go/token"
 	"log"
 	"os"
@@ -132,14 +134,7 @@ func (ft *Formatter) formatFile(path string) error {
 	}
 	ft.log("formatFile: moduleName: %+v\n", moduleName)
 
-	// Parse ast
-	pathASTFile, err := ft.parseAST(path, pathBytes)
-	if err != nil {
-		return err
-	}
-	ft.log("formatFile: pathASTFile: %+v\n", pathASTFile)
-
-	if err := ft.formatASTFile(pathASTFile, moduleName); err != nil {
+	if err := ft.formatImports(path, pathBytes, moduleName); err != nil {
 		return err
 	}
 
@@ -150,36 +145,36 @@ func (ft *Formatter) formatFile(path string) error {
 	return nil
 }
 
-func (ft *Formatter) parseAST(path string, pathBytes []byte) (*ast.File, error) {
+// Copy from goimports-reviser
+func (ft *Formatter) formatImports(
+	path string,
+	pathBytes []byte,
+	moduleName string,
+) error {
+	// Parse ast
 	fset := token.NewFileSet()
 
 	parserMode := parser.Mode(0)
 	parserMode |= parser.ParseComments
 
-	pathASTFile, err := parser.ParseFile(fset, path, pathBytes, parserMode)
+	astFile, err := parser.ParseFile(fset, path, pathBytes, parserMode)
 	if err != nil {
-		return nil, fmt.Errorf("parser: failed to parse file [%s]: %w", path, err)
+		return fmt.Errorf("parser: failed to parse file [%s]: %w", path, err)
 	}
 
 	// Ignore generated file
-	if isGoGenerated(pathASTFile) {
-		return nil, ErrGoGeneratedFile
+	if isGoGenerated(astFile) {
+		return ErrGoGeneratedFile
 	}
 
-	return pathASTFile, nil
-}
-
-// Copy from goimports-reviser
-// If exist multi import, combine them into one
-// This func will edit pathASTFile directly to combine
-func (ft *Formatter) formatASTFile(
-	pathASTFile *ast.File,
-	moduleName string,
-) error {
 	// Extract imports
-	importSpecs := make([]ast.Spec, 0, len(pathASTFile.Imports))
-	for _, importSpec := range pathASTFile.Imports {
-		ft.log("parseImportsAndCombine: importSpec: %+v %+v\n", importSpec.Name.String(), importSpec.Path.Value)
+	importSpecs := make([]ast.Spec, 0, len(astFile.Imports))
+	for _, importSpec := range astFile.Imports {
+		if importSpec.Path.Value == "" {
+			continue
+		}
+
+		ft.log("formatImports: importSpec: %+v %+v\n", importSpec.Name.String(), importSpec.Path.Value)
 		importSpecs = append(importSpecs, importSpec)
 	}
 
@@ -195,12 +190,13 @@ func (ft *Formatter) formatASTFile(
 	if err != nil {
 		return err
 	}
+	ft.mustLogImportSpecs("formatImports: formattedImportSpecs: ", formattedImportSpecs)
 
-	// Combine multi import decl
+	// Combine multi import decl into one
 	isMultiImportDecl := false
 	isExistFirstImportDecl := false
-	decls := make([]ast.Decl, 0, len(pathASTFile.Decls))
-	for _, decl := range pathASTFile.Decls {
+	decls := make([]ast.Decl, 0, len(astFile.Decls))
+	for _, decl := range astFile.Decls {
 		genDecl, ok := decl.(*ast.GenDecl)
 		if !ok {
 			decls = append(decls, decl)
@@ -215,8 +211,8 @@ func (ft *Formatter) formatASTFile(
 		if isExistFirstImportDecl {
 			isMultiImportDecl = true
 			// TODO: explain this
-			storedGenDecl := decls[len(decls)-1].(*ast.GenDecl)
-			if storedGenDecl.Tok == token.IMPORT {
+			storedGenDecl, ok := decls[len(decls)-1].(*ast.GenDecl)
+			if ok && storedGenDecl.Tok == token.IMPORT {
 				storedGenDecl.Rparen = genDecl.End()
 			}
 			continue
@@ -227,12 +223,20 @@ func (ft *Formatter) formatASTFile(
 		genDecl.Specs = formattedImportSpecs
 		decls = append(decls, genDecl)
 	}
-	ft.log("parseImportsAndCombine: decls: %+v\n", decls)
 
 	if isMultiImportDecl {
-		pathASTFile.Decls = decls
+		astFile.Decls = decls
 	}
 
+	// Print formatted bytes from formatted ast
+	var formattedBytes []byte
+	formattedBuffer := bytes.NewBuffer(formattedBytes)
+	if err := printer.Fprint(formattedBuffer, fset, astFile); err != nil {
+		return err
+	}
+
+	fmt.Println(formattedBuffer.String())
+
 	return nil
 }
 
@@ -278,16 +282,17 @@ func (ft *Formatter) groupImportSpecs(
 		result[thirdPartyImport] = append(result[thirdPartyImport], importSpec)
 	}
 
-	ft.log("groupImports: std: %+v\n", result[stdImport])
-	ft.log("groupImports: third-party: %+v\n", result[thirdPartyImport])
+	ft.logImportSpecs("stdImport", result[stdImport])
+	ft.logImportSpecs("thirdPartyImport", result[thirdPartyImport])
 	if ft.companyPrefix != "" {
-		ft.log("groupImports: company: %+v\n", result[companyImport])
+		ft.logImportSpecs("companyImport", result[companyImport])
 	}
-	ft.log("groupImports: local: %+v\n", result[localImport])
+	ft.logImportSpecs("localImport", result[localImport])
 
 	return result, nil
 }
 
+// Copy from goimports-reviser
 func (ft *Formatter) formatImportSpecs(
 	importSpecs []ast.Spec,
 	groupedImportSpecs map[string][]*ast.ImportSpec,
@@ -350,6 +355,7 @@ func (ft *Formatter) formatImportSpecs(
 	return result, nil
 }
 
+// Copy from goimports-reviser
 func (ft *Formatter) moduleName(path string) (string, error) {
 	ft.muModuleNames.RLock()
 	if pkgName, ok := ft.moduleNames[path]; ok {
@@ -413,3 +419,24 @@ func (ft *Formatter) log(format string, v ...any) {
 		log.Printf(format, v...)
 	}
 }
+
+func (ft *Formatter) logImportSpecs(logPrefix string, importSpecs []*ast.ImportSpec) {
+	if ft.isVerbose {
+		for _, importSpec := range importSpecs {
+			log.Printf("%s: importSpec: %+v %+v\n", logPrefix, importSpec.Name.String(), importSpec.Path.Value)
+		}
+	}
+}
+
+func (ft *Formatter) mustLogImportSpecs(logPrefix string, importSpecs []ast.Spec) {
+	if ft.isVerbose {
+		for _, importSpec := range importSpecs {
+			importSpec, ok := importSpec.(*ast.ImportSpec)
+			if !ok {
+				continue
+			}
+
+			log.Printf("%s: importSpec: %+v %+v\n", logPrefix, importSpec.Name.String(), importSpec.Path.Value)
+		}
+	}
+}