feat: support combine multi import decl (wip)

copy from goimports-reviser

internal/imports/formatter.go

@@ -65,7 +65,7 @@ func NewFormmater(opts ...FormatterOptionFn) (*Formatter, error) {
 	for _, stdPackage := range stdPackages {
 		ft.stdPackages[stdPackage.PkgPath] = struct{}{}
 	}
-	ft.log("stdPackages: %+v\n", ft.stdPackages)
+	ft.log("NewFormmater: stdPackages: %+v\n", ft.stdPackages)
 
 	ft.moduleNames = make(map[string]string)
 	ft.formattedPaths = make(map[string]struct{})
@@ -133,7 +133,7 @@ func (ft *Formatter) formatFile(path string) error {
 	}
 
 	// Parse imports
-	importsAST, err := ft.parseImports(pathASTFile)
+	importsAST, err := ft.parseImportsAndCombine(pathASTFile)
 	if err != nil {
 		return err
 	}
@@ -142,19 +142,19 @@ func (ft *Formatter) formatFile(path string) error {
 	if len(importsAST) == 0 {
 		return nil
 	}
-	ft.log("importsAST: %+v\n", importsAST)
+	ft.log("formatFile: importsAST: %+v\n", importsAST)
 
 	moduleName, err := ft.moduleName(path)
 	if err != nil {
 		return err
 	}
-	ft.log("moduleName: %+v\n", moduleName)
+	ft.log("formatFile: moduleName: %+v\n", moduleName)
 
 	groupImports, err := ft.groupImports(importsAST, moduleName)
 	if err != nil {
 		return err
 	}
-	ft.log("groupImports: %+v\n", groupImports)
+	ft.log("formatFile: groupImports: %+v\n", groupImports)
 
 	ft.muFormattedPaths.Lock()
 	ft.formattedPaths[path] = struct{}{}
@@ -183,24 +183,16 @@ func (ft *Formatter) wrapParseAST(path string, pathBytes []byte) (*ast.File, err
 }
 
 // Copy from goimports-reviser
-func (ft *Formatter) parseImports(pathASTFile *ast.File) (map[string]*ast.ImportSpec, error) {
+// If exist multi import, combine them into one
+// This func will edit pathASTFile directly to combine
+func (ft *Formatter) parseImportsAndCombine(pathASTFile *ast.File) (map[string]*ast.ImportSpec, error) {
 	result := make(map[string]*ast.ImportSpec)
 
-	for _, decl := range pathASTFile.Decls {
-		genDecl, ok := decl.(*ast.GenDecl)
-		if !ok {
-			continue
-		}
-
-		if genDecl.Tok != token.IMPORT {
-			continue
-		}
-
-		for _, spec := range genDecl.Specs {
-			importSpec, ok := spec.(*ast.ImportSpec)
-			if !ok {
-				continue
-			}
+	// 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 = append(importSpecs, importSpec)
 
 		var importNameAndPath string
 		if importSpec.Name != nil {
@@ -215,6 +207,42 @@ func (ft *Formatter) parseImports(pathASTFile *ast.File) (map[string]*ast.Import
 
 		result[importNameAndPath] = importSpec
 	}
+
+	// Combine multi import decl
+	isMultiImportDecl := false
+	isExistFirstImportDecl := false
+	decls := make([]ast.Decl, 0, len(pathASTFile.Decls))
+	for _, decl := range pathASTFile.Decls {
+		genDecl, ok := decl.(*ast.GenDecl)
+		if !ok {
+			decls = append(decls, decl)
+			continue
+		}
+
+		if genDecl.Tok != token.IMPORT {
+			decls = append(decls, decl)
+			continue
+		}
+
+		if isExistFirstImportDecl {
+			isMultiImportDecl = true
+			// TODO: explain this
+			storedGenDecl := decls[len(decls)-1].(*ast.GenDecl)
+			if storedGenDecl.Tok == token.IMPORT {
+				storedGenDecl.Rparen = genDecl.End()
+			}
+			continue
+		}
+
+		// First import decl take all
+		isExistFirstImportDecl = true
+		genDecl.Specs = importSpecs
+		decls = append(decls, genDecl)
+	}
+	ft.log("parseImportsAndCombine: decls: %+v\n", decls)
+
+	if isMultiImportDecl {
+		pathASTFile.Decls = decls
 	}
 
 	return result, nil
@@ -257,12 +285,12 @@ func (ft *Formatter) groupImports(
 		result[thirdPartyImport] = append(result[thirdPartyImport], importNameAndPath)
 	}
 
-	ft.log("std %+v\n", result[stdImport])
-	ft.log("third-party %+v\n", result[thirdPartyImport])
+	ft.log("groupImports: std: %+v\n", result[stdImport])
+	ft.log("groupImports: third-party: %+v\n", result[thirdPartyImport])
 	if ft.companyPrefix != "" {
-		ft.log("company %+v\n", result[companyImport])
+		ft.log("groupImports: company: %+v\n", result[companyImport])
 	}
-	ft.log("local %+v\n", result[localImport])
+	ft.log("groupImports: local: %+v\n", result[localImport])
 
 	// TODO: not sure if this match gofumpt output, but at lease it is sorted
 	sort.Strings(result[stdImport])
@@ -308,7 +336,7 @@ func (ft *Formatter) moduleName(path string) (string, error) {
 	if goModPath == "" {
 		return "", ErrGoModNotExist
 	}
-	ft.log("goModPath: %+v\n", goModPath)
+	ft.log("moduleName: goModPath: %+v\n", goModPath)
 
 	goModPathBytes, err := os.ReadFile(goModPath)
 	if err != nil {