feat(code_helper): add stdin support for piping file lists

Add ability to pipe file lists to code_helper via stdin, enabling
use cases like:
  find . -name '*.go' | code_helper "instructions"
  git ls-files '*.py' | code_helper "Add type hints"

The tool now detects if stdin is a pipe and accepts a single argument
(instructions) in that mode, reading file paths from stdin line by line.

Backward compatible with existing directory scanning mode.

Signed-off-by: majiayu000 <1835304752@qq.com>

cmd/code_helper/code.go

@@ -131,6 +131,75 @@ func ScanDirectory(rootDir string, maxDepth int, instructions string, ignoreList
 	return json.MarshalIndent(data, "", "  ")
 }
 
+// ScanFiles scans specific files and returns a JSON representation
+func ScanFiles(files []string, instructions string) ([]byte, error) {
+	fileCount := 0
+	dirSet := make(map[string]bool)
+
+	// Create root directory item
+	rootItem := FileItem{
+		Type:     "directory",
+		Name:     ".",
+		Contents: []FileItem{},
+	}
+
+	for _, filePath := range files {
+		// Skip directories
+		info, err := os.Stat(filePath)
+		if err != nil {
+			return nil, fmt.Errorf("error accessing file %s: %v", filePath, err)
+		}
+		if info.IsDir() {
+			continue
+		}
+
+		// Track unique directories
+		dir := filepath.Dir(filePath)
+		if dir != "." {
+			dirSet[dir] = true
+		}
+
+		fileCount++
+
+		// Read file content
+		content, err := os.ReadFile(filePath)
+		if err != nil {
+			return nil, fmt.Errorf("error reading file %s: %v", filePath, err)
+		}
+
+		// Clean path for consistent handling
+		cleanPath := filepath.Clean(filePath)
+		if strings.HasPrefix(cleanPath, "./") {
+			cleanPath = cleanPath[2:]
+		}
+
+		// Add file to the structure
+		addFileToDirectory(&rootItem, cleanPath, string(content), ".")
+	}
+
+	// Create final data structure
+	var data []any
+	data = append(data, rootItem)
+
+	// Add report
+	reportItem := map[string]any{
+		"type":        "report",
+		"directories": len(dirSet) + 1,
+		"files":       fileCount,
+	}
+	data = append(data, reportItem)
+
+	// Add instructions
+	instructionsItem := map[string]any{
+		"type":    "instructions",
+		"name":    "code_change_instructions",
+		"details": instructions,
+	}
+	data = append(data, instructionsItem)
+
+	return json.MarshalIndent(data, "", "  ")
+}
+
 // addFileToDirectory adds a file to the correct directory in the structure
 func addFileToDirectory(root *FileItem, path, content, rootDir string) {
 	parts := strings.Split(path, string(filepath.Separator))

cmd/code_helper/code_test.go

@@ -0,0 +1,100 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestScanFiles(t *testing.T) {
+	// Create temp directory with test files
+	tmpDir := t.TempDir()
+
+	// Create test files
+	file1 := filepath.Join(tmpDir, "test1.go")
+	file2 := filepath.Join(tmpDir, "test2.go")
+	subDir := filepath.Join(tmpDir, "subdir")
+	file3 := filepath.Join(subDir, "test3.go")
+
+	require.NoError(t, os.WriteFile(file1, []byte("package main\n"), 0644))
+	require.NoError(t, os.WriteFile(file2, []byte("package main\n\nfunc main() {}\n"), 0644))
+	require.NoError(t, os.MkdirAll(subDir, 0755))
+	require.NoError(t, os.WriteFile(file3, []byte("package subdir\n"), 0644))
+
+	// Test scanning specific files
+	files := []string{file1, file3}
+	instructions := "Test instructions"
+
+	jsonData, err := ScanFiles(files, instructions)
+	require.NoError(t, err)
+
+	// Parse the JSON output
+	var result []any
+	err = json.Unmarshal(jsonData, &result)
+	require.NoError(t, err)
+	assert.Len(t, result, 3) // directory, report, instructions
+
+	// Check report
+	report := result[1].(map[string]any)
+	assert.Equal(t, "report", report["type"])
+	assert.Equal(t, float64(2), report["files"])
+
+	// Check instructions
+	instr := result[2].(map[string]any)
+	assert.Equal(t, "instructions", instr["type"])
+	assert.Equal(t, "Test instructions", instr["details"])
+}
+
+func TestScanFilesSkipsDirectories(t *testing.T) {
+	tmpDir := t.TempDir()
+
+	file1 := filepath.Join(tmpDir, "test.go")
+	subDir := filepath.Join(tmpDir, "subdir")
+
+	require.NoError(t, os.WriteFile(file1, []byte("package main\n"), 0644))
+	require.NoError(t, os.MkdirAll(subDir, 0755))
+
+	// Include a directory in the file list - should be skipped
+	files := []string{file1, subDir}
+
+	jsonData, err := ScanFiles(files, "test")
+	require.NoError(t, err)
+
+	var result []any
+	err = json.Unmarshal(jsonData, &result)
+	require.NoError(t, err)
+
+	// Check that only 1 file was counted (directory was skipped)
+	report := result[1].(map[string]any)
+	assert.Equal(t, float64(1), report["files"])
+}
+
+func TestScanFilesNonExistentFile(t *testing.T) {
+	files := []string{"/nonexistent/file.go"}
+	_, err := ScanFiles(files, "test")
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "error accessing file")
+}
+
+func TestScanDirectory(t *testing.T) {
+	tmpDir := t.TempDir()
+
+	file1 := filepath.Join(tmpDir, "main.go")
+	require.NoError(t, os.WriteFile(file1, []byte("package main\n"), 0644))
+
+	jsonData, err := ScanDirectory(tmpDir, 3, "Test instructions", []string{})
+	require.NoError(t, err)
+
+	var result []any
+	err = json.Unmarshal(jsonData, &result)
+	require.NoError(t, err)
+	assert.Len(t, result, 3)
+
+	// Check instructions
+	instr := result[2].(map[string]any)
+	assert.Equal(t, "Test instructions", instr["details"])
+}

cmd/code_helper/main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bufio"
 	"flag"
 	"fmt"
 	"os"
@@ -15,7 +16,45 @@ func main() {
 	flag.Usage = printUsage
 	flag.Parse()
 
-	// Require exactly two positional arguments: directory and instructions
+	// Check if stdin has data (is a pipe)
+	stdinInfo, _ := os.Stdin.Stat()
+	hasStdin := (stdinInfo.Mode() & os.ModeCharDevice) == 0
+
+	var jsonData []byte
+	var err error
+
+	if hasStdin {
+		// Stdin mode: read file list from stdin, instructions from argument
+		if flag.NArg() != 1 {
+			fmt.Fprintf(os.Stderr, "Error: When piping file list via stdin, provide exactly 1 argument: <instructions>\n")
+			fmt.Fprintf(os.Stderr, "Usage: find . -name '*.go' | code_helper \"instructions\"\n")
+			os.Exit(1)
+		}
+
+		instructions := flag.Arg(0)
+
+		// Read file paths from stdin
+		var files []string
+		scanner := bufio.NewScanner(os.Stdin)
+		for scanner.Scan() {
+			line := strings.TrimSpace(scanner.Text())
+			if line != "" {
+				files = append(files, line)
+			}
+		}
+		if err := scanner.Err(); err != nil {
+			fmt.Fprintf(os.Stderr, "Error reading stdin: %v\n", err)
+			os.Exit(1)
+		}
+
+		if len(files) == 0 {
+			fmt.Fprintf(os.Stderr, "Error: No files provided via stdin\n")
+			os.Exit(1)
+		}
+
+		jsonData, err = ScanFiles(files, instructions)
+	} else {
+		// Directory mode: require directory and instructions arguments
 		if flag.NArg() != 2 {
 			printUsage()
 			os.Exit(1)
@@ -31,9 +70,11 @@ func main() {
 		}
 
 		// Parse ignore patterns and scan directory
-	jsonData, err := ScanDirectory(directory, *maxDepth, instructions, strings.Split(*ignorePatterns, ","))
+		jsonData, err = ScanDirectory(directory, *maxDepth, instructions, strings.Split(*ignorePatterns, ","))
+	}
+
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "Error scanning directory: %v\n", err)
+		fmt.Fprintf(os.Stderr, "Error scanning: %v\n", err)
 		os.Exit(1)
 	}
 
@@ -53,11 +94,14 @@ func printUsage() {
 
 Usage:
   code_helper [options] <directory> <instructions>
+  <file_list> | code_helper [options] <instructions>
 
 Examples:
   code_helper . "Add input validation to all user inputs"
   code_helper -depth 4 ./my-project "Implement error handling"
   code_helper -out project.json ./src "Fix security issues"
+  find . -name '*.go' | code_helper "Refactor error handling"
+  git ls-files '*.py' | code_helper "Add type hints"
 
 Options:
 `)