finished, also added cobra cli

internal/renderer/renderer.go

@@ -0,0 +1,133 @@
+package renderer
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"unicode/utf8"
+
+	"dirmd/internal/tree"
+	"dirmd/internal/walker"
+)
+
+const fenceChars = "~~~"
+
+func Write(result *walker.Result, outputPath string, appendMode bool, singleFile bool) error {
+	flags := os.O_CREATE | os.O_WRONLY
+	if appendMode {
+		flags |= os.O_APPEND
+	} else {
+		flags |= os.O_TRUNC
+	}
+
+	f, err := os.OpenFile(outputPath, flags, 0644)
+	if err != nil {
+		return fmt.Errorf("cannot open output file: %w", err)
+	}
+	defer f.Close()
+
+	var sb strings.Builder
+
+	// Determine the correct H1 path
+	h1Path := result.AbsRoot
+	if singleFile && len(result.Entries) > 0 {
+		h1Path = filepath.Join(result.AbsRoot, result.Entries[0].RelPath)
+	}
+
+	fmt.Fprintf(&sb, "# %s\n\n", h1Path)
+
+	if !singleFile {
+		root := tree.Build(result.Entries)
+		rootName := filepath.Base(result.AbsRoot)
+		sb.WriteString("## Directory Tree\n\n")
+		sb.WriteString(fenceChars + "\n")
+		sb.WriteString(tree.Render(root, rootName))
+		sb.WriteString(fenceChars + "\n\n")
+	}
+
+	if len(result.Entries) > 0 {
+		if !singleFile {
+			sb.WriteString("## Contents\n\n")
+		}
+
+		for _, entry := range result.Entries {
+			fullPath := filepath.Join(result.AbsRoot, entry.RelPath)
+
+			content, err := readFile(fullPath)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "warning: cannot read %s: %v\n", entry.RelPath, err)
+				continue
+			}
+
+			language := extToLang(filepath.Ext(entry.RelPath))
+
+			fmt.Fprintf(&sb, "### ./%s\n\n", entry.RelPath)
+			fmt.Fprintf(&sb, "%s", fenceChars)
+			if language != "" {
+				fmt.Fprintf(&sb, "%s", language)
+			}
+			fmt.Fprintf(&sb, "\n")
+			fmt.Fprintf(&sb, "%s", content)
+			if !strings.HasSuffix(content, "\n") {
+				fmt.Fprintf(&sb, "\n")
+			}
+			fmt.Fprintf(&sb, "%s\n\n", fenceChars)
+		}
+	}
+
+	_, err = f.WriteString(sb.String())
+	return err
+}
+
+func readFile(path string) (string, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return "", err
+	}
+
+	for i, b := range data {
+		if b == 0 {
+			return "", fmt.Errorf("contains null byte at position %d", i)
+		}
+	}
+
+	if !utf8.Valid(data) {
+		return "", fmt.Errorf("invalid UTF-8 encoding")
+	}
+
+	content := string(data)
+	content = strings.ReplaceAll(content, "\r\n", "\n")
+	content = strings.ReplaceAll(content, "\r", "\n")
+
+	return content, nil
+}
+
+func extToLang(ext string) string {
+	mapping := map[string]string{
+		".go":   "go",
+		".md":   "markdown",
+		".yml":  "yaml",
+		".yaml": "yaml",
+		".js":   "javascript",
+		".ts":   "typescript",
+		".css":  "css",
+		".html": "html",
+		".json": "json",
+		".xml":  "xml",
+		".sql":  "sql",
+		".sh":   "bash",
+		".py":   "python",
+		".rs":   "rust",
+		".c":    "c",
+		".h":    "c",
+		".cpp":  "cpp",
+		".hpp":  "cpp",
+		".txt":  "text",
+	}
+
+	if lang, ok := mapping[strings.ToLower(ext)]; ok {
+		return lang
+	}
+	return ""
+}