pat/main.go

package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path"
	"strings"

	"golang.design/x/clipboard"
)

const DELEMITTER = "---------------------------------------------------------------------------\n"

func main() {
	if len(os.Args) < 2 {
		fmt.Println("Usage: go-cat <file-or-directory> [<file-or-directory>...]")
		os.Exit(1)
	}

	var sb strings.Builder
	for _, path := range os.Args[1:] {
		err := processPath(&sb, path)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Error processing %s: %v\n", path, err)
		}
	}

	str := sb.String()
	fmt.Println(str)

	if err := writeClipboard(str); err != nil {
		panic(err)
	}
}

func writeClipboard(str string) error {

	if os.Getenv("WAYLAND_DISPLAY") != "" {
		cmd := exec.Command("wl-copy")

		p, err := cmd.StdinPipe()
		if err != nil {
			return err
		}

		if err := cmd.Start(); err != nil {
			return err
		}
		p.Write([]byte(str))
		p.Close()
		return cmd.Wait()
	}

	if err := clipboard.Init(); err != nil {
		return err
	}

	clipboard.Write(clipboard.FmtText, []byte(str))

	return nil
}

func processPath(sb *strings.Builder, path string) error {
	info, err := os.Stat(path)
	if err != nil {
		return err
	}

	if info.IsDir() {
		return catDir(sb, path)
	}

	return catFile(sb, path)
}

func catDir(sb *strings.Builder, dir string) error {
	files, err := os.ReadDir(dir)
	if err != nil {
		return err
	}

	fmt.Printf("Directory: %s\n", dir)
	for _, file := range files {
		i, err := file.Info()
		if err != nil {
			continue
		}
		path := path.Join(dir, i.Name())

		if !file.IsDir() {
			catFile(sb, path)
		} else {
			catDir(sb, path)
		}
	}
	return nil
}

func catFile(sb *strings.Builder, filePath string) error {
	file, err := os.Open(filePath)
	if err != nil {
		return err
	}
	defer file.Close()

	sb.WriteString(DELEMITTER)
	sb.WriteString(filePath + "\n")

	reader := bufio.NewReader(file)
	for {
		line, err := reader.ReadString('\n')
		if err != nil && err != io.EOF {
			return err
		}
		sb.WriteString(line)
		if err == io.EOF {
			break
		}
	}
	return nil
}