main.go

package main

import (
	"flag"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
)

var (
	remote   = flag.String("r", "", "remotes can be https or ssh")
	username = flag.String("u", "", "specifies usernames to be changed, format is oldusername:newusername")
	github   = "[email protected]"
)

func main() {
	flag.Parse()

	if *remote == "" || *remote != "https" && *remote != "ssh" {
		fmt.Println("invalid remote type")
		return
	}

	s := strings.Split(*username, ":")
	if *username == "" || len(s) != 2 {
		fmt.Println("the format for usernames is oldusername:newusername")
		return
	}
	oldu, newu := s[0], s[1]
	filepath.Walk(os.Getenv("GOGITHUB"),
		ChangeUsernames(oldu, newu, *remote))
}

// ChangeUsernames returns the func that runs inside the walk
func ChangeUsernames(oldu, newu, remote string) filepath.WalkFunc {
	fmt.Printf("old username: %v\nnew username: %v\n", oldu, newu)
	return func(path string, info os.FileInfo, err error) error {
		if !info.IsDir() {
			// just a file, ignore it
			return nil
		}
		if _, err := os.Stat(filepath.Join(path, ".git")); os.IsNotExist(err) {
			// this is not a repo
			return nil
		}
		// this is a repo
		cmd := exec.Command("git", "remote", "-v")
		cmd.Dir = path
		out, err := cmd.Output()
		if err != nil {
			fmt.Println(err)
			panic("NOOOO")
		}
		res := string(out)
		if res == "" {
			return filepath.SkipDir
		}
		// rem = remote type, repo = the repo, rname = origin or something else
		rem, rname, un, repo, err := fetchInfo(oldu, strings.Split(res, "\n")[0])
		fmt.Printf("old: %v:%v/%v\n", rem, un, repo)
		if err != nil {
			return err
		}
		newrepo := fmt.Sprintf("%v:%v/%v", github, newu, repo)
		fmt.Printf("new: %v\n", newrepo)
		cmd = exec.Command("git", "remote", "set-url", rname, newrepo)
		cmd.Dir = path
		if err = cmd.Run(); err != nil {
			fmt.Println(err)
			panic("GAAAA")
		}

		return filepath.SkipDir
	}
}

func fetchInfo(oldu, details string) (rem string, rname string, un string, repo string, err error) {
	aux := strings.Split(strings.Trim(string(details), "(fetch)"), "\t")
	rname = aux[0]
	tmp := strings.Split(aux[1], ":")
	rem, repo, un = tmp[0], strings.Split(tmp[1], "/")[1], strings.Split(tmp[1], "/")[0]
	repo = strings.Trim(strings.Trim(repo, "\t"), " ")
	if rem != github || un != oldu {
		err = filepath.SkipDir
		return
	}
	return
}