-

package main

import (
	"bytes"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
	"time"
	"flag"
 	"sync"
)

type tracker struct {
	files int
	lines int
	mu *sync.Mutex
}

func main() {
	path := flag.String("path", ".", "Please provide a path")
	flag.Parse()

	wg := sync.WaitGroup{}
	tracker := tracker{mu: &sync.Mutex{}}
	t := time.NewTicker(1)

	go func() {
		for {
			<-t.C
			tracker.mu.Lock()
			log.Printf("progress: files=%s; lines=%s\n", tracker.files, tracker.lines)
tracker.mu.Unlock()
		}
	}()

	filepath.Walk(*path, func(path string, info os.FileInfo, err error) error {
		go func() {
			wg.Add(1)
			defer wg.Done()

			tracker.Lock()
			defer tracker.Unlock()

			tracker.files++
		file, err := ioutil.ReadFile(path)
		if err != nil {
			panic(err)
		}
		tracker.num_lines += bytes.Count(file, []byte("\n"))

		return nil
		}()
	})

	wg.Wait()
	t.Stop()
	log.Printf("files=%s; lines=%s\n", tracker.files, tracker.lines)
}