---

package main

import (
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"sync"
)

func calculateMD5(filePath string, sema chan struct{}, wg *sync.WaitGroup, results chan<- string) {
	defer wg.Done()

	sema <- struct{}{}
	defer func() { <-sema }()

	file, err := os.Open(filePath)
	if err != nil {
		results <- fmt.Sprintf("Ошибка открытия %s: %v", filePath, err)
		return
	}
	defer file.Close()

	hash := md5.New()
	if _, err := io.Copy(hash, file); err != nil {
		results <- fmt.Sprintf("Ошибка чтения %s: %v", filePath, err)
		return
	}

	hashInBytes := hash.Sum(nil)
	hashString := hex.EncodeToString(hashInBytes)
	results <- fmt.Sprintf("Файл: %s | MD5: %s", filepath.Base(filePath), hashString)
}

func main() {
	files := []string{"test1.txt", "test2.txt", "test3.txt"}

	for _, name := range files {
		os.WriteFile(name, []byte("содержимое файла "+name), 0644)
		defer os.Remove(name)
	}

	var wg sync.WaitGroup
	sema := make(chan struct{}, 2)
	results := make(chan string, len(files))

	for _, file := range files {
		wg.Add(1)
		go calculateMD5(file, sema, &wg, results)
	}

	wg.Wait()
	close(results)

	for res := range results {
		fmt.Println(res)
	}
}