package ioutils

import (
	"io"
	"log"
	"time"
)

func SynchronizeStreams(description string, stream1, stream2 io.ReadWriter) {
	waitChannel := make(chan bool, 2)

	go func() {
		defer func() {
			waitChannel <- true
		}()
		_, err := io.Copy(&RetryWriter{stream1}, stream2)
		if err != nil {
			log.Printf("SynchronizeStreams: %s: error <-: %v\n", description, err)
		}
	}()

	go func() {
		defer func() {
			waitChannel <- true
		}()
		_, err := io.Copy(&RetryWriter{stream2}, stream1)
		if err != nil {
			log.Printf("SynchronizeStreams: %s: error ->: %v\n", description, err)
		}
	}()

	<-waitChannel
	// wait until the second connection closes with a timeout to make it more likely
	// that all data will be written.
	select {
	case <-waitChannel:
	// the other connection also closed
	case <-time.After(500 * time.Millisecond):
		// the timeout expired
	}
	log.Printf("SynchronizeStreams: %s: Connection closed", description)
}