From 7b6d3ffe549520ae5aaa36939f4240c14d07a988 Mon Sep 17 00:00:00 2001
From: structix <amateurdoedel@gmail.com>
Date: Sat, 21 Apr 2018 21:08:29 +0200
Subject: [PATCH] Fixed go routines syncing

---
 download.go | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/download.go b/download.go
index 24cb340..ed74390 100644
--- a/download.go
+++ b/download.go
@@ -6,6 +6,7 @@ import (
 	"log"
 	"os"
 	"regexp"
+	"sync"
 	//"path/filepath"
 
 	. "github.com/kkdai/youtube"
@@ -21,7 +22,7 @@ func NewBatch(batchFile, destinationDir string) *Batch {
 
 func (b *Batch) Start() {
 	//Start downloading all videos
-
+	log.Println("Start downloading...")
 	//open the file containing yt links
 	linkfile, err := os.Open(b.batchfile)
 	if err != nil {
@@ -34,18 +35,27 @@ func (b *Batch) Start() {
 	//That should be enough for yt links.
 	scanner := bufio.NewScanner(linkfile)
 
+	var wg sync.WaitGroup
+
 	for scanner.Scan() {
 		//Call download
-		go downloadVideo(b.destDir, scanner.Text())
+		log.Println(scanner.Text())
+		//add go routine to wait for
+		wg.Add(1)
+		go downloadVideo(b.destDir, scanner.Text(), wg)
 	}
 
+	//wait for all go routines to finish
+	wg.Wait()
 	if err := scanner.Err(); err != nil {
 		log.Fatal(err)
 	}
 }
 
-func downloadVideo(destDir, url string) {
+func downloadVideo(destDir, url string, wg sync.WaitGroup) {
 	// NewYoutube(debug) if debug parameter will set true we can log of messages
+	//defer Done() so that WaitGroup knows when the routine finishes
+	defer wg.Done()
 	y := NewYoutube(false)
 	y.DecodeURL(url)
 	re := regexp.MustCompile("(mp4|webm|3gpp)")