From 44487b590f2e2409317688a152716028ed8e40cb Mon Sep 17 00:00:00 2001
From: Mohamed Tawous <mmtawous@ncsu.edu>
Date: Sun, 5 May 2024 04:40:04 -0400
Subject: [PATCH] Fixed issue #45

---
 web/download/multi.go | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/web/download/multi.go b/web/download/multi.go
index 3c6750e..a584829 100644
--- a/web/download/multi.go
+++ b/web/download/multi.go
@@ -2,13 +2,14 @@ package download
 
 import (
 	"crypto"
+	"log"
+	"path/filepath"
+	"sync"
+
 	"github.com/nothub/hashutils/chksum"
 	"github.com/nothub/hashutils/encoding"
 	modrinth "github.com/nothub/mrpack-install/modrinth/api"
 	"github.com/nothub/mrpack-install/web"
-	"log"
-	"path/filepath"
-	"sync"
 )
 
 type Download struct {
@@ -19,17 +20,25 @@ type Download struct {
 
 type Downloader struct {
 	Downloads []*Download
-	Threads   int // TODO
+	Threads   int // Maximum number of concurrent downloads
 	Retries   int
 }
 
 func (g *Downloader) Download(baseDir string) {
+	semaphore := make(chan struct{}, g.Threads) // Create a semaphore to limit concurrency
 	var wg sync.WaitGroup
+
 	for i := range g.Downloads {
 		wg.Add(1)
 		dl := g.Downloads[i]
+
+		semaphore <- struct{}{} // Acquire a slot in the semaphore
 		go func() {
-			defer wg.Done()
+			defer func() {
+				<-semaphore // Release the slot in the semaphore
+				wg.Done()
+			}()
+
 			absPath, _ := filepath.Abs(filepath.Join(baseDir, dl.Path))
 			success := false
 			for _, link := range dl.Urls {
@@ -62,5 +71,6 @@ func (g *Downloader) Download(baseDir string) {
 			}
 		}()
 	}
+
 	wg.Wait()
 }