From 14f115fbe083d7fcafc276b35687150461ddb56d Mon Sep 17 00:00:00 2001
From: Anton Vakhrushev <anwinged@ya.ru>
Date: Fri, 13 Jun 2025 17:28:26 +0300
Subject: [PATCH] Add command line flags

---
 main.go | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/main.go b/main.go
index b5fff82..70bc99a 100644
--- a/main.go
+++ b/main.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/json"
+	"flag"
 	"fmt"
 	"io"
 	"net/http"
@@ -12,18 +13,28 @@ import (
 )
 
 // HTTP клиент с таймаутом
-var httpClient = &http.Client{
-	Timeout: 30 * time.Second,
-}
+var httpClient *http.Client
 
 func main() {
-	if len(os.Args) != 3 {
+	timeout := flag.Duration("t", 60*time.Second, "request timeout")
+	retries := flag.Int("r", 5, "number of download attempts")
+	jobs := flag.Int("j", 5, "concurrent downloads")
+
+	flag.Parse()
+
+	args := flag.Args()
+
+	if len(args) != 2 {
 		fmt.Println("Usage: program <json-file> <output-dir>")
 		os.Exit(1)
 	}
 
-	jsonFile := os.Args[1]
-	outputDir := os.Args[2]
+	jsonFile := args[0]
+	outputDir := args[1]
+
+	httpClient = &http.Client{
+		Timeout: *timeout,
+	}
 
 	// Создаем директорию для загрузок
 	if err := os.MkdirAll(outputDir, 0755); err != nil {
@@ -46,7 +57,7 @@ func main() {
 	}
 
 	// Семафор для ограничения параллелизма
-	sem := make(chan struct{}, 5)
+	sem := make(chan struct{}, *jobs)
 	var wg sync.WaitGroup
 
 	start := time.Now()
@@ -59,7 +70,7 @@ func main() {
 			defer func() { <-sem }() // Освобождаем слот
 
 			filename := filepath.Join(outputDir, fmt.Sprintf("image_%06d%s", idx, fileExtension(url)))
-			if err := downloadImage(url, filename); err != nil {
+			if err := downloadImage(url, filename, *retries); err != nil {
 				fmt.Printf("Error downloading %s: %v\n", url, err)
 			} else {
 				fmt.Printf("Downloaded %s -> %s\n", url, filename)
@@ -92,8 +103,7 @@ func fileExtension(url string) string {
 }
 
 // Скачиваем и сохраняем изображение
-func downloadImage(url, filename string) error {
-	const maxRetries = 3
+func downloadImage(url, filename string, maxRetries int) error {
 	const retryDelay = 1 * time.Second
 
 	var lastErr error