move the go source files to src directory

src/download.go

@@ -0,0 +1,90 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"path"
+	"strconv"
+	"strings"
+	"sync"
+
+	"github.com/dustin/go-humanize"
+)
+
+// BeginDownload is meant to be called as a goroutine and begins the post download process.
+func BeginDownload(posts *[]Post, saveDirectory *string, maxConcurrents *int) {
+	var wg sync.WaitGroup
+	var completed int
+
+	total := len(*posts)
+
+	// Distribute the posts based on the number of workers
+	ppw := len(*posts) / *maxConcurrents
+	mod := len(*posts) % *maxConcurrents
+
+	for i := 0; i < *maxConcurrents; i++ {
+		postsLower := i * ppw
+		postsUpper := i*ppw + ppw
+
+		if i == *maxConcurrents-1 {
+			// Give the last worker the remaining posts
+			// TODO: compensate it for labor
+			postsUpper += mod
+		}
+
+		wg.Add(1)
+		go work(i+1, (*posts)[postsLower:postsUpper], *saveDirectory, &completed, &total, &wg)
+	}
+
+	wg.Wait()
+}
+
+func work(wn int, posts []Post, directory string, completed *int, total *int, wg *sync.WaitGroup) {
+	defer wg.Done()
+
+	for _, post := range posts {
+		*completed++
+		fmt.Printf(
+			"[%d/%d] [w%d] Downloading post %d (%s) -> %s...\n",
+			*completed,
+			*total,
+			wn,
+			post.ID,
+			humanize.Bytes(uint64(post.FileSize)),
+			getSavePath(&post, &directory),
+		)
+		downloadPost(&post, directory)
+	}
+}
+
+func getSavePath(post *Post, directory *string) string {
+	pathSliced := strings.Split(post.FileURL, ".")
+	extension := pathSliced[len(pathSliced)-1]
+
+	savePath := path.Join(*directory, strconv.Itoa(post.ID)+"."+extension)
+
+	return savePath
+}
+
+func downloadPost(post *Post, directory string) {
+	savePath := getSavePath(post, &directory)
+
+	resp, err := HTTPGet(post.FileURL)
+	if err != nil {
+		fmt.Println("Unable to download, skipping...")
+		return
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		fmt.Println("Unable to read post response body, skipping...")
+		return
+	}
+
+	err = ioutil.WriteFile(savePath, body, 0755)
+	if err != nil {
+		fmt.Printf("Error: could not write to file: %v\n", err)
+		return
+	}
+}