Add download package

internal/download/Download.go

@@ -0,0 +1,160 @@
+package download
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+)
+
+// DownloadStatus holds information related to downloads and is
+// the container for information returned via channels within this
+// package.
+type DownloadStatus struct {
+	Min int64  // Current file's bytes downloaded
+	Max int64  // Current file's total size
+	Cur int64  // Overall bytes downloaded
+	Msg string // Status message
+	Err error  // Error, if any
+}
+
+// DownloadAudioFiles downloads multiple audio files and sends progress updates
+// to the provided channel. The channel is closed when all downloads are complete.
+func DownloadAudioFiles(progressChan chan<- DownloadStatus, filenames []string, destDir string) {
+	defer close(progressChan)
+
+	urlBase := "https://files.rhemawavetech.com/audio/"
+	totalDownloaded := int64(0)
+	totalSize := int64(0)
+
+	// First, get the total size of all files
+	for _, filename := range filenames {
+		url := urlBase + filename
+		resp, err := http.Head(url)
+		if err != nil {
+			progressChan <- DownloadStatus{
+				Msg: fmt.Sprintf("Failed to get size for %s: %v", filename, err),
+				Err: err,
+			}
+			return
+		}
+		resp.Body.Close()
+		if resp.StatusCode != http.StatusOK {
+			progressChan <- DownloadStatus{
+				Msg: fmt.Sprintf("Failed to get size for %s: status %s", filename, resp.Status),
+				Err: fmt.Errorf("bad status: %s", resp.Status),
+			}
+			return
+		}
+		totalSize += resp.ContentLength
+	}
+
+	// Send initial status
+	progressChan <- DownloadStatus{
+		Min: 0,
+		Max: totalSize,
+		Cur: 0,
+		Msg: "Starting download...",
+	}
+
+	// Download each file
+	for _, filename := range filenames {
+		url := urlBase + filename
+		destPath := filepath.Join(destDir, filename)
+
+		// Create the destination file
+		out, err := os.Create(destPath)
+		if err != nil {
+			progressChan <- DownloadStatus{
+				Msg: fmt.Sprintf("Failed to create file %s: %v", destPath, err),
+				Err: err,
+			}
+			return
+		}
+
+		// Get the file
+		resp, err := http.Get(url)
+		if err != nil {
+			out.Close()
+			os.Remove(destPath)
+			progressChan <- DownloadStatus{
+				Msg: fmt.Sprintf("Failed to download %s: %v", filename, err),
+				Err: err,
+			}
+			return
+		}
+		defer resp.Body.Close()
+
+		if resp.StatusCode != http.StatusOK {
+			out.Close()
+			os.Remove(destPath)
+			progressChan <- DownloadStatus{
+				Msg: fmt.Sprintf("Failed to download %s: status %s", filename, resp.Status),
+				Err: fmt.Errorf("bad status: %s", resp.Status),
+			}
+			return
+		}
+
+		// Track progress for this file
+		fileSize := resp.ContentLength
+		downloaded := int64(0)
+
+		// Use a buffered reader for efficiency
+		buf := make([]byte, 8192)
+		for {
+			n, err := resp.Body.Read(buf)
+			if err != nil && err != io.EOF {
+				out.Close()
+				os.Remove(destPath)
+				progressChan <- DownloadStatus{
+					Msg: fmt.Sprintf("Failed to read %s: %v", filename, err),
+					Err: err,
+				}
+				return
+			}
+			if n == 0 {
+				break
+			}
+
+			// Write to file
+			if _, err := out.Write(buf[:n]); err != nil {
+				out.Close()
+				os.Remove(destPath)
+				progressChan <- DownloadStatus{
+					Msg: fmt.Sprintf("Failed to write %s: %v", filename, err),
+					Err: err,
+				}
+				return
+			}
+
+			// Update progress
+			downloaded += int64(n)
+			totalDownloaded += int64(n)
+			progressChan <- DownloadStatus{
+				Min: downloaded,
+				Max: fileSize,
+				Cur: totalDownloaded,
+				Msg: fmt.Sprintf("Downloading %s...", filename),
+			}
+		}
+
+		out.Close()
+
+		// Send completion for this file
+		progressChan <- DownloadStatus{
+			Min: fileSize,
+			Max: fileSize,
+			Cur: totalDownloaded,
+			Msg: fmt.Sprintf("Finished downloading %s", filename),
+		}
+	}
+
+	// Send final status
+	progressChan <- DownloadStatus{
+		Min: totalSize,
+		Max: totalSize,
+		Cur: totalDownloaded,
+		Msg: "All downloads completed!",
+	}
+}