add mirror downloaders to only handle downloading of a mirror

SPTInstaller/Interfaces/IMirrorDownloader.cs

@@ -0,0 +1,9 @@
+using SPTInstaller.Models.Mirrors;
+using System.Threading.Tasks;
+
+namespace SPTInstaller.Interfaces;
+public interface IMirrorDownloader
+{
+    public DownloadMirror MirrorInfo { get; }
+    public Task<FileInfo?> Download(IProgress<double> progress);
+}

SPTInstaller/Models/Mirrors/DownloadMirror.cs

@@ -1,4 +1,4 @@
-namespace SPTInstaller.Models;
+namespace SPTInstaller.Models.Mirrors;
 
 public class DownloadMirror
 {

SPTInstaller/Models/Mirrors/Downloaders/HttpMirrorDownloader.cs

@@ -0,0 +1,15 @@
+using SPTInstaller.Helpers;
+using System.Threading.Tasks;
+
+namespace SPTInstaller.Models.Mirrors.Downloaders;
+public class HttpMirrorDownloader : MirrorDownloaderBase
+{
+    public HttpMirrorDownloader(DownloadMirror mirror) : base(mirror)
+    {
+    }
+
+    public override async Task<FileInfo?> Download(IProgress<double> progress)
+    {
+        return await DownloadCacheHelper.DownloadFileAsync("patcher.zip", MirrorInfo.Link, progress);
+    }
+}

SPTInstaller/Models/Mirrors/Downloaders/MegaMirrorDownloader.cs

@@ -0,0 +1,33 @@
+using CG.Web.MegaApiClient;
+using SPTInstaller.Helpers;
+using System.Threading.Tasks;
+
+namespace SPTInstaller.Models.Mirrors.Downloaders;
+public class MegaMirrorDownloader : MirrorDownloaderBase
+{
+    public MegaMirrorDownloader(DownloadMirror mirrorInfo) : base(mirrorInfo)
+    {
+    }
+
+    public override async Task<FileInfo?> Download(IProgress<double> progress)
+    {
+        var megaClient = new MegaApiClient();
+        await megaClient.LoginAnonymousAsync();
+
+        // if mega fails to connect, just return
+        if (!megaClient.IsLoggedIn)
+            return null;
+
+        try
+        {
+            using var megaDownloadStream = await megaClient.DownloadAsync(new Uri(MirrorInfo.Link), progress);
+
+            return await DownloadCacheHelper.DownloadFileAsync("patcher.zip", megaDownloadStream);
+        }
+        catch
+        {
+            //most likely a 509 (Bandwidth limit exceeded) due to mega's user quotas.
+            return null;
+        }
+    }
+}

SPTInstaller/Models/Mirrors/Downloaders/MirrorDownloaderBase.cs

@@ -0,0 +1,13 @@
+using SPTInstaller.Interfaces;
+using System.Threading.Tasks;
+
+namespace SPTInstaller.Models.Mirrors.Downloaders;
+public abstract class MirrorDownloaderBase : IMirrorDownloader
+{
+    public DownloadMirror MirrorInfo { get; private set; }
+    public abstract Task<FileInfo?> Download(IProgress<double> progress);
+    public MirrorDownloaderBase(DownloadMirror mirrorInfo)
+    {
+        MirrorInfo = mirrorInfo;
+    }
+}