chore: migrate release pipeline to signed filemap and wire rainyun s3

LanMountainDesktop/Services/PdcReleaseUpdateService.cs

@@ -0,0 +1,464 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Net.Http;
+using System.Runtime.InteropServices;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace LanMountainDesktop.Services;
+
+/// <summary>
+/// Best-effort PDC client that maps PDC responses to the existing update result model.
+/// This keeps launcher update contracts stable while allowing a gradual migration.
+/// </summary>
+public sealed class PdcReleaseUpdateService : IDisposable
+{
+    private readonly HttpClient _httpClient;
+    private readonly bool _ownsHttpClient;
+
+    public PdcReleaseUpdateService(HttpClient? httpClient = null)
+    {
+        if (httpClient is null)
+        {
+            _httpClient = new HttpClient
+            {
+                Timeout = TimeSpan.FromSeconds(20)
+            };
+            _ownsHttpClient = true;
+        }
+        else
+        {
+            _httpClient = httpClient;
+            _ownsHttpClient = false;
+        }
+    }
+
+    public void Dispose()
+    {
+        if (_ownsHttpClient)
+        {
+            _httpClient.Dispose();
+        }
+    }
+
+    public Task<UpdateCheckResult> CheckForUpdatesAsync(
+        Version currentVersion,
+        bool includePrerelease,
+        CancellationToken cancellationToken = default)
+    {
+        return CheckForUpdatesCoreAsync(currentVersion, includePrerelease, isForce: false, cancellationToken);
+    }
+
+    public Task<UpdateCheckResult> ForceCheckForUpdatesAsync(
+        Version currentVersion,
+        bool includePrerelease,
+        CancellationToken cancellationToken = default)
+    {
+        return CheckForUpdatesCoreAsync(currentVersion, includePrerelease, isForce: true, cancellationToken);
+    }
+
+    private async Task<UpdateCheckResult> CheckForUpdatesCoreAsync(
+        Version currentVersion,
+        bool includePrerelease,
+        bool isForce,
+        CancellationToken cancellationToken)
+    {
+        var normalizedCurrentVersion = NormalizeVersion(currentVersion);
+        var normalizedCurrentVersionText = FormatVersionText(normalizedCurrentVersion);
+        var endpoint = ResolveEndpoint();
+
+        if (string.IsNullOrWhiteSpace(endpoint))
+        {
+            return new UpdateCheckResult(
+                Success: false,
+                IsUpdateAvailable: false,
+                CurrentVersionText: normalizedCurrentVersionText,
+                LatestVersionText: "-",
+                Release: null,
+                PreferredAsset: null,
+                ErrorMessage: "PDC endpoint is not configured.",
+                ForceMode: isForce);
+        }
+
+        try
+        {
+            var metadataUrl = BuildUri(endpoint, "api/v1/public/distributions/metadata");
+            var metadata = await GetContentNodeAsync(metadataUrl, cancellationToken).ConfigureAwait(false);
+
+            var channelId = ResolveChannelId(metadata, includePrerelease);
+            if (string.IsNullOrWhiteSpace(channelId))
+            {
+                channelId = includePrerelease ? "preview" : "stable";
+            }
+
+            var latestUrl = BuildUri(
+                endpoint,
+                $"api/v1/public/distributions/latest/{Uri.EscapeDataString(channelId)}?appVersion={Uri.EscapeDataString(normalizedCurrentVersionText)}");
+            var latestNode = await GetContentNodeAsync(latestUrl, cancellationToken).ConfigureAwait(false);
+
+            var latestVersionText = ReadString(latestNode, "version") ?? "-";
+            if (!TryParseVersion(latestVersionText, out var latestVersion) || latestVersion is null)
+            {
+                return new UpdateCheckResult(
+                    Success: false,
+                    IsUpdateAvailable: false,
+                    CurrentVersionText: normalizedCurrentVersionText,
+                    LatestVersionText: latestVersionText,
+                    Release: null,
+                    PreferredAsset: null,
+                    ErrorMessage: "PDC latest distribution version is invalid.",
+                    ForceMode: isForce);
+            }
+
+            var distributionId = ReadString(latestNode, "distributionId");
+            if (string.IsNullOrWhiteSpace(distributionId))
+            {
+                return new UpdateCheckResult(
+                    Success: false,
+                    IsUpdateAvailable: false,
+                    CurrentVersionText: normalizedCurrentVersionText,
+                    LatestVersionText: latestVersionText,
+                    Release: null,
+                    PreferredAsset: null,
+                    ErrorMessage: "PDC latest distribution id is missing.",
+                    ForceMode: isForce);
+            }
+
+            var hasUpdate = latestVersion > normalizedCurrentVersion;
+            if (!isForce && !hasUpdate)
+            {
+                return new UpdateCheckResult(
+                    Success: true,
+                    IsUpdateAvailable: false,
+                    CurrentVersionText: normalizedCurrentVersionText,
+                    LatestVersionText: latestVersionText,
+                    Release: null,
+                    PreferredAsset: null,
+                    ErrorMessage: null,
+                    ForceMode: false);
+            }
+
+            var subChannel = ResolveSubChannel();
+            var distributionUrl = BuildUri(
+                endpoint,
+                $"api/v1/public/distributions/{Uri.EscapeDataString(distributionId)}/{Uri.EscapeDataString(subChannel)}");
+            var distributionNode = await GetContentNodeAsync(distributionUrl, cancellationToken).ConfigureAwait(false);
+
+            var assets = ResolveAssets(distributionNode);
+            if (assets.Count == 0)
+            {
+                return new UpdateCheckResult(
+                    Success: false,
+                    IsUpdateAvailable: false,
+                    CurrentVersionText: normalizedCurrentVersionText,
+                    LatestVersionText: latestVersionText,
+                    Release: null,
+                    PreferredAsset: null,
+                    ErrorMessage: "PDC distribution response does not expose downloadable update assets.",
+                    ForceMode: isForce);
+            }
+
+            var release = new GitHubReleaseInfo(
+                TagName: $"v{latestVersionText}",
+                Name: $"PDC Distribution {latestVersionText}",
+                IsPrerelease: includePrerelease,
+                IsDraft: false,
+                PublishedAt: DateTimeOffset.UtcNow,
+                Assets: assets);
+
+            return new UpdateCheckResult(
+                Success: true,
+                IsUpdateAvailable: true,
+                CurrentVersionText: normalizedCurrentVersionText,
+                LatestVersionText: latestVersionText,
+                Release: release,
+                PreferredAsset: null,
+                ErrorMessage: null,
+                ForceMode: isForce);
+        }
+        catch (OperationCanceledException)
+        {
+            throw;
+        }
+        catch (Exception ex)
+        {
+            return new UpdateCheckResult(
+                Success: false,
+                IsUpdateAvailable: false,
+                CurrentVersionText: normalizedCurrentVersionText,
+                LatestVersionText: "-",
+                Release: null,
+                PreferredAsset: null,
+                ErrorMessage: $"PDC request failed: {ex.Message}",
+                ForceMode: isForce);
+        }
+    }
+
+    private async Task<JsonElement> GetContentNodeAsync(string url, CancellationToken cancellationToken)
+    {
+        using var request = new HttpRequestMessage(HttpMethod.Get, url);
+        var token = ResolveToken();
+        if (!string.IsNullOrWhiteSpace(token))
+        {
+            request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", token);
+        }
+
+        using var response = await _httpClient.SendAsync(request, cancellationToken).ConfigureAwait(false);
+        var body = await response.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
+        if (!response.IsSuccessStatusCode)
+        {
+            throw new InvalidOperationException($"HTTP {(int)response.StatusCode}: {Truncate(body, 180)}");
+        }
+
+        using var document = JsonDocument.Parse(body);
+        var root = document.RootElement;
+        if (root.ValueKind == JsonValueKind.Object &&
+            root.TryGetProperty("content", out var content))
+        {
+            return content.Clone();
+        }
+
+        return root.Clone();
+    }
+
+    private static IReadOnlyList<GitHubReleaseAsset> ResolveAssets(JsonElement distributionNode)
+    {
+        var assets = new List<GitHubReleaseAsset>();
+        if (distributionNode.ValueKind != JsonValueKind.Object)
+        {
+            return assets;
+        }
+
+        if (distributionNode.TryGetProperty("assets", out var assetsNode) &&
+            assetsNode.ValueKind == JsonValueKind.Array)
+        {
+            foreach (var assetNode in assetsNode.EnumerateArray())
+            {
+                if (assetNode.ValueKind != JsonValueKind.Object)
+                {
+                    continue;
+                }
+
+                var name = ReadString(assetNode, "name");
+                var url = ReadString(assetNode, "url") ??
+                          ReadString(assetNode, "downloadUrl") ??
+                          ReadString(assetNode, "browserDownloadUrl");
+                if (string.IsNullOrWhiteSpace(name) || string.IsNullOrWhiteSpace(url))
+                {
+                    continue;
+                }
+
+                var size = ReadInt64(assetNode, "size") ?? 0L;
+                var sha256 = ReadString(assetNode, "sha256");
+                assets.Add(new GitHubReleaseAsset(name, url, size, sha256));
+            }
+        }
+
+        if (assets.Count > 0)
+        {
+            return assets;
+        }
+
+        // Field-level fallback for service-side URL projection.
+        var manifestUrl = ReadString(distributionNode, "manifestUrl")
+                          ?? ReadString(distributionNode, "fileMapUrl");
+        var signatureUrl = ReadString(distributionNode, "signatureUrl")
+                           ?? ReadString(distributionNode, "fileMapSignatureUrl");
+        var archiveUrl = ReadString(distributionNode, "archiveUrl")
+                         ?? ReadString(distributionNode, "updateArchiveUrl")
+                         ?? ReadString(distributionNode, "payloadUrl");
+
+        if (!string.IsNullOrWhiteSpace(manifestUrl))
+        {
+            assets.Add(new GitHubReleaseAsset("files.json", manifestUrl, 0, null));
+        }
+
+        if (!string.IsNullOrWhiteSpace(signatureUrl))
+        {
+            assets.Add(new GitHubReleaseAsset("files.json.sig", signatureUrl, 0, null));
+        }
+
+        if (!string.IsNullOrWhiteSpace(archiveUrl))
+        {
+            assets.Add(new GitHubReleaseAsset("update.zip", archiveUrl, 0, null));
+        }
+
+        return assets;
+    }
+
+    private static string ResolveChannelId(JsonElement metadataNode, bool includePrerelease)
+    {
+        if (metadataNode.ValueKind != JsonValueKind.Object ||
+            !metadataNode.TryGetProperty("channels", out var channelsNode))
+        {
+            return includePrerelease ? "preview" : "stable";
+        }
+
+        var defaultChannelId = ReadString(metadataNode, "defaultChannelId") ?? string.Empty;
+        if (channelsNode.ValueKind != JsonValueKind.Object)
+        {
+            return defaultChannelId;
+        }
+
+        string? matchedPreview = null;
+        string? matchedStable = null;
+
+        foreach (var channel in channelsNode.EnumerateObject())
+        {
+            var name = ReadString(channel.Value, "name") ?? channel.Name;
+            if (string.IsNullOrWhiteSpace(matchedPreview) &&
+                (name.Contains("preview", StringComparison.OrdinalIgnoreCase) ||
+                 name.Contains("beta", StringComparison.OrdinalIgnoreCase) ||
+                 name.Contains("dev", StringComparison.OrdinalIgnoreCase)))
+            {
+                matchedPreview = channel.Name;
+            }
+
+            if (string.IsNullOrWhiteSpace(matchedStable) &&
+                (name.Contains("stable", StringComparison.OrdinalIgnoreCase) ||
+                 name.Contains("release", StringComparison.OrdinalIgnoreCase)))
+            {
+                matchedStable = channel.Name;
+            }
+        }
+
+        if (includePrerelease)
+        {
+            return matchedPreview ?? defaultChannelId ?? "preview";
+        }
+
+        return matchedStable ?? defaultChannelId ?? "stable";
+    }
+
+    private static string ResolveSubChannel()
+    {
+        var configured = Environment.GetEnvironmentVariable("LANMOUNTAIN_PDC_SUBCHANNEL")
+                         ?? Environment.GetEnvironmentVariable("PDC_SUBCHANNEL");
+        if (!string.IsNullOrWhiteSpace(configured))
+        {
+            return configured.Trim();
+        }
+
+        var os = OperatingSystem.IsWindows()
+            ? "windows"
+            : OperatingSystem.IsLinux()
+                ? "linux"
+                : OperatingSystem.IsMacOS()
+                    ? "macos"
+                    : "unknown";
+
+        var arch = RuntimeInformation.OSArchitecture switch
+        {
+            Architecture.X86 => "x86",
+            Architecture.Arm => "arm",
+            Architecture.Arm64 => "arm64",
+            _ => "x64"
+        };
+
+        return $"{os}_{arch}_release_folderClassic";
+    }
+
+    private static string? ResolveEndpoint()
+    {
+        var endpoint = Environment.GetEnvironmentVariable("LANMOUNTAIN_PDC_ENDPOINT")
+                      ?? Environment.GetEnvironmentVariable("PDC_ENDPOINT");
+        return string.IsNullOrWhiteSpace(endpoint) ? null : endpoint.Trim().TrimEnd('/');
+    }
+
+    private static string? ResolveToken()
+    {
+        var token = Environment.GetEnvironmentVariable("LANMOUNTAIN_PDC_TOKEN")
+                    ?? Environment.GetEnvironmentVariable("PDC_TOKEN");
+        return string.IsNullOrWhiteSpace(token) ? null : token.Trim();
+    }
+
+    private static string BuildUri(string endpoint, string relativePath)
+    {
+        return $"{endpoint.TrimEnd('/')}/{relativePath.TrimStart('/')}";
+    }
+
+    private static string? ReadString(JsonElement node, string propertyName)
+    {
+        if (node.ValueKind != JsonValueKind.Object || !node.TryGetProperty(propertyName, out var value))
+        {
+            return null;
+        }
+
+        return value.ValueKind == JsonValueKind.String
+            ? value.GetString()
+            : value.ToString();
+    }
+
+    private static long? ReadInt64(JsonElement node, string propertyName)
+    {
+        if (node.ValueKind != JsonValueKind.Object || !node.TryGetProperty(propertyName, out var value))
+        {
+            return null;
+        }
+
+        if (value.TryGetInt64(out var number))
+        {
+            return number;
+        }
+
+        var text = value.ToString();
+        return long.TryParse(text, NumberStyles.Integer, CultureInfo.InvariantCulture, out var parsed)
+            ? parsed
+            : null;
+    }
+
+    private static bool TryParseVersion(string? value, out Version? version)
+    {
+        version = null;
+        if (string.IsNullOrWhiteSpace(value))
+        {
+            return false;
+        }
+
+        var normalized = value.Trim().TrimStart('v', 'V');
+        var separatorIndex = normalized.IndexOfAny(['-', '+', ' ']);
+        if (separatorIndex > 0)
+        {
+            normalized = normalized[..separatorIndex];
+        }
+
+        if (!Version.TryParse(normalized, out var parsed))
+        {
+            return false;
+        }
+
+        version = NormalizeVersion(parsed);
+        return true;
+    }
+
+    private static Version NormalizeVersion(Version version)
+    {
+        var major = Math.Max(0, version.Major);
+        var minor = Math.Max(0, version.Minor);
+        var build = Math.Max(0, version.Build >= 0 ? version.Build : 0);
+        var revision = Math.Max(0, version.Revision >= 0 ? version.Revision : 0);
+        return revision > 0
+            ? new Version(major, minor, build, revision)
+            : new Version(major, minor, build);
+    }
+
+    private static string FormatVersionText(Version version)
+    {
+        return version.Revision > 0
+            ? version.ToString(4)
+            : version.ToString(3);
+    }
+
+    private static string Truncate(string value, int maxLength)
+    {
+        if (string.IsNullOrEmpty(value) || value.Length <= maxLength)
+        {
+            return value;
+        }
+
+        return value[..maxLength];
+    }
+}

LanMountainDesktop/Services/Settings/SettingsDomainServices.cs

@@ -751,7 +751,8 @@ internal sealed class PrivacySettingsService : IPrivacySettingsService
 internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposable
 {
     private readonly ISettingsService _settingsService;
-    private readonly GitHubReleaseUpdateService _releaseUpdateService = new("wwiinnddyy", "LanMountainDesktop");
+    private readonly GitHubReleaseUpdateService _githubReleaseUpdateService = new("wwiinnddyy", "LanMountainDesktop");
+    private readonly PdcReleaseUpdateService _pdcReleaseUpdateService = new();
 
     public UpdateSettingsService(ISettingsService settingsService)
     {
@@ -830,7 +831,7 @@ internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposabl
         bool includePrerelease,
         CancellationToken cancellationToken = default)
     {
-        return _releaseUpdateService.CheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken);
+        return CheckForUpdatesCoreAsync(currentVersion, includePrerelease, isForce: false, cancellationToken);
     }
 
     public Task<UpdateCheckResult> ForceCheckForUpdatesAsync(
@@ -838,7 +839,7 @@ internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposabl
         bool includePrerelease,
         CancellationToken cancellationToken = default)
     {
-        return _releaseUpdateService.ForceCheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken);
+        return CheckForUpdatesCoreAsync(currentVersion, includePrerelease, isForce: true, cancellationToken);
     }
 
     public Task<UpdateDownloadResult> DownloadAssetAsync(
@@ -849,7 +850,7 @@ internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposabl
         IProgress<double>? progress = null,
         CancellationToken cancellationToken = default)
     {
-        return _releaseUpdateService.DownloadAssetAsync(
+        return _githubReleaseUpdateService.DownloadAssetAsync(
             asset,
             destinationFilePath,
             downloadSource,
@@ -866,7 +867,7 @@ internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposabl
         IProgress<double>? progress = null,
         CancellationToken cancellationToken = default)
     {
-        return _releaseUpdateService.RedownloadAssetAsync(
+        return _githubReleaseUpdateService.RedownloadAssetAsync(
             asset,
             destinationFilePath,
             downloadSource,
@@ -877,7 +878,36 @@ internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposabl
 
     public void Dispose()
     {
-        _releaseUpdateService.Dispose();
+        _githubReleaseUpdateService.Dispose();
+        _pdcReleaseUpdateService.Dispose();
+    }
+
+    private async Task<UpdateCheckResult> CheckForUpdatesCoreAsync(
+        Version currentVersion,
+        bool includePrerelease,
+        bool isForce,
+        CancellationToken cancellationToken)
+    {
+        var source = UpdateSettingsValues.NormalizeDownloadSource(_settingsService.Load().UpdateDownloadSource);
+        if (string.Equals(source, UpdateSettingsValues.DownloadSourcePdc, StringComparison.OrdinalIgnoreCase))
+        {
+            var pdcResult = isForce
+                ? await _pdcReleaseUpdateService.ForceCheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken)
+                : await _pdcReleaseUpdateService.CheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken);
+
+            if (pdcResult.Success)
+            {
+                return pdcResult;
+            }
+
+            AppLogger.Warn(
+                "UpdateSettings",
+                $"PDC update check failed and will fallback to GitHub. Error: {pdcResult.ErrorMessage}");
+        }
+
+        return isForce
+            ? await _githubReleaseUpdateService.ForceCheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken)
+            : await _githubReleaseUpdateService.CheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken);
     }
 }
 

LanMountainDesktop/Services/UpdateSettingsValues.cs

@@ -11,6 +11,7 @@ public static class UpdateSettingsValues
     public const string ModeDownloadThenConfirm = "download_then_confirm";
     public const string ModeSilentOnExit = "silent_on_exit";
 
+    public const string DownloadSourcePdc = "pdc";
     public const string DownloadSourceGitHub = "github";
     public const string DownloadSourceGhProxy = "gh-proxy";
 
@@ -51,9 +52,23 @@ public static class UpdateSettingsValues
 
     public static string NormalizeDownloadSource(string? value)
     {
-        return string.Equals(value, DownloadSourceGhProxy, StringComparison.OrdinalIgnoreCase)
-            ? DownloadSourceGhProxy
-            : DownloadSourceGitHub;
+        if (string.Equals(value, DownloadSourcePdc, StringComparison.OrdinalIgnoreCase))
+        {
+            return DownloadSourcePdc;
+        }
+
+        if (string.Equals(value, DownloadSourceGhProxy, StringComparison.OrdinalIgnoreCase))
+        {
+            return DownloadSourceGhProxy;
+        }
+
+        if (string.Equals(value, DownloadSourceGitHub, StringComparison.OrdinalIgnoreCase))
+        {
+            return DownloadSourceGitHub;
+        }
+
+        // Default to PDC. Runtime will fallback to GitHub if PDC is unavailable.
+        return DownloadSourcePdc;
     }
 
     public static int NormalizeDownloadThreads(int value)

LanMountainDesktop/Services/UpdateWorkflowService.cs

@@ -5,6 +5,7 @@ using System.Diagnostics;
 using System.Globalization;
 using System.IO;
 using System.Linq;
+using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
 using LanMountainDesktop.PluginSdk;
@@ -52,7 +53,9 @@ public sealed class UpdateWorkflowService
     private const string LauncherDirectoryName = ".launcher";
     private const string UpdateDirectoryName = "update";
     private const string IncomingDirectoryName = "incoming";
-    private const string VelopackReleasesFileName = "releases.win.json";
+    private const string SignedFileMapName = "files.json";
+    private const string SignedFileMapSignatureName = "files.json.sig";
+    private const string UpdateArchiveName = "update.zip";
 
     public UpdateWorkflowService(ISettingsFacadeService settingsFacade)
     {
@@ -79,7 +82,7 @@ public sealed class UpdateWorkflowService
     }
 
     /// <summary>
-    /// Checks whether a GitHub Release contains Velopack assets needed for incremental updates.
+    /// Checks whether a GitHub Release contains signed file-map assets needed for incremental updates.
     /// </summary>
     public static bool IsDeltaUpdateAvailable(GitHubReleaseInfo release)
     {
@@ -88,13 +91,11 @@ public sealed class UpdateWorkflowService
             return false;
         }
 
-        var hasFeed = release.Assets.Any(a => string.Equals(a.Name, VelopackReleasesFileName, StringComparison.OrdinalIgnoreCase));
-        var hasFull = release.Assets.Any(a => a.Name.EndsWith("-full.nupkg", StringComparison.OrdinalIgnoreCase));
-        return hasFeed && hasFull;
+        return TryResolveDeltaAssets(release.Assets, out _, out _, out _);
     }
 
     /// <summary>
-    /// Downloads Velopack release feed and package files to the Launcher's incoming directory.
+    /// Downloads signed file-map assets to the Launcher's incoming directory.
     /// </summary>
     public async Task<UpdateDownloadResult> DownloadDeltaUpdateAsync(
         UpdateCheckResult checkResult,
@@ -108,11 +109,9 @@ public sealed class UpdateWorkflowService
             return new UpdateDownloadResult(false, null, "No update available for delta download.");
         }
 
-        var releasesFeedAsset = checkResult.Release.Assets.FirstOrDefault(a =>
-            string.Equals(a.Name, VelopackReleasesFileName, StringComparison.OrdinalIgnoreCase));
-        if (releasesFeedAsset is null)
+        if (!TryResolveDeltaAssets(checkResult.Release.Assets, out var manifestAsset, out var signatureAsset, out var archiveAsset))
         {
-            return new UpdateDownloadResult(false, null, "Release does not contain releases.win.json.");
+            return new UpdateDownloadResult(false, null, "Release does not contain compatible signed file-map assets.");
         }
 
         var incomingDir = GetLauncherIncomingDirectory();
@@ -130,29 +129,19 @@ public sealed class UpdateWorkflowService
         var downloadSource = state.UpdateDownloadSource;
         var downloadThreads = state.UpdateDownloadThreads;
 
-        var latestVersionText = checkResult.LatestVersionText.Trim();
-        var targetPackages = checkResult.Release.Assets
-            .Where(a => a.Name.EndsWith(".nupkg", StringComparison.OrdinalIgnoreCase))
-            .Where(a => a.Name.Contains(latestVersionText, StringComparison.OrdinalIgnoreCase))
-            .Where(a =>
-                a.Name.EndsWith("-full.nupkg", StringComparison.OrdinalIgnoreCase) ||
-                a.Name.EndsWith("-delta.nupkg", StringComparison.OrdinalIgnoreCase))
-            .ToList();
-
-        if (targetPackages.Count == 0)
+        var requiredAssets = new List<(GitHubReleaseAsset Asset, string DestinationFileName)>
         {
-            return new UpdateDownloadResult(false, null, "No Velopack nupkg asset found for the target version.");
-        }
-
-        var requiredAssets = new List<GitHubReleaseAsset> { releasesFeedAsset };
-        requiredAssets.AddRange(targetPackages);
+            (manifestAsset, SignedFileMapName),
+            (signatureAsset, SignedFileMapSignatureName),
+            (archiveAsset, UpdateArchiveName)
+        };
 
         var totalAssets = requiredAssets.Count;
         var completedAssets = 0;
 
-        foreach (var asset in requiredAssets)
+        foreach (var (asset, destinationFileName) in requiredAssets)
         {
-            var destinationPath = Path.Combine(incomingDir, asset.Name);
+            var destinationPath = Path.Combine(incomingDir, destinationFileName);
 
             // Skip if already downloaded and file exists
             if (File.Exists(destinationPath))
@@ -160,7 +149,7 @@ public sealed class UpdateWorkflowService
                 var existingHash = await GitHubReleaseUpdateService.ComputeFileSha256Async(destinationPath, cancellationToken);
                 if (asset.Sha256 is not null && string.Equals(existingHash, asset.Sha256, StringComparison.OrdinalIgnoreCase))
                 {
-                    AppLogger.Info("UpdateWorkflow", $"Velopack asset {asset.Name} already downloaded with matching hash, skipping.");
+                    AppLogger.Info("UpdateWorkflow", $"Update asset {asset.Name} already downloaded with matching hash, skipping.");
                     completedAssets++;
                     progress?.Report((double)completedAssets / totalAssets);
                     continue;
@@ -184,21 +173,21 @@ public sealed class UpdateWorkflowService
             if (!result.Success)
             {
                 // Clean up partially downloaded files
-                foreach (var file in requiredAssets.Select(a => a.Name))
+                foreach (var file in requiredAssets.Select(a => a.DestinationFileName))
                 {
                     try { File.Delete(Path.Combine(incomingDir, file)); } catch { }
                 }
-                return new UpdateDownloadResult(false, null, $"Failed to download Velopack asset {asset.Name}: {result.ErrorMessage}");
+                return new UpdateDownloadResult(false, null, $"Failed to download update asset {asset.Name}: {result.ErrorMessage}");
             }
 
             completedAssets++;
             progress?.Report((double)completedAssets / totalAssets);
         }
 
-        // Save state indicating a Velopack update is pending.
+        // Save state indicating a signed file-map update is pending.
         SaveState(state with
         {
-            PendingUpdateInstallerPath = Path.Combine(incomingDir, VelopackReleasesFileName),
+            PendingUpdateInstallerPath = Path.Combine(incomingDir, SignedFileMapName),
             PendingUpdateVersion = checkResult.LatestVersionText,
             PendingUpdatePublishedAtUtcMs = checkResult.Release.PublishedAt == DateTimeOffset.MinValue
                 ? null
@@ -207,9 +196,9 @@ public sealed class UpdateWorkflowService
             PendingUpdateSha256 = null
         });
 
-        AppLogger.Info("UpdateWorkflow", $"Velopack update payload downloaded to {incomingDir}. Will be applied by Launcher on next startup.");
+        AppLogger.Info("UpdateWorkflow", $"Signed file-map update payload downloaded to {incomingDir}. Will be applied by Launcher on next startup.");
 
-        return new UpdateDownloadResult(true, Path.Combine(incomingDir, VelopackReleasesFileName), null);
+        return new UpdateDownloadResult(true, Path.Combine(incomingDir, SignedFileMapName), null);
     }
 
     /// <summary>
@@ -224,11 +213,71 @@ public sealed class UpdateWorkflowService
             return false;
         }
 
-        // Velopack updates are identified by the releases feed path.
-        return pendingPath.EndsWith(VelopackReleasesFileName, StringComparison.OrdinalIgnoreCase)
+        // Incoming payload updates are identified by files.json or incoming directory path.
+        return pendingPath.EndsWith(SignedFileMapName, StringComparison.OrdinalIgnoreCase)
             || pendingPath.Contains(IncomingDirectoryName, StringComparison.OrdinalIgnoreCase);
     }
 
+    private static bool TryResolveDeltaAssets(
+        IReadOnlyList<GitHubReleaseAsset> assets,
+        out GitHubReleaseAsset manifestAsset,
+        out GitHubReleaseAsset signatureAsset,
+        out GitHubReleaseAsset archiveAsset)
+    {
+        manifestAsset = default!;
+        signatureAsset = default!;
+        archiveAsset = default!;
+
+        if (assets is null || assets.Count == 0)
+        {
+            return false;
+        }
+
+        var platformSuffix = GetPlatformAssetSuffix();
+        var platformManifest = $"files-{platformSuffix}.json";
+        var platformSignature = $"files-{platformSuffix}.json.sig";
+        var platformArchive = $"update-{platformSuffix}.zip";
+
+        var manifestCandidate = FindAsset(assets, platformManifest) ?? FindAsset(assets, SignedFileMapName);
+        var signatureCandidate = FindAsset(assets, platformSignature) ?? FindAsset(assets, SignedFileMapSignatureName);
+        var archiveCandidate = FindAsset(assets, platformArchive) ?? FindAsset(assets, UpdateArchiveName);
+        if (manifestCandidate is null || signatureCandidate is null || archiveCandidate is null)
+        {
+            return false;
+        }
+
+        manifestAsset = manifestCandidate;
+        signatureAsset = signatureCandidate;
+        archiveAsset = archiveCandidate;
+        return true;
+    }
+
+    private static GitHubReleaseAsset? FindAsset(IReadOnlyList<GitHubReleaseAsset> assets, string name)
+    {
+        return assets.FirstOrDefault(a => string.Equals(a.Name, name, StringComparison.OrdinalIgnoreCase));
+    }
+
+    private static string GetPlatformAssetSuffix()
+    {
+        var os = OperatingSystem.IsWindows()
+            ? "windows"
+            : OperatingSystem.IsLinux()
+                ? "linux"
+                : OperatingSystem.IsMacOS()
+                    ? "macos"
+                    : "unknown";
+
+        var arch = RuntimeInformation.OSArchitecture switch
+        {
+            Architecture.X86 => "x86",
+            Architecture.Arm => "arm",
+            Architecture.Arm64 => "arm64",
+            _ => "x64"
+        };
+
+        return $"{os}-{arch}";
+    }
+
     public UpdatePendingInfo? GetPendingUpdate()
     {
         var state = _settingsFacade.Update.Get();