AnotherReplayReader/UpdateChecker.cs

using AnotherReplayReader.Utils;
using System;
using System.Collections.Immutable;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json;
using System.Threading.Tasks;
using System.Windows;

namespace AnotherReplayReader
{
    internal class UpdateCheckerVersionData
    {
        public string NewVersion { get; }
        public string Description { get; }
        public ImmutableArray<string> Urls { get; }

        public UpdateCheckerVersionData(string newVersion,
                                        string description,
                                        ImmutableArray<string> urls)
        {
            NewVersion = newVersion;
            Description = description;
            Urls = urls;
        }

        public bool IsNewVersion() => NewVersion != App.Version;
    }

    internal class UpdateChecker
    {
        public const string CheckForUpdatesKey = "checkForUpdates";
        public const string CachedDataKey = "cachedUpdateData";
        private static readonly ImmutableArray<string> _updateSources = new[]
        {
            "https://lanyi.altervista.org/playertable/file.json"
        }.ToImmutableArray();

        public static Task<UpdateCheckerVersionData> CheckForUpdates(Cache cache)
        {
            var taskSource = new TaskCompletionSource<UpdateCheckerVersionData>();
            if (cache.GetOrDefault(CheckForUpdatesKey, false) is not true)
            {
                return taskSource.Task;
            }
            foreach (var source in _updateSources)
            {
                Task.Run(async () =>
                {
                    try
                    {
                        var data = await DownloadAndVerify(source).ConfigureAwait(false);
                        if (data.IsNewVersion())
                        {
                            cache.Set(CachedDataKey, data);
                            taskSource.TrySetResult(data);
                        }
                    }
                    catch (Exception e)
                    {
                        Debug.Instance.DebugMessage += $"Update check failed: {e}";
                    }
                });
            }
            return taskSource.Task;
        }

        private static async Task<UpdateCheckerVersionData> DownloadAndVerify(string url)
        {
            var payload = await Network.HttpGetJson<VerifierPayload>(url)
                ?? throw new InvalidDataException(nameof(VerifierPayload) + " is null");
            if (!Verifier.Verify(payload))
            {
                throw new InvalidDataException(nameof(VerifierPayload) + " cannot be verified");
            }
            return JsonSerializer.Deserialize<UpdateCheckerVersionData>(payload.ByteData.Value, Network.CommonJsonOptions)
                ?? throw new InvalidDataException(nameof(UpdateCheckerVersionData) + " is null");
        }

        public static void Sign()
        {
            var sample = new UpdateCheckerVersionData(App.Version, "Alice Margatroid", _updateSources);
            var sampleText = JsonSerializer.Serialize(sample, Network.CommonJsonOptions);
            Verifier.Sign(sampleText);
        }
    }
}