refactor: add platform messenger contracts

Introduce platform-neutral PlatformKind, PlatformUser, PlatformGroup, and IPlatformMessenger contracts in GmRelay.Shared.

Route Telegram session schedule updates, direct notifications, interaction replies, and calendar export through TelegramPlatformMessenger while preserving existing Telegram behavior.

Bump version -> 2.0.1

src/GmRelay.Bot/Infrastructure/Telegram/TelegramPlatformIds.cs

@@ -0,0 +1,29 @@
+using System.Globalization;
+using GmRelay.Shared.Platform;
+
+namespace GmRelay.Bot.Infrastructure.Telegram;
+
+internal static class TelegramPlatformIds
+{
+    public static PlatformGroup Group(long chatId, int? threadId = null, string? displayName = null) =>
+        new(
+            PlatformKind.Telegram,
+            chatId.ToString(CultureInfo.InvariantCulture),
+            displayName ?? "Telegram chat",
+            ExternalChannelId: chatId.ToString(CultureInfo.InvariantCulture),
+            ExternalThreadId: threadId?.ToString(CultureInfo.InvariantCulture));
+
+    public static PlatformUser User(long telegramId, string displayName, string? username = null) =>
+        new(
+            PlatformKind.Telegram,
+            telegramId.ToString(CultureInfo.InvariantCulture),
+            displayName,
+            username);
+
+    public static PlatformMessageRef Message(long chatId, int? threadId, int messageId) =>
+        new(
+            PlatformKind.Telegram,
+            chatId.ToString(CultureInfo.InvariantCulture),
+            threadId?.ToString(CultureInfo.InvariantCulture),
+            messageId.ToString(CultureInfo.InvariantCulture));
+}

src/GmRelay.Bot/Infrastructure/Telegram/TelegramPlatformMessenger.cs

@@ -0,0 +1,188 @@
+using System.Globalization;
+using GmRelay.Shared.Platform;
+using Telegram.Bot;
+using Telegram.Bot.Types;
+using Telegram.Bot.Types.Enums;
+using Telegram.Bot.Types.ReplyMarkups;
+
+namespace GmRelay.Bot.Infrastructure.Telegram;
+
+public sealed class TelegramPlatformMessenger(
+    ITelegramBotClient bot,
+    ILogger<TelegramPlatformMessenger> logger) : IPlatformMessenger
+{
+    public async Task<PlatformMessageRef> SendScheduleAsync(PlatformScheduleMessage message, CancellationToken ct)
+    {
+        EnsureTelegram(message.Group.Platform);
+
+        var chatId = ParseLong(message.Group.ExternalGroupId);
+        var threadId = ParseNullableInt(message.Group.ExternalThreadId);
+        var renderResult = TelegramSessionBatchRenderer.Render(message.View);
+        Message sentMessage;
+
+        if (!string.IsNullOrWhiteSpace(message.ImageReference) && renderResult.Text.Length <= 1024)
+        {
+            try
+            {
+                sentMessage = await bot.SendPhoto(
+                    chatId: chatId,
+                    messageThreadId: threadId,
+                    photo: InputFile.FromString(message.ImageReference),
+                    caption: renderResult.Text,
+                    parseMode: ParseMode.Html,
+                    replyMarkup: renderResult.Markup,
+                    cancellationToken: ct);
+            }
+            catch (Exception ex)
+            {
+                logger.LogWarning(ex, "Failed to send Telegram schedule image for group {ExternalGroupId}", message.Group.ExternalGroupId);
+                sentMessage = await SendScheduleTextMessage(chatId, threadId, renderResult.Text, renderResult.Markup, ct);
+            }
+        }
+        else
+        {
+            if (!string.IsNullOrWhiteSpace(message.ImageReference))
+            {
+                await TrySendScheduleImageOnly(chatId, threadId, message.View.Title, message.ImageReference, ct);
+            }
+
+            sentMessage = await SendScheduleTextMessage(chatId, threadId, renderResult.Text, renderResult.Markup, ct);
+        }
+
+        return new PlatformMessageRef(
+            PlatformKind.Telegram,
+            message.Group.ExternalGroupId,
+            message.Group.ExternalThreadId,
+            sentMessage.MessageId.ToString(CultureInfo.InvariantCulture));
+    }
+
+    public async Task UpdateScheduleAsync(PlatformScheduleMessage message, CancellationToken ct)
+    {
+        EnsureTelegram(message.Group.Platform);
+        if (message.ExistingMessage is null)
+        {
+            throw new ArgumentException("Existing schedule message reference is required.", nameof(message));
+        }
+
+        var renderResult = TelegramSessionBatchRenderer.Render(message.View);
+        await BatchMessageEditor.EditBatchMessageAsync(
+            bot,
+            chatId: ParseLong(message.Group.ExternalGroupId),
+            messageId: ParseInt(message.ExistingMessage.ExternalMessageId),
+            text: renderResult.Text,
+            replyMarkup: renderResult.Markup,
+            ct);
+    }
+
+    public Task SendGroupMessageAsync(PlatformGroup group, string htmlText, CancellationToken ct)
+    {
+        EnsureTelegram(group.Platform);
+        return bot.SendMessage(
+            chatId: ParseLong(group.ExternalGroupId),
+            messageThreadId: ParseNullableInt(group.ExternalThreadId),
+            text: htmlText,
+            parseMode: ParseMode.Html,
+            cancellationToken: ct);
+    }
+
+    public Task SendPrivateMessageAsync(PlatformPrivateMessage message, CancellationToken ct)
+    {
+        EnsureTelegram(message.Recipient.Platform);
+        return bot.SendMessage(
+            chatId: ParseLong(message.Recipient.ExternalUserId),
+            text: message.HtmlText,
+            parseMode: ParseMode.Html,
+            cancellationToken: ct);
+    }
+
+    public Task AnswerInteractionAsync(PlatformInteractionReply reply, CancellationToken ct) =>
+        bot.AnswerCallbackQuery(
+            callbackQueryId: reply.InteractionId,
+            text: reply.Text,
+            showAlert: reply.ShowAlert,
+            cancellationToken: ct);
+
+    public async Task SendCalendarFileAsync(PlatformCalendarFile file, CancellationToken ct)
+    {
+        EnsureTelegram(file.Group.Platform);
+
+        using var stream = new MemoryStream(file.Content);
+        await bot.SendDocument(
+            chatId: ParseLong(file.Group.ExternalGroupId),
+            messageThreadId: ParseNullableInt(file.Group.ExternalThreadId),
+            document: InputFile.FromStream(stream, file.FileName),
+            caption: file.CaptionHtml,
+            parseMode: ParseMode.Html,
+            replyMarkup: BuildActionsMarkup(file.Actions),
+            cancellationToken: ct);
+    }
+
+    private async Task<Message> SendScheduleTextMessage(
+        long chatId,
+        int? threadId,
+        string text,
+        InlineKeyboardMarkup markup,
+        CancellationToken ct) =>
+        await bot.SendMessage(
+            chatId: chatId,
+            messageThreadId: threadId,
+            text: text,
+            parseMode: ParseMode.Html,
+            replyMarkup: markup,
+            cancellationToken: ct);
+
+    private async Task TrySendScheduleImageOnly(
+        long chatId,
+        int? threadId,
+        string title,
+        string imageReference,
+        CancellationToken ct)
+    {
+        try
+        {
+            await bot.SendPhoto(
+                chatId: chatId,
+                messageThreadId: threadId,
+                photo: InputFile.FromString(imageReference),
+                caption: $"🎲 {System.Net.WebUtility.HtmlEncode(title)}",
+                parseMode: ParseMode.Html,
+                cancellationToken: ct);
+        }
+        catch (Exception ex)
+        {
+            logger.LogWarning(ex, "Failed to send Telegram schedule image for chat {ChatId}", chatId);
+        }
+    }
+
+    private static InlineKeyboardMarkup? BuildActionsMarkup(IReadOnlyList<PlatformMessageAction> actions)
+    {
+        if (actions.Count == 0)
+        {
+            return null;
+        }
+
+        return new InlineKeyboardMarkup(
+            actions.Select(action => new[]
+            {
+                Uri.TryCreate(action.Payload, UriKind.Absolute, out var uri) &&
+                (uri.Scheme == Uri.UriSchemeHttp || uri.Scheme == Uri.UriSchemeHttps)
+                    ? InlineKeyboardButton.WithUrl(action.Label, action.Payload)
+                    : InlineKeyboardButton.WithCallbackData(action.Label, action.Payload)
+            }));
+    }
+
+    private static void EnsureTelegram(PlatformKind platform)
+    {
+        if (platform != PlatformKind.Telegram)
+        {
+            throw new NotSupportedException($"Telegram messenger cannot send messages for platform {platform}.");
+        }
+    }
+
+    private static long ParseLong(string value) => long.Parse(value, CultureInfo.InvariantCulture);
+
+    private static int ParseInt(string value) => int.Parse(value, CultureInfo.InvariantCulture);
+
+    private static int? ParseNullableInt(string? value) =>
+        string.IsNullOrWhiteSpace(value) ? null : int.Parse(value, CultureInfo.InvariantCulture);
+}