using Microsoft.Extensions.Options;
using PnvPanel.Application.Admin.Activation;
using PnvPanel.Application.Admin.Billing;
using PnvPanel.Application.Admin.Support;
using PnvPanel.Application.Billing;
using PnvPanel.Application.Billing.GetMyBillingStatus;
using PnvPanel.Application.Common.Interfaces;
using LiteCqrs;
using PnvPanel.Application.Configs.GetConfigLink;
using PnvPanel.Application.Configs.GetMyConfigs;
using PnvPanel.Application.Telegram;
using PnvPanel.Application.Telegram.Bot;
using PnvPanel.Domain.Activation;
using PnvPanel.Domain.Configs;
using PnvPanel.Infrastructure.Telegram;
using Telegram.Bot;
using Telegram.Bot.Polling;
using Telegram.Bot.Types;
using Telegram.Bot.Types.Enums;
using Telegram.Bot.Types.ReplyMarkups;

namespace PnvPanel.Api.Telegram;

/// <summary>
/// Обрабатывает апдейты бота. Каждый апдейт — свой DI-scope (как HTTP-запрос), чтобы получить
/// свежие scoped-сервисы (ISender, ICurrentUserSetter, ...). Бот — read-only по конфигам в MVP.
/// </summary>
public sealed class PnvBotUpdateHandler(
    IServiceScopeFactory scopeFactory,
    IOptions<TelegramOptions> options,
    ILogger<PnvBotUpdateHandler> logger
) : IUpdateHandler
{
    // Показывается везде, где боту нужен привязанный аккаунт, а его нет — явно проговариваем оба шага,
    // иначе новые пользователи не понимают, что сначала нужен обычный аккаунт на сайте.
    private const string NotLinkedMessage =
        "Сначала зарегистрируйтесь и войдите на сайте, затем привяжите Telegram: Настройки → «Привязать Telegram».";

    public async Task HandleUpdateAsync(
        ITelegramBotClient botClient,
        Update update,
        CancellationToken cancellationToken
    )
    {
        await using var scope = scopeFactory.CreateAsyncScope();

        try
        {
            if (update.Message is { Text: { } text } message)
                await HandleMessageAsync(
                    botClient,
                    scope.ServiceProvider,
                    message,
                    text,
                    cancellationToken
                );
            else if (update.CallbackQuery is { } callback)
                await HandleCallbackAsync(
                    botClient,
                    scope.ServiceProvider,
                    callback,
                    cancellationToken
                );
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "Failed to process Telegram update {UpdateId}", update.Id);
        }
    }

    public Task HandleErrorAsync(
        ITelegramBotClient botClient,
        Exception exception,
        HandleErrorSource source,
        CancellationToken cancellationToken
    )
    {
        logger.LogError(exception, "Telegram bot error (source {Source})", source);
        return Task.CompletedTask;
    }

    private async Task HandleMessageAsync(
        ITelegramBotClient botClient,
        IServiceProvider services,
        Message message,
        string text,
        CancellationToken cancellationToken
    )
    {
        var chatId = message.Chat.Id;
        var fromId = message.From?.Id;
        if (fromId is null)
            return;

        if (text.StartsWith("/start", StringComparison.Ordinal))
        {
            var payload = text.Length > 7 ? text[7..].Trim() : string.Empty;

            if (payload.StartsWith("link_", StringComparison.Ordinal))
                await HandleLinkAsync(
                    botClient,
                    services,
                    chatId,
                    fromId.Value,
                    message.From?.Username,
                    payload[5..],
                    cancellationToken
                );
            else if (payload.StartsWith("login_", StringComparison.Ordinal))
                await HandleLoginPromptAsync(
                    botClient,
                    services,
                    chatId,
                    fromId.Value,
                    payload[6..],
                    cancellationToken
                );
            else
                await SendWelcomeAsync(
                    botClient,
                    services,
                    chatId,
                    fromId.Value,
                    cancellationToken
                );

            return;
        }

        switch (text)
        {
            case "/configs":
                await HandleConfigsAsync(
                    botClient,
                    services,
                    chatId,
                    fromId.Value,
                    cancellationToken
                );
                break;
            case "/billing":
                await HandleBillingStatusAsync(
                    botClient,
                    services,
                    chatId,
                    fromId.Value,
                    cancellationToken
                );
                break;
            case "/unlink":
                await HandleUnlinkAsync(
                    botClient,
                    services,
                    chatId,
                    fromId.Value,
                    cancellationToken
                );
                break;
            case "/requests":
                await HandleRequestsAsync(
                    botClient,
                    services,
                    chatId,
                    fromId.Value,
                    cancellationToken
                );
                break;
            case "/help":
                await SendWelcomeAsync(
                    botClient,
                    services,
                    chatId,
                    fromId.Value,
                    cancellationToken
                );
                break;
            default:
                await botClient.SendMessage(
                    chatId,
                    "Не понимаю эту команду. /help — список команд.",
                    cancellationToken: cancellationToken
                );
                break;
        }
    }

    private async Task HandleCallbackAsync(
        ITelegramBotClient botClient,
        IServiceProvider services,
        CallbackQuery callback,
        CancellationToken cancellationToken
    )
    {
        var data = callback.Data;
        var chatId = callback.Message?.Chat.Id;
        var fromId = callback.From.Id;
        if (data is null || chatId is null)
            return;

        if (data == "reg:new")
        {
            await HandleRegisterCallbackAsync(
                botClient,
                services,
                chatId.Value,
                fromId,
                callback.From.Username,
                callback.Id,
                cancellationToken
            );
            return;
        }

        if (data == "menu:configs")
        {
            if (!await TrySetCurrentUserAsync(services, fromId, cancellationToken))
            {
                await botClient.AnswerCallbackQuery(
                    callback.Id,
                    "Telegram не привязан.",
                    cancellationToken: cancellationToken
                );
                return;
            }

            await botClient.AnswerCallbackQuery(callback.Id, cancellationToken: cancellationToken);

            var (configsText, configsKeyboard) = await BuildConfigsMenuAsync(
                services,
                cancellationToken
            );
            if (callback.Message is not null)
                await botClient.EditMessageText(
                    chatId.Value,
                    callback.Message.Id,
                    configsText,
                    replyMarkup: configsKeyboard,
                    cancellationToken: cancellationToken
                );

            return;
        }

        if (data == "menu:billing")
        {
            if (!await TrySetCurrentUserAsync(services, fromId, cancellationToken))
            {
                await botClient.AnswerCallbackQuery(
                    callback.Id,
                    "Telegram не привязан.",
                    cancellationToken: cancellationToken
                );
                return;
            }

            await botClient.AnswerCallbackQuery(callback.Id, cancellationToken: cancellationToken);

            var (billingText, billingKeyboard) = await BuildBillingStatusMenuAsync(
                services,
                cancellationToken
            );
            if (callback.Message is not null)
                await botClient.EditMessageText(
                    chatId.Value,
                    callback.Message.Id,
                    billingText,
                    replyMarkup: billingKeyboard,
                    cancellationToken: cancellationToken
                );

            return;
        }

        if (data == "menu:back")
        {
            await botClient.AnswerCallbackQuery(callback.Id, cancellationToken: cancellationToken);
            if (callback.Message is null)
                return;

            var identityService = services.GetRequiredService<IIdentityService>();
            var linkedUserId = await identityService.FindUserIdByTelegramUserIdAsync(
                fromId,
                cancellationToken
            );
            var linkedProfile =
                linkedUserId is { } uid ? await identityService.GetProfileAsync(uid, cancellationToken) : null;
            var (menuText, menuKeyboard) = BuildMainMenu(
                isLinked: linkedUserId is not null,
                billingEnabled: linkedProfile?.BillingEnabled ?? false
            );
            await botClient.EditMessageText(
                chatId.Value,
                callback.Message.Id,
                menuText,
                replyMarkup: menuKeyboard,
                cancellationToken: cancellationToken
            );

            return;
        }

        if (data == "menu:unlink")
        {
            if (!await TrySetCurrentUserAsync(services, fromId, cancellationToken))
            {
                await botClient.AnswerCallbackQuery(
                    callback.Id,
                    "Telegram не привязан.",
                    cancellationToken: cancellationToken
                );
                return;
            }

            var unlinkSender = services.GetRequiredService<ISender>();
            var unlinkResult = await unlinkSender.Send(
                new UnlinkTelegramCommand(),
                cancellationToken
            );
            await botClient.AnswerCallbackQuery(callback.Id, cancellationToken: cancellationToken);

            if (callback.Message is null)
                return;

            if (!unlinkResult.IsSuccess)
            {
                await botClient.EditMessageText(
                    chatId.Value,
                    callback.Message.Id,
                    $"❌ Ошибка: {unlinkResult.Error.Message}",
                    replyMarkup: BackToMenuKeyboard(),
                    cancellationToken: cancellationToken
                );
                return;
            }

            var (unlinkedText, unlinkedKeyboard) = BuildMainMenu(isLinked: false);
            await botClient.EditMessageText(
                chatId.Value,
                callback.Message.Id,
                "✅ Telegram отвязан от аккаунта.\n\n" + unlinkedText,
                replyMarkup: unlinkedKeyboard,
                cancellationToken: cancellationToken
            );

            return;
        }

        var parts = data.Split(':');
        if (parts.Length != 3 || !Guid.TryParse(parts[2], out var requestId))
            return;

        var sender = services.GetRequiredService<ISender>();

        switch (parts[0])
        {
            case "login":
                {
                    var result =
                        parts[1] == "approve"
                            ? await sender.Send(
                                new ApproveTelegramLoginCommand(requestId, fromId),
                                cancellationToken
                            )
                            : await sender.Send(
                                new RejectTelegramLoginCommand(requestId, fromId),
                                cancellationToken
                            );

                    await botClient.AnswerCallbackQuery(
                        callback.Id,
                        result.IsSuccess ? "Готово" : result.Error.Message,
                        cancellationToken: cancellationToken
                    );
                    if (callback.Message is not null)
                    {
                        var statusText = result.IsSuccess
                            ? (parts[1] == "approve" ? "✅ Вход подтверждён." : "❌ Вход отклонён.")
                            : $"⚠️ {result.Error.Message}";
                        var text = $"{Escape(callback.Message.Text ?? "")}\n\n{statusText}";
                        await botClient.EditMessageText(
                            chatId.Value,
                            callback.Message.Id,
                            text,
                            parseMode: ParseMode.Html,
                            cancellationToken: cancellationToken
                        );
                    }

                    break;
                }
            case "act":
                {
                    if (!await TrySetAdminCurrentUserAsync(services, fromId, cancellationToken))
                    {
                        await botClient.AnswerCallbackQuery(
                            callback.Id,
                            "Недостаточно прав.",
                            cancellationToken: cancellationToken
                        );
                        return;
                    }

                    var result =
                        parts[1] == "approve"
                            ? await sender.Send(
                                new ApproveActivationCommand(requestId),
                                cancellationToken
                            )
                            : await sender.Send(
                                new RejectActivationCommand(requestId, Reason: null),
                                cancellationToken
                            );

                    await botClient.AnswerCallbackQuery(
                        callback.Id,
                        result.IsSuccess ? "Готово" : result.Error.Message,
                        cancellationToken: cancellationToken
                    );
                    if (callback.Message is not null)
                    {
                        // Редактируем исходное сообщение с запросом вместо отдельного — иначе кнопки
                        // «Активировать/Отклонить» остаются висеть под уже обработанным запросом (в т.ч.
                        // если его обработали в другом месте — на сайте или из другого чата).
                        var statusText = result.IsSuccess
                            ? (
                                parts[1] == "approve"
                                    ? "✅ Пользователь активирован."
                                    : "❌ Запрос отклонён."
                            )
                            : $"⚠️ {result.Error.Message}";
                        var text = $"{Escape(callback.Message.Text ?? "")}\n\n{statusText}";
                        await botClient.EditMessageText(
                            chatId.Value,
                            callback.Message.Id,
                            text,
                            parseMode: ParseMode.Html,
                            cancellationToken: cancellationToken
                        );
                    }

                    break;
                }
            case "erq":
                {
                    if (!await TrySetAdminCurrentUserAsync(services, fromId, cancellationToken))
                    {
                        await botClient.AnswerCallbackQuery(
                            callback.Id,
                            "Недостаточно прав.",
                            cancellationToken: cancellationToken
                        );
                        return;
                    }

                    var result =
                        parts[1] == "approve"
                            ? await sender.Send(
                                new ApproveExtensionRequestCommand(requestId),
                                cancellationToken
                            )
                            : await sender.Send(
                                new RejectExtensionRequestCommand(requestId, Reason: null),
                                cancellationToken
                            );

                    await botClient.AnswerCallbackQuery(
                        callback.Id,
                        result.IsSuccess ? "Готово" : result.Error.Message,
                        cancellationToken: cancellationToken
                    );
                    if (callback.Message is not null)
                    {
                        var statusText = result.IsSuccess
                            ? (
                                parts[1] == "approve"
                                    ? "✅ Заявка на продление одобрена."
                                    : "❌ Заявка отклонена."
                            )
                            : $"⚠️ {result.Error.Message}";
                        var text = $"{Escape(callback.Message.Text ?? "")}\n\n{statusText}";
                        await botClient.EditMessageText(
                            chatId.Value,
                            callback.Message.Id,
                            text,
                            parseMode: ParseMode.Html,
                            cancellationToken: cancellationToken
                        );
                    }

                    break;
                }
            case "pay":
                {
                    if (!await TrySetAdminCurrentUserAsync(services, fromId, cancellationToken))
                    {
                        await botClient.AnswerCallbackQuery(
                            callback.Id,
                            "Недостаточно прав.",
                            cancellationToken: cancellationToken
                        );
                        return;
                    }

                    var result =
                        parts[1] == "approve"
                            ? await sender.Send(
                                new ConfirmPaymentRequestCommand(requestId),
                                cancellationToken
                            )
                            : await sender.Send(
                                new RejectPaymentRequestCommand(requestId, Reason: null),
                                cancellationToken
                            );

                    await botClient.AnswerCallbackQuery(
                        callback.Id,
                        result.IsSuccess ? "Готово" : result.Error.Message,
                        cancellationToken: cancellationToken
                    );
                    if (callback.Message is not null)
                    {
                        var statusText = result.IsSuccess
                            ? (
                                parts[1] == "approve"
                                    ? "✅ Оплата подтверждена."
                                    : "❌ Оплата отклонена."
                            )
                            : $"⚠️ {result.Error.Message}";
                        var text = $"{Escape(callback.Message.Text ?? "")}\n\n{statusText}";
                        await botClient.EditMessageText(
                            chatId.Value,
                            callback.Message.Id,
                            text,
                            parseMode: ParseMode.Html,
                            cancellationToken: cancellationToken
                        );
                    }

                    break;
                }
            case "cfg":
                {
                    if (!await TrySetCurrentUserAsync(services, fromId, cancellationToken))
                    {
                        await botClient.AnswerCallbackQuery(
                            callback.Id,
                            "Telegram не привязан.",
                            cancellationToken: cancellationToken
                        );
                        return;
                    }

                    var linkResult = await sender.Send(
                        new GetConfigLinkQuery(requestId),
                        cancellationToken
                    );
                    await botClient.AnswerCallbackQuery(
                        callback.Id,
                        cancellationToken: cancellationToken
                    );

                    if (!linkResult.IsSuccess)
                    {
                        await botClient.SendMessage(
                            chatId.Value,
                            $"Не удалось получить ссылку: {linkResult.Error.Message}",
                            cancellationToken: cancellationToken
                        );
                        return;
                    }

                    if (callback.Message is null)
                        break;

                    // Редактируем то же сообщение (не плодим отдельное с сырым URL) — ссылка моноширинным
                    // блоком, по нему в Telegram можно тапнуть и скопировать целиком одним движением.
                    // Убираем именно эту кнопку из клавиатуры — остальные конфиги и «В меню» остаются на месте.
                    var text =
                        $"{Escape(callback.Message.Text ?? "")}\n\n<code>{Escape(linkResult.Value.ConnectionString)}</code>";
                    var remainingRows = (callback.Message.ReplyMarkup?.InlineKeyboard ?? [])
                        .Where(row => row.All(b => b.CallbackData != data))
                        .ToArray();

                    await botClient.EditMessageText(
                        chatId.Value,
                        callback.Message.Id,
                        text,
                        parseMode: ParseMode.Html,
                        replyMarkup: remainingRows.Length > 0
                            ? new InlineKeyboardMarkup(remainingRows)
                            : null,
                        cancellationToken: cancellationToken
                    );

                    break;
                }
        }
    }

    private async Task HandleLinkAsync(
        ITelegramBotClient botClient,
        IServiceProvider services,
        long chatId,
        long fromId,
        string? username,
        string token,
        CancellationToken cancellationToken
    )
    {
        var sender = services.GetRequiredService<ISender>();
        var result = await sender.Send(
            new LinkTelegramCommand(token, fromId, username),
            cancellationToken
        );

        var text = result.IsSuccess
            ? "✅ Telegram успешно привязан к вашему аккаунту."
            : $"❌ Не удалось привязать: {result.Error.Message}";

        await botClient.SendMessage(chatId, text, cancellationToken: cancellationToken);
    }

    private async Task HandleLoginPromptAsync(
        ITelegramBotClient botClient,
        IServiceProvider services,
        long chatId,
        long fromId,
        string requestIdRaw,
        CancellationToken cancellationToken
    )
    {
        if (!Guid.TryParse(requestIdRaw, out var requestId))
        {
            await botClient.SendMessage(
                chatId,
                "Некорректная ссылка входа.",
                cancellationToken: cancellationToken
            );
            return;
        }

        var identityService = services.GetRequiredService<IIdentityService>();
        var userId = await identityService.FindUserIdByTelegramUserIdAsync(
            fromId,
            cancellationToken
        );
        if (userId is null)
        {
            await botClient.SendMessage(
                chatId,
                NotLinkedMessage,
                replyMarkup: new InlineKeyboardMarkup(
                    new[]
                    {
                        InlineKeyboardButton.WithCallbackData("📝 Зарегистрироваться", "reg:new"),
                    }
                ),
                cancellationToken: cancellationToken
            );
            return;
        }

        var keyboard = new InlineKeyboardMarkup(
            new[]
            {
                InlineKeyboardButton.WithCallbackData(
                    "✅ Подтвердить вход",
                    $"login:approve:{requestId}"
                ),
                InlineKeyboardButton.WithCallbackData("❌ Отклонить", $"login:reject:{requestId}"),
            }
        );

        await botClient.SendMessage(
            chatId,
            "Кто-то пытается войти в PnvPanel через ваш аккаунт. Подтвердить вход?",
            replyMarkup: keyboard,
            cancellationToken: cancellationToken
        );
    }

    private async Task HandleConfigsAsync(
        ITelegramBotClient botClient,
        IServiceProvider services,
        long chatId,
        long fromId,
        CancellationToken cancellationToken
    )
    {
        if (!await TrySetCurrentUserAsync(services, fromId, cancellationToken))
        {
            await botClient.SendMessage(
                chatId,
                NotLinkedMessage,
                replyMarkup: new InlineKeyboardMarkup(
                    new[]
                    {
                        InlineKeyboardButton.WithCallbackData("📝 Зарегистрироваться", "reg:new"),
                    }
                ),
                cancellationToken: cancellationToken
            );
            return;
        }

        var (text, keyboard) = await BuildConfigsMenuAsync(services, cancellationToken);
        await botClient.SendMessage(
            chatId,
            text,
            replyMarkup: keyboard,
            cancellationToken: cancellationToken
        );
    }

    /// <summary>Список конфигов одним сообщением: строка на конфиг + кнопка «🔗 {Label}» на каждый
    /// не отозванный, плюс «🔙 В меню» внизу.</summary>
    private static async Task<(string Text, InlineKeyboardMarkup Keyboard)> BuildConfigsMenuAsync(
        IServiceProvider services,
        CancellationToken cancellationToken
    )
    {
        var sender = services.GetRequiredService<ISender>();
        var result = await sender.Send(new GetMyConfigsQuery(), cancellationToken);

        if (!result.IsSuccess || result.Value.Configs.Count == 0)
            return ("У вас пока нет конфигов.", BackToMenuKeyboard());

        var text =
            "Ваши конфиги:\n"
            + string.Join(
                '\n',
                result.Value.Configs.Select(c =>
                    $"• {c.Label ?? c.Location} ({c.Protocol}) — {c.Status}"
                )
            );

        // Отозванному конфигу нечего показывать — кнопку не даём.
        var rows = result
            .Value.Configs.Where(c => c.Status != ConfigStatus.Revoked)
            .Select(c =>
                new[]
                {
                    InlineKeyboardButton.WithCallbackData(
                        $"🔗 {c.Label ?? c.Location}",
                        $"cfg:link:{c.Id}"
                    ),
                }
            )
            .Append(BackToMenuRow())
            .ToArray();

        return (text, new InlineKeyboardMarkup(rows));
    }

    private async Task HandleBillingStatusAsync(
        ITelegramBotClient botClient,
        IServiceProvider services,
        long chatId,
        long fromId,
        CancellationToken cancellationToken
    )
    {
        if (!await TrySetCurrentUserAsync(services, fromId, cancellationToken))
        {
            await botClient.SendMessage(chatId, NotLinkedMessage, cancellationToken: cancellationToken);
            return;
        }

        var (text, keyboard) = await BuildBillingStatusMenuAsync(services, cancellationToken);
        await botClient.SendMessage(
            chatId,
            text,
            replyMarkup: keyboard,
            cancellationToken: cancellationToken
        );
    }

    /// <summary>До какого числа оплачено + остаток в человекочитаемом виде (дни, либо часы/минуты,
    /// если меньше суток) — то же форматирование, что и на сайте (PaidUntilBadge).</summary>
    private static async Task<(string Text, InlineKeyboardMarkup Keyboard)> BuildBillingStatusMenuAsync(
        IServiceProvider services,
        CancellationToken cancellationToken
    )
    {
        var sender = services.GetRequiredService<ISender>();
        var result = await sender.Send(new GetMyBillingStatusQuery(), cancellationToken);

        if (!result.IsSuccess)
            return ($"⚠️ {result.Error.Message}", BackToMenuKeyboard());

        var status = result.Value;
        if (!status.BillingEnabled)
            return ("Биллинг не применяется к вашей роли.", BackToMenuKeyboard());

        if (status.PaidUntil is not { } paidUntil)
            return ("Оплата ещё не производилась.", BackToMenuKeyboard());

        var text =
            $"💳 Оплачено до {paidUntil:dd.MM.yyyy HH:mm}\nОсталось: {FormatRemaining(paidUntil)}"
            + (status.Suspended ? "\n\n⛔ Конфиги приостановлены за неуплату." : "");

        return (text, BackToMenuKeyboard());
    }

    private static string FormatRemaining(DateTimeOffset paidUntil)
    {
        var remaining = paidUntil - DateTimeOffset.UtcNow;
        if (remaining <= TimeSpan.Zero)
            return "истекло";

        if (remaining < TimeSpan.FromDays(1))
        {
            var totalMinutes = (int)Math.Ceiling(remaining.TotalMinutes);
            var hours = totalMinutes / 60;
            var minutes = totalMinutes % 60;
            return hours > 0 ? $"{hours} ч {minutes} мин" : $"{minutes} мин";
        }

        var days = (int)Math.Ceiling(remaining.TotalDays);
        return $"{days} дн.";
    }

    private static InlineKeyboardButton[] BackToMenuRow() =>
        new[] { InlineKeyboardButton.WithCallbackData("🔙 В меню", "menu:back") };

    private static InlineKeyboardMarkup BackToMenuKeyboard() => new(new[] { BackToMenuRow() });

    private async Task HandleUnlinkAsync(
        ITelegramBotClient botClient,
        IServiceProvider services,
        long chatId,
        long fromId,
        CancellationToken cancellationToken
    )
    {
        if (!await TrySetCurrentUserAsync(services, fromId, cancellationToken))
        {
            await botClient.SendMessage(
                chatId,
                "Telegram не привязан.",
                cancellationToken: cancellationToken
            );
            return;
        }

        var sender = services.GetRequiredService<ISender>();
        var result = await sender.Send(new UnlinkTelegramCommand(), cancellationToken);

        await botClient.SendMessage(
            chatId,
            result.IsSuccess ? "Telegram отвязан от аккаунта." : $"Ошибка: {result.Error.Message}",
            cancellationToken: cancellationToken
        );
    }

    private async Task HandleRequestsAsync(
        ITelegramBotClient botClient,
        IServiceProvider services,
        long chatId,
        long fromId,
        CancellationToken cancellationToken
    )
    {
        if (!await TrySetAdminCurrentUserAsync(services, fromId, cancellationToken))
        {
            await botClient.SendMessage(
                chatId,
                "Недостаточно прав.",
                cancellationToken: cancellationToken
            );
            return;
        }

        var sender = services.GetRequiredService<ISender>();
        var result = await sender.Send(
            new ListActivationRequestsQuery(ActivationStatus.Pending, 1, 10),
            cancellationToken
        );

        if (!result.IsSuccess || result.Value.Items.Count == 0)
        {
            await botClient.SendMessage(
                chatId,
                "Нет ожидающих запросов на активацию.",
                cancellationToken: cancellationToken
            );
            return;
        }

        foreach (var item in result.Value.Items)
        {
            var text =
                $"Запрос от <b>{item.UserName}</b>"
                + (string.IsNullOrWhiteSpace(item.Comment) ? "" : $"\n{item.Comment}");
            var keyboard = new InlineKeyboardMarkup(
                new[]
                {
                    InlineKeyboardButton.WithCallbackData(
                        "✅ Активировать",
                        $"act:approve:{item.Id}"
                    ),
                    InlineKeyboardButton.WithCallbackData("❌ Отклонить", $"act:reject:{item.Id}"),
                }
            );
            await botClient.SendMessage(
                chatId,
                text,
                parseMode: ParseMode.Html,
                replyMarkup: keyboard,
                cancellationToken: cancellationToken
            );
        }
    }

    private async Task SendWelcomeAsync(
        ITelegramBotClient botClient,
        IServiceProvider services,
        long chatId,
        long fromId,
        CancellationToken cancellationToken
    )
    {
        var identityService = services.GetRequiredService<IIdentityService>();
        var userId = await identityService.FindUserIdByTelegramUserIdAsync(
            fromId,
            cancellationToken
        );
        var profile =
            userId is { } uid ? await identityService.GetProfileAsync(uid, cancellationToken) : null;

        var (text, keyboard) = BuildMainMenu(
            isLinked: userId is not null,
            billingEnabled: profile?.BillingEnabled ?? false
        );
        await botClient.SendMessage(
            chatId,
            text,
            replyMarkup: keyboard,
            cancellationToken: cancellationToken
        );
    }

    /// <summary>Привязанному аккаунту — кнопки-действия вместо текстовых команд; непривязанному —
    /// только регистрация (остальное ему всё равно недоступно). Кнопка на сайт — если задан PublicSiteUrl.
    /// billingEnabled — показать «Статус оплаты» только для billing-ролей (см. AppRole.BillingEnabled).</summary>
    private (string Text, InlineKeyboardMarkup Keyboard) BuildMainMenu(bool isLinked, bool billingEnabled = false)
    {
        const string text =
            "Привет! Это бот PnvPanel.\n\n"
            + "Вход без пароля запускается кнопкой «Войти через Telegram» на сайте — бот пришлёт запрос на подтверждение.";

        var rows = new List<InlineKeyboardButton[]>();
        if (isLinked)
        {
            rows.Add(
                new[] { InlineKeyboardButton.WithCallbackData("📋 Мои конфиги", "menu:configs") }
            );
            if (billingEnabled)
                rows.Add(
                    new[]
                    {
                        InlineKeyboardButton.WithCallbackData("💳 Статус оплаты", "menu:billing"),
                    }
                );
            rows.Add(
                new[]
                {
                    InlineKeyboardButton.WithCallbackData("🔓 Отвязать Telegram", "menu:unlink"),
                }
            );
        }
        else
        {
            rows.Add(
                new[] { InlineKeyboardButton.WithCallbackData("📝 Зарегистрироваться", "reg:new") }
            );
        }

        if (!string.IsNullOrWhiteSpace(options.Value.PublicSiteUrl))
            rows.Add(
                new[]
                {
                    InlineKeyboardButton.WithUrl("🌐 Сайт панели", options.Value.PublicSiteUrl),
                }
            );

        return (text, new InlineKeyboardMarkup(rows));
    }

    private static async Task HandleRegisterCallbackAsync(
        ITelegramBotClient botClient,
        IServiceProvider services,
        long chatId,
        long fromId,
        string? username,
        string callbackId,
        CancellationToken cancellationToken
    )
    {
        var sender = services.GetRequiredService<ISender>();
        var result = await sender.Send(
            new RegisterViaTelegramCommand(fromId, username),
            cancellationToken
        );

        await botClient.AnswerCallbackQuery(callbackId, cancellationToken: cancellationToken);

        if (!result.IsSuccess)
        {
            await botClient.SendMessage(
                chatId,
                $"Не удалось зарегистрироваться: {result.Error.Message}",
                cancellationToken: cancellationToken
            );
            return;
        }

        var text =
            "✅ Аккаунт создан.\n\n"
            + $"Логин: <code>{result.Value.UserName}</code>\n"
            + $"Пароль: <code>{result.Value.Password}</code>\n\n"
            + "Сохраните пароль — он присылается только один раз. Логин можно сменить в Настройках на сайте.\n\n"
            + "Дальше нужно дождаться активации администратором — после неё будут доступны конфиги. "
            + "Входить можно как по паролю, так и кнопкой «Войти через Telegram».";

        await botClient.SendMessage(
            chatId,
            text,
            parseMode: ParseMode.Html,
            cancellationToken: cancellationToken
        );
    }

    private static string Escape(string text) =>
        text.Replace("&", "&amp;").Replace("<", "&lt;").Replace(">", "&gt;");

    private static async Task<bool> TrySetCurrentUserAsync(
        IServiceProvider services,
        long telegramUserId,
        CancellationToken cancellationToken
    )
    {
        var identityService = services.GetRequiredService<IIdentityService>();
        var userId = await identityService.FindUserIdByTelegramUserIdAsync(
            telegramUserId,
            cancellationToken
        );
        if (userId is null)
            return false;

        var profile = await identityService.GetProfileAsync(userId.Value, cancellationToken);
        if (profile is null)
            return false;

        services.GetRequiredService<ICurrentUserSetter>().SetUser(profile.Id, profile.UserName);
        return true;
    }

    private async Task<bool> TrySetAdminCurrentUserAsync(
        IServiceProvider services,
        long telegramUserId,
        CancellationToken cancellationToken
    )
    {
        if (!options.Value.ParseAdminTelegramUserIds().Contains(telegramUserId))
            return false;

        return await TrySetCurrentUserAsync(services, telegramUserId, cancellationToken);
    }
}