taxbaik/TaxBaik.Web/Services/TelegramNotificationService.cs

namespace TaxBaik.Web.Services;

using System.Net.Http.Json;

/// <summary>
/// Telegram Bot 알림 서비스
/// 중요 로깅 및 오류를 Telegram으로 전송
/// </summary>
public interface ITelegramNotificationService
{
    Task SendMessageAsync(string message, CancellationToken ct = default);
    Task SendErrorAsync(string title, string details, CancellationToken ct = default);
    Task SendInfoAsync(string title, string message, CancellationToken ct = default);
}

public class TelegramNotificationService : ITelegramNotificationService
{
    private readonly HttpClient _httpClient;
    private readonly ILogger<TelegramNotificationService> _logger;
    private readonly string _botToken;
    private readonly string _chatId;
    private const string TelegramApiUrl = "https://api.telegram.org";

    public TelegramNotificationService(
        HttpClient httpClient,
        ILogger<TelegramNotificationService> logger,
        IConfiguration config)
    {
        _httpClient = httpClient;
        _logger = logger;
        _botToken = config["Telegram:BotToken"] ?? "";
        _chatId = config["Telegram:ChatId"] ?? "";
    }

    public async Task SendMessageAsync(string message, CancellationToken ct = default)
    {
        if (string.IsNullOrEmpty(_botToken) || string.IsNullOrEmpty(_chatId))
        {
            _logger.LogWarning("Telegram credentials not configured");
            return;
        }

        try
        {
            var url = $"{TelegramApiUrl}/bot{_botToken}/sendMessage";
            var payload = new
            {
                chat_id = _chatId,
                text = message,
                parse_mode = "HTML"
            };

            var response = await _httpClient.PostAsJsonAsync(url, payload, cancellationToken: ct);
            if (!response.IsSuccessStatusCode)
            {
                _logger.LogError("Failed to send Telegram message: {StatusCode}", response.StatusCode);
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error sending Telegram message");
        }
    }

    public async Task SendErrorAsync(string title, string details, CancellationToken ct = default)
    {
        var message = $"<b>❌ {title}</b>\n\n{details}\n\n<i>{DateTime.UtcNow:yyyy-MM-dd HH:mm:ss} UTC</i>";
        await SendMessageAsync(message, ct);
    }

    public async Task SendInfoAsync(string title, string message, CancellationToken ct = default)
    {
        var text = $"<b>ℹ️ {title}</b>\n\n{message}\n\n<i>{DateTime.UtcNow:yyyy-MM-dd HH:mm:ss} UTC</i>";
        await SendMessageAsync(text, ct);
    }
}