taxbaik/src/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);
    Task SendInquiryNotificationAsync(string message, CancellationToken ct = default);
    Task SendSystemNotificationAsync(string message, CancellationToken ct = default);
    Task SendReportAsync(string reportTitle, string reportContent, CancellationToken ct = default);
}

public class TelegramNotificationService : ITelegramNotificationService
{
    private readonly HttpClient _httpClient;
    private readonly ILogger<TelegramNotificationService> _logger;
    private readonly string _botToken;
    private readonly string _defaultChatId;
    private readonly string _inquiryChatId;
    private readonly string _systemChatId;
    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"] ?? "";
        _defaultChatId = config["Telegram:ChatId"] ?? "-5434691215";
        _inquiryChatId = config["Telegram:InquiryChatId"] ?? _defaultChatId;
        _systemChatId = config["Telegram:SystemChatId"] ?? "-5585148480";
    }

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

        if (!TelegramAlertGate.ShouldSend("telegram:default", message, TimeSpan.FromMinutes(5)))
            return;

        await SendToChat(_defaultChatId, message, ct);
    }

    public async Task SendInquiryNotificationAsync(string message, CancellationToken ct = default)
    {
        var text = $"<b>📋 문의 사항</b>\n\n{message}";
        if (!TelegramAlertGate.ShouldSend("telegram:inquiry", text, TimeSpan.FromMinutes(10)))
            return;

        await SendToChat(_inquiryChatId, text, ct);
    }

    public async Task SendSystemNotificationAsync(string message, CancellationToken ct = default)
    {
        var text = $"<b>🔧 시스템 알림</b>\n\n{message}";
        if (!TelegramAlertGate.ShouldSend("telegram:system", text, TimeSpan.FromMinutes(10)))
            return;

        await SendToChat(_systemChatId, text, ct);
    }

    private async Task SendToChat(string chatId, string message, CancellationToken ct)
    {
        if (string.IsNullOrEmpty(_botToken) || string.IsNullOrEmpty(chatId))
        {
            _logger.LogWarning("Telegram credentials not configured for chatId {ChatId}", chatId);
            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 to {ChatId}: {StatusCode}", chatId, response.StatusCode);
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error sending Telegram message to {ChatId}", chatId);
        }
    }

    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>";
        if (!TelegramAlertGate.ShouldSend("telegram:error", message, TimeSpan.FromMinutes(15)))
            return;

        await SendToChat(_systemChatId, 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>";
        if (!TelegramAlertGate.ShouldSend("telegram:info", text, TimeSpan.FromMinutes(30)))
            return;

        await SendToChat(_defaultChatId, text, ct);
    }

    public async Task SendReportAsync(string reportTitle, string reportContent, CancellationToken ct = default)
    {
        var text = $"<b>📊 {reportTitle}</b>\n\n{reportContent}\n\n<i>{DateTime.UtcNow:yyyy-MM-dd HH:mm:ss} UTC</i>";
        if (!TelegramAlertGate.ShouldSend("telegram:report", text, TimeSpan.FromHours(20)))
            return;

        await SendToChat(_systemChatId, text, ct);
    }
}