SPMS.Application/DTOs/Push/PushResultDto.cs

@@ -0,0 +1,11 @@
+namespace SPMS.Application.DTOs.Push;
+
+public class PushResultDto
+{
+    public string DeviceToken { get; set; } = string.Empty;
+    public bool IsSuccess { get; set; }
+    public string? ErrorCode { get; set; }
+    public string? ErrorMessage { get; set; }
+    public bool ShouldRemoveDevice { get; set; }
+    public bool ShouldRetry { get; set; }
+}

SPMS.Application/Interfaces/IFcmSender.cs

@@ -0,0 +1,24 @@
+using SPMS.Application.DTOs.Push;
+
+namespace SPMS.Application.Interfaces;
+
+public interface IFcmSender
+{
+    Task<PushResultDto> SendAsync(
+        string fcmCredentialsJson,
+        string deviceToken,
+        string title,
+        string body,
+        string? imageUrl,
+        Dictionary<string, string>? data,
+        CancellationToken cancellationToken = default);
+
+    Task<List<PushResultDto>> SendBatchAsync(
+        string fcmCredentialsJson,
+        List<string> deviceTokens,
+        string title,
+        string body,
+        string? imageUrl,
+        Dictionary<string, string>? data,
+        CancellationToken cancellationToken = default);
+}

SPMS.Infrastructure/DependencyInjection.cs

@@ -7,6 +7,7 @@ using SPMS.Domain.Interfaces;
 using SPMS.Infrastructure.Auth;
 using SPMS.Infrastructure.Messaging;
 using SPMS.Infrastructure.Persistence;
+using SPMS.Infrastructure.Push;
 using SPMS.Infrastructure.Persistence.Repositories;
 using SPMS.Infrastructure.Security;
 using SPMS.Infrastructure.Services;
@@ -51,6 +52,9 @@ public static class DependencyInjection
         services.AddHostedService<RabbitMQInitializer>();
         services.AddScoped<IPushQueueService, PushQueueService>();
 
+        // Push Senders
+        services.AddSingleton<IFcmSender, FcmSender>();
+
         // Token Store & Email Service
         services.AddMemoryCache();
         services.AddSingleton<ITokenStore, InMemoryTokenStore>();

SPMS.Infrastructure/Push/FcmSender.cs

@@ -0,0 +1,206 @@
+using System.Collections.Concurrent;
+using System.Security.Cryptography;
+using System.Text;
+using FirebaseAdmin;
+using FirebaseAdmin.Messaging;
+using Google.Apis.Auth.OAuth2;
+using Microsoft.Extensions.Logging;
+using SPMS.Application.DTOs.Push;
+using SPMS.Application.Interfaces;
+
+namespace SPMS.Infrastructure.Push;
+
+public class FcmSender : IFcmSender
+{
+    private readonly ConcurrentDictionary<string, FirebaseApp> _apps = new();
+    private readonly ILogger<FcmSender> _logger;
+
+    public FcmSender(ILogger<FcmSender> logger)
+    {
+        _logger = logger;
+    }
+
+    public async Task<PushResultDto> SendAsync(
+        string fcmCredentialsJson,
+        string deviceToken,
+        string title,
+        string body,
+        string? imageUrl,
+        Dictionary<string, string>? data,
+        CancellationToken cancellationToken = default)
+    {
+        var app = GetOrCreateApp(fcmCredentialsJson);
+        var messaging = FirebaseMessaging.GetMessaging(app);
+
+        var message = BuildMessage(deviceToken, title, body, imageUrl, data);
+
+        try
+        {
+            await messaging.SendAsync(message, cancellationToken);
+            return new PushResultDto
+            {
+                DeviceToken = deviceToken,
+                IsSuccess = true
+            };
+        }
+        catch (FirebaseMessagingException ex)
+        {
+            return MapException(deviceToken, ex);
+        }
+    }
+
+    public async Task<List<PushResultDto>> SendBatchAsync(
+        string fcmCredentialsJson,
+        List<string> deviceTokens,
+        string title,
+        string body,
+        string? imageUrl,
+        Dictionary<string, string>? data,
+        CancellationToken cancellationToken = default)
+    {
+        var app = GetOrCreateApp(fcmCredentialsJson);
+        var messaging = FirebaseMessaging.GetMessaging(app);
+        var results = new List<PushResultDto>();
+
+        foreach (var chunk in deviceTokens.Chunk(500))
+        {
+            var multicastMessage = new MulticastMessage
+            {
+                Tokens = chunk.ToList(),
+                Notification = new Notification
+                {
+                    Title = title,
+                    Body = body,
+                    ImageUrl = imageUrl
+                },
+                Data = data,
+                Android = new AndroidConfig
+                {
+                    Priority = Priority.High
+                }
+            };
+
+            var response = await messaging.SendEachForMulticastAsync(
+                multicastMessage, cancellationToken);
+
+            for (var i = 0; i < chunk.Length; i++)
+            {
+                var sendResponse = response.Responses[i];
+                var token = chunk[i];
+
+                if (sendResponse.IsSuccess)
+                {
+                    results.Add(new PushResultDto
+                    {
+                        DeviceToken = token,
+                        IsSuccess = true
+                    });
+                }
+                else
+                {
+                    var result = sendResponse.Exception is FirebaseMessagingException fme
+                        ? MapException(token, fme)
+                        : new PushResultDto
+                        {
+                            DeviceToken = token,
+                            IsSuccess = false,
+                            ErrorCode = "UNKNOWN",
+                            ErrorMessage = sendResponse.Exception?.Message,
+                            ShouldRetry = true
+                        };
+                    results.Add(result);
+                }
+            }
+
+            _logger.LogInformation(
+                "FCM 배치 발송 완료: {SuccessCount}/{Total} 성공",
+                response.SuccessCount, chunk.Length);
+        }
+
+        return results;
+    }
+
+    private FirebaseApp GetOrCreateApp(string fcmCredentialsJson)
+    {
+        var key = Convert.ToHexString(
+            SHA256.HashData(Encoding.UTF8.GetBytes(fcmCredentialsJson)));
+
+        return _apps.GetOrAdd(key, _ =>
+        {
+            var credential = GoogleCredential.FromJson(fcmCredentialsJson);
+            var app = FirebaseApp.Create(new AppOptions
+            {
+                Credential = credential
+            }, key);
+
+            _logger.LogInformation("Firebase App 인스턴스 생성: {AppName}", key[..8]);
+            return app;
+        });
+    }
+
+    private static Message BuildMessage(
+        string deviceToken, string title, string body,
+        string? imageUrl, Dictionary<string, string>? data)
+    {
+        return new Message
+        {
+            Token = deviceToken,
+            Notification = new Notification
+            {
+                Title = title,
+                Body = body,
+                ImageUrl = imageUrl
+            },
+            Data = data,
+            Android = new AndroidConfig
+            {
+                Priority = Priority.High
+            }
+        };
+    }
+
+    private PushResultDto MapException(string deviceToken, FirebaseMessagingException ex)
+    {
+        var errorCode = ex.MessagingErrorCode;
+
+        var result = new PushResultDto
+        {
+            DeviceToken = deviceToken,
+            IsSuccess = false,
+            ErrorCode = errorCode?.ToString() ?? "UNKNOWN",
+            ErrorMessage = ex.Message
+        };
+
+        switch (errorCode)
+        {
+            case MessagingErrorCode.Unregistered:
+                result.ShouldRemoveDevice = true;
+                _logger.LogWarning("FCM 토큰 만료/삭제: {Token}", deviceToken[..Math.Min(20, deviceToken.Length)]);
+                break;
+
+            case MessagingErrorCode.InvalidArgument:
+            case MessagingErrorCode.SenderIdMismatch:
+                result.ShouldRemoveDevice = true;
+                _logger.LogWarning("FCM 잘못된 토큰: {ErrorCode}, {Token}",
+                    errorCode, deviceToken[..Math.Min(20, deviceToken.Length)]);
+                break;
+
+            case MessagingErrorCode.Unavailable:
+            case MessagingErrorCode.Internal:
+                result.ShouldRetry = true;
+                _logger.LogWarning("FCM 일시 오류 (재시도 필요): {ErrorCode}", errorCode);
+                break;
+
+            case MessagingErrorCode.QuotaExceeded:
+                result.ShouldRetry = true;
+                _logger.LogError("FCM 할당량 초과: {Message}", ex.Message);
+                break;
+
+            default:
+                _logger.LogError(ex, "FCM 알 수 없는 오류: {ErrorCode}", errorCode);
+                break;
+        }
+
+        return result;
+    }
+}

SPMS.Infrastructure/SPMS.Infrastructure.csproj

@@ -12,6 +12,7 @@
     </ItemGroup>
 
     <ItemGroup>
+      <PackageReference Include="FirebaseAdmin" Version="3.4.0" />
       <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.0" />
       <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="10.0.2" />
       <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="10.0.2" />