feat: extract channel management to IChannelService and implement CRUD operations

src/EchoHub.Tests/Irc/IrcCommandHandlerTests.cs

@@ -12,10 +12,11 @@ public class IrcCommandHandlerTests
 {
     private readonly IrcOptions _options = new() { ServerName = "testserver", Motd = null };
     private readonly FakeChatService _chatService = new();
+    private readonly FakeChannelService _channelService = new();
     private readonly FakeEncryptionService _encryption = new();
 
     private IrcCommandHandler CreateHandler(IrcClientConnection conn) =>
-        new(conn, _options, _chatService, _encryption, NullLogger.Instance);
+        new(conn, _options, _chatService, _channelService, _encryption, NullLogger.Instance);
 
     private async Task<List<string>> RunAndCapture(string[] inputLines,
         Action<IrcClientConnection>? setup = null)
@@ -242,7 +243,7 @@ public class IrcCommandHandlerTests
     [Fact]
     public async Task Join_ValidChannel_ConfirmsJoin()
     {
-        _chatService.TopicResult = ("Welcome!", true);
+        _channelService.TopicResult = ("Welcome!", true);
 
         var lines = await RunAuthenticated(["JOIN #general"]);
 
@@ -254,7 +255,7 @@ public class IrcCommandHandlerTests
     [Fact]
     public async Task Join_SendsTopic()
     {
-        _chatService.TopicResult = ("Welcome to general!", true);
+        _channelService.TopicResult = ("Welcome to general!", true);
 
         var lines = await RunAuthenticated(["JOIN #general"]);
 
@@ -264,7 +265,7 @@ public class IrcCommandHandlerTests
     [Fact]
     public async Task Join_NoTopic_SendsNoTopicReply()
     {
-        _chatService.TopicResult = (null, true);
+        _channelService.TopicResult = (null, true);
 
         var lines = await RunAuthenticated(["JOIN #general"]);
 
@@ -439,7 +440,7 @@ public class IrcCommandHandlerTests
     [Fact]
     public async Task Topic_Query_ReturnsTopic()
     {
-        _chatService.TopicResult = ("Chat about everything", true);
+        _channelService.TopicResult = ("Chat about everything", true);
 
         var lines = await RunAuthenticated(["TOPIC #general"]);
 
@@ -543,7 +544,7 @@ public class IrcCommandHandlerTests
     [Fact]
     public async Task List_ReturnsChannels()
     {
-        _chatService.ChannelListToReturn =
+        _channelService.ChannelListToReturn =
         [
             new("general", "General chat", 5),
             new("random", null, 2),

src/EchoHub.Tests/Irc/TestHelpers.cs

@@ -158,8 +158,6 @@ internal sealed class FakeChatService : IChatService
     public string? SendMessageError { get; set; }
     public (Guid UserId, string Username)? AuthResult { get; set; }
     public UserProfileDto? ProfileToReturn { get; set; }
-    public (string? Topic, bool Exists) TopicResult { get; set; } = (null, true);
-    public List<ChannelListItem> ChannelListToReturn { get; set; } = [];
     public List<string> ChannelsForUserToReturn { get; set; } = [];
     public List<UserPresenceDto> OnlineUsersToReturn { get; set; } = [];
 
@@ -215,15 +213,48 @@ internal sealed class FakeChatService : IChatService
     public Task<UserProfileDto?> GetUserProfileAsync(string username) =>
         Task.FromResult(ProfileToReturn);
 
-    public Task<(string? Topic, bool Exists)> GetChannelTopicAsync(string channelName) =>
-        Task.FromResult(TopicResult);
-
-    public Task<List<ChannelListItem>> GetChannelListAsync() =>
-        Task.FromResult(ChannelListToReturn);
-
     public Task<List<string>> GetChannelsForUserAsync(string username) =>
         Task.FromResult(ChannelsForUserToReturn);
 
     public Task<(Guid UserId, string Username)?> AuthenticateUserAsync(string username, string password) =>
         Task.FromResult(AuthResult);
 }
+
+/// <summary>
+/// Fake channel service that records method calls and returns pre-configured results.
+/// </summary>
+internal sealed class FakeChannelService : IChannelService
+{
+    // Configurable results
+    public (string? Topic, bool Exists) TopicResult { get; set; } = (null, true);
+    public List<ChannelListItem> ChannelListToReturn { get; set; } = [];
+    public ChannelDto? ChannelByNameToReturn { get; set; }
+    public ChannelOperationResult? CreateResult { get; set; }
+    public ChannelOperationResult? UpdateTopicResult { get; set; }
+    public ChannelOperationResult? DeleteResult { get; set; }
+    public (bool Success, string? Error) MembershipResult { get; set; } = (true, null);
+
+    public Task<PaginatedResponse<ChannelDto>> GetChannelsAsync(Guid userId, int offset, int limit) =>
+        Task.FromResult(new PaginatedResponse<ChannelDto>([], 0, offset, limit));
+
+    public Task<ChannelOperationResult> CreateChannelAsync(Guid creatorUserId, string name, string? topic, bool isPublic) =>
+        Task.FromResult(CreateResult ?? ChannelOperationResult.Fail(ChannelError.ValidationFailed, "Not configured"));
+
+    public Task<ChannelOperationResult> UpdateTopicAsync(Guid callerUserId, string channelName, string? topic) =>
+        Task.FromResult(UpdateTopicResult ?? ChannelOperationResult.Fail(ChannelError.ValidationFailed, "Not configured"));
+
+    public Task<ChannelOperationResult> DeleteChannelAsync(Guid callerUserId, string channelName) =>
+        Task.FromResult(DeleteResult ?? ChannelOperationResult.Fail(ChannelError.ValidationFailed, "Not configured"));
+
+    public Task<(string? Topic, bool Exists)> GetChannelTopicAsync(string channelName) =>
+        Task.FromResult(TopicResult);
+
+    public Task<List<ChannelListItem>> GetChannelListAsync() =>
+        Task.FromResult(ChannelListToReturn);
+
+    public Task<ChannelDto?> GetChannelByNameAsync(string channelName) =>
+        Task.FromResult(ChannelByNameToReturn);
+
+    public Task<(bool Success, string? Error)> EnsureChannelMembershipAsync(Guid userId, string channelName) =>
+        Task.FromResult(MembershipResult);
+}