feat: Add support for message attachments

- Introduced Attachment model to handle file attachments associated with messages.
- Updated ModerationController to manage message deletions and attachment cleanup.
- Enhanced ChatService to include attachments in message retrieval.
- Implemented migration for legacy single-attachment messages to the new Attachments model.
- Added unit tests for attachment handling in message formatting and parsing.
- Updated database context and migrations to support new Attachments table.

src/EchoHub.Tests/DroppedFileParserTests.cs

@@ -0,0 +1,116 @@
+using EchoHub.Client.UI.Helpers;
+using Xunit;
+
+namespace EchoHub.Tests;
+
+public class DroppedFileParserTests
+{
+    // ── LooksLikePath ─────────────────────────────────────────────────
+
+    [Theory]
+    [InlineData("C:\\Users\\me\\cat.png")]
+    [InlineData("D:/photos/pic.jpg")]
+    [InlineData("\"C:\\My Files\\a b.png\"")]
+    [InlineData("/home/me/song.mp3")]
+    [InlineData("\\\\server\\share\\file.txt")]
+    public void LooksLikePath_PathLikeInput_ReturnsTrue(string text)
+    {
+        Assert.True(DroppedFileParser.LooksLikePath(text));
+    }
+
+    [Theory]
+    [InlineData("hello world")]
+    [InlineData("check out my cat")]
+    [InlineData("no")]
+    [InlineData("")]
+    [InlineData("@someone hi")]
+    public void LooksLikePath_NormalChat_ReturnsFalse(string text)
+    {
+        Assert.False(DroppedFileParser.LooksLikePath(text));
+    }
+
+    // ── TryGetFiles (injected existence check) ────────────────────────
+
+    [Fact]
+    public void TryGetFiles_SingleWindowsPath_Detected()
+    {
+        var exists = Exists("C:\\Users\\me\\cat.png");
+        Assert.True(DroppedFileParser.TryGetFiles("C:\\Users\\me\\cat.png", out var files, exists));
+        Assert.Equal(["C:\\Users\\me\\cat.png"], files);
+    }
+
+    [Fact]
+    public void TryGetFiles_QuotedPathWithSpaces_StripsQuotes()
+    {
+        var path = "C:\\My Files\\a b.png";
+        Assert.True(DroppedFileParser.TryGetFiles($"\"{path}\"", out var files, Exists(path)));
+        Assert.Equal([path], files);
+    }
+
+    [Fact]
+    public void TryGetFiles_MultipleQuotedPaths_Detected()
+    {
+        var a = "C:\\a.png";
+        var b = "C:\\b.mp3";
+        Assert.True(DroppedFileParser.TryGetFiles($"\"{a}\" \"{b}\"", out var files, Exists(a, b)));
+        Assert.Equal([a, b], files);
+    }
+
+    [Fact]
+    public void TryGetFiles_PosixAbsolutePath_Detected()
+    {
+        // Path.IsPathFullyQualified treats "/x" as fully qualified only on non-Windows;
+        // this asserts the parser defers that judgment to the platform.
+        var isPosix = !OperatingSystem.IsWindows();
+        var detected = DroppedFileParser.TryGetFiles("/home/me/song.mp3", out var files, Exists("/home/me/song.mp3"));
+        Assert.Equal(isPosix, detected);
+        if (isPosix)
+            Assert.Equal(["/home/me/song.mp3"], files);
+    }
+
+    [Fact]
+    public void TryGetFiles_NonExistentPath_ReturnsFalse()
+    {
+        Assert.False(DroppedFileParser.TryGetFiles("C:\\nope\\missing.png", out _, _ => false));
+    }
+
+    [Fact]
+    public void TryGetFiles_PartialPathDuringTyping_ReturnsFalseUntilComplete()
+    {
+        // Only the fully typed path exists; prefixes do not.
+        var full = "C:\\Users\\me\\cat.png";
+        var exists = Exists(full);
+        Assert.False(DroppedFileParser.TryGetFiles("C:\\Users\\me\\ca", out _, exists));
+        Assert.True(DroppedFileParser.TryGetFiles(full, out _, exists));
+    }
+
+    [Fact]
+    public void TryGetFiles_OneMissingAmongMultiple_ReturnsFalse()
+    {
+        var a = "C:\\a.png";
+        Assert.False(DroppedFileParser.TryGetFiles($"\"{a}\" \"C:\\gone.png\"", out _, Exists(a)));
+    }
+
+    [Fact]
+    public void TryGetFiles_RealTempFile_DetectedWithDefaultExists()
+    {
+        var temp = Path.Combine(Path.GetTempPath(), $"echohub_drop_{Guid.NewGuid():N}.txt");
+        File.WriteAllText(temp, "x");
+        try
+        {
+            Assert.True(DroppedFileParser.TryGetFiles(temp, out var files));
+            Assert.Single(files);
+            Assert.Equal(temp, files[0]);
+        }
+        finally
+        {
+            File.Delete(temp);
+        }
+    }
+
+    private static Func<string, bool> Exists(params string[] existing)
+    {
+        var set = new HashSet<string>(existing, StringComparer.OrdinalIgnoreCase);
+        return set.Contains;
+    }
+}

src/EchoHub.Tests/Irc/IrcBroadcasterTests.cs

@@ -80,8 +80,7 @@ public class IrcBroadcasterTests
 
         var encryptedContent = _encryption.Encrypt("Hello world!");
         var message = new MessageDto(
-            Guid.NewGuid(), encryptedContent, "alice", null, "general",
-            MessageType.Text, null, null, DateTimeOffset.UtcNow);
+            Guid.NewGuid(), encryptedContent, "alice", null, "general", DateTimeOffset.UtcNow);
 
         await _broadcaster.SendMessageToChannelAsync("general", message);
 
@@ -97,8 +96,7 @@ public class IrcBroadcasterTests
         var (_, bobStream) = AddConnectionWithCapture("bob", "general");
 
         var message = new MessageDto(
-            Guid.NewGuid(), _encryption.Encrypt("Hi"), "alice", null, "general",
-            MessageType.Text, null, null, DateTimeOffset.UtcNow);
+            Guid.NewGuid(), _encryption.Encrypt("Hi"), "alice", null, "general", DateTimeOffset.UtcNow);
 
         await _broadcaster.SendMessageToChannelAsync("general", message);
 
@@ -116,8 +114,7 @@ public class IrcBroadcasterTests
         var (_, randomStream) = AddConnectionWithCapture("charlie", "random");
 
         var message = new MessageDto(
-            Guid.NewGuid(), _encryption.Encrypt("Hi"), "alice", null, "general",
-            MessageType.Text, null, null, DateTimeOffset.UtcNow);
+            Guid.NewGuid(), _encryption.Encrypt("Hi"), "alice", null, "general", DateTimeOffset.UtcNow);
 
         await _broadcaster.SendMessageToChannelAsync("general", message);
 

src/EchoHub.Tests/Irc/IrcCommandHandlerTests.cs

@@ -340,8 +340,7 @@ public class IrcCommandHandlerTests
         var encryptedContent = _encryption.Encrypt("Hello from history!");
         _chatService.HistoryToReturn =
         [
-            new(Guid.NewGuid(), encryptedContent, "bob", null, "general",
-                MessageType.Text, null, null, DateTimeOffset.UtcNow)
+            new(Guid.NewGuid(), encryptedContent, "bob", null, "general", DateTimeOffset.UtcNow)
         ];
 
         var lines = await RunAuthenticated(["JOIN #general"]);

src/EchoHub.Tests/Irc/IrcMessageFormatterTests.cs

@@ -11,32 +11,31 @@ public class IrcMessageFormatterTests
         string channel = "general", List<EmbedDto>? embeds = null)
     {
         return new MessageDto(
-            Guid.NewGuid(), content, sender, null, channel,
-            MessageType.Text, null, null, DateTimeOffset.UtcNow, Embeds: embeds);
+            Guid.NewGuid(), content, sender, null, channel, DateTimeOffset.UtcNow, Embeds: embeds);
     }
 
     private static MessageDto CreateImageMessage(string asciiArt, string fileName = "image.png",
         string url = "https://example.com/image.png", string sender = "alice", string channel = "general")
     {
         return new MessageDto(
-            Guid.NewGuid(), asciiArt, sender, null, channel,
-            MessageType.Image, url, fileName, DateTimeOffset.UtcNow);
+            Guid.NewGuid(), "", sender, null, channel, DateTimeOffset.UtcNow,
+            [new AttachmentDto(AttachmentKind.Image, url, fileName, 0, asciiArt)]);
     }
 
     private static MessageDto CreateFileMessage(string fileName = "doc.pdf",
         string url = "https://example.com/doc.pdf", string sender = "alice", string channel = "general")
     {
         return new MessageDto(
-            Guid.NewGuid(), "", sender, null, channel,
-            MessageType.File, url, fileName, DateTimeOffset.UtcNow);
+            Guid.NewGuid(), "", sender, null, channel, DateTimeOffset.UtcNow,
+            [new AttachmentDto(AttachmentKind.File, url, fileName, 0)]);
     }
 
     private static MessageDto CreateAudioMessage(string fileName = "song.mp3",
         string url = "https://example.com/song.mp3", string sender = "alice", string channel = "general")
     {
         return new MessageDto(
-            Guid.NewGuid(), "", sender, null, channel,
-            MessageType.Audio, url, fileName, DateTimeOffset.UtcNow);
+            Guid.NewGuid(), "", sender, null, channel, DateTimeOffset.UtcNow,
+            [new AttachmentDto(AttachmentKind.Audio, url, fileName, 0)]);
     }
 
     // ── FormatMessage ────────────────────────────────────────────────────
@@ -115,8 +114,7 @@ public class IrcMessageFormatterTests
         var msg = CreateImageMessage("##\n##", "photo.jpg", "https://example.com/photo.jpg");
         var lines = IrcMessageFormatter.FormatMessage(msg);
 
-        Assert.Contains(lines, l => l.Contains("[Image: photo.jpg]"));
-        Assert.Contains(lines, l => l.Contains("Download: https://example.com/photo.jpg"));
+        Assert.Contains(lines, l => l.Contains("[Image: photo.jpg]") && l.Contains("https://example.com/photo.jpg"));
     }
 
     [Fact]

src/EchoHub.Tests/IrcMessageFormatterTests.cs

@@ -8,22 +8,18 @@ namespace EchoHub.Tests;
 public class IrcMessageFormatterTests
 {
     private static MessageDto CreateMessage(
-        MessageType type = MessageType.Text,
         string content = "hello",
         string sender = "alice",
         string channel = "general",
-        string? attachmentUrl = null,
-        string? attachmentFileName = null,
+        List<AttachmentDto>? attachments = null,
         List<EmbedDto>? embeds = null) => new(
         Id: Guid.NewGuid(),
         Content: content,
         SenderUsername: sender,
         SenderNicknameColor: null,
         ChannelName: channel,
-        Type: type,
-        AttachmentUrl: attachmentUrl,
-        AttachmentFileName: attachmentFileName,
         SentAt: DateTimeOffset.UtcNow,
+        Attachments: attachments,
         Embeds: embeds);
 
     // ── FormatMessage ─────────────────────────────────────────────────
@@ -51,34 +47,29 @@ public class IrcMessageFormatterTests
 
         Assert.True(lines.Count >= 2);
         Assert.Contains("PRIVMSG #general :check this out", lines[0]);
-        // Embed lines contain the Unicode pipe char and site/title
         Assert.Contains("GitHub", lines[1]);
         Assert.Contains("Repo Title", lines[1]);
     }
 
     [Fact]
-    public void FormatMessage_ImageMessage_IncludesImageTagAndDownloadUrl()
+    public void FormatMessage_ImageAttachment_IncludesImageTagAndDownloadUrl()
     {
         var msg = CreateMessage(
-            type: MessageType.Image,
-            content: "{F:FF0000}\u2588{X}",
-            attachmentUrl: "/api/files/abc",
-            attachmentFileName: "photo.png");
+            content: "",
+            attachments: [new AttachmentDto(AttachmentKind.Image, "/api/files/abc", "photo.png", 0, "{F:FF0000}█{X}")]);
         var lines = IrcMessageFormatter.FormatMessage(msg);
 
         Assert.True(lines.Count >= 2);
         Assert.Contains("[Image: photo.png]", lines[0]);
-        Assert.Contains("Download: /api/files/abc", lines[1]);
+        Assert.Contains("/api/files/abc", lines[0]);
     }
 
     [Fact]
-    public void FormatMessage_FileMessage_IncludesFileTag()
+    public void FormatMessage_FileAttachment_IncludesFileTag()
     {
         var msg = CreateMessage(
-            type: MessageType.File,
-            content: "report.pdf",
-            attachmentUrl: "/api/files/xyz",
-            attachmentFileName: "report.pdf");
+            content: "",
+            attachments: [new AttachmentDto(AttachmentKind.File, "/api/files/xyz", "report.pdf", 0)]);
         var lines = IrcMessageFormatter.FormatMessage(msg);
 
         Assert.Single(lines);
@@ -87,21 +78,49 @@ public class IrcMessageFormatterTests
     }
 
     [Fact]
-    public void FormatMessage_AudioMessage_IncludesMusicNoteAndAudioTag()
+    public void FormatMessage_AudioAttachment_IncludesMusicNoteAndAudioTag()
     {
         var msg = CreateMessage(
-            type: MessageType.Audio,
-            content: "song.mp3",
-            attachmentUrl: "/api/files/def",
-            attachmentFileName: "song.mp3");
+            content: "",
+            attachments: [new AttachmentDto(AttachmentKind.Audio, "/api/files/def", "song.mp3", 0)]);
         var lines = IrcMessageFormatter.FormatMessage(msg);
 
         Assert.Single(lines);
-        Assert.Contains("\u266a", lines[0]); // ♪
+        Assert.Contains("♪", lines[0]);
         Assert.Contains("[Audio: song.mp3]", lines[0]);
         Assert.Contains("/api/files/def", lines[0]);
     }
 
+    [Fact]
+    public void FormatMessage_CaptionWithAttachment_RendersBoth()
+    {
+        var msg = CreateMessage(
+            content: "check this photo",
+            attachments: [new AttachmentDto(AttachmentKind.Image, "/api/files/p", "pic.png", 0, null)]);
+        var lines = IrcMessageFormatter.FormatMessage(msg);
+
+        Assert.Contains(lines, l => l.Contains("check this photo"));
+        Assert.Contains(lines, l => l.Contains("[Image: pic.png]"));
+    }
+
+    [Fact]
+    public void FormatMessage_MultipleAttachments_RendersEach()
+    {
+        var msg = CreateMessage(
+            content: "",
+            attachments:
+            [
+                new AttachmentDto(AttachmentKind.Image, "/api/files/1", "a.png", 0, null),
+                new AttachmentDto(AttachmentKind.Audio, "/api/files/2", "b.mp3", 0),
+                new AttachmentDto(AttachmentKind.File, "/api/files/3", "c.pdf", 0),
+            ]);
+        var lines = IrcMessageFormatter.FormatMessage(msg);
+
+        Assert.Contains(lines, l => l.Contains("[Image: a.png]"));
+        Assert.Contains(lines, l => l.Contains("[Audio: b.mp3]"));
+        Assert.Contains(lines, l => l.Contains("[File: c.pdf]"));
+    }
+
     // ── ColorTagsToAnsi ───────────────────────────────────────────────
 
     [Fact]
@@ -179,7 +198,6 @@ public class IrcMessageFormatterTests
         var longWord = new string('a', 500);
         var result = IrcMessageFormatter.SplitMessage(longWord, 400);
 
-        // Single word can't be split at word boundary, so it stays as one chunk
         Assert.Single(result);
         Assert.Equal(longWord, result[0]);
     }