Add forward spam detection via quote text and external reply photo OCR

src/VahterBanBot.Tests/ContainerTestBase.fs

@@ -128,12 +128,15 @@ type VahterTestContainers(mlEnabled: bool) =
                 .WithEnvironment("REACTION_SPAM_ENABLED", "true")
                 .WithEnvironment("REACTION_SPAM_MIN_MESSAGES", "3")
                 .WithEnvironment("REACTION_SPAM_MAX_REACTIONS", "5")
+                // Forward spam detection
+                .WithEnvironment("FORWARD_SPAM_DETECTION_ENABLED", "true")
                 .Build()
         else
             builder
                 .WithEnvironment("ML_ENABLED", "false")
                 .WithEnvironment("OCR_ENABLED", "false")
                 .WithEnvironment("REACTION_SPAM_ENABLED", "false")
+                .WithEnvironment("FORWARD_SPAM_DETECTION_ENABLED", "false")
                 .Build()
 
     let startContainers() = task {

src/VahterBanBot.Tests/MLBanTests.fs

@@ -494,4 +494,70 @@ type MLBanTests(fixture: MlEnabledVahterTestContainers, _unused: MlAwaitFixture)
         Assert.True(userBanned, "User should be auto-banned after reaching karma threshold via soft spam")
     }
 
+    [<Fact>]
+    let ``Message with spam in quote text triggers auto-delete`` () = task {
+        let msgUpdate = Tg.quickMsg(
+            chat = fixture.ChatsToMonitor[0],
+            text = "hello",
+            quote = Tg.textQuote("2222222")
+        )
+        let! _ = fixture.SendMessage msgUpdate
+
+        let! msgBanned = fixture.MessageIsAutoDeleted msgUpdate.Message
+        Assert.True msgBanned
+    }
+
+    [<Fact>]
+    let ``Message with non-spam quote text does NOT trigger auto-delete`` () = task {
+        let msgUpdate = Tg.quickMsg(
+            chat = fixture.ChatsToMonitor[0],
+            text = "hello",
+            quote = Tg.textQuote("b")
+        )
+        let! _ = fixture.SendMessage msgUpdate
+
+        let! msgBanned = fixture.MessageIsAutoDeleted msgUpdate.Message
+        Assert.False msgBanned
+    }
+
+    [<Fact>]
+    let ``Quote text is prepended to message text`` () = task {
+        let msgUpdate = Tg.quickMsg(
+            chat = fixture.ChatsToMonitor[0],
+            text = "hello",
+            quote = Tg.textQuote("b")
+        )
+        let! _ = fixture.SendMessage msgUpdate
+
+        let! dbMsg = fixture.TryGetDbMessage msgUpdate.Message
+        Assert.True dbMsg.IsSome
+        Assert.Equal("b\nhello", dbMsg.Value.text)
+    }
+
+    [<Fact>]
+    let ``Spam in external reply photo triggers auto-delete via OCR`` () = task {
+        let msgUpdate = Tg.quickMsg(
+            chat = fixture.ChatsToMonitor[0],
+            text = "hello",
+            externalReply = Tg.externalReply(photos = [| Tg.spamPhoto |])
+        )
+        let! _ = fixture.SendMessage msgUpdate
+
+        let! msgBanned = fixture.MessageIsAutoDeleted msgUpdate.Message
+        Assert.True msgBanned
+    }
+
+    [<Fact>]
+    let ``Ham in external reply photo does NOT trigger auto-delete`` () = task {
+        let msgUpdate = Tg.quickMsg(
+            chat = fixture.ChatsToMonitor[0],
+            text = "hello",
+            externalReply = Tg.externalReply(photos = [| Tg.hamPhoto |])
+        )
+        let! _ = fixture.SendMessage msgUpdate
+
+        let! msgBanned = fixture.MessageIsAutoDeleted msgUpdate.Message
+        Assert.False msgBanned
+    }
+
     interface IClassFixture<MlAwaitFixture>

src/VahterBanBot.Tests/TgMessageUtils.fs

@@ -60,7 +60,16 @@ type Tg() =
     static member emoji(?offset: int) = MessageEntity(Type = MessageEntityType.CustomEmoji, Offset = defaultArg offset 0 , Length = 1)
     static member emojies(n: int) = Array.init n (fun i -> Tg.emoji i)
 
-    static member quickMsg (?text: string, ?chat: Chat, ?from: User, ?date: DateTime, ?callback: CallbackQuery, ?caption: string, ?editedText: string, ?entities: MessageEntity[], ?photos: PhotoSize[], ?isAutomaticForward: bool, ?senderChat: Chat) =
+    static member textQuote(text: string) =
+        TextQuote(Text = text, Position = 0)
+
+    static member externalReply(?photos: PhotoSize[], ?chat: Chat) =
+        ExternalReplyInfo(
+            Photo = (photos |> Option.defaultValue null),
+            Chat = (chat |> Option.defaultValue null)
+        )
+
+    static member quickMsg (?text: string, ?chat: Chat, ?from: User, ?date: DateTime, ?callback: CallbackQuery, ?caption: string, ?editedText: string, ?entities: MessageEntity[], ?photos: PhotoSize[], ?isAutomaticForward: bool, ?senderChat: Chat, ?quote: TextQuote, ?externalReply: ExternalReplyInfo) =
         let updateId = next()
         let msgId = next()
         Update(
@@ -77,7 +86,9 @@ type Tg() =
                     Entities = (entities |> Option.defaultValue null),
                     Photo = (photos |> Option.defaultValue null),
                     IsAutomaticForward = (isAutomaticForward |> Option.defaultValue false),
-                    SenderChat = (senderChat |> Option.defaultValue null)
+                    SenderChat = (senderChat |> Option.defaultValue null),
+                    Quote = (quote |> Option.defaultValue null),
+                    ExternalReply = (externalReply |> Option.defaultValue null)
                 ),
             EditedMessage =
                 if editedText |> Option.isSome then

src/VahterBanBot/Bot.fs

@@ -889,6 +889,96 @@ let onMessage
         do! justMessage botUser botClient botConfig logger ml message
 }
 
+let private selectLargestPhoto (photos: PhotoSize array) =
+    let withSize = photos |> Array.filter (fun p -> p.FileSize.HasValue)
+    if withSize.Length > 0 then
+        withSize |> Array.maxBy (fun p -> p.FileSize.Value)
+    else
+        photos |> Array.maxBy (fun p -> p.Width * p.Height)
+
+let private ocrPhotos
+    (botClient: ITelegramBotClient)
+    (botConfig: BotConfiguration)
+    (computerVision: IComputerVision)
+    (logger: ILogger)
+    (photos: PhotoSize array)
+    (messageId: int) = task {
+    let candidatePhotos =
+        photos
+        |> Array.filter (fun p ->
+            let size = int64 p.FileSize
+            size = 0L || size <= botConfig.OcrMaxFileSizeBytes)
+
+    if candidatePhotos.Length = 0 then
+        logger.LogWarning(
+            "No photos under OCR limit of {LimitBytes} bytes for message {MessageId}",
+            botConfig.OcrMaxFileSizeBytes,
+            messageId)
+        return None
+    else
+        let largestPhoto = selectLargestPhoto candidatePhotos
+
+        let! file = botClient.GetFile(largestPhoto.FileId)
+
+        if String.IsNullOrWhiteSpace file.FilePath then
+            logger.LogWarning("Failed to resolve file path for photo {PhotoId}", largestPhoto.FileId)
+            return None
+        else
+            let fileUrl = $"https://api.telegram.org/file/bot{botConfig.BotToken}/{file.FilePath}"
+            let! ocrText = computerVision.TextFromImageUrl fileUrl
+            if String.IsNullOrWhiteSpace ocrText then
+                return None
+            else
+                return Some ocrText
+}
+
+let tryEnrichMessageWithForwardedContent
+    (botClient: ITelegramBotClient)
+    (botConfig: BotConfiguration)
+    (computerVision: IComputerVision)
+    (logger: ILogger)
+    (update: Update) = task {
+    if botConfig.ForwardSpamDetectionEnabled then
+        let message = update.EditedOrMessage
+        if not (isNull message) && isMessageFromAllowedChats botConfig message then
+            use activity = botActivity.StartActivity("forwardedContentEnrichment")
+            try
+                let mutable forwardedText: string = null
+
+                if not (isNull message.Quote)
+                   && not (String.IsNullOrWhiteSpace message.Quote.Text) then
+                    forwardedText <- message.Quote.Text
+                    %activity.SetTag("quoteTextLength", message.Quote.Text.Length)
+
+                if botConfig.OcrEnabled
+                   && not (isNull message.ExternalReply)
+                   && not (isNull message.ExternalReply.Photo)
+                   && message.ExternalReply.Photo.Length > 0 then
+                    let! ocrText = ocrPhotos botClient botConfig computerVision logger message.ExternalReply.Photo message.MessageId
+                    match ocrText with
+                    | Some text ->
+                        forwardedText <-
+                            if isNull forwardedText then text
+                            else $"{forwardedText}\n{text}"
+                        %activity.SetTag("externalReplyOcrLength", text.Length)
+                    | None -> ()
+
+                if not (String.IsNullOrWhiteSpace forwardedText) then
+                    let baseText = message.TextOrCaption
+                    let enrichedText =
+                        if String.IsNullOrWhiteSpace baseText then forwardedText
+                        else $"{forwardedText}\n{baseText}"
+                    logger.LogDebug(
+                        "Enriched message {MessageId} with forwarded content of length {ForwardedLength}",
+                        message.MessageId,
+                        forwardedText.Length
+                    )
+                    message.Text <- enrichedText
+                    %activity.SetTag("enrichedTextLength", enrichedText.Length)
+            with ex ->
+                logger.LogError(ex, "Failed to process forwarded content for message {MessageId}", update.EditedOrMessage.MessageId)
+}
+
 let tryEnrichMessageWithOcr
     (botClient: ITelegramBotClient)
     (botConfig: BotConfiguration)
@@ -897,52 +987,25 @@ let tryEnrichMessageWithOcr
     (update: Update) = task {
     if botConfig.OcrEnabled then
         let message = update.EditedOrMessage
-        if not (isNull message.Photo) && message.Photo.Length > 0 then
+        if not (isNull message.Photo) && message.Photo.Length > 0 && isMessageFromAllowedChats botConfig message then
             use activity = botActivity.StartActivity("ocrEnrichment")
             try
-                let candidatePhotos =
-                    message.Photo
-                    |> Array.filter (fun p ->
-                        let size = int64 p.FileSize
-                        size = 0L || size <= botConfig.OcrMaxFileSizeBytes)
-
-                if candidatePhotos.Length = 0 then
-                    logger.LogWarning(
-                        "No photos under OCR limit of {LimitBytes} bytes for message {MessageId}",
-                        botConfig.OcrMaxFileSizeBytes,
-                        message.MessageId)
-                else
-                    let largestPhoto =
-                        candidatePhotos
-                        |> Seq.filter (fun p -> p.FileSize.HasValue)
-                        |> Seq.maxBy (fun p -> p.FileSize.Value)
-
-                    %activity.SetTag("photoId", largestPhoto.FileId)
-
-                    let! file = botClient.GetFile(largestPhoto.FileId)
-
-                    if String.IsNullOrWhiteSpace file.FilePath then
-                        logger.LogWarning("Failed to resolve file path for photo {PhotoId}", largestPhoto.FileId)
-                    else
-                        let fileUrl = $"https://api.telegram.org/file/bot{botConfig.BotToken}/{file.FilePath}"
-                        %activity.SetTag("fileUrl", fileUrl)
-                        let! ocrText = computerVision.TextFromImageUrl fileUrl
-
-                        if not (String.IsNullOrWhiteSpace ocrText) then
-                            let baseText = message.TextOrCaption
-                            let enrichedText =
-                                if String.IsNullOrWhiteSpace baseText then
-                                    ocrText
-                                else
-                                    $"{baseText}\n{ocrText}"
-                            logger.LogDebug (
-                                "Enriched message {MessageId} with OCR text {EnrichedText} of length {OcrTextLength}",
-                                update.EditedOrMessage.MessageId,
-                                enrichedText,
-                                ocrText.Length
-                            )
-                            message.Text <- enrichedText
-                            %activity.SetTag("ocrTextLength", enrichedText.Length)
+                let! ocrResult = ocrPhotos botClient botConfig computerVision logger message.Photo message.MessageId
+                match ocrResult with
+                | Some ocrText ->
+                    let baseText = message.TextOrCaption
+                    let enrichedText =
+                        if String.IsNullOrWhiteSpace baseText then ocrText
+                        else $"{baseText}\n{ocrText}"
+                    logger.LogDebug (
+                        "Enriched message {MessageId} with OCR text {EnrichedText} of length {OcrTextLength}",
+                        update.EditedOrMessage.MessageId,
+                        enrichedText,
+                        ocrText.Length
+                    )
+                    message.Text <- enrichedText
+                    %activity.SetTag("ocrTextLength", enrichedText.Length)
+                | None -> ()
             with ex ->
                 logger.LogError(ex, "Failed to process OCR for message {MessageId}", update.EditedOrMessage.MessageId)
 }
@@ -1222,6 +1285,7 @@ let onUpdate
     elif update.MessageReaction <> null then
         do! onMessageReaction botClient botConfig logger update.MessageReaction
     elif update.EditedOrMessage <> null then
+        do! tryEnrichMessageWithForwardedContent botClient botConfig computerVision logger update
         do! tryEnrichMessageWithOcr botClient botConfig computerVision logger update
         do! onMessage botUser botClient botConfig logger ml update.EditedOrMessage
     elif update.ChatMember <> null || update.MyChatMember <> null then

src/VahterBanBot/Program.fs

@@ -101,7 +101,9 @@ let botConf =
       // Reaction spam detection
       ReactionSpamEnabled = getEnvOr "REACTION_SPAM_ENABLED" "false" |> bool.Parse
       ReactionSpamMinMessages = getEnvOr "REACTION_SPAM_MIN_MESSAGES" "10" |> int
-      ReactionSpamMaxReactions = getEnvOr "REACTION_SPAM_MAX_REACTIONS" "5" |> int }
+      ReactionSpamMaxReactions = getEnvOr "REACTION_SPAM_MAX_REACTIONS" "5" |> int
+      // Forward spam detection
+      ForwardSpamDetectionEnabled = getEnvOr "FORWARD_SPAM_DETECTION_ENABLED" "true" |> bool.Parse }
 
 let validateApiKey (ctx : HttpContext) =
     match ctx.TryGetRequestHeader "X-Telegram-Bot-Api-Secret-Token" with

src/VahterBanBot/Types.fs

@@ -60,7 +60,9 @@ type BotConfiguration =
       // Reaction spam detection
       ReactionSpamEnabled: bool
       ReactionSpamMinMessages: int
-      ReactionSpamMaxReactions: int }
+      ReactionSpamMaxReactions: int
+      // Forward spam detection
+      ForwardSpamDetectionEnabled: bool }
 
 [<CLIMutable>]
 type DbUser =