Add hashtag spam filter to automatically mute posts with too many hashtags

Posts with more than the configured number of hashtags (default: 3) are
now automatically filtered from timelines. This helps reduce hashtag spam.

- Add hide_hashtag_spam and max_hashtags settings to UserSettingsStore
- Add hashtag_spam_filter that counts hashtags in content text
- Add toggle and slider UI in Appearance > Content filters settings

Changelog-Added: Added hashtag spam filter setting to hide posts with too many hashtags
Closes: #1677
Signed-off-by: alltheseas

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: alltheseas

CHANGELOG.md

@@ -4,7 +4,8 @@
 
 ### Added
 
-- Added new onboarding suggestions based on user-selected interests (Daniel D’Aquino)
+- Added hashtag spam filter setting to hide posts with too many hashtags (alltheseas)
+- Added new onboarding suggestions based on user-selected interests (Daniel D'Aquino)
 - Added adjustable max budget setting for Coinos one-click wallets (Daniel D’Aquino)
 - Added send feature to the wallet view (Daniel D’Aquino)
 - Added popover tips to DMs and Notifications toolbars on Trusted Network button (Terry Yiu)

damus/Features/Settings/Models/UserSettingsStore.swift

@@ -138,7 +138,13 @@ class UserSettingsStore: ObservableObject {
 
     @Setting(key: "hide_nsfw_tagged_content", default_value: false)
     var hide_nsfw_tagged_content: Bool
-    
+
+    @Setting(key: "hide_hashtag_spam", default_value: true)
+    var hide_hashtag_spam: Bool
+
+    @Setting(key: "max_hashtags", default_value: 3)
+    var max_hashtags: Int
+
     @Setting(key: "reduce_bitcoin_content", default_value: false)
     var reduce_bitcoin_content: Bool
 

damus/Features/Settings/Views/AppearanceSettingsView.swift

@@ -36,6 +36,14 @@ struct AppearanceSettingsView: View {
     @State var showing_enable_animation_alert: Bool = false
     @State var enable_animation_toggle_is_user_initiated: Bool = true
 
+    var max_hashtags_binding: Binding<Double> {
+        Binding<Double>(get: {
+            return Double(settings.max_hashtags)
+        }, set: {
+            settings.max_hashtags = Int($0)
+        })
+    }
+
     var FontSize: some View {
         VStack(alignment: .leading) {
             Slider(value: $settings.font_size, in: 0.5...2.0, step: 0.1)
@@ -104,6 +112,14 @@ struct AppearanceSettingsView: View {
                     .toggleStyle(.switch)
                 Toggle(NSLocalizedString("Hide notes with #nsfw tags", comment: "Setting to hide notes with the #nsfw (not safe for work) tags"), isOn: $settings.hide_nsfw_tagged_content)
                     .toggleStyle(.switch)
+                Toggle(NSLocalizedString("Hide posts with too many hashtags", comment: "Setting to hide notes that contain too many hashtags (spam)"), isOn: $settings.hide_hashtag_spam)
+                    .toggleStyle(.switch)
+                if settings.hide_hashtag_spam {
+                    VStack(alignment: .leading) {
+                        Text(String(format: NSLocalizedString("Maximum hashtags: %d", comment: "Label showing the maximum number of hashtags allowed before a post is hidden"), settings.max_hashtags))
+                        Slider(value: max_hashtags_binding, in: 1...20, step: 1)
+                    }
+                }
             }
 
             // MARK: - Profiles

damus/Features/Timeline/Models/ContentFilters.swift

@@ -54,6 +54,33 @@ func nsfw_tag_filter(ev: NostrEvent) -> Bool {
     return ev.referenced_hashtags.first(where: { t in t.hashtag.caseInsensitiveCompare("nsfw") == .orderedSame }) == nil
 }
 
+/// Filter to hide posts with too many hashtags (spam detection)
+/// Counts hashtags from the note content text, not just the tags array,
+/// since many clients don't properly add hashtag tags.
+func hashtag_spam_filter(ev: NostrEvent, max_hashtags: Int) -> Bool {
+    let content = ev.content
+    var count = 0
+    var i = content.startIndex
+
+    while i < content.endIndex {
+        if content[i] == "#" {
+            let nextIndex = content.index(after: i)
+            if nextIndex < content.endIndex {
+                let nextChar = content[nextIndex]
+                // Check if next char is a valid hashtag start (letter, number, emoji, non-ASCII)
+                if nextChar.isLetter || nextChar.isNumber || !nextChar.isASCII {
+                    count += 1
+                    if count > max_hashtags {
+                        return false
+                    }
+                }
+            }
+        }
+        i = content.index(after: i)
+    }
+    return true
+}
+
 @MainActor
 func get_repost_of_muted_user_filter(damus_state: DamusState) -> ((_ ev: NostrEvent) -> Bool) {
     return { ev in
@@ -97,6 +124,10 @@ extension ContentFilters {
         if damus_state.settings.hide_nsfw_tagged_content {
             filters.append(nsfw_tag_filter)
         }
+        if damus_state.settings.hide_hashtag_spam {
+            let max_hashtags = damus_state.settings.max_hashtags
+            filters.append({ ev in hashtag_spam_filter(ev: ev, max_hashtags: max_hashtags) })
+        }
         filters.append(get_repost_of_muted_user_filter(damus_state: damus_state))
         filters.append(timestamp_filter)
         return filters