Fix Post button always being disabled when require attachment descriptions is enabled

Also fix post button state not updating when description edited

Closes #371

Packages/ComposeUI/Sources/ComposeUI/Controllers/AttachmentsListController.swift

@@ -17,18 +17,20 @@ class AttachmentsListController: ViewController {
     var isValid: Bool {
         !requiresAttachmentDescriptions && validAttachmentCombination
     }
-    
+
     private var requiresAttachmentDescriptions: Bool {
         if parent.config.requireAttachmentDescriptions {
-            return draft.attachments.allSatisfy {
-                !$0.attachmentDescription.isEmpty
+            if draft.attachments.isEmpty {
+                return false
+            } else {
+                return !parent.attachmentsMissingDescriptions.isEmpty
             }
         } else {
             return false
         }
     }
     
-    private var validAttachmentCombination: Bool {
+    var validAttachmentCombination: Bool {
         if !parent.mastodonController.instanceFeatures.mastodonAttachmentRestrictions {
             return true
         } else if draft.attachments.contains(where: { $0.data.type == .video }) &&
@@ -139,6 +141,13 @@ class AttachmentsListController: ViewController {
                     .onDrag {
                         NSItemProvider(object: attachment)
                     }
+                    .onReceive(attachment.$attachmentDescription.map(\.isEmpty).removeDuplicates()) { isEmpty in
+                        if isEmpty {
+                            controller.parent.attachmentsMissingDescriptions.insert(attachment.id)
+                        } else {
+                            controller.parent.attachmentsMissingDescriptions.remove(attachment.id)
+                        }
+                    }
             }
             .onMove(perform: controller.moveAttachments)
             .onDelete(perform: controller.deleteAttachments)

Packages/ComposeUI/Sources/ComposeUI/Controllers/ComposeController.swift

@@ -32,6 +32,9 @@ public final class ComposeController: ViewController {
     @Published var toolbarController: ToolbarController!
     @Published var attachmentsListController: AttachmentsListController!
     
+    // this property is here rather than on the AttachmentsListController so that the ComposeView
+    // updates when it changes, because changes to it may alter postButtonEnabled
+    @Published var attachmentsMissingDescriptions = Set<UUID>()
     @Published var contentWarningBecomeFirstResponder = false
     @Published var mainComposeTextViewBecomeFirstResponder = false
     @Published var currentInput: (any ComposeInput)? = nil