feat: handle paste event and insert images on the clipboard

Signed-off-by: NanoSector <rick@nanosector.nl>

Mastodon/Scene/Compose/ComposeViewController.swift

@@ -1449,3 +1449,32 @@ extension ComposeViewController {
     }
     
 }
+
+extension ComposeViewController {
+    public override func canPerformAction(_ action: Selector, withSender sender: Any?) -> Bool {
+        
+        // Enable pasting images
+        if (action == #selector(UIResponderStandardEditActions.paste(_:))) {
+            return UIPasteboard.general.hasStrings || UIPasteboard.general.hasImages;
+        }
+
+        return super.canPerformAction(action, withSender: sender);
+    }
+    
+    override func paste(_ sender: Any?) {
+        logger.debug("Paste event received")
+        
+        // Look for images on the clipboard
+        if (UIPasteboard.general.hasImages) {
+            if let images = UIPasteboard.general.images {
+                viewModel.attachmentServices = viewModel.attachmentServices + images.map({ image in
+                    MastodonAttachmentService(
+                        context: context,
+                        image: image,
+                        initialAuthenticationBox: viewModel.authenticationBox
+                    )
+                })
+            }
+        }
+    }
+}

Mastodon/Scene/Compose/View/MetaTextView+PasteExtensions.swift

@@ -0,0 +1,29 @@
+//
+//  MetaTextView+PasteExtensions.swift
+//  Mastodon
+//
+//  Created by Rick Kerkhof on 30/10/2022.
+//
+
+import Foundation
+import MetaTextKit
+import UIKit
+
+extension MetaTextView {
+    public override func paste(_ sender: Any?) {
+        super.paste(sender)
+        
+        var nextResponder = self.next;
+        
+        // Force the event to bubble through ALL responders
+        // This is a workaround as somewhere down the chain the paste event gets eaten
+        while (nextResponder != nil) {
+            if let nextResponder = nextResponder {
+                if (nextResponder.responds(to: #selector(UIResponderStandardEditActions.paste(_:)))) {
+                    nextResponder.perform(#selector(UIResponderStandardEditActions.paste(_:)), with: sender)
+                }
+            }
+            nextResponder = nextResponder?.next;
+        }
+    }
+}