Add share extension, rework bookmarks model

Open in Yattee/ShareViewController.swift

@@ -0,0 +1,54 @@
+import Social
+import UIKit
+
+final class ShareViewController: SLComposeServiceViewController {
+    override func viewWillAppear(_ animated: Bool) {
+        super.viewWillAppear(animated)
+
+        for item in extensionContext!.inputItems as! [NSExtensionItem] {
+            if let attachments = item.attachments {
+                for itemProvider in attachments where itemProvider.hasItemConformingToTypeIdentifier("public.url") {
+                    itemProvider.loadItem(forTypeIdentifier: "public.url", options: nil) { item, _ in
+                        if let url = (item as? NSURL), let absoluteURL = url.absoluteURL {
+                            URLBookmarkModel.shared.saveBookmark(absoluteURL)
+                            if let url = URL(string: "yattee://\(absoluteURL.absoluteString)") {
+                                self.open(url: url)
+                            }
+                        }
+                        self.extensionContext!.completeRequest(returningItems: nil, completionHandler: nil)
+                    }
+                }
+            }
+        }
+    }
+
+    private func open(url: URL) {
+        var responder: UIResponder? = self as UIResponder
+        let selector = #selector(openURL(_:))
+
+        while responder != nil {
+            if responder!.responds(to: selector), responder != self {
+                responder!.perform(selector, with: url)
+
+                return
+            }
+
+            responder = responder?.next
+        }
+    }
+
+    @objc
+    private func openURL(_: URL) {}
+
+    override func isContentValid() -> Bool {
+        true
+    }
+
+    override func didSelectPost() {
+        extensionContext!.completeRequest(returningItems: [], completionHandler: nil)
+    }
+
+    override func configurationItems() -> [Any]! {
+        []
+    }
+}