Add signer action extension with shared keychain and data store

YetiSignerAction/YetiSignerActionView.swift

@@ -0,0 +1,54 @@
+//
+//  YetiSignerActionView.swift
+//  YetiSignerAction
+//
+//  Created by Terry Yiu on 1/26/25.
+//
+
+import NostrSDK
+import SwiftUI
+
+struct YetiSignerActionView: View {
+    @State private var text: String
+    @State private var result: String = ""
+
+    init(text: String) {
+        self.text = text
+    }
+
+    var body: some View {
+        EmptyView()
+            .onAppear {
+                do {
+                    try sign()
+                    done()
+                } catch {
+                    result = error.localizedDescription
+                }
+            }
+    }
+
+    func sign() throws {
+        let data = Data(text.utf8)
+        let unsignedNostrEvent = try JSONDecoder().decode(NostrEvent.self, from: data)
+        let pubkey = unsignedNostrEvent.pubkey
+        if let publicKey = PublicKey(hex: pubkey),
+           let keypair = PrivateKeySecureStorage.shared.keypair(for: publicKey) {
+            let signedNostrEvent = try NostrEvent.Builder(nostrEvent: unsignedNostrEvent)
+                .build(signedBy: keypair)
+
+            let encodedSignedEvent = try JSONEncoder().encode(signedNostrEvent)
+            let encodedSignedEventString = String(data: encodedSignedEvent, encoding: .utf8)!
+
+            self.result = encodedSignedEventString
+        }
+    }
+
+    func done() {
+        NotificationCenter.default.post(name: NSNotification.Name("done"), object: result)
+    }
+}
+
+#Preview {
+    YetiSignerActionView(text: "Hello, world!")
+}