Implement NIP-21 URI handling

Changelog-Added: Added nostr: uri handling

damus/Util/Bech32Object.swift

@@ -0,0 +1,31 @@
+//
+//  Bech32Object.swift
+//  damus
+//
+//  Created by William Casarin on 2023-01-28.
+//
+
+import Foundation
+
+
+enum Bech32Object {
+    case nsec(String)
+    case npub(String)
+    case note(String)
+    
+    static func parse(_ str: String) -> Bech32Object? {
+        guard let decoded = try? bech32_decode(str) else {
+            return nil
+        }
+        
+        if decoded.hrp == "npub" {
+            return .npub(hex_encode(decoded.data))
+        } else if decoded.hrp == "nsec" {
+            return .nsec(hex_encode(decoded.data))
+        } else if decoded.hrp == "note" {
+            return .note(hex_encode(decoded.data))
+        }
+        
+        return nil
+    }
+}