nwc: Add WalletModel

This model will be used for controlling the logic in the Wallet views

damus/Models/WalletModel.swift

@@ -0,0 +1,59 @@
+//
+//  WalletModel.swift
+//  damus
+//
+//  Created by William Casarin on 2023-05-09.
+//
+
+import Foundation
+
+enum WalletConnectState {
+    case new(WalletConnectURL)
+    case existing(WalletConnectURL)
+    case none
+}
+
+class WalletModel: ObservableObject {
+    let settings: UserSettingsStore?
+    private(set) var previous_state: WalletConnectState
+    @Published private(set) var connect_state: WalletConnectState
+    
+    init() {
+        self.connect_state = .none
+        self.previous_state = .none
+        self.settings = nil
+    }
+    
+    init(settings: UserSettingsStore) {
+        self.settings = settings
+        if let str = settings.nostr_wallet_connect,
+           let nwc = WalletConnectURL(str: str) {
+            self.previous_state = .existing(nwc)
+            self.connect_state = .existing(nwc)
+        } else {
+            self.previous_state = .none
+            self.connect_state = .none
+        }
+    }
+    
+    func cancel() {
+        self.connect_state = previous_state
+        self.objectWillChange.send()
+    }
+    
+    func disconnect() {
+        self.settings?.nostr_wallet_connect = nil
+        self.connect_state = .none
+        self.previous_state = .none
+    }
+    
+    func new(_ nwc: WalletConnectURL) {
+        self.connect_state = .new(nwc)
+    }
+    
+    func connect(_ nwc: WalletConnectURL) {
+        self.settings?.nostr_wallet_connect = nwc.to_url().absoluteString
+        self.connect_state = .existing(nwc)
+        self.previous_state = .existing(nwc)
+    }
+}