Add camera QR pairing, Bonjour discovery and pinned address recovery

MusicBridge/ContentView.swift

@@ -11,7 +11,7 @@ struct ContentView: View {
                     Label(store.status, systemImage: store.connected ? "wifi" : "wifi.slash")
                         .font(.subheadline).foregroundStyle(.secondary)
                     if store.connection == nil {
-                        PairingView(store: store)
+                        PairingView(store: store, discovery: store.discovery)
                     } else {
                         PlayerView(store: store)
                         Text(store.connection?.endpoint.host ?? "")
@@ -40,10 +40,12 @@ struct ContentView: View {
 
 private struct PairingView: View {
     @ObservedObject var store: PlayerStore
+    @ObservedObject var discovery: DiscoveryStore
     @State private var endpoint = "https://"
     @State private var fingerprint = ""
     @State private var code = ""
     @State private var invitation = ""
+    @State private var showScanner = false
 
     var body: some View {
         VStack(alignment: .leading, spacing: 18) {
@@ -53,6 +55,36 @@ private struct PairingView: View {
             Text("Музыка на ПК. Управление здесь.").font(.title2.bold())
             Text("Откройте сопряжение в MusicBridge на Windows. Подключите iPhone к той же домашней сети.")
                 .foregroundStyle(.secondary)
+            Button { showScanner = true } label: {
+                Label("Сканировать QR с ПК", systemImage: "qrcode.viewfinder")
+                    .frame(maxWidth: .infinity)
+            }.buttonStyle(.borderedProminent).controlSize(.large).disabled(store.pairing)
+            Text("QR заполнит адрес, отпечаток и код. Затем нажмите «Подключить компьютер».")
+                .font(.caption).foregroundStyle(.secondary)
+            DisclosureGroup("Найти ПК в сети") {
+                VStack(alignment: .leading, spacing: 12) {
+                    Text(discovery.message).font(.footnote).foregroundStyle(.secondary)
+                    ForEach(discovery.computers) { computer in
+                        Button {
+                            endpoint = computer.endpoint
+                            fingerprint = computer.fingerprint
+                            code = ""
+                            store.error = nil
+                        } label: {
+                            VStack(alignment: .leading) {
+                                Label(computer.name, systemImage: "desktopcomputer")
+                                Text(computer.endpoint).font(.caption)
+                            }
+                        }
+                    }
+                    Text("Выберите ПК, сверьте весь отпечаток с его экраном и введите свежий код сопряжения.")
+                        .font(.caption).foregroundStyle(.secondary)
+                    Button("Повторить поиск") { discovery.restart() }
+                    Button("Настройки доступа к сети") {
+                        if let url = URL(string: UIApplication.openSettingsURLString) { UIApplication.shared.open(url) }
+                    }
+                }.padding(.top, 8)
+            }.disabled(store.pairing)
             Group {
                 TextField("Адрес ПК: https://192.168.1.10:8765", text: $endpoint).keyboardType(.URL)
                 TextField("SHA-256 сертификата с экрана ПК", text: $fingerprint)
@@ -74,17 +106,30 @@ private struct PairingView: View {
                     TextField("musicbridge://pair?data=…", text: $invitation, axis: .vertical)
                         .lineLimit(3...5).textInputAutocapitalization(.never).autocorrectionDisabled()
                     Button("Заполнить из приглашения") {
-                        do {
-                            let parsed = try Invitation.parse(invitation.trimmingCharacters(in: .whitespacesAndNewlines))
-                            endpoint = parsed.endpoint
-                            fingerprint = parsed.certificateSha256
-                            code = parsed.code
-                            store.error = nil
-                        } catch { store.error = error.localizedDescription }
+                        importText(invitation)
                     }
                 }.padding(.top, 12)
             }.disabled(store.pairing)
         }
+        .sheet(isPresented: $showScanner) { QRScannerSheet(receive: importText) }
+        .onAppear { consumeIncoming() }
+        .onChange(of: store.incomingInvitation) { _, _ in consumeIncoming() }
+    }
+
+    private func consumeIncoming() {
+        guard let text = store.incomingInvitation else { return }
+        store.incomingInvitation = nil
+        importText(text)
+    }
+
+    private func importText(_ text: String) {
+        do {
+            let parsed = try Invitation.parse(text.trimmingCharacters(in: .whitespacesAndNewlines))
+            endpoint = parsed.endpoint
+            fingerprint = parsed.certificateSha256
+            code = parsed.code
+            store.error = nil
+        } catch { store.error = error.localizedDescription }
     }
 }