extract MainTabView

Start to clean ContentView up a bit.

We need it to be cleaner before we introduce the SetupView

Signed-off-by: William Casarin <jb55@jb55.com>

damus/Views/MainTabView.swift

@@ -0,0 +1,81 @@
+//
+//  MainTabView.swift
+//  damus
+//
+//  Created by William Casarin on 2022-05-19.
+//
+
+import SwiftUI
+
+struct MainTabView: View {
+    var body: some View {
+        Text(/*@START_MENU_TOKEN@*/"Hello, World!"/*@END_MENU_TOKEN@*/)
+    }
+}
+
+struct MainTabView_Previews: PreviewProvider {
+    static var previews: some View {
+        MainTabView()
+    }
+}
+
+struct NotificationsTab: View {
+    @Binding var new_notifications: Bool
+    @Binding var selected: Timeline?
+    
+    let action: (Timeline) -> ()
+    
+    var body: some View {
+        ZStack(alignment: .center) {
+            TabButton(timeline: .notifications, img: "bell", selected: $selected, action: action)
+            
+            if new_notifications {
+                Circle()
+                    .size(CGSize(width: 8, height: 8))
+                    .frame(width: 10, height: 10, alignment: .topTrailing)
+                    .alignmentGuide(VerticalAlignment.center) { a in a.height + 2.0 }
+                    .alignmentGuide(HorizontalAlignment.center) { a in a.width - 12.0 }
+                    .foregroundColor(.accentColor)
+            }
+        }
+    }
+}
+
+    
+struct TabButton: View {
+    let timeline: Timeline
+    let img: String
+    
+    @Binding var selected: Timeline?
+    
+    let action: (Timeline) -> ()
+    
+    var body: some View {
+        Button(action: {action(timeline)}) {
+            Label("", systemImage: selected == timeline ? "\(img).fill" : img)
+                .contentShape(Rectangle())
+                .frame(maxWidth: .infinity, minHeight: 30.0)
+        }
+        .foregroundColor(selected != timeline ? .gray : .primary)
+    }
+}
+    
+
+struct TabBar: View {
+    @Binding var new_notifications: Bool
+    @Binding var selected: Timeline?
+    
+    let action: (Timeline) -> ()
+    
+    var body: some View {
+        VStack {
+            Divider()
+            HStack {
+                TabButton(timeline: .home, img: "house", selected: $selected, action: action)
+                NotificationsTab(new_notifications: $new_notifications, selected: $selected, action: action)
+                TabButton(timeline: .global, img: "globe.americas", selected: $selected, action: action)
+            }
+        }
+    }
+}
+

damus/Views/SetupView.swift

@@ -0,0 +1,20 @@
+//
+//  SetupView.swift
+//  damus
+//
+//  Created by William Casarin on 2022-05-18.
+//
+
+import SwiftUI
+
+struct SetupView: View {
+    var body: some View {
+        Text(/*@START_MENU_TOKEN@*/"Hello, World!"/*@END_MENU_TOKEN@*/)
+    }
+}
+
+struct SetupView_Previews: PreviewProvider {
+    static var previews: some View {
+        SetupView()
+    }
+}