Improve post entry views, add post link data

CHDataManagement/Views/Posts/PostList.swift

@@ -5,51 +5,96 @@ struct PostList: View {
     @EnvironmentObject
     private var content: Content
 
-    @State
-    private var showNewPostIdSheet = false
+    @Environment(\.language)
+    private var language: ContentLanguage
 
     @State
     private var newPostId = ""
 
+    @State
+    private var selected: Post? = nil
+
+    @State
+    private var showNewPostView = false
+
+    @State
+    private var newPostIdIsValid = false
+
+    private let allowedCharactersInPostId = CharacterSet.alphanumerics.union(CharacterSet(charactersIn: "-")).inverted
+
+    private var cleanPostId: String {
+        newPostId.trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+
     var body: some View {
-        List {
-            if content.posts.isEmpty {
-                HorizontalCenter {
-                    Text("No posts yet.")
-                        .padding()
-                }
-                .listRowSeparator(.hidden)
+        NavigationSplitView {
+            List(content.posts, selection: $selected) { post in
+                Text(post.localized(in: language).title)
+                    .tag(post)
             }
-            HorizontalCenter {
-                Button(action: { showNewPostIdSheet = true }) {
-                    Text("Add post")
+            .frame(minWidth: 200)
+            .toolbar {
+                ToolbarItem(placement: .primaryAction) {
+                    Button(action: { showNewPostView = true }) {
+                        Label("New post", systemSymbol: .plus)
+                    }
                 }
-                .padding()
-                .listRowSeparator(.hidden)
             }
-            ForEach(content.posts) { post in
-                HorizontalCenter {
-                    PostView(post: post)
-                        .frame(maxWidth: 600)
-                }
-                .listRowSeparator(.hidden)
-                .listRowInsets(.init(top: 0, leading: 0, bottom: 30, trailing: 0))
+        } content: {
+            if let selected {
+                PostContentView(post: selected)
+                    .layoutPriority(1)
+            } else {
+                HStack {
+                    Spacer()
+                    Text("Select a post to show the content")
+                        .font(.largeTitle)
+                        .foregroundColor(.secondary)
+                    Spacer()
+                }.layoutPriority(1)
+            }
+        } detail: {
+            if let selected {
+                PostDetailView(post: selected)
+                    .frame(minWidth: 280)
+            } else {
+                Text("No post selected")
+                    .frame(minWidth: 280)
             }
         }
-        .listStyle(.plain)
-        .sheet(isPresented: $showNewPostIdSheet, onDismiss: addNewPost) {
-            TextEntrySheet(title: "Enter the new post id", text: $newPostId)
+        .sheet(isPresented: $showNewPostView,
+               onDismiss: addNewPost) {
+            TextEntrySheet(
+                title: "Enter the id for the new post",
+                text: $newPostId,
+                isValid: $newPostIdIsValid)
+        }
+        .onChange(of: newPostId) { _, newValue in
+            newPostIdIsValid = isValid(id: newValue)
+        }
+        .onAppear {
+            if selected == nil {
+                selected = content.posts.first
+            }
         }
     }
 
-    private func addNewPost() {
-        let id = newPostId.trimmingCharacters(in: .whitespacesAndNewlines)
+    private func isValid(id: String) -> Bool {
+        let id = cleanPostId
         guard id != "" else {
-            return
+            return false
         }
 
         guard !content.posts.contains(where: { $0.id == id }) else {
-            print("ID \(id) already exists")
+            return false
+        }
+        // Only allow alphanumeric characters and hyphens
+        return id.rangeOfCharacter(from: allowedCharactersInPostId) == nil
+    }
+
+    private func addNewPost() {
+        let id = cleanPostId
+        guard isValid(id: id) else {
             return
         }
 
@@ -63,6 +108,7 @@ struct PostList: View {
             german: .init(title: "Titel", content: "Text"),
             english: .init(title: "Title", content: "Text"))
         content.posts.insert(post, at: 0)
+        selected = post
     }
 }