From 317ebb4e842c576b1b05c4c410682d722266ca22 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timoth=C3=A9=20LARIVIERE?= <timothe.lariviere@outlook.com>
Date: Tue, 14 Feb 2023 10:34:02 +0100
Subject: [PATCH] .

---
 samples/Playground/App.fs                     | 100 ++++++++++--------
 .../Fabulous.MauiControls.fsproj              |   1 +
 .../Views/Pages/NavigationStack.fs            |  70 ++++++++++++
 3 files changed, 124 insertions(+), 47 deletions(-)
 create mode 100644 src/Fabulous.MauiControls/Views/Pages/NavigationStack.fs

diff --git a/samples/Playground/App.fs b/samples/Playground/App.fs
index fad3c5b..89f81c9 100644
--- a/samples/Playground/App.fs
+++ b/samples/Playground/App.fs
@@ -10,59 +10,65 @@ open Microsoft.Maui.Primitives
 open type Fabulous.Maui.View
 
 module App =
-    type FieldFocused =
-        | Entry1
-        | Entry2
-        | Entry3
-
-    type Model = { Focus: FieldFocused option }
-
+    type Path =
+        | Home
+        | Details
+        | Subdetails of int
+        
+    type Model =
+        { Stack: Path list }
+        
     type Msg =
-        | TextChanged of string
-        | FocusChanged of FieldFocused * bool
-        | SetFocus of FieldFocused option
-
-    let init () = { Focus = None }
-
+        | StackUpdated of Path list
+        | GoTo of Path
+        | GoBack
+        | GoToRoot
+        
+    let init() =
+        { Stack = [ Home ] }
+        
     let update msg model =
         match msg with
-        | TextChanged _ -> model
-        | FocusChanged(field, isFocused) ->
-            if isFocused then
-                { model with Focus = Some field }
-            else
-                { model with Focus = None }
-
-        | SetFocus field -> { model with Focus = field }
-
-    let focusChanged field args = FocusChanged(field, args)
+        | StackUpdated stack ->
+            { model with Stack = stack }
+        | GoTo path ->
+            { model with Stack = path :: model.Stack }
+        | GoBack ->
+            { model with Stack = model.Stack |> List.tail }
+        | GoToRoot ->
+            { model with Stack = [model.Stack |> List.last] }
 
     let view model =
         Application(
-            ContentPage(
-                (VStack(spacing = 20.) {
-                    let text =
-                        match model.Focus with
-                        | None -> "None"
-                        | Some f -> f.ToString()
-
-                    Label($"Field currently selected: {text}")
-
-                    Entry("Entry1", TextChanged)
-                        .focus(model.Focus = Some Entry1, focusChanged Entry1)
-
-                    Entry("Entry2", TextChanged)
-                        .focus(model.Focus = Some Entry2, focusChanged Entry2)
-
-                    Entry("Entry3", TextChanged)
-                        .focus(model.Focus = Some Entry3, focusChanged Entry3)
-
-                    Button("Set focus on Entry1", SetFocus(Some Entry1))
-                    Button("Set focus on Entry2", SetFocus(Some Entry2))
-                    Button("Set focus on Entry3", SetFocus(Some Entry3))
-                    Button("Unfocus", SetFocus None)
-                })
-                    .margin(20.)
+            NavigationStack(List.rev model.Stack, StackUpdated, fun path ->
+                match path with
+                | Home ->
+                    ContentPage(
+                        VStack(spacing = 15.) {
+                            Label("Home")
+                            Button("Go to Details", GoTo Details)
+                        }
+                    )
+                        .title("Home")
+                | Details ->
+                    ContentPage(
+                        VStack(spacing = 15.) {
+                            Label("Details")
+                            for i in 1..3 do
+                                Button($"Go to Subdetails {i}", GoTo (Subdetails i))
+                            Button("Go back", GoBack)
+                        }
+                    )
+                        .title("Details")
+                | Subdetails i ->
+                    ContentPage(
+                        VStack(spacing = 15.) {
+                            Label($"Subdetails {i}")
+                            Button("Go back", GoBack)
+                            Button("Go to root", GoToRoot)
+                        }
+                    )
+                        .title($"Subdetails {i}")
             )
         )
 
diff --git a/src/Fabulous.MauiControls/Fabulous.MauiControls.fsproj b/src/Fabulous.MauiControls/Fabulous.MauiControls.fsproj
index 3020042..e6a83ff 100644
--- a/src/Fabulous.MauiControls/Fabulous.MauiControls.fsproj
+++ b/src/Fabulous.MauiControls/Fabulous.MauiControls.fsproj
@@ -57,6 +57,7 @@
     <Compile Include="Views\Pages\_Page.fs" />
     <Compile Include="Views\Pages\ContentPage.fs" />
     <Compile Include="Views\Pages\NavigationPage.fs" />
+    <Compile Include="Views\Pages\NavigationStack.fs" />
     <Compile Include="Views\Pages\_MultiPageOfPage.fs" />
     <Compile Include="Views\Pages\TabbedPage.fs" />
     <Compile Include="Views\Pages\FlyoutPage.fs" />
diff --git a/src/Fabulous.MauiControls/Views/Pages/NavigationStack.fs b/src/Fabulous.MauiControls/Views/Pages/NavigationStack.fs
new file mode 100644
index 0000000..6a242ac
--- /dev/null
+++ b/src/Fabulous.MauiControls/Views/Pages/NavigationStack.fs
@@ -0,0 +1,70 @@
+namespace Fabulous.Maui
+
+open System
+open System.Collections.Generic
+open Fabulous
+open Fabulous.Maui
+open Fabulous.StackAllocatedCollections.StackList
+open Microsoft.Maui.Controls
+
+type IFabNavigationStack =
+    inherit IFabNavigationPage
+    
+
+    
+    
+type FabNavigationStack() =
+    inherit NavigationPage()
+    
+    let stackUpdated = Event<EventHandler<EventArgs>, EventArgs>()
+    let mutable stack: IEnumerable<Page> = [||]
+    
+    [<CLIEvent>]
+    member _.StackUpdated = stackUpdated.Publish
+    
+    member this.Stack
+        with get () = stack
+        and set value =
+            if stack <> value then
+                stack <- value
+                this.ApplyStack()
+        
+    member private this.ApplyStack() =
+        // TODO: Diff the stack and only update the pages that changed
+        stackUpdated.Trigger(this, EventArgs())
+    
+    
+    
+    
+    
+    
+    
+    
+    
+    
+    
+
+module NavigationStack =
+    let WidgetKey = Widgets.register<FabNavigationStack>()
+    
+    let Stack = Attributes.defineSimpleScalarWithEquality<ArraySlice<Widget>> "NavigationStack_Stack" (fun prevOpt currOpt node ->
+        ()
+    )
+    
+[<AutoOpen>]
+module NavigationStackBuilders =
+    type Fabulous.Maui.View with
+        static member inline NavigationStack(stack: 'path list, onStackUpdated: 'path list -> 'msg, router: 'path -> WidgetBuilder<'msg, #IFabPage>) =            
+            let pages = [| for path in stack do (router path).Compile() |]
+            let pages: ArraySlice<Widget> = (uint16 pages.Length, pages)
+            
+            WidgetBuilder<'msg, IFabNavigationStack>(
+                NavigationStack.WidgetKey,
+                AttributesBundle(
+                    StackList.empty(),
+                    ValueNone,
+                    ValueSome [|
+                        NavigationPage.Pages.WithValue(pages)
+                    |]
+                )
+            )
\ No newline at end of file