From 7419e124a3b3836681ad564aaa51f88f96cff910 Mon Sep 17 00:00:00 2001
From: Assaf Tirangel <assaf.tirangel@ermetic.com>
Date: Sat, 1 Jul 2023 01:11:34 +0300
Subject: [PATCH] Adds prompt tree

---
 examples/Console/Prompt/Program.cs            | 58 +++++++++++++++++++
 examples/Console/Prompt/SelectableItem.cs     | 25 ++++++++
 .../Prompts/MultiSelectionPromptExtensions.cs | 40 +++++++++++++
 3 files changed, 123 insertions(+)
 create mode 100644 examples/Console/Prompt/SelectableItem.cs

diff --git a/examples/Console/Prompt/Program.cs b/examples/Console/Prompt/Program.cs
index 0008bfa37..baf66aa8d 100644
--- a/examples/Console/Prompt/Program.cs
+++ b/examples/Console/Prompt/Program.cs
@@ -1,3 +1,5 @@
+using System.Collections.Generic;
+using System.Linq;
 using Spectre.Console;
 
 namespace Prompt
@@ -26,6 +28,9 @@ public static void Main(string[] args)
             WriteDivider("Lists");
             var fruit = AskFruit();
 
+            WriteDivider("Prompt Tree");
+            var deepSpaceObjects = AskDeepSpaceObjects();
+
             WriteDivider("Choices");
             var sport = AskSport();
 
@@ -52,6 +57,7 @@ public static void Main(string[] args)
                 .BorderColor(Color.Grey)
                 .AddRow("[grey]Name[/]", name)
                 .AddRow("[grey]Favorite fruit[/]", fruit)
+                .AddRow("[grey]Favorite DSOs[/]", string.Join(", ", deepSpaceObjects))
                 .AddRow("[grey]Favorite sport[/]", sport)
                 .AddRow("[grey]Age[/]", age.ToString())
                 .AddRow("[grey]Password[/]", password)
@@ -119,6 +125,58 @@ public static string AskFruit()
             return fruit;
         }
 
+        public static IEnumerable<string> AskDeepSpaceObjects()
+        {
+            var tree =
+                new SelectableItems(
+                    "All",
+                    new SelectableItems(
+                        "Galaxies",
+                        new SelectableItem("Milky Way"),
+                        new SelectableItem("M33 (Triangulum)"),
+                        new SelectableItem("M51 (Whirlpool)"),
+                        new SelectableItems(
+                            "M31 (Andromeda)",
+                            new SelectableItem("Andromeda's Parachute"),
+                            new SelectableItem("G1 (Mayall II)"),
+                            new SelectableItem("NGC 206"))),
+                    new SelectableItems(
+                        "Globular Clusters",
+                        new SelectableItem("NGC 5139 (Omega Centauri)"),
+                        new SelectableItem("M13 (Hercules)"),
+                        new SelectableItem("M3"),
+                        new SelectableItem("M5")),
+                    new SelectableItems(
+                        "Open Clusters",
+                        new SelectableItem("M45 (The Pleiades)"),
+                        new SelectableItem("M44 (The Beehive Cluster)"),
+                        new SelectableItem("M6 (the Butterfly Cluster)"),
+                        new SelectableItem("M7 (Ptolemy's Cluster)")),
+                    new SelectableItems(
+                        "Nebulas",
+                        new SelectableItem("M42 (Orion Nebula)"),
+                        new SelectableItem("M16 (Eagle Nebula)"),
+                        new SelectableItem("M6 (the Butterfly Cluster)"),
+                        new SelectableItem("M7 (Ptolemy's Cluster)")));
+
+            return AnsiConsole.Prompt(
+                    new MultiSelectionPrompt<SelectableItem>()
+                        .AddChoiceTree(
+                            tree,
+                            selectableItem =>
+                                selectableItem is SelectableItems selectableItems
+                                    ? selectableItems.Children
+                                    : Enumerable.Empty<SelectableItem>())
+                        .PageSize(10)
+                        .Title("What are your favorite DSOs?")
+                        .HighlightStyle(
+                            new Style(
+                                Color.Black,
+                                Color.SteelBlue1))
+                        .UseConverter(selectable => selectable.Name))
+                .Select(selectableItem => selectableItem.Name);
+        }
+
         public static string AskSport()
         {
             return AnsiConsole.Prompt(
diff --git a/examples/Console/Prompt/SelectableItem.cs b/examples/Console/Prompt/SelectableItem.cs
new file mode 100644
index 000000000..30d341b27
--- /dev/null
+++ b/examples/Console/Prompt/SelectableItem.cs
@@ -0,0 +1,25 @@
+using System.Collections.Generic;
+
+namespace Prompt
+{
+    internal class SelectableItem
+    {
+        public string Name { get; set; }
+
+        public SelectableItem(string name)
+        {
+            Name = name;
+        }
+    }
+
+    internal class SelectableItems : SelectableItem
+    {
+        public IEnumerable<SelectableItem> Children { get; set; }
+
+        public SelectableItems(string name, params SelectableItem[] children) :
+            base(name)
+        {
+            Children = children;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Spectre.Console/Prompts/MultiSelectionPromptExtensions.cs b/src/Spectre.Console/Prompts/MultiSelectionPromptExtensions.cs
index a4aaecf51..a881e367e 100644
--- a/src/Spectre.Console/Prompts/MultiSelectionPromptExtensions.cs
+++ b/src/Spectre.Console/Prompts/MultiSelectionPromptExtensions.cs
@@ -147,6 +147,46 @@ public static MultiSelectionPrompt<T> AddChoiceGroup<T>(this MultiSelectionPromp
         return obj;
     }
 
+    /// <summary>
+    /// Adds choice tree.
+    /// </summary>
+    /// <typeparam name="T">The prompt result type.</typeparam>
+    /// <param name="obj">The prompt.</param>
+    /// <param name="rootChoice">The tree's root.</param>
+    /// <param name="getChildChoices">A function to get node child choices.</param>
+    /// <returns>The same instance so that multiple calls can be chained.</returns>
+    public static MultiSelectionPrompt<T> AddChoiceTree<T>(this MultiSelectionPrompt<T> obj, T rootChoice, Func<T, IEnumerable<T>> getChildChoices)
+        where T : notnull
+    {
+        var multiSelectionItem = obj.AddChoice(rootChoice);
+        AddChildChoice(
+            getChildChoices,
+            rootChoice,
+            multiSelectionItem,
+            rootChoice: true);
+        return obj;
+
+        static void AddChildChoice(
+            Func<T, IEnumerable<T>> getChildChoices,
+            T parentChoice,
+            ISelectionItem<T> selectionItem,
+            bool rootChoice = false)
+        {
+            if (!rootChoice)
+            {
+                selectionItem = selectionItem.AddChild(parentChoice);
+            }
+
+            foreach (var childChoice in getChildChoices(parentChoice))
+            {
+                AddChildChoice(
+                    getChildChoices,
+                    childChoice,
+                    selectionItem);
+            }
+        }
+    }
+
     /// <summary>
     /// Marks an item as selected.
     /// </summary>