1 files changed, 67 insertions, 0 deletions
diff --git a/src/SMAPI/Events/ButtonsChangedEventArgs.cs b/src/SMAPI/Events/ButtonsChangedEventArgs.cs
new file mode 100644
index 00000000..dda41692
--- /dev/null
+++ b/src/SMAPI/Events/ButtonsChangedEventArgs.cs
@@ -0,0 +1,67 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using StardewModdingAPI.Framework.Input;
+
+namespace StardewModdingAPI.Events
+{
+    /// <summary>Event arguments when any buttons were pressed or released.</summary>
+    public class ButtonsChangedEventArgs : EventArgs
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>The buttons that were pressed, held, or released since the previous tick.</summary>
+        private readonly Lazy<Dictionary<SButtonState, SButton[]>> ButtonsByState;
+
+
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>The current cursor position.</summary>
+        public ICursorPosition Cursor { get; }
+
+        /// <summary>The buttons which were pressed since the previous tick.</summary>
+        public IEnumerable<SButton> Pressed => this.ButtonsByState.Value[SButtonState.Pressed];
+
+        /// <summary>The buttons which were held since the previous tick.</summary>
+        public IEnumerable<SButton> Held => this.ButtonsByState.Value[SButtonState.Held];
+
+        /// <summary>The buttons which were released since the previous tick.</summary>
+        public IEnumerable<SButton> Released => this.ButtonsByState.Value[SButtonState.Released];
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="cursor">The cursor position.</param>
+        /// <param name="inputState">The game's current input state.</param>
+        internal ButtonsChangedEventArgs(ICursorPosition cursor, SInputState inputState)
+        {
+            this.Cursor = cursor;
+            this.ButtonsByState = new Lazy<Dictionary<SButtonState, SButton[]>>(() => this.GetButtonsByState(inputState));
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>Get the buttons that were pressed, held, or released since the previous tick.</summary>
+        /// <param name="inputState">The game's current input state.</param>
+        private Dictionary<SButtonState, SButton[]> GetButtonsByState(SInputState inputState)
+        {
+            Dictionary<SButtonState, SButton[]> lookup = inputState.ButtonStates
+                .GroupBy(p => p.Value)
+                .ToDictionary(p => p.Key, p => p.Select(p => p.Key).ToArray());
+
+            foreach (var state in new[] { SButtonState.Pressed, SButtonState.Held, SButtonState.Released })
+            {
+                if (!lookup.ContainsKey(state))
+                    lookup[state] = new SButton[0];
+            }
+
+            return lookup;
+        }
+    }
+}