encapsulate logic for each input type

1 files changed, 63 insertions, 30 deletions

diff --git a/src/SMAPI/Framework/Input/MouseStateBuilder.cs b/src/SMAPI/Framework/Input/MouseStateBuilder.cs
index 9c6f6f95..cff3e05e 100644
--- a/src/SMAPI/Framework/Input/MouseStateBuilder.cs
+++ b/src/SMAPI/Framework/Input/MouseStateBuilder.cs
@@ -3,43 +3,61 @@ using Microsoft.Xna.Framework.Input;
 
 namespace StardewModdingAPI.Framework.Input
 {
-    /// <summary>Manipulates mouse state.</summary>
-    internal class MouseStateBuilder
+    /// <summary>Manages mouse state.</summary>
+    internal class MouseStateBuilder : IInputStateBuilder<MouseStateBuilder, MouseState>
     {
         /*********
         ** Fields
         *********/
+        /// <summary>The underlying mouse state.</summary>
+        private MouseState? State;
+
         /// <summary>The current button states.</summary>
-        private readonly IDictionary<SButton, ButtonState> ButtonStates;
+        private IDictionary<SButton, ButtonState> ButtonStates;
+
+        /// <summary>The mouse wheel scroll value.</summary>
+        private int ScrollWheelValue;
 
+
+        /*********
+        ** Accessors
+        *********/
         /// <summary>The X cursor position.</summary>
-        private readonly int X;
+        public int X { get; private set; }
 
         /// <summary>The Y cursor position.</summary>
-        private readonly int Y;
-
-        /// <summary>The mouse wheel scroll value.</summary>
-        private readonly int ScrollWheelValue;
+        public int Y { get; private set; }
 
 
         /*********
         ** Public methods
         *********/
         /// <summary>Construct an instance.</summary>
-        /// <param name="state">The initial state.</param>
-        public MouseStateBuilder(MouseState state)
+        /// <param name="state">The initial state, or <c>null</c> to get the latest state.</param>
+        public MouseStateBuilder(MouseState? state = null)
+        {
+            this.Reset(state);
+        }
+
+        /// <summary>Reset the tracked state.</summary>
+        /// <param name="state">The state from which to reset, or <c>null</c> to get the latest state.</param>
+        public MouseStateBuilder Reset(MouseState? state = null)
         {
+            this.State = state ??= Mouse.GetState();
+
             this.ButtonStates = new Dictionary<SButton, ButtonState>
             {
-                [SButton.MouseLeft] = state.LeftButton,
-                [SButton.MouseMiddle] = state.MiddleButton,
-                [SButton.MouseRight] = state.RightButton,
-                [SButton.MouseX1] = state.XButton1,
-                [SButton.MouseX2] = state.XButton2
+                [SButton.MouseLeft] = state.Value.LeftButton,
+                [SButton.MouseMiddle] = state.Value.MiddleButton,
+                [SButton.MouseRight] = state.Value.RightButton,
+                [SButton.MouseX1] = state.Value.XButton1,
+                [SButton.MouseX2] = state.Value.XButton2
             };
-            this.X = state.X;
-            this.Y = state.Y;
-            this.ScrollWheelValue = state.ScrollWheelValue;
+            this.X = state.Value.X;
+            this.Y = state.Value.Y;
+            this.ScrollWheelValue = state.Value.ScrollWheelValue;
+
+            return this;
         }
 
         /// <summary>Override the states for a set of buttons.</summary>
@@ -56,19 +74,34 @@ namespace StardewModdingAPI.Framework.Input
             return this;
         }
 
-        /// <summary>Construct an equivalent mouse state.</summary>
-        public MouseState ToMouseState()
+        /// <summary>Get the currently pressed buttons.</summary>
+        public IEnumerable<SButton> GetPressedButtons()
         {
-            return new MouseState(
-                x: this.X,
-                y: this.Y,
-                scrollWheel: this.ScrollWheelValue,
-                leftButton: this.ButtonStates[SButton.MouseLeft],
-                middleButton: this.ButtonStates[SButton.MouseMiddle],
-                rightButton: this.ButtonStates[SButton.MouseRight],
-                xButton1: this.ButtonStates[SButton.MouseX1],
-                xButton2: this.ButtonStates[SButton.MouseX2]
-            );
+            foreach (var pair in this.ButtonStates)
+            {
+                if (pair.Value == ButtonState.Pressed)
+                    yield return pair.Key;
+            }
+        }
+
+        /// <summary>Get the equivalent state.</summary>
+        public MouseState GetState()
+        {
+            if (this.State == null)
+            {
+                this.State = new MouseState(
+                    x: this.X,
+                    y: this.Y,
+                    scrollWheel: this.ScrollWheelValue,
+                    leftButton: this.ButtonStates[SButton.MouseLeft],
+                    middleButton: this.ButtonStates[SButton.MouseMiddle],
+                    rightButton: this.ButtonStates[SButton.MouseRight],
+                    xButton1: this.ButtonStates[SButton.MouseX1],
+                    xButton2: this.ButtonStates[SButton.MouseX2]
+                );
+            }
+
+            return this.State.Value;
         }
     }
 }