3 files changed, 120 insertions, 0 deletions
diff --git a/src/SMAPI/Framework/Patching/GameLocationPatch.cs b/src/SMAPI/Framework/Patching/GameLocationPatch.cs
new file mode 100644
index 00000000..c0216b8f
--- /dev/null
+++ b/src/SMAPI/Framework/Patching/GameLocationPatch.cs
@@ -0,0 +1,60 @@
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
+using System.Reflection;
+using Harmony;
+using StardewValley;
+using xTile.Tiles;
+
+namespace StardewModdingAPI.Framework.Patching
+{
+    /// <summary>A Harmony patch for the <see cref="GameLocation.updateSeasonalTileSheets"/> method.</summary>
+    internal class GameLocationPatch : IHarmonyPatch
+    {
+        /*********
+        ** Accessors
+        *********/
+        /// <summary>A unique name for this patch.</summary>
+        public string Name => $"{nameof(GameLocation)}.{nameof(GameLocation.updateSeasonalTileSheets)}";
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Apply the Harmony patch.</summary>
+        /// <param name="harmony">The Harmony instance.</param>
+        public void Apply(HarmonyInstance harmony)
+        {
+            MethodInfo method = AccessTools.Method(typeof(GameLocation), nameof(GameLocation.updateSeasonalTileSheets));
+            MethodInfo prefix = AccessTools.Method(this.GetType(), nameof(GameLocationPatch.Prefix));
+
+            harmony.Patch(method, new HarmonyMethod(prefix), null);
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>An implementation of <see cref="GameLocation.updateSeasonalTileSheets"/> which correctly handles custom map tilesheets.</summary>
+        /// <param name="__instance">The location instance being patched.</param>
+        [SuppressMessage("ReSharper", "InconsistentNaming", Justification = "Argument name is defined by Harmony.")]
+        private static bool Prefix(GameLocation __instance)
+        {
+            if (!__instance.IsOutdoors || __instance.Name.Equals("Desert"))
+                return false;
+            foreach (TileSheet tilesheet in __instance.Map.TileSheets)
+            {
+                string imageSource = tilesheet.ImageSource;
+                string imageFile = Path.GetFileName(imageSource);
+                if (imageFile.StartsWith("spring_") || imageFile.StartsWith("summer_") || imageFile.StartsWith("fall_") || imageFile.StartsWith("winter_"))
+                {
+                    string imageDir = Path.GetDirectoryName(imageSource);
+                    if (string.IsNullOrWhiteSpace(imageDir))
+                        imageDir = "Maps";
+                    tilesheet.ImageSource = Path.Combine(imageDir, Game1.currentSeason + "_" + imageFile.Split('_')[1]);
+                }
+            }
+
+            return false;
+        }
+    }
+}
diff --git a/src/SMAPI/Framework/Patching/GamePatcher.cs b/src/SMAPI/Framework/Patching/GamePatcher.cs
new file mode 100644
index 00000000..71ca8e55
--- /dev/null
+++ b/src/SMAPI/Framework/Patching/GamePatcher.cs
@@ -0,0 +1,45 @@
+using System;
+using Harmony;
+
+namespace StardewModdingAPI.Framework.Patching
+{
+    /// <summary>Encapsulates applying Harmony patches to the game.</summary>
+    internal class GamePatcher
+    {
+        /*********
+        ** Properties
+        *********/
+        /// <summary>Encapsulates monitoring and logging.</summary>
+        private readonly IMonitor Monitor;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="monitor">Encapsulates monitoring and logging.</param>
+        public GamePatcher(IMonitor monitor)
+        {
+            this.Monitor = monitor;
+        }
+
+        /// <summary>Apply all loaded patches to the game.</summary>
+        /// <param name="patches">The patches to apply.</param>
+        public void Apply(params IHarmonyPatch[] patches)
+        {
+            HarmonyInstance harmony = HarmonyInstance.Create("io.smapi");
+            foreach (IHarmonyPatch patch in patches)
+            {
+                try
+                {
+                    patch.Apply(harmony);
+                }
+                catch (Exception ex)
+                {
+                    this.Monitor.Log($"Couldn't apply runtime patch '{patch.Name}' to the game. Some SMAPI features may not work correctly. See log file for details.", LogLevel.Error);
+                    this.Monitor.Log(ex.GetLogSummary(), LogLevel.Trace);
+                }
+            }
+        }
+    }
+}
diff --git a/src/SMAPI/Framework/Patching/IHarmonyPatch.cs b/src/SMAPI/Framework/Patching/IHarmonyPatch.cs
new file mode 100644
index 00000000..cb42f40e
--- /dev/null
+++ b/src/SMAPI/Framework/Patching/IHarmonyPatch.cs
@@ -0,0 +1,15 @@
+using Harmony;
+
+namespace StardewModdingAPI.Framework.Patching
+{
+    /// <summary>A Harmony patch to apply.</summary>
+    internal interface IHarmonyPatch
+    {
+        /// <summary>A unique name for this patch.</summary>
+        string Name { get; }
+
+        /// <summary>Apply the Harmony patch.</summary>
+        /// <param name="harmony">The Harmony instance.</param>
+        void Apply(HarmonyInstance harmony);
+    }
+}