Mapping merge driver: continued (#2803)

Co-authored-by: DrSmugleaf <DrSmugleaf@users.noreply.github.com>
Co-authored-by: Pieter-Jan Briers <pieterjan.briers+git@gmail.com>

Content.Tools/MappingMergeDriver.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using YamlDotNet.Core;
+using YamlDotNet.RepresentationModel;
+
+namespace Content.Tools
+{
+    internal static class MappingMergeDriver
+    {
+        /// %A: Our file
+        /// %O: Origin (common, base) file
+        /// %B: Other file
+        /// %P: Actual filename of the resulting file
+        public static void Main(string[] args)
+        {
+            var ours = new Map(args[0]);
+            var based = new Map(args[1]); // On what?
+            var other = new Map(args[2]);
+
+            if ((ours.GridsNode.Children.Count != 1) || (based.GridsNode.Children.Count != 1) || (other.GridsNode.Children.Count != 1))
+            {
+                Console.WriteLine("one or more files had an amount of grids not equal to 1");
+                Environment.Exit(1);
+            }
+
+            if (!(new Merger(ours, based, other).Merge()))
+            {
+                Console.WriteLine("unable to merge!");
+                Environment.Exit(1);
+            }
+
+            ours.Save();
+            Environment.Exit(0);
+        }
+    }
+}