add mechanism for GIDClientID

Author: Thaina

GoogleSignIn/Editor/iOS.meta

@@ -0,0 +1,36 @@
+#if UNITY_EDITOR
+using System;
+using System.IO;
+using System.Linq;
+
+using UnityEditor;
+using UnityEditor.iOS.Xcode;
+
+using UnityEditor.Build;
+using UnityEditor.Build.Reporting;
+
+public class GameBuilder : IPostprocessBuildWithReport
+{
+	public int callbackOrder => 999;
+
+	public void OnPostprocessBuild(BuildReport report)
+    {
+        if(report.summary.platform != BuildTarget.iOS)
+            return;
+
+        string infoPlist = Path.Combine(report.summary.outputPath,"Info.plist");
+        if(!File.Exists(infoPlist))
+            return;
+
+        string googleScheme = PlayerSettings.iOS.iOSUrlSchemes.FirstOrDefault((scheme) => scheme.StartsWith("com.googleusercontent.apps."));
+        if(string.IsNullOrEmpty(googleScheme))
+            return;
+
+        PlistDocument plistDoc = new();
+        plistDoc.ReadFromFile(infoPlist);
+        plistDoc.root.SetString("GIDClientID",string.Join('.',googleScheme.Split('.').Reverse()));
+
+        plistDoc.WriteToFile(infoPlist);
+    }
+}
+#endif