Greatly improve performance due to ScriptIterator changes

PkmnLib.Dynamic/ScriptHandling/ScriptIterator.cs

@@ -8,6 +8,7 @@ namespace PkmnLib.Dynamic.ScriptHandling;
 public class ScriptIterator : IEnumerable<ScriptContainer>
 {
     private readonly IReadOnlyList<IEnumerable<ScriptContainer>> _scripts;
+    private int _currentIndex = 0;
 
     /// <inheritdoc cref="ScriptIterator"/>
     public ScriptIterator(IReadOnlyList<IEnumerable<ScriptContainer>> scripts)
@@ -15,39 +16,41 @@ public class ScriptIterator : IEnumerable<ScriptContainer>
         _scripts = scripts;
     }
 
-    private IEnumerable<ScriptContainer> GetAsEnumerable()
+    /// <inheritdoc />
+    public IEnumerator<ScriptContainer> GetEnumerator()
     {
-        foreach (var enumerable in _scripts)
+        while (_currentIndex < _scripts.Count)
         {
-            if (enumerable is IScriptSet set)
+            var enumerable = _scripts[_currentIndex++];
+            switch (enumerable)
             {
-                // We can't assume that the set remains the same size, so we need to iterate through it
-                // with a for loop.
-                for (var j = 0; j < set.Count; j++)
+                case IScriptSet set:
                 {
-                    var script = set.At(j);
-                    // We can ignore empty scripts.
-                    if (script.IsEmpty)
-                        continue;
-                    yield return script;
-                }
-            }
-            else
-            {
-                foreach (var script in enumerable)
-                {
-                    // We can ignore empty scripts.
-                    if (script.IsEmpty)
-                        continue;
-                    yield return script;
+                    // We can't assume that the set remains the same size, so we need to iterate through it
+                    // with a for loop.
+                    for (var j = 0; j < set.Count; j++)
+                    {
+                        var script = set.At(j);
+                        // We can ignore empty scripts.
+                        if (script.IsEmpty)
+                            continue;
+                        yield return script;
+                    }
+                    break;
                 }
+                case ScriptContainer { IsEmpty: true }:
+                    continue;
+                case ScriptContainer container:
+                    yield return container;
+                    break;
+                default:
+                    throw new InvalidOperationException(
+                        $"Unexpected script type: {enumerable.GetType().Name}. Expected IScriptSet or ScriptContainer.");
             }
         }
+        _currentIndex = 0;
     }
 
-    /// <inheritdoc />
-    public IEnumerator<ScriptContainer> GetEnumerator() => GetAsEnumerable().GetEnumerator();
-
     /// <inheritdoc />
     IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
 }