// Created by Daniele Giardini - 2011 - Holoville - http://www.holoville.com

using UnityEditor;
using UnityEngine;

#if UNITY_4_3 || UNITY_4_5 || UNITY_4_6 || UNITY_5_0 || UNITY_5_1 || UNITY_5_2 || UNITY_5_3 || UNITY_5_4 || UNITY_5_5 || UNITY_5_6 || UNITY_2017 || UNITY_2018 || UNITY_2019 || UNITY_2020
public class MegaUndo
{
	private     Object              defTarget;
	private     string              defName;
	//private     bool                autoSetDirty;
	//private     bool                listeningForGuiChanges;
	//private     bool                isMouseDown;
	//private     Object              waitingToRecordPrefab; // If different than NULL indicates the prefab instance that will need to record its state as soon as the mouse is released.

	public MegaUndo(Object p_target, string p_name) : this(p_target, p_name, true) { }
	public MegaUndo(Object p_target, string p_name, bool p_autoSetDirty)
	{
		defTarget = p_target;
		defName = p_name;
		//autoSetDirty = p_autoSetDirty;
	}

	public void CheckUndo() { CheckUndo(defTarget, defName); }
	public void CheckUndo(Object obj, string name)
	{
	}
	public bool CheckDirty(Object obj)
	{
		if ( GUI.changed )	// Wont work for dragging points
		{
			Undo.RecordObject(obj, defName);
		}
		return false;	//CheckDirty(defTarget, defName);
	}

	public bool CheckDirty()
	{
		return CheckDirty(defTarget);
	}

	public static void SetSnapshotTarget(Object obj, string name)
	{
		Undo.RecordObject(obj, name);
	}

	public static void CreateSnapshot()
	{
		//Undo.CreateSnapshot();
	}

	public static void RegisterSnapshot()
	{
		//Undo.RegisterSnapshot();
	}

	public static void ClearSnapshotTarget()
	{
		//Undo.ClearSnapshotTarget();
	}
}
#else
public class MegaUndo
{
	private     Object              defTarget;
	private     string              defName;
	private     bool                autoSetDirty;
	private     bool                listeningForGuiChanges;
	private     bool                isMouseDown;
	private     Object              waitingToRecordPrefab; // If different than NULL indicates the prefab instance that will need to record its state as soon as the mouse is released.

	public MegaUndo(Object p_target, string p_name) : this(p_target, p_name, true) { }
	public MegaUndo(Object p_target, string p_name, bool p_autoSetDirty)
	{
		defTarget = p_target;
		defName = p_name;
		autoSetDirty = p_autoSetDirty;
	}

	public void CheckUndo() { CheckUndo(defTarget, defName); }
	public void CheckUndo(Object p_target) { CheckUndo(p_target, defName); }
	public void CheckUndo(Object p_target, string p_name)
	{
		Event e = Event.current;

		if ( waitingToRecordPrefab != null )
		{
			// Record eventual prefab instance modification.
			// TODO Avoid recording if nothing changed (no harm in doing so, but it would be nicer).
			switch ( e.type )
			{
				case EventType.MouseDown:
				case EventType.MouseUp:
				case EventType.KeyDown:
				case EventType.KeyUp:
					PrefabUtility.RecordPrefabInstancePropertyModifications(waitingToRecordPrefab);
					break;
			}
		}

		if ( (e.type == EventType.MouseDown && e.button == 0) || (e.type == EventType.KeyUp && e.keyCode == KeyCode.Tab) )
		{
			// When the LMB is pressed or the TAB key is released,
			// store a snapshot, but don't register it as an undo
			// (so that if nothing changes we avoid storing a useless undo).
			Undo.SetSnapshotTarget(p_target, p_name);
			Undo.CreateSnapshot();
			Undo.ClearSnapshotTarget(); // Not sure if this is necessary.
			listeningForGuiChanges = true;
		}

	}

	public bool CheckDirty() { return CheckDirty(defTarget, defName); }
	public bool CheckDirty(Object p_target) { return CheckDirty(p_target, defName); }
	public bool CheckDirty(Object p_target, string p_name)
	{
		if ( listeningForGuiChanges && GUI.changed )
		{
			// Some GUI value changed after pressing the mouse
			// or releasing the TAB key.
			// Register the previous snapshot as a valid undo.
			SetDirty(p_target, p_name);
			return true;
		}
		return false;
	}

	public void ForceDirty() { ForceDirty(defTarget, defName); }
	public void ForceDirty(Object p_target) { ForceDirty(p_target, defName); }
	public void ForceDirty(Object p_target, string p_name)
	{
		if ( !listeningForGuiChanges )
		{
			// Create a new snapshot.
			Undo.SetSnapshotTarget(p_target, p_name);
			Undo.CreateSnapshot();
			Undo.ClearSnapshotTarget();
		}
		SetDirty(p_target, p_name);
	}

	private void SetDirty(Object p_target, string p_name)
	{
		Undo.SetSnapshotTarget(p_target, p_name);
		Undo.RegisterSnapshot();
		Undo.ClearSnapshotTarget(); // Not sure if this is necessary.
		if ( autoSetDirty ) EditorUtility.SetDirty(p_target);
		listeningForGuiChanges = false;

		if ( CheckTargetIsPrefabInstance(p_target) )
		{
			// Prefab instance: record immediately and also wait for value to be changed and than re-record it
			// (otherwise prefab instances are not updated correctly when using Custom Inspectors).
			PrefabUtility.RecordPrefabInstancePropertyModifications(p_target);
			waitingToRecordPrefab = p_target;
		}
		else
		{
			waitingToRecordPrefab = null;
		}
	}

	private bool CheckTargetIsPrefabInstance(Object p_target)
	{
		return (PrefabUtility.GetPrefabType(p_target) == PrefabType.PrefabInstance);
	}

	public static void SetSnapshotTarget(Object obj, string name)
	{
		Undo.SetSnapshotTarget(obj, name);
	}

	public static void CreateSnapshot()
	{
		Undo.CreateSnapshot();
	}

	public static void RegisterSnapshot()
	{
		Undo.RegisterSnapshot();
	}

	public static void ClearSnapshotTarget()
	{
		Undo.ClearSnapshotTarget();
	}
}
#endif