iTweenPath - better usability

// Copyright (c) 2010 Bob Berkebile
//
// Modified by ~PeterSvP
//  Made initial points at the transform position and close to it,
//  added a [+Add] button - adds a point nesr the last one,
//  added Drop field where you can drop scene object to add its transform as a point,
//  added a [M] button that adds point in between its row and the next
//  added DELETE buttons for each point to be able to delete it
//
// Please direct any bugs/comments/suggestions to http://www.pixelplacement.com
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

using UnityEngine;
using UnityEditor;
using System.Collections;
using System.Linq;

[CustomEditor(typeof(iTweenPath))]
public class iTweenPathEditor : Editor
{
    iTweenPath _target;
    GUIStyle style = new GUIStyle();
    public static int count = 0;
    static GameObject drop;
    static string dropName = "\n\nDrop object to add its pos\n\n";    // the (Transform) is out of view and it's centered :D

    void OnEnable()
    {
        //i like bold handle labels since I'm getting old:
        style.fontStyle = FontStyle.Bold;
        style.normal.textColor = Color.white;
        _target = (iTweenPath)target;

        //lock in a default path name:
        if (!_target.initialized)
        {
            _target.initialized = true;
            _target.pathName = "New Path " + ++count;
            _target.initialName = _target.pathName;
        }
    }

    public override void OnInspectorGUI()
    {
        //draw the path?
        EditorGUILayout.BeginHorizontal();
        EditorGUILayout.PrefixLabel("Path Visible");
        _target.pathVisible = EditorGUILayout.Toggle(_target.pathVisible);
        EditorGUILayout.EndHorizontal();

        //path name:
        EditorGUILayout.BeginHorizontal();
        EditorGUILayout.PrefixLabel("Path Name");
        _target.pathName = EditorGUILayout.TextField(_target.pathName);
        EditorGUILayout.EndHorizontal();

        if (_target.pathName == "")
        {
            _target.pathName = _target.initialName;
        }

        //path color:
        EditorGUILayout.BeginHorizontal();
        EditorGUILayout.PrefixLabel("Path Color");
        _target.pathColor = EditorGUILayout.ColorField(_target.pathColor);
        EditorGUILayout.EndHorizontal();

        //exploration segment count control:
        EditorGUILayout.BeginHorizontal();
        //EditorGUILayout.PrefixLabel("Node Count");
        _target.nodeCount = Mathf.Max(2, EditorGUILayout.IntField("Node Count", _target.nodeCount));
        //_target.nodeCount =  Mathf.Clamp(EditorGUILayout.IntSlider(_target.nodeCount, 0, 10), 2,100);
        EditorGUILayout.EndHorizontal();

        //add node?
        if (_target.nodeCount > _target.nodes.Count)
        {
            // if noone, add small tween from current to +1 forward instead of (0,0,0)
            if (_target.nodes.Count == 0)
            {
                _target.nodes.Add(_target.transform.position);
                _target.nodes.Add(_target.transform.position + Vector3.forward);
            }
            // Else add close to last
            else for (int i = 0; i < _target.nodeCount - _target.nodes.Count; i++)
                {
                    int c = _target.nodes.Count;
                    _target.nodes.Add(Vector3.LerpUnclamped(_target.nodes[c - 2], _target.nodes[c - 1], 1.5f));
                }
        }

        //remove node?
        if (_target.nodeCount < _target.nodes.Count)
        {
            if (EditorUtility.DisplayDialog("Remove path node?", "Shortening the node list will permantently destory parts of your path. This operation cannot be undone.", "OK", "Cancel"))
            {
                int removeCount = _target.nodes.Count - _target.nodeCount;
                _target.nodes.RemoveRange(_target.nodes.Count - removeCount, removeCount);
            }
            else {
                _target.nodeCount = _target.nodes.Count;
            }
        }

        //node display:
        bool disableDelete = _target.nodeCount <= 2;
        for (int i = 0; i < _target.nodes.Count; i++)
        {
            EditorGUILayout.BeginHorizontal();
            GUILayout.Label((i + 1) + ":", GUILayout.MaxWidth(20));
            _target.nodes[i] = EditorGUILayout.Vector3Field("", _target.nodes[i]);

            GUI.enabled = i < _target.nodes.Count - 1;
            if (GUILayout.Button("M", GUILayout.MaxWidth(20)))
            {
                Vector3 mid = (_target.nodes[i] + _target.nodes[i + 1]) / 2;
                _target.nodes.Insert(i+1, mid); _target.nodeCount++; return;
            }
            GUI.enabled = !disableDelete;
            if (GUILayout.Button("X", GUILayout.MaxWidth(20))) { _target.nodes.RemoveAt(i); _target.nodeCount--; return; }
            GUI.enabled = true;
            EditorGUILayout.EndHorizontal();
        }

        // Utility buttons feature - add new close to last or add from scene object
        EditorGUILayout.BeginHorizontal();
        if (GUILayout.Button("+ Add")) _target.nodeCount++;

        // Hack to dislay custom text into the ObjectField
        if (drop == null)
        {
            drop = new GameObject();
            drop.hideFlags = HideFlags.HideAndDontSave;
            drop.name = dropName;
        }

        // If something was selected, add its position
        Transform changed = EditorGUILayout.ObjectField(drop, typeof(Transform), true) as Transform;
        if (changed != null)
        {
            _target.nodeCount++;
            _target.nodes.Add(changed.position);
        }
        EditorGUILayout.EndHorizontal();

        // Update and redraw:
        if (GUI.changed)
        {
            EditorUtility.SetDirty(_target);
        }
    }

    void OnSceneGUI()
    {
        if (_target.pathVisible)
        {
            if (_target.nodes.Count > 0)
            {
                //allow path adjustment undo:
                Undo.SetSnapshotTarget(_target, "Adjust iTween Path");

                //path begin and end labels:
                Handles.Label(_target.nodes[0], "'" + _target.pathName + "' Begin", style);
                Handles.Label(_target.nodes[_target.nodes.Count - 1], "'" + _target.pathName + "' End", style);

                //node handle display:
                for (int i = 0; i < _target.nodes.Count; i++)
                {
                    _target.nodes[i] = Handles.PositionHandle(_target.nodes[i], Quaternion.identity);
                }
            }
        }
    }
}