https://helle.ai/audio-editor/state.js

1(function ( PKAE ) {
2	'use strict';
3	
4	function PKState ( _depth, app ) {
5		if (!_depth) _depth = 1;
6
7		var q = this;
8
9		var _id = 1;
10		var _fireEvent = app.fireEvent;
11		var _listenFor = app.listenFor;
12
13		var undo_state_list = [];
14		var redo_state_list = [];
15
16		q.getLastUndoState = function () {
17			return (undo_state_list [ undo_state_list.length - 1]);
18		};
19
20		q.pushUndoState = function ( state ) {
21			if (!state) return (false);
22
23			if (!state.id) state.id = ++_id;
24			if (undo_state_list.length >= _depth) undo_state_list.shift ();
25
26			if (undo_state_list.length > 0)
27			{
28				if (undo_state_list[undo_state_list.length - 1].id !== state.id - 1)
29					undo_state_list = [];
30			}
31			if (redo_state_list.length > 0)
32			{
33				if (redo_state_list[0].id !== state.id + 1)
34					redo_state_list = [];
35			}
36
37			undo_state_list.push ( state );
38
39			_fireEvent ( 'StatePush', undo_state_list.length );
40			_fireEvent ( 'DidStateChange', undo_state_list, redo_state_list);
41			
42			return (true);
43		};
44
45		q.popUndoState = function () {
46			var last_state =undo_state_list.pop ();
47
48			if (last_state) {	
49				if (redo_state_list.length > 0)
50				{
51					if (redo_state_list[0].id !== last_state.id + 1)
52						redo_state_list = [];
53				}
54
55				var temp = app.engine.wavesurfer.backend.buffer;
56				_fireEvent ( 'StateDidPop', last_state, 1 );
57				
58				last_state.data = temp; 
59				redo_state_list.unshift (last_state);
60
61				_fireEvent ( 'DidStateChange', undo_state_list, redo_state_list);
62			}
63
64			return (last_state);
65		};
66		
67		q.shiftRedoState = function () {
68			var last_state = redo_state_list.shift ();
69			
70			if (last_state) {
71				if (undo_state_list.length > 0)
72				{
73					if (undo_state_list[undo_state_list.length - 1].id !== last_state.id - 1)
74						undo_state_list = [];
75				}
76
77				var temp = app.engine.wavesurfer.backend.buffer;
78				_fireEvent ( 'StateDidPop', last_state, 0 );
79
80				last_state.data = temp; 
81				undo_state_list.push (last_state);
82
83				_fireEvent ( 'DidStateChange', undo_state_list, redo_state_list);
84			}
85			
86			return (last_state);
87		};
88		
89		q.clearAllState = function () {
90			undo_state_list = [];
91			redo_state_list = [];
92
93			_fireEvent ( 'StateClearAll' );
94			_fireEvent ( 'DidStateChange', [], []);
95		};
96
97		_listenFor ('StateRequestPush', function ( _state ) {
98			q.pushUndoState ( _state );
99		});
100		_listenFor ('StateRequestUndo', function () {
101			q.popUndoState ();
102		});
103		_listenFor ('StateRequestRedo', function () {
104			q.shiftRedoState ();
105		});
106		_listenFor ('StateRequestClearAll', function () {
107			q.clearAllState ();
108		});
109		_listenFor ('StateRequestLastState', function () {
110			_fireEvent ('StateDidLastState', q.getLastUndoState ());
111		});
112		// -
113	};
114	
115	PKAE._deps.state = PKState;
116	
117})( PKAudioEditor );