1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
#![allow(non_upper_case_globals)]
use crate::event_source::CGEventSource;
use crate::geometry::CGPoint;
use core_foundation::{
    base::{CFRelease, CFRetain, CFTypeID, TCFType},
    mach_port::{CFMachPort, CFMachPortRef},
};
use foreign_types::ForeignType;
use libc::c_void;
use std::mem::ManuallyDrop;

pub type CGEventField = u32;
pub type CGKeyCode = u16;
pub type CGScrollEventUnit = u32;

bitflags! {
    /// Flags for events
    ///
    /// [Ref](http://opensource.apple.com/source/IOHIDFamily/IOHIDFamily-700/IOHIDSystem/IOKit/hidsystem/IOLLEvent.h)
    #[repr(C)]
    pub struct CGEventFlags: u64 {
        const CGEventFlagNull = 0;

        // Device-independent modifier key bits.
        const CGEventFlagAlphaShift = 0x00010000;
        const CGEventFlagShift = 0x00020000;
        const CGEventFlagControl = 0x00040000;
        const CGEventFlagAlternate = 0x00080000;
        const CGEventFlagCommand = 0x00100000;

        // Special key identifiers.
        const CGEventFlagHelp = 0x00400000;
        const CGEventFlagSecondaryFn = 0x00800000;

        // Identifies key events from numeric keypad area on extended keyboards.
        const CGEventFlagNumericPad = 0x00200000;

        // Indicates if mouse/pen movement events are not being coalesced
        const CGEventFlagNonCoalesced = 0x00000100;
    }
}

/// Key codes for keys that are independent of keyboard layout.
///
/// [Ref](https://github.com/phracker/MacOSX-SDKs/blob/master/MacOSX10.13.sdk/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/Headers/Events.h)
#[repr(C)]
pub struct KeyCode;
impl KeyCode {
    pub const RETURN: CGKeyCode = 0x24;
    pub const TAB: CGKeyCode = 0x30;
    pub const SPACE: CGKeyCode = 0x31;
    pub const DELETE: CGKeyCode = 0x33;
    pub const ESCAPE: CGKeyCode = 0x35;
    pub const COMMAND: CGKeyCode = 0x37;
    pub const SHIFT: CGKeyCode = 0x38;
    pub const CAPS_LOCK: CGKeyCode = 0x39;
    pub const OPTION: CGKeyCode = 0x3A;
    pub const CONTROL: CGKeyCode = 0x3B;
    pub const RIGHT_COMMAND: CGKeyCode = 0x36;
    pub const RIGHT_SHIFT: CGKeyCode = 0x3C;
    pub const RIGHT_OPTION: CGKeyCode = 0x3D;
    pub const RIGHT_CONTROL: CGKeyCode = 0x3E;
    pub const FUNCTION: CGKeyCode = 0x3F;
    pub const VOLUME_UP: CGKeyCode = 0x48;
    pub const VOLUME_DOWN: CGKeyCode = 0x49;
    pub const MUTE: CGKeyCode = 0x4A;
    pub const F1: CGKeyCode = 0x7A;
    pub const F2: CGKeyCode = 0x78;
    pub const F3: CGKeyCode = 0x63;
    pub const F4: CGKeyCode = 0x76;
    pub const F5: CGKeyCode = 0x60;
    pub const F6: CGKeyCode = 0x61;
    pub const F7: CGKeyCode = 0x62;
    pub const F8: CGKeyCode = 0x64;
    pub const F9: CGKeyCode = 0x65;
    pub const F10: CGKeyCode = 0x6D;
    pub const F11: CGKeyCode = 0x67;
    pub const F12: CGKeyCode = 0x6F;
    pub const F13: CGKeyCode = 0x69;
    pub const F14: CGKeyCode = 0x6B;
    pub const F15: CGKeyCode = 0x71;
    pub const F16: CGKeyCode = 0x6A;
    pub const F17: CGKeyCode = 0x40;
    pub const F18: CGKeyCode = 0x4F;
    pub const F19: CGKeyCode = 0x50;
    pub const F20: CGKeyCode = 0x5A;
    pub const HELP: CGKeyCode = 0x72;
    pub const HOME: CGKeyCode = 0x73;
    pub const PAGE_UP: CGKeyCode = 0x74;
    pub const FORWARD_DELETE: CGKeyCode = 0x75;
    pub const END: CGKeyCode = 0x77;
    pub const PAGE_DOWN: CGKeyCode = 0x79;
    pub const LEFT_ARROW: CGKeyCode = 0x7B;
    pub const RIGHT_ARROW: CGKeyCode = 0x7C;
    pub const DOWN_ARROW: CGKeyCode = 0x7D;
    pub const UP_ARROW: CGKeyCode = 0x7E;
}

#[repr(C)]
pub struct ScrollEventUnit {}
impl ScrollEventUnit {
    pub const PIXEL: CGScrollEventUnit = 0;
    pub const LINE: CGScrollEventUnit = 1;
}

/// Constants that specify the different types of input events.
///
/// [Ref](http://opensource.apple.com/source/IOHIDFamily/IOHIDFamily-700/IOHIDSystem/IOKit/hidsystem/IOLLEvent.h)
#[repr(u32)]
#[derive(Clone, Copy, Debug)]
pub enum CGEventType {
    Null = 0,

    // Mouse events.
    LeftMouseDown = 1,
    LeftMouseUp = 2,
    RightMouseDown = 3,
    RightMouseUp = 4,
    MouseMoved = 5,
    LeftMouseDragged = 6,
    RightMouseDragged = 7,

    // Keyboard events.
    KeyDown = 10,
    KeyUp = 11,
    FlagsChanged = 12,

    // Specialized control devices.
    ScrollWheel = 22,
    TabletPointer = 23,
    TabletProximity = 24,
    OtherMouseDown = 25,
    OtherMouseUp = 26,
    OtherMouseDragged = 27,

    // Out of band event types. These are delivered to the event tap callback
    // to notify it of unusual conditions that disable the event tap.
    TapDisabledByTimeout = 0xFFFFFFFE,
    TapDisabledByUserInput = 0xFFFFFFFF,
}

/// Constants used as keys to access specialized fields in low-level events.
///
/// [Ref](https://developer.apple.com/documentation/coregraphics/cgeventfield)
pub struct EventField;
impl EventField {
    /// Key to access an integer field that contains the mouse button event
    /// number. Matching mouse-down and mouse-up events will have the same
    /// event number.
    pub const MOUSE_EVENT_NUMBER: CGEventField = 0;

    /// Key to access an integer field that contains the mouse button click
    /// state. A click state of 1 represents a single click. A click state of
    /// 2 represents a double-click. A click state of 3 represents a
    /// triple-click.
    pub const MOUSE_EVENT_CLICK_STATE: CGEventField = 1;

    /// Key to access a double field that contains the mouse button pressure.
    /// The pressure value may range from 0 to 1, with 0 representing the
    /// mouse being up. This value is commonly set by tablet pens mimicking a
    /// mouse.
    pub const MOUSE_EVENT_PRESSURE: CGEventField = 2;

    /// Key to access an integer field that contains the mouse button number.
    pub const MOUSE_EVENT_BUTTON_NUMBER: CGEventField = 3;

    /// Key to access an integer field that contains the horizontal mouse
    /// delta since the last mouse movement event.
    pub const MOUSE_EVENT_DELTA_X: CGEventField = 4;

    /// Key to access an integer field that contains the vertical mouse delta
    /// since the last mouse movement event.
    pub const MOUSE_EVENT_DELTA_Y: CGEventField = 5;

    /// Key to access an integer field. The value is non-zero if the event
    /// should be ignored by the Inkwell subsystem.
    pub const MOUSE_EVENT_INSTANT_MOUSER: CGEventField = 6;

    /// Key to access an integer field that encodes the mouse event subtype as
    /// a `kCFNumberIntType`.
    pub const MOUSE_EVENT_SUB_TYPE: CGEventField = 7;

    /// Key to access an integer field, non-zero when this is an autorepeat of
    /// a key-down, and zero otherwise.
    pub const KEYBOARD_EVENT_AUTOREPEAT: CGEventField = 8;

    /// Key to access an integer field that contains the virtual keycode of the
    /// key-down or key-up event.
    pub const KEYBOARD_EVENT_KEYCODE: CGEventField = 9;

    /// Key to access an integer field that contains the keyboard type
    /// identifier.
    pub const KEYBOARD_EVENT_KEYBOARD_TYPE: CGEventField = 10;

    /// Key to access an integer field that contains scrolling data. This field
    /// typically contains the change in vertical position since the last
    /// scrolling event from a Mighty Mouse scroller or a single-wheel mouse
    /// scroller.
    pub const SCROLL_WHEEL_EVENT_DELTA_AXIS_1: CGEventField = 11;

    /// Key to access an integer field that contains scrolling data. This field
    /// typically contains the change in horizontal position since the last
    /// scrolling event from a Mighty Mouse scroller.
    pub const SCROLL_WHEEL_EVENT_DELTA_AXIS_2: CGEventField = 12;

    /// Key to access a field that contains scrolling data. The scrolling data
    /// represents a line-based or pixel-based change in vertical position
    /// since the last scrolling event from a Mighty Mouse scroller or a
    /// single-wheel mouse scroller. The scrolling data uses a fixed-point
    /// 16.16 signed integer format. If this key is passed to
    /// `CGEventGetDoubleValueField`, the fixed-point value is converted to a
    /// double value.
    pub const SCROLL_WHEEL_EVENT_FIXED_POINT_DELTA_AXIS_1: CGEventField = 93;

    /// Key to access a field that contains scrolling data. The scrolling data
    /// represents a line-based or pixel-based change in horizontal position
    /// since the last scrolling event from a Mighty Mouse scroller. The
    /// scrolling data uses a fixed-point 16.16 signed integer format. If this
    /// key is passed to `CGEventGetDoubleValueField`, the fixed-point value is
    /// converted to a double value.
    pub const SCROLL_WHEEL_EVENT_FIXED_POINT_DELTA_AXIS_2: CGEventField = 94;

    /// Key to access an integer field that contains pixel-based scrolling
    /// data. The scrolling data represents the change in vertical position
    /// since the last scrolling event from a Mighty Mouse scroller or a
    /// single-wheel mouse scroller.
    pub const SCROLL_WHEEL_EVENT_POINT_DELTA_AXIS_1: CGEventField = 96;

    /// Key to access an integer field that contains pixel-based scrolling
    /// data. The scrolling data represents the change in horizontal position
    /// since the last scrolling event from a Mighty Mouse scroller.
    pub const SCROLL_WHEEL_EVENT_POINT_DELTA_AXIS_2: CGEventField = 97;

    /// Key to access an integer field that indicates whether the event should
    /// be ignored by the Inkwell subsystem. If the value is non-zero, the
    /// event should be ignored.
    pub const SCROLL_WHEEL_EVENT_INSTANT_MOUSER: CGEventField = 14;

    /// Key to access an integer field that contains the absolute X coordinate
    /// in tablet space at full tablet resolution.
    pub const TABLET_EVENT_POINT_X: CGEventField = 15;

    /// Key to access an integer field that contains the absolute Y coordinate
    /// in tablet space at full tablet resolution.
    pub const TABLET_EVENT_POINT_Y: CGEventField = 16;

    /// Key to access an integer field that contains the absolute Z coordinate
    /// in tablet space at full tablet resolution.
    pub const TABLET_EVENT_POINT_Z: CGEventField = 17;

    /// Key to access an integer field that contains the tablet button state.
    /// Bit 0 is the first button, and a set bit represents a closed or pressed
    /// button. Up to 16 buttons are supported.
    pub const TABLET_EVENT_POINT_BUTTONS: CGEventField = 18;

    /// Key to access a double field that contains the tablet pen pressure. A
    /// value of 0.0 represents no pressure, and 1.0 represents maximum
    /// pressure.
    pub const TABLET_EVENT_POINT_PRESSURE: CGEventField = 19;

    /// Key to access a double field that contains the horizontal tablet pen
    /// tilt. A value of 0 represents no tilt, and 1 represents maximum tilt.
    pub const TABLET_EVENT_TILT_X: CGEventField = 20;

    /// Key to access a double field that contains the vertical tablet pen
    /// tilt. A value of 0 represents no tilt, and 1 represents maximum tilt.
    pub const TABLET_EVENT_TILT_Y: CGEventField = 21;

    /// Key to access a double field that contains the tablet pen rotation.
    pub const TABLET_EVENT_ROTATION: CGEventField = 22;

    /// Key to access a double field that contains the tangential pressure on
    /// the device. A value of 0.0 represents no pressure, and 1.0 represents
    /// maximum pressure.
    pub const TABLET_EVENT_TANGENTIAL_PRESSURE: CGEventField = 23;

    /// Key to access an integer field that contains the system-assigned unique
    /// device ID.
    pub const TABLET_EVENT_DEVICE_ID: CGEventField = 24;

    /// Key to access an integer field that contains a vendor-specified value.
    pub const TABLET_EVENT_VENDOR_1: CGEventField = 25;

    /// Key to access an integer field that contains a vendor-specified value.
    pub const TABLET_EVENT_VENDOR_2: CGEventField = 26;

    /// Key to access an integer field that contains a vendor-specified value.
    pub const TABLET_EVENT_VENDOR_3: CGEventField = 27;

    /// Key to access an integer field that contains the vendor-defined ID,
    /// typically the USB vendor ID.
    pub const TABLET_PROXIMITY_EVENT_VENDOR_ID: CGEventField = 28;

    /// Key to access an integer field that contains the vendor-defined tablet
    /// ID, typically the USB product ID.
    pub const TABLET_PROXIMITY_EVENT_TABLET_ID: CGEventField = 29;

    /// Key to access an integer field that contains the vendor-defined ID of
    /// the pointing device.
    pub const TABLET_PROXIMITY_EVENT_POINTER_ID: CGEventField = 30;

    /// Key to access an integer field that contains the system-assigned
    /// device ID.
    pub const TABLET_PROXIMITY_EVENT_DEVICE_ID: CGEventField = 31;

    /// Key to access an integer field that contains the system-assigned
    /// unique tablet ID.
    pub const TABLET_PROXIMITY_EVENT_SYSTEM_TABLET_ID: CGEventField = 32;

    /// Key to access an integer field that contains the vendor-assigned
    /// pointer type.
    pub const TABLET_PROXIMITY_EVENT_VENDOR_POINTER_TYPE: CGEventField = 33;

    /// Key to access an integer field that contains the vendor-defined
    /// pointer serial number.
    pub const TABLET_PROXIMITY_EVENT_VENDOR_POINTER_SERIAL_NUMBER: CGEventField = 34;

    /// Key to access an integer field that contains the vendor-defined unique
    /// ID.
    pub const TABLET_PROXIMITY_EVENT_VENDOR_UNIQUE_ID: CGEventField = 35;

    /// Key to access an integer field that contains the device capabilities
    /// mask.
    pub const TABLET_PROXIMITY_EVENT_CAPABILITY_MASK: CGEventField = 36;

    /// Key to access an integer field that contains the pointer type.
    pub const TABLET_PROXIMITY_EVENT_POINTER_TYPE: CGEventField = 37;

    /// Key to access an integer field that indicates whether the pen is in
    /// proximity to the tablet. The value is non-zero if the pen is in
    /// proximity to the tablet and zero when leaving the tablet.
    pub const TABLET_PROXIMITY_EVENT_ENTER_PROXIMITY: CGEventField = 38;

    /// Key to access a field that contains the event target process serial
    /// number. The value is a 64-bit value.
    pub const EVENT_TARGET_PROCESS_SERIAL_NUMBER: CGEventField = 39;

    /// Key to access a field that contains the event target Unix process ID.
    pub const EVENT_TARGET_UNIX_PROCESS_ID: CGEventField = 40;

    /// Key to access a field that contains the event source Unix process ID.
    pub const EVENT_SOURCE_UNIX_PROCESS_ID: CGEventField = 41;

    /// Key to access a field that contains the event source user-supplied
    /// data, up to 64 bits.
    pub const EVENT_SOURCE_USER_DATA: CGEventField = 42;

    /// Key to access a field that contains the event source Unix effective UID.
    pub const EVENT_SOURCE_USER_ID: CGEventField = 43;

    /// Key to access a field that contains the event source Unix effective
    /// GID.
    pub const EVENT_SOURCE_GROUP_ID: CGEventField = 44;

    /// Key to access a field that contains the event source state ID used to
    /// create this event.
    pub const EVENT_SOURCE_STATE_ID: CGEventField = 45;

    /// Key to access an integer field that indicates whether a scrolling event
    /// contains continuous, pixel-based scrolling data. The value is non-zero
    /// when the scrolling data is pixel-based and zero when the scrolling data
    /// is line-based.
    pub const SCROLL_WHEEL_EVENT_IS_CONTINUOUS: CGEventField = 88;

    /// Added in 10.5; made public in 10.7.
    pub const MOUSE_EVENT_WINDOW_UNDER_MOUSE_POINTER: CGEventField = 91;
    pub const MOUSE_EVENT_WINDOW_UNDER_MOUSE_POINTER_THAT_CAN_HANDLE_THIS_EVENT: CGEventField = 92;
}

// Constants that specify buttons on a one, two, or three-button mouse.
#[repr(C)]
#[derive(Clone, Copy, Debug)]
pub enum CGMouseButton {
    Left,
    Right,
    Center,
}

/// Possible tapping points for events.
#[repr(C)]
#[derive(Clone, Copy, Debug)]
pub enum CGEventTapLocation {
    HID,
    Session,
    AnnotatedSession,
}

// The next three enums are taken from:
// [Ref](https://github.com/phracker/MacOSX-SDKs/blob/ef9fe35d5691b6dd383c8c46d867a499817a01b6/MacOSX10.15.sdk/System/Library/Frameworks/CoreGraphics.framework/Versions/A/Headers/CGEventTypes.h)
/* Constants that specify where a new event tap is inserted into the list of
active event taps. */
#[repr(u32)]
#[derive(Clone, Copy, Debug)]
pub enum CGEventTapPlacement {
    HeadInsertEventTap = 0,
    TailAppendEventTap,
}

/* Constants that specify whether a new event tap is an active filter or a
passive listener. */
#[repr(u32)]
#[derive(Clone, Copy, Debug)]
pub enum CGEventTapOptions {
    Default = 0x00000000,
    ListenOnly = 0x00000001,
}

pub type CGEventMask = u64;
/* Generate an event mask for a single type of event. */
macro_rules! CGEventMaskBit {
    ($eventType:expr) => {
        1 << $eventType as CGEventMask
    };
}

pub type CGEventTapProxy = *const c_void;
pub type CGEventTapCallBackFn<'tap_life> =
    Box<dyn Fn(CGEventTapProxy, CGEventType, &CGEvent) -> Option<CGEvent> + 'tap_life>;
type CGEventTapCallBackInternal = unsafe extern "C" fn(
    proxy: CGEventTapProxy,
    etype: CGEventType,
    event: crate::sys::CGEventRef,
    user_info: *const c_void,
) -> crate::sys::CGEventRef;

unsafe extern "C" fn cg_event_tap_callback_internal(
    _proxy: CGEventTapProxy,
    _etype: CGEventType,
    _event: crate::sys::CGEventRef,
    _user_info: *const c_void,
) -> crate::sys::CGEventRef {
    let callback = _user_info as *mut CGEventTapCallBackFn;
    let event = CGEvent::from_ptr(_event);
    let new_event = (*callback)(_proxy, _etype, &event);
    let event = match new_event {
        Some(new_event) => new_event,
        None => event,
    };
    ManuallyDrop::new(event).as_ptr()
}

/// ```no_run
///extern crate core_foundation;
///use core_foundation::runloop::{kCFRunLoopCommonModes, CFRunLoop};
///use core_graphics::event::{CGEventTap, CGEventTapLocation, CGEventTapPlacement, CGEventTapOptions, CGEventType};
///let current = CFRunLoop::get_current();
///match CGEventTap::new(
///     CGEventTapLocation::HID,
///     CGEventTapPlacement::HeadInsertEventTap,
///     CGEventTapOptions::Default,
///     vec![CGEventType::MouseMoved],
///     |_a, _b, d| {
///         println!("{:?}", d.location());
///         None
///     },
/// ) {
///     Ok(tap) => unsafe {
///         let loop_source = tap
///             .mach_port
///             .create_runloop_source(0)
///             .expect("Somethings is bad ");
///         current.add_source(&loop_source, kCFRunLoopCommonModes);
///         tap.enable();
///         CFRunLoop::run_current();
///     },
///     Err(_) => (assert!(false)),
/// }
/// ```
pub struct CGEventTap<'tap_life> {
    pub mach_port: CFMachPort,
    pub callback_ref:
        Box<dyn Fn(CGEventTapProxy, CGEventType, &CGEvent) -> Option<CGEvent> + 'tap_life>,
}

impl<'tap_life> CGEventTap<'tap_life> {
    pub fn new<F: Fn(CGEventTapProxy, CGEventType, &CGEvent) -> Option<CGEvent> + 'tap_life>(
        tap: CGEventTapLocation,
        place: CGEventTapPlacement,
        options: CGEventTapOptions,
        events_of_interest: std::vec::Vec<CGEventType>,
        callback: F,
    ) -> Result<CGEventTap<'tap_life>, ()> {
        let event_mask: CGEventMask = events_of_interest
            .iter()
            .fold(CGEventType::Null as CGEventMask, |mask, &etype| {
                mask | CGEventMaskBit!(etype)
            });
        let cb = Box::new(Box::new(callback) as CGEventTapCallBackFn);
        let cbr = Box::into_raw(cb);
        unsafe {
            let event_tap_ref = CGEventTapCreate(
                tap,
                place,
                options,
                event_mask,
                cg_event_tap_callback_internal,
                cbr as *const c_void,
            );

            if !event_tap_ref.is_null() {
                Ok(Self {
                    mach_port: (CFMachPort::wrap_under_create_rule(event_tap_ref)),
                    callback_ref: Box::from_raw(cbr),
                })
            } else {
                let _ = Box::from_raw(cbr);
                Err(())
            }
        }
    }

    pub fn enable(&self) {
        unsafe { CGEventTapEnable(self.mach_port.as_concrete_TypeRef(), true) }
    }
}

foreign_type! {
    #[doc(hidden)]
    pub unsafe type CGEvent {
        type CType = crate::sys::CGEvent;
        fn drop = |p| CFRelease(p as *mut _);
        fn clone = |p| CFRetain(p as *const _) as *mut _;
    }
}

impl CGEvent {
    pub fn type_id() -> CFTypeID {
        unsafe { CGEventGetTypeID() }
    }

    pub fn new(source: CGEventSource) -> Result<CGEvent, ()> {
        unsafe {
            let event_ref = CGEventCreate(source.as_ptr());
            if !event_ref.is_null() {
                Ok(Self::from_ptr(event_ref))
            } else {
                Err(())
            }
        }
    }

    pub fn new_keyboard_event(
        source: CGEventSource,
        keycode: CGKeyCode,
        keydown: bool,
    ) -> Result<CGEvent, ()> {
        unsafe {
            let event_ref = CGEventCreateKeyboardEvent(source.as_ptr(), keycode, keydown);
            if !event_ref.is_null() {
                Ok(Self::from_ptr(event_ref))
            } else {
                Err(())
            }
        }
    }

    pub fn new_mouse_event(
        source: CGEventSource,
        mouse_type: CGEventType,
        mouse_cursor_position: CGPoint,
        mouse_button: CGMouseButton,
    ) -> Result<CGEvent, ()> {
        unsafe {
            let event_ref = CGEventCreateMouseEvent(
                source.as_ptr(),
                mouse_type,
                mouse_cursor_position,
                mouse_button,
            );
            if !event_ref.is_null() {
                Ok(Self::from_ptr(event_ref))
            } else {
                Err(())
            }
        }
    }

    #[cfg(feature = "highsierra")]
    pub fn new_scroll_event(
        source: CGEventSource,
        units: CGScrollEventUnit,
        wheel_count: u32,
        wheel1: i32,
        wheel2: i32,
        wheel3: i32,
    ) -> Result<CGEvent, ()> {
        unsafe {
            let event_ref = CGEventCreateScrollWheelEvent2(
                source.as_ptr(),
                units,
                wheel_count,
                wheel1,
                wheel2,
                wheel3,
            );
            if !event_ref.is_null() {
                Ok(Self::from_ptr(event_ref))
            } else {
                Err(())
            }
        }
    }

    pub fn post(&self, tap_location: CGEventTapLocation) {
        unsafe {
            CGEventPost(tap_location, self.as_ptr());
        }
    }

    pub fn post_from_tap(&self, tap_proxy: CGEventTapProxy) {
        unsafe {
            CGEventTapPostEvent(tap_proxy, self.as_ptr());
        }
    }

    pub fn location(&self) -> CGPoint {
        unsafe { CGEventGetLocation(self.as_ptr()) }
    }

    #[cfg(feature = "elcapitan")]
    pub fn post_to_pid(&self, pid: libc::pid_t) {
        unsafe {
            CGEventPostToPid(pid, self.as_ptr());
        }
    }

    pub fn set_flags(&self, flags: CGEventFlags) {
        unsafe {
            CGEventSetFlags(self.as_ptr(), flags);
        }
    }

    pub fn get_flags(&self) -> CGEventFlags {
        unsafe { CGEventGetFlags(self.as_ptr()) }
    }

    pub fn set_type(&self, event_type: CGEventType) {
        unsafe {
            CGEventSetType(self.as_ptr(), event_type);
        }
    }

    pub fn get_type(&self) -> CGEventType {
        unsafe { CGEventGetType(self.as_ptr()) }
    }

    pub fn set_string_from_utf16_unchecked(&self, buf: &[u16]) {
        let buflen = buf.len() as libc::c_ulong;
        unsafe {
            CGEventKeyboardSetUnicodeString(self.as_ptr(), buflen, buf.as_ptr());
        }
    }

    pub fn set_string(&self, string: &str) {
        let buf: Vec<u16> = string.encode_utf16().collect();
        self.set_string_from_utf16_unchecked(&buf);
    }

    pub fn get_integer_value_field(&self, field: CGEventField) -> i64 {
        unsafe { CGEventGetIntegerValueField(self.as_ptr(), field) }
    }

    pub fn set_integer_value_field(&self, field: CGEventField, value: i64) {
        unsafe { CGEventSetIntegerValueField(self.as_ptr(), field, value) }
    }

    pub fn get_double_value_field(&self, field: CGEventField) -> f64 {
        unsafe { CGEventGetDoubleValueField(self.as_ptr(), field) }
    }

    pub fn set_double_value_field(&self, field: CGEventField, value: f64) {
        unsafe { CGEventSetDoubleValueField(self.as_ptr(), field, value) }
    }
}

#[cfg_attr(feature = "link", link(name = "CoreGraphics", kind = "framework"))]
extern "C" {
    /// Return the type identifier for the opaque type `CGEventRef'.
    fn CGEventGetTypeID() -> CFTypeID;

    /// Return a new event using the event source `source'. If `source' is NULL,
    /// the default source is used.
    fn CGEventCreate(source: crate::sys::CGEventSourceRef) -> crate::sys::CGEventRef;

    /// Return a new keyboard event.
    ///
    /// The event source may be taken from another event, or may be NULL. Based
    /// on the virtual key code values entered, the appropriate key down, key up,
    /// or flags changed events are generated.
    ///
    /// All keystrokes needed to generate a character must be entered, including
    /// SHIFT, CONTROL, OPTION, and COMMAND keys. For example, to produce a 'Z',
    /// the SHIFT key must be down, the 'z' key must go down, and then the SHIFT
    /// and 'z' key must be released:
    fn CGEventCreateKeyboardEvent(
        source: crate::sys::CGEventSourceRef,
        keycode: CGKeyCode,
        keydown: bool,
    ) -> crate::sys::CGEventRef;

    /// Return a new mouse event.
    ///
    /// The event source may be taken from another event, or may be NULL.
    /// `mouseType' should be one of the mouse event types. `mouseCursorPosition'
    /// should be the position of the mouse cursor in global coordinates.
    /// `mouseButton' should be the button that's changing state; `mouseButton'
    /// is ignored unless `mouseType' is one of `kCGEventOtherMouseDown',
    /// `kCGEventOtherMouseDragged', or `kCGEventOtherMouseUp'.
    ///
    /// The current implementation of the event system supports a maximum of
    /// thirty-two buttons. Mouse button 0 is the primary button on the mouse.
    /// Mouse button 1 is the secondary mouse button (right). Mouse button 2 is
    /// the center button, and the remaining buttons are in USB device order.
    fn CGEventCreateMouseEvent(
        source: crate::sys::CGEventSourceRef,
        mouseType: CGEventType,
        mouseCursorPosition: CGPoint,
        mouseButton: CGMouseButton,
    ) -> crate::sys::CGEventRef;

    /// A non-variadic variant version of CGEventCreateScrollWheelEvent.
    ///
    /// Returns a new Quartz scrolling event.
    ///
    /// This function allows you to create a scrolling event and customize the
    /// event before posting it to the event system.
    #[cfg(feature = "highsierra")]
    fn CGEventCreateScrollWheelEvent2(
        source: crate::sys::CGEventSourceRef,
        units: CGScrollEventUnit,
        wheelCount: u32,
        wheel1: i32,
        wheel2: i32,
        wheel3: i32,
    ) -> crate::sys::CGEventRef;

    /// Post an event into the event stream at a specified location.
    ///
    /// This function posts the specified event immediately before any event taps
    /// instantiated for that location, and the event passes through any such
    /// taps.
    fn CGEventPost(tapLocation: CGEventTapLocation, event: crate::sys::CGEventRef);

    fn CGEventTapPostEvent(tapProxy: CGEventTapProxy, event: crate::sys::CGEventRef);

    #[cfg(feature = "elcapitan")]
    /// Post an event to a specified process ID
    fn CGEventPostToPid(pid: libc::pid_t, event: crate::sys::CGEventRef);

    /// Set the event flags of an event.
    fn CGEventSetFlags(event: crate::sys::CGEventRef, flags: CGEventFlags);

    /// Return the event flags of an event.
    fn CGEventGetFlags(event: crate::sys::CGEventRef) -> CGEventFlags;

    /// Return the location of an event in global display coordinates.
    /// CGPointZero is returned if event is not a valid crate::sys::CGEventRef.
    fn CGEventGetLocation(event: crate::sys::CGEventRef) -> CGPoint;

    /// Set the event type of an event.
    fn CGEventSetType(event: crate::sys::CGEventRef, eventType: CGEventType);

    /// Return the event type of an event (left mouse down, for example).
    fn CGEventGetType(event: crate::sys::CGEventRef) -> CGEventType;

    /// Set the Unicode string associated with a keyboard event.
    ///
    /// By default, the system translates the virtual key code in a keyboard
    /// event into a Unicode string based on the keyboard ID in the event
    /// source.  This function allows you to manually override this string.
    /// Note that application frameworks may ignore the Unicode string in a
    /// keyboard event and do their own translation based on the virtual
    /// keycode and perceived event state.
    fn CGEventKeyboardSetUnicodeString(
        event: crate::sys::CGEventRef,
        length: libc::c_ulong,
        string: *const u16,
    );

    /// Return the integer value of a field in an event.
    fn CGEventGetIntegerValueField(event: crate::sys::CGEventRef, field: CGEventField) -> i64;

    /// Set the integer value of a field in an event.
    ///
    /// Before calling this function, the event type must be set using a typed
    /// event creation function such as `CGEventCreateMouseEvent', or by
    /// calling `CGEventSetType'.
    ///
    /// If you are creating a mouse event generated by a tablet, call this
    /// function and specify the field `kCGMouseEventSubtype' with a value of
    /// `kCGEventMouseSubtypeTabletPoint' or
    /// `kCGEventMouseSubtypeTabletProximity' before setting other parameters.
    fn CGEventSetIntegerValueField(event: crate::sys::CGEventRef, field: CGEventField, value: i64);

    /// Return the floating-point value of a field in an event.
    ///
    /// In cases where the field value is represented within the event by a fixed
    /// point number or an integer, the result is scaled to the appropriate range
    /// as part of creating the floating-point representation.
    fn CGEventGetDoubleValueField(event: crate::sys::CGEventRef, field: CGEventField) -> f64;

    /// Set the floating-point value of a field in an event.
    ///
    /// Before calling this function, the event type must be set using a typed
    /// event creation function such as `CGEventCreateMouseEvent', or by calling
    /// `CGEventSetType'.
    ///
    /// In cases where the field’s value is represented within the event by a
    /// fixed point number or integer, the value parameter is scaled as needed
    /// and converted to the appropriate type.
    fn CGEventSetDoubleValueField(event: crate::sys::CGEventRef, field: CGEventField, value: f64);

    // ::sys::CGEventTapRef is actually an CFMachPortRef
    fn CGEventTapCreate(
        tap: CGEventTapLocation,
        place: CGEventTapPlacement,
        options: CGEventTapOptions,
        eventsOfInterest: CGEventMask,
        callback: CGEventTapCallBackInternal,
        userInfo: *const c_void,
    ) -> CFMachPortRef;

    fn CGEventTapEnable(tap: CFMachPortRef, enable: bool);

}