//go:build darwin

package darwin

/*
#cgo CFLAGS: -x objective-c
#cgo LDFLAGS: -framework Cocoa -framework Carbon
#include <stdint.h>
#import <Cocoa/Cocoa.h>
#import <Carbon/Carbon.h>

extern void keydownCallback(uintptr_t handle);
extern void keyupCallback(uintptr_t handle);
int registerHotKey(int mod, int key, uintptr_t handle, EventHotKeyRef* ref);
int unregisterHotKey(EventHotKeyRef ref);
*/
import "C"
import (
	"errors"
	"fmt"
	"runtime/cgo"
	"sync"
)

// Standard errors
var (
	ErrAlreadyRegistered  = errors.New("hotkey: already registered")
	ErrNotRegistered      = errors.New("hotkey: not registered")
	ErrFailedToRegister   = errors.New("hotkey: failed to register")
	ErrFailedToUnregister = errors.New("hotkey: failed to unregister")
)

// PlatformHotkey is a combination of modifiers and key to trigger an event
type PlatformHotkey struct {
	mu         sync.Mutex
	registered bool
	hkref      C.EventHotKeyRef
	handle     cgo.Handle
}

func (ph *PlatformHotkey) Register(mods []Modifier, key Key, keydownIn, keyupIn chan<- interface{}) error {
	ph.mu.Lock()
	defer ph.mu.Unlock()
	if ph.registered {
		return ErrAlreadyRegistered
	}

	// Store callbacks info for C side
	callbacks := &callbackData{
		keydownIn: keydownIn,
		keyupIn:   keyupIn,
	}

	ph.handle = cgo.NewHandle(callbacks)
	var mod Modifier
	for _, m := range mods {
		mod += m
	}

	ret := C.registerHotKey(C.int(mod), C.int(key), C.uintptr_t(ph.handle), &ph.hkref)
	if ret == C.int(-1) {
		ph.handle.Delete()
		return fmt.Errorf("%w: Carbon API returned error", ErrFailedToRegister)
	}

	ph.registered = true
	return nil
}

func (ph *PlatformHotkey) Unregister() error {
	ph.mu.Lock()
	defer ph.mu.Unlock()
	if !ph.registered {
		return ErrNotRegistered
	}

	ret := C.unregisterHotKey(ph.hkref)
	if ret == C.int(-1) {
		return fmt.Errorf("%w: Carbon API returned error", ErrFailedToUnregister)
	}

	// Clean up CGO handle
	ph.handle.Delete()
	ph.registered = false
	return nil
}

type callbackData struct {
	keydownIn chan<- interface{}
	keyupIn   chan<- interface{}
}

//export keydownCallback
func keydownCallback(h uintptr) {
	cb := cgo.Handle(h).Value().(*callbackData)
	cb.keydownIn <- struct{}{}
}

//export keyupCallback
func keyupCallback(h uintptr) {
	cb := cgo.Handle(h).Value().(*callbackData)
	cb.keyupIn <- struct{}{}
}

// Modifier represents a modifier.
// See: /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/Headers/Events.h
type Modifier uint32

// All kinds of Modifiers
const (
	ModCtrl   Modifier = 0x1000
	ModShift  Modifier = 0x200
	ModOption Modifier = 0x800
	ModCmd    Modifier = 0x100
)

// Key represents a key.
// See: /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/Headers/Events.h
type Key uint8

// All kinds of keys
const (
	KeySpace Key = 49
	Key1     Key = 18
	Key2     Key = 19
	Key3     Key = 20
	Key4     Key = 21
	Key5     Key = 23
	Key6     Key = 22
	Key7     Key = 26
	Key8     Key = 28
	Key9     Key = 25
	Key0     Key = 29
	KeyA     Key = 0
	KeyB     Key = 11
	KeyC     Key = 8
	KeyD     Key = 2
	KeyE     Key = 14
	KeyF     Key = 3
	KeyG     Key = 5
	KeyH     Key = 4
	KeyI     Key = 34
	KeyJ     Key = 38
	KeyK     Key = 40
	KeyL     Key = 37
	KeyM     Key = 46
	KeyN     Key = 45
	KeyO     Key = 31
	KeyP     Key = 35
	KeyQ     Key = 12
	KeyR     Key = 15
	KeyS     Key = 1
	KeyT     Key = 17
	KeyU     Key = 32
	KeyV     Key = 9
	KeyW     Key = 13
	KeyX     Key = 7
	KeyY     Key = 16
	KeyZ     Key = 6

	KeyReturn Key = 0x24
	KeyEscape Key = 0x35
	KeyDelete Key = 0x33
	KeyTab    Key = 0x30

	KeyLeft  Key = 0x7B
	KeyRight Key = 0x7C
	KeyUp    Key = 0x7E
	KeyDown  Key = 0x7D

	KeyF1  Key = 0x7A
	KeyF2  Key = 0x78
	KeyF3  Key = 0x63
	KeyF4  Key = 0x76
	KeyF5  Key = 0x60
	KeyF6  Key = 0x61
	KeyF7  Key = 0x62
	KeyF8  Key = 0x64
	KeyF9  Key = 0x65
	KeyF10 Key = 0x6D
	KeyF11 Key = 0x67
	KeyF12 Key = 0x6F
	KeyF13 Key = 0x69
	KeyF14 Key = 0x6B
	KeyF15 Key = 0x71
	KeyF16 Key = 0x6A
	KeyF17 Key = 0x40
	KeyF18 Key = 0x4F
	KeyF19 Key = 0x50
	KeyF20 Key = 0x5A
)