//go:build windows

/*
 *    Copyright (c) 2018 Unrud <unrud@outlook.com>
 *
 *    This file is part of Remote-Touchpad.
 *
 *    Remote-Touchpad is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation, either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    Remote-Touchpad is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with Remote-Touchpad.  If not, see <http://www.gnu.org/licenses/>.
 */

package inputcontrol

import (
	"fmt"
	"syscall"
	"unsafe"
)

const (
	inputMouse    uintptr = 0x0
	inputKeyboard uintptr = 0x1

	keyeventfKeyup   uint32 = 0x2
	keyeventfUnicode uint32 = 0x4

	vkBack           uint16 = 0x8
	vkReturn         uint16 = 0xD
	vkEnd            uint16 = 0x23
	vkHome           uint16 = 0x24
	vkLeft           uint16 = 0x25
	vkUp             uint16 = 0x26
	vkRight          uint16 = 0x27
	vkDown           uint16 = 0x28
	vkDelete         uint16 = 0x2E
	vkLwin           uint16 = 0x5B
	vkBrowserBack    uint16 = 0xA6
	vkBrowserForward uint16 = 0xA7
	vkVolumeMute     uint16 = 0xAD
	vkVolumeDown     uint16 = 0xAE
	vkVolumeUp       uint16 = 0xAF
	vkMediaNextTrack uint16 = 0xB0
	vkMediaPrevTrack uint16 = 0xB1
	vkMediaPlayPause uint16 = 0xB3

	mouseeventfMove       uint32 = 0x1
	mouseeventfLeftdown   uint32 = 0x2
	mouseeventfLeftup     uint32 = 0x4
	mouseeventfRightdown  uint32 = 0x8
	mouseeventfRightup    uint32 = 0x10
	mouseeventfMiddledown uint32 = 0x20
	mouseeventfMiddleup   uint32 = 0x40
	mouseeventfWheel      uint32 = 0x800
	mouseeventfHwheel     uint32 = 0x1000

	scrollMult int = 6
)

var (
	user32DLL     = syscall.NewLazyDLL("user32.dll")
	sendInputProc = user32DLL.NewProc("SendInput")
)

type mouseInput struct {
	typ uintptr // HACK: padded uint32

	dx, dy                   int32
	mouseData, dwFlags, time uint32
	dwExtraInfo              uintptr
}

type keybdInput struct {
	typ uintptr // HACK: padded uint32

	wVk, wScan    uint16
	dwFlags, time uint32
	dwExtraInfo   uintptr

	padding [8]byte
}

type windowsController struct{}

func init() {
	RegisterController("Windows", InitWindowsController, 0)
}

func InitWindowsController(saveRestoreToken bool) (Controller, error) {
	p := &windowsController{}
	if err := sendInputProc.Find(); err != nil {
		return nil, &UnsupportedPlatformError{err}
	}
	return p, nil
}

func (p *windowsController) Close() error {
	return nil
}

func (p *windowsController) sendInput(inputs []keybdInput) error {
	if len(inputs) == 0 {
		return nil
	}
	if sent, _, err := sendInputProc.Call(uintptr(len(inputs)),
		uintptr(unsafe.Pointer(&inputs[0])), unsafe.Sizeof(inputs[0])); int(sent) != len(inputs) {
		return err
	}
	return nil
}

func (p *windowsController) KeyboardText(text string) error {
	inputs := make([]keybdInput, 0, len(text)*2)
	for _, runeValue := range text {
		in := keybdInput{typ: inputKeyboard, wScan: uint16(runeValue), dwFlags: keyeventfUnicode}
		inputs = append(inputs, in)
		in.dwFlags |= keyeventfKeyup
		inputs = append(inputs, in)
	}
	if len(inputs) == 0 {
		return nil
	}
	return p.sendInput(inputs)
}

func (p *windowsController) KeyboardKey(key Key) error {
	input := keybdInput{typ: inputKeyboard}
	switch key {
	case KeyBackSpace:
		input.wVk = vkBack
	case KeyReturn:
		input.wVk = vkReturn
	case KeyEnd:
		input.wVk = vkEnd
	case KeyHome:
		input.wVk = vkHome
	case KeyLeft:
		input.wVk = vkLeft
	case KeyUp:
		input.wVk = vkUp
	case KeyRight:
		input.wVk = vkRight
	case KeyDown:
		input.wVk = vkDown
	case KeyDelete:
		input.wVk = vkDelete
	case KeySuper:
		input.wVk = vkLwin
	case KeyBrowserBack:
		input.wVk = vkBrowserBack
	case KeyBrowserForward:
		input.wVk = vkBrowserForward
	case KeyVolumeMute:
		input.wVk = vkVolumeMute
	case KeyVolumeDown:
		input.wVk = vkVolumeDown
	case KeyVolumeUp:
		input.wVk = vkVolumeUp
	case KeyMediaNextTrack:
		input.wVk = vkMediaNextTrack
	case KeyMediaPrevTrack:
		input.wVk = vkMediaPrevTrack
	case KeyMediaPlayPause:
		input.wVk = vkMediaPlayPause
	default:
		return fmt.Errorf("key not mapped to virtual-key code: %#v", key)
	}
	inputs := [...]keybdInput{input, input}
	inputs[1].dwFlags |= keyeventfKeyup
	return p.sendInput(inputs[:])
}

func (p *windowsController) PointerButton(button PointerButton, press bool) error {
	input := mouseInput{typ: inputMouse}
	if button == PointerButtonLeft && press {
		input.dwFlags = mouseeventfLeftdown
	} else if button == PointerButtonLeft {
		input.dwFlags = mouseeventfLeftup
	} else if button == PointerButtonMiddle && press {
		input.dwFlags = mouseeventfMiddledown
	} else if button == PointerButtonMiddle {
		input.dwFlags = mouseeventfMiddleup
	} else if button == PointerButtonRight && press {
		input.dwFlags = mouseeventfRightdown
	} else if button == PointerButtonRight {
		input.dwFlags = mouseeventfRightup
	} else {
		return fmt.Errorf("unsupported pointer button: %#v", button)
	}
	if sent, _, err := sendInputProc.Call(1, uintptr(unsafe.Pointer(&input)),
		unsafe.Sizeof(input)); int(sent) != 1 {
		return err
	}
	return nil
}

func (p *windowsController) PointerMove(deltaX, deltaY int) error {
	input := mouseInput{
		typ:     inputMouse,
		dx:      int32(deltaX),
		dy:      int32(deltaY),
		dwFlags: mouseeventfMove,
	}
	if sent, _, err := sendInputProc.Call(1, uintptr(unsafe.Pointer(&input)),
		unsafe.Sizeof(input)); int(sent) != 1 {
		return err
	}
	return nil
}

func (p *windowsController) PointerScroll(deltaHorizontal, deltaVertical int, finish bool) error {
	inputs := make([]mouseInput, 0, 2)
	if deltaHorizontal != 0 {
		inputs = append(inputs, mouseInput{
			typ:       inputMouse,
			dwFlags:   mouseeventfHwheel,
			mouseData: uint32(deltaHorizontal * scrollMult),
		})
	}
	if deltaVertical != 0 {
		inputs = append(inputs, mouseInput{
			typ:       inputMouse,
			dwFlags:   mouseeventfWheel,
			mouseData: uint32(-deltaVertical * scrollMult),
		})
	}
	if len(inputs) == 0 {
		return nil
	}
	if sent, _, err := sendInputProc.Call(uintptr(len(inputs)),
		uintptr(unsafe.Pointer(&inputs[0])), unsafe.Sizeof(inputs[0])); int(sent) != len(inputs) {
		return err
	}
	return nil
}