package hotkey

import (
    "fmt"
    "runtime"
    "strings"
    "syscall"
    "unsafe"
)

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

const (
    INPUT_KEYBOARD    = 1
    KEYEVENTF_KEYDOWN = 0x0000
    KEYEVENTF_KEYUP   = 0x0002
)

type INPUT struct {
    Type uint32
    Ki   KEYBDINPUT
}

type KEYBDINPUT struct {
    WVirtKey uint16
    WScan    uint16
    DwFlags  uint32
    Time     uint32
    DwExtra  uint32
}

// Виртуальные коды клавиш
var keyCodes = map[string]uint16{
    "A": 0x41, "B": 0x42, "C": 0x43, "D": 0x44, "E": 0x45, "F": 0x46, "G": 0x47, "H": 0x48,
    "I": 0x49, "J": 0x4A, "K": 0x4B, "L": 0x4C, "M": 0x4D, "N": 0x4E, "O": 0x4F, "P": 0x50,
    "Q": 0x51, "R": 0x52, "S": 0x53, "T": 0x54, "U": 0x55, "V": 0x56, "W": 0x57, "X": 0x58,
    "Y": 0x59, "Z": 0x5A,
    "0": 0x30, "1": 0x31, "2": 0x32, "3": 0x33, "4": 0x34, "5": 0x35, "6": 0x36, "7": 0x37, "8": 0x38, "9": 0x39,
    "F1": 0x70, "F2": 0x71, "F3": 0x72, "F4": 0x73, "F5": 0x74, "F6": 0x75, "F7": 0x76, "F8": 0x77,
    "F9": 0x78, "F10": 0x79, "F11": 0x7A, "F12": 0x7B,
    "SPACE": 0x20, "ENTER": 0x0D, "TAB": 0x09, "ESC": 0x1B,
    "SHIFT": 0x10, "CTRL": 0x11, "ALT": 0x12, "WIN": 0x5B,
    "LEFT": 0x25, "UP": 0x26, "RIGHT": 0x27, "DOWN": 0x28,
}

var modCodes = map[string]uint16{
    "ALT":   0x12,
    "CTRL":  0x11,
    "SHIFT": 0x10,
    "WIN":   0x5B,
}

var enabled bool = false

func Init() error {
    if runtime.GOOS != "windows" {
        return fmt.Errorf("hotkey emulation only supported on Windows")
    }
    enabled = true
    return nil
}

func SetEnabled(e bool) {
    enabled = e
}

func PressCombination(combination string) error {
    if !enabled {
        return fmt.Errorf("hotkey emulation disabled by user")
    }
    parts := strings.Split(combination, "+")
    if len(parts) == 0 {
        return fmt.Errorf("invalid combination")
    }

    var mods []uint16
    var mainKey uint16

    for _, p := range parts {
        upper := strings.ToUpper(p)
        if code, ok := modCodes[upper]; ok {
            mods = append(mods, code)
        } else if code, ok := keyCodes[upper]; ok {
            mainKey = code
        } else {
            return fmt.Errorf("unknown key: %s", p)
        }
    }
    if mainKey == 0 {
        return fmt.Errorf("no main key found")
    }

    for _, mod := range mods {
        pressKey(mod, true)
    }
    pressKey(mainKey, true)
    pressKey(mainKey, false)
    for i := len(mods) - 1; i >= 0; i-- {
        pressKey(mods[i], false)
    }
    return nil
}

func pressKey(vk uint16, down bool) {
    var flags uint32 = KEYEVENTF_KEYDOWN
    if !down {
        flags = KEYEVENTF_KEYUP
    }
    input := INPUT{
        Type: INPUT_KEYBOARD,
        Ki: KEYBDINPUT{
            WVirtKey: vk,
            DwFlags:  flags,
        },
    }
    procSendInput.Call(1, uintptr(unsafe.Pointer(&input)), unsafe.Sizeof(input))
}