//go:build windows
package input

import (
	"context"
	"fmt"
	"runtime"
	"unsafe"

	"golang.org/x/sys/windows"
)

var (
	user32 = windows.NewLazySystemDLL("user32.dll")
	kernel32 = windows.NewLazySystemDLL("kernel32.dll")

	procSetWindowsHookExW     = user32.NewProc("SetWindowsHookExW")
	procUnhookWindowsHookEx   = user32.NewProc("UnhookWindowsHookEx")
	procCallNextHookEx        = user32.NewProc("CallNextHookEx")
	procGetMessageW           = user32.NewProc("GetMessageW")
	procSetCursorPos          = user32.NewProc("SetCursorPos")
	procShowCursor            = user32.NewProc("ShowCursor")
	procGetModuleHandleW      = kernel32.NewProc("GetModuleHandleW")
	procGetSystemMetrics      = user32.NewProc("GetSystemMetrics")
	procSetProcessDPIAware    = user32.NewProc("SetProcessDPIAware")
	procPostThreadMessageW    = user32.NewProc("PostThreadMessageW")
)

const (
	WH_KEYBOARD_LL = 13
	WH_MOUSE_LL    = 14
	SM_CXSCREEN    = 0
	SM_CYSCREEN    = 1
	WM_QUIT        = 0x0012
)

func init() {
	procSetProcessDPIAware.Call()
}

type MSLLHOOKSTRUCT struct {
	Pt          Point
	MouseData   uint32 // Mantemos uint32 mas vamos converter no callback
	Flags       uint32
	Time        uint32
	DwExtraInfo uintptr
}

type KBDLLHOOKSTRUCT struct {
	VkCode      uint32
	ScanCode    uint32
	Flags       uint32
	Time        uint32
	DwExtraInfo uintptr
}

type windowsInputHandler struct {
	mouseHook uintptr
	keyHook   uintptr
	tid       uint32
}

func NewInputHandler() InputHandler {
	return &windowsInputHandler{}
}

func (h *windowsInputHandler) Install(ctx context.Context, onMouse func(MouseEvent) bool, onKey func(KeyboardEvent) bool) error {
	ready := make(chan error, 1)

	go func() {
		runtime.LockOSThread()
		h.tid = windows.GetCurrentThreadId()
		hMod, _, _ := procGetModuleHandleW.Call(0)

		mouseCallback := windows.NewCallback(func(nCode int, wParam uintptr, lParam uintptr) uintptr {
			if nCode >= 0 {
				info := (*MSLLHOOKSTRUCT)(unsafe.Pointer(lParam))
				ev := MouseEvent{
					Message: uint32(wParam),
					Point:   info.Pt,
					Data:    info.MouseData,
				}
				
				// Se a engine tratar o evento, não passamos para o próximo hook
				if onMouse(ev) {
					return 1 
				}
			}
			ret, _, _ := procCallNextHookEx.Call(h.mouseHook, uintptr(nCode), wParam, lParam)
			return ret
		})

		keyCallback := windows.NewCallback(func(nCode int, wParam uintptr, lParam uintptr) uintptr {
			if nCode >= 0 {
				info := (*KBDLLHOOKSTRUCT)(unsafe.Pointer(lParam))
				ev := KeyboardEvent{
					Message:  uint32(wParam),
					VKCode:   info.VkCode,
					ScanCode: info.ScanCode,
					Flags:    info.Flags,
				}
				if onKey(ev) {
					return 1
				}
			}
			ret, _, _ := procCallNextHookEx.Call(h.keyHook, uintptr(nCode), wParam, lParam)
			return ret
		})

		mh, _, _ := procSetWindowsHookExW.Call(WH_MOUSE_LL, mouseCallback, hMod, 0)
		if mh == 0 {
			ready <- fmt.Errorf("failed mouse hook")
			return
		}
		h.mouseHook = mh

		kh, _, _ := procSetWindowsHookExW.Call(WH_KEYBOARD_LL, keyCallback, hMod, 0)
		if kh == 0 {
			ready <- fmt.Errorf("failed key hook")
			return
		}
		h.keyHook = kh

		ready <- nil

		var msg struct {
			Hwnd    windows.Handle
			Message uint32
			WParam  uintptr
			LParam  uintptr
			Time    uint32
			Pt      Point
		}
		for {
			ret, _, _ := procGetMessageW.Call(uintptr(unsafe.Pointer(&msg)), 0, 0, 0)
			if ret == 0 || msg.Message == WM_QUIT {
				break
			}
		}
		procUnhookWindowsHookEx.Call(h.mouseHook)
		procUnhookWindowsHookEx.Call(h.keyHook)
	}()

	return <-ready
}

func (h *windowsInputHandler) Uninstall() {
	if h.tid != 0 {
		procPostThreadMessageW.Call(uintptr(h.tid), WM_QUIT, 0, 0)
	}
}

func (h *windowsInputHandler) SetCursorPos(x, y int32) bool {
	ret, _, _ := procSetCursorPos.Call(uintptr(x), uintptr(y))
	return ret != 0
}

func (h *windowsInputHandler) ShowCursor(show bool) {
	s := -1 // No Windows, ShowCursor(FALSE) decrementa um contador
	if show {
		s = 1
	}
	// Vamos usar uma abordagem mais direta se necessário, mas por enquanto:
	procShowCursor.Call(uintptr(s))
}

func (h *windowsInputHandler) GetScreenResolution() (int32, int32) {
	w, _, _ := procGetSystemMetrics.Call(SM_CXSCREEN)
	h_res, _, _ := procGetSystemMetrics.Call(SM_CYSCREEN)
	return int32(w), int32(h_res)
}