//go:build windows

package platform

import (
	"os"
	"syscall"
	"unsafe"
)

var (
	user32   = syscall.NewLazyDLL("user32.dll")
	kernel32 = syscall.NewLazyDLL("kernel32.dll")

	setWindowLong            = user32.NewProc("SetWindowLongW")
	getWindowLong            = user32.NewProc("GetWindowLongW")
	setWindowPos             = user32.NewProc("SetWindowPos")
	enumWindows              = user32.NewProc("EnumWindows")
	getWindowThreadProcessId = user32.NewProc("GetWindowThreadProcessId")
	getCurrentProcessId      = kernel32.NewProc("GetCurrentProcessId")
)

const (
	GWL_STYLE        = ^uintptr(15) // -16
	WS_THICKFRAME    = 0x00040000
	WS_MAXIMIZEBOX   = 0x00010000
	WS_MINIMIZEBOX   = 0x00020000
	SWP_FRAMECHANGED = 0x0020
	SWP_NOMOVE       = 0x0002
	SWP_NOSIZE       = 0x0001
	SWP_NOZORDER     = 0x0004
	SWP_NOACTIVATE   = 0x0010
)

var mainHwnd uintptr

// EnableResizeBorder re-adds the WS_THICKFRAME style to
// the frameless Wails window so it can be resized from edges.
func EnableResizeBorder() {
	pid, _, _ := getCurrentProcessId.Call()

	// Find our main window by enumerating top-level windows
	cb := syscall.NewCallback(func(hwnd uintptr, lparam uintptr) uintptr {
		var wpid uintptr
		getWindowThreadProcessId.Call(hwnd, uintptr(unsafe.Pointer(&wpid)))
		if wpid == pid {
			// Check if it's a visible owned window (not a child/message-only)
			style, _, _ := getWindowLong.Call(hwnd, GWL_STYLE)
			if style&0x10000000 != 0 && style&0x40000000 == 0 { // WS_VISIBLE && !WS_CHILD
				mainHwnd = hwnd
				return 0 // stop enumeration
			}
		}
		return 1 // continue
	})
	enumWindows.Call(cb, 0)

	if mainHwnd == 0 {
		return
	}

	style, _, _ := getWindowLong.Call(mainHwnd, GWL_STYLE)
	newStyle := style | WS_THICKFRAME | WS_MAXIMIZEBOX | WS_MINIMIZEBOX
	setWindowLong.Call(mainHwnd, GWL_STYLE, newStyle)
	setWindowPos.Call(mainHwnd, 0, 0, 0, 0, 0,
		SWP_FRAMECHANGED|SWP_NOMOVE|SWP_NOSIZE|SWP_NOZORDER|SWP_NOACTIVATE)

	// Log for debugging
	os.Stdout.WriteString("[platform] WS_THICKFRAME enabled on frameless window\n")
}