/* 17 july 2014 */

#include "winapi_windows.h"
#include "_cgo_export.h"

HWND newControl(LPWSTR class, DWORD style, DWORD extstyle)
{
	HWND hwnd;

	hwnd = CreateWindowExW(
		extstyle,
		class, L"",
		style | WS_CHILD | WS_VISIBLE,
		CW_USEDEFAULT, CW_USEDEFAULT,
		CW_USEDEFAULT, CW_USEDEFAULT,
		/*
		the following has the consequence of making the control message-only at first
		this shouldn't cause any problems... hopefully not
		but see the msgwndproc() for caveat info
		also don't use low control IDs as they will conflict with dialog boxes (IDCANCEL, etc.)
		*/
		msgwin, (HMENU) 100, hInstance, NULL);
	if (hwnd == NULL)
		xpanic("error creating control", GetLastError());
	return hwnd;
}

void controlSetParent(HWND control, HWND parent)
{
	if (SetParent(control, parent) == NULL)
		xpanic("error changing control parent", GetLastError());
}

void controlSetControlFont(HWND which)
{
	SendMessageW(which, WM_SETFONT, (WPARAM) controlFont, TRUE);
}

/*
all controls that have events receive the events themselves through subclasses
to do this, all windows (including the message-only window; see http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q104069) forward WM_COMMAND to each control with this function
*/
LRESULT forwardCommand(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
	HWND control = (HWND) lParam;

	/* don't generate an event if the control (if there is one) is unparented (a child of the message-only window) */
	if (control != NULL && IsChild(msgwin, control) == 0)
		return SendMessageW(control, msgCOMMAND, wParam, lParam);
	return DefWindowProcW(hwnd, uMsg, wParam, lParam);
}

LRESULT forwardNotify(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
	NMHDR *nmhdr = (NMHDR *) lParam;
	HWND control = nmhdr->hwndFrom;

	/* don't generate an event if the control (if there is one) is unparented (a child of the message-only window) */
	if (control != NULL && IsChild(msgwin, control) == 0)
		return SendMessageW(control, msgNOTIFY, wParam, lParam);
	return DefWindowProcW(hwnd, uMsg, wParam, lParam);
}

void moveWindow(HWND hwnd, int x, int y, int width, int height)
{
	if (MoveWindow(hwnd, x, y, width, height, TRUE) == 0)
		xpanic("error setting window/control rect", GetLastError());
}

LONG controlTextLength(HWND hwnd, LPWSTR text)
{
	HDC dc;
	HFONT prev;
	SIZE size;

	dc = GetDC(hwnd);
	if (dc == NULL)
		xpanic("error getting DC of control for text length", GetLastError());
	prev = SelectObject(dc, controlFont);
	if (prev == NULL)
		xpanic("error setting control font to DC for text length", GetLastError());
	if (GetTextExtentPoint32W(dc, text, wcslen(text), &size) == 0)
		xpanic("error actually getting text length", GetLastError());
	if (SelectObject(dc, prev) != controlFont)
		xpanic("error restoring previous control font to DC for text length", GetLastError());
	if (ReleaseDC(hwnd, dc) == 0)
		xpanic("error releasing DC of control for text length", GetLastError());
	return size.cx;
}