#include <X11/Xlib.h>

#include "WINGsP.h"

typedef struct W_IMContext {
	XIM xim;
	XIMStyle ximstyle;
} WMIMContext;

static void instantiateIM_cb(Display * display, XPointer client_data, XPointer call_data)
{
	/* Parameter not used, but tell the compiler that it is ok */
	(void) display;
	(void) call_data;

	W_InitIM((W_Screen *) client_data);
}

static void destroyIM_cb(XIM xim, XPointer client_data, XPointer call_data)
{
	W_Screen *scr = (W_Screen *) client_data;
	W_View *target;

	/* Parameter not used, but tell the compiler that it is ok */
	(void) call_data;

	if (scr->imctx->xim != xim)
		return;

	target = scr->rootView->childrenList;
	while (target != NULL) {
		W_DestroyIC(target);
		target = target->nextSister;
	}

	wfree(scr->imctx);
	scr->imctx = NULL;

	XRegisterIMInstantiateCallback(scr->display, NULL, NULL, NULL, instantiateIM_cb, (XPointer) scr);
}

void W_InitIM(W_Screen * scr)
{
	XIM xim;

	if (scr->imctx)
		return;

	xim = XOpenIM(scr->display, NULL, NULL, NULL);

	if (xim) {
		XIMStyles *im_styles;
		XIMCallback cb;
		int i;

		scr->imctx = wmalloc(sizeof(WMIMContext));
		scr->imctx->xim = xim;

		cb.callback = destroyIM_cb;
		cb.client_data = (XPointer) scr;
		if (XSetIMValues(scr->imctx->xim, XNDestroyCallback, &cb, NULL))
			wwarning("could not add destroy callback for input method");
		XUnregisterIMInstantiateCallback(scr->display, NULL, NULL, NULL, instantiateIM_cb, (XPointer) scr);
		/* Get available input style */
		XGetIMValues(scr->imctx->xim, XNQueryInputStyle, &im_styles, NULL);

		scr->imctx->ximstyle = 0;

		for (i = 0; i < im_styles->count_styles && scr->imctx->ximstyle == 0; i++) {
			if ((im_styles->supported_styles[i] & XIMPreeditPosition) &&
			    (im_styles->supported_styles[i] & XIMStatusNothing)) {
				scr->imctx->ximstyle = XIMPreeditPosition | XIMStatusNothing;
			} else if ((im_styles->supported_styles[i] & XIMPreeditNothing) &&
				   (im_styles->supported_styles[i] & XIMStatusNothing)) {
				scr->imctx->ximstyle = XIMPreeditNothing | XIMStatusNothing;
			}
		}
		XFree(im_styles);
	} else {
		XRegisterIMInstantiateCallback(scr->display, NULL, NULL, NULL, instantiateIM_cb, (XPointer) scr);
	}
}

void W_CreateIC(WMView * view)
{
	WMScreen *scr = W_VIEW_SCREEN(view);
	XVaNestedList preedit_attr = NULL;

	if (view->xic || !view->flags.realized || !scr->imctx)
		return;

	if (scr->imctx->ximstyle & XIMPreeditPosition) {
		XPoint spot;
		XRectangle rect;
		int ofs;

		ofs = (view->size.height - WMFontHeight(scr->normalFont)) / 2;

		rect.x = ofs;
		rect.y = ofs;
		rect.height = WMFontHeight(scr->normalFont);
		rect.width = view->size.width - ofs * 2;
		spot.x = rect.x;
		spot.y = rect.y + rect.height;

		// this really needs to be changed, but I don't know how yet -Dan
		// it used to be like this with fontsets, but no longer applies to xft
		preedit_attr = XVaCreateNestedList(0, XNSpotLocation, &spot,
						   XNArea, &rect, XNFontInfo, scr->normalFont->font, NULL);
	}

	view->xic = XCreateIC(scr->imctx->xim, XNInputStyle, scr->imctx->ximstyle,
			      XNClientWindow, view->window,
			      preedit_attr ? XNPreeditAttributes : NULL, preedit_attr, NULL);

	if (preedit_attr)
		XFree(preedit_attr);

	if (view->xic) {
		unsigned long fevent = 0;
		XGetICValues(view->xic, XNFilterEvents, &fevent, NULL);
		XSelectInput(scr->display, view->window,
			     ButtonPressMask | ButtonReleaseMask | ExposureMask |
			     KeyPressMask | FocusChangeMask | ButtonMotionMask | fevent);
	}
}

void W_DestroyIC(WMView * view)
{
	if (view->xic) {
		XDestroyIC(view->xic);
		view->xic = 0;
	}
}

static void setPreeditArea(W_View * view)
{
	WMScreen *scr = W_VIEW_SCREEN(view);
	XVaNestedList preedit_attr = NULL;

	if (view->xic && (scr->imctx->ximstyle & XIMPreeditPosition)) {
		XRectangle rect;
		int ofs;

		ofs = (view->size.height - WMFontHeight(scr->normalFont)) / 2;
		rect.x = ofs;
		rect.y = ofs;
		rect.height = WMFontHeight(scr->normalFont);
		rect.width = view->size.width - ofs * 2;

		preedit_attr = XVaCreateNestedList(0, XNArea, &rect, NULL);
		XSetICValues(view->xic, XNPreeditAttributes, preedit_attr, NULL);

		if (preedit_attr) {
			XFree(preedit_attr);
		}
	}
}

void W_FocusIC(WMView * view)
{
	WMScreen *scr = W_VIEW_SCREEN(view);

	if (view->xic) {
		XSetICFocus(view->xic);
		XSetICValues(view->xic, XNFocusWindow, view->window, NULL);

		if (scr->imctx->ximstyle & XIMPreeditPosition) {
			setPreeditArea(view);
		}
	}
}

void W_UnFocusIC(WMView * view)
{
	if (view->xic) {
		XUnsetICFocus(view->xic);
	}
}

void W_SetPreeditPositon(W_View * view, int x, int y)
{
	WMScreen *scr = W_VIEW_SCREEN(view);
	XVaNestedList preedit_attr = NULL;

	if (view->xic && (scr->imctx->ximstyle & XIMPreeditPosition)) {
		XPoint spot;
		int ofs;

		ofs = (view->size.height - WMFontHeight(scr->normalFont)) / 2;
		spot.x = x;
		spot.y = y + view->size.height - ofs - 3;
		preedit_attr = XVaCreateNestedList(0, XNSpotLocation, &spot, NULL);
		XSetICValues(view->xic, XNPreeditAttributes, preedit_attr, NULL);
		if (preedit_attr) {
			XFree(preedit_attr);
		}
	}
}

int W_LookupString(W_View *view, XKeyPressedEvent *event, char *buffer, int buflen, KeySym *keysym, Status *status)
{
	WMScreen *scr = W_VIEW_SCREEN(view);

	XSetInputFocus(scr->display, view->window, RevertToParent, CurrentTime);

#ifdef X_HAVE_UTF8_STRING
	if (view->xic)
		return Xutf8LookupString(view->xic, event, buffer, buflen, keysym, status);
#endif
	return XLookupString(event, buffer, buflen, keysym, (XComposeStatus *) status);
}