#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)
{
    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;

    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);

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