ui/gtk/button.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2017 Olaf Wintermann. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>

#include "button.h"
#include "container.h"
#include <cx/allocator.h>
#include <cx/buffer.h>
#include <cx/json.h>
#include "../common/context.h"
#include "../common/object.h"

void ui_button_set_icon_name(GtkWidget *button, const char *icon) {
    if(!icon) {
        return;
    }
    
#ifdef UI_GTK4
    gtk_button_set_icon_name(GTK_BUTTON(button), icon);
#else
#if GTK_CHECK_VERSION(2, 6, 0)
    GtkWidget *image = gtk_image_new_from_icon_name(icon, GTK_ICON_SIZE_BUTTON);
    if(image) {
        gtk_button_set_image(GTK_BUTTON(button), image);
    }
#else
    // TODO
#endif
#endif
}

GtkWidget* ui_create_button(
        UiObject *obj,
        const char *label,
        const char *icon,
        ui_callback onclick,
        void *userdata,
        int event_value,
        bool activate_event)
{
    GtkWidget *button = gtk_button_new_with_label(label);
    ui_button_set_icon_name(button, icon);
    
    if(onclick) {
        UiEventData *event = malloc(sizeof(UiEventData));
        event->obj = obj;
        event->userdata = userdata;
        event->callback = onclick;
        event->value = event_value;
        event->customdata = NULL;
        event->customint = 0;

        g_signal_connect(
                button,
                "clicked",
                G_CALLBACK(ui_button_clicked),
                event);
        g_signal_connect(
                button,
                "destroy",
                G_CALLBACK(ui_destroy_userdata),
                event);
        if(activate_event) {
            g_signal_connect(
                button,
                "activate",
                G_CALLBACK(ui_button_clicked),
                event);
        }
    }
    
    return button;
}

UIWIDGET ui_button_create(UiObject *obj, UiButtonArgs *args) {
    UiObject* current = uic_current_obj(obj);
    GtkWidget *button = ui_create_button(obj, args->label, args->icon, args->onclick, args->onclickdata, 0, FALSE);
    ui_set_name_and_style(button, args->name, args->style_class);
    ui_set_widget_groups(obj->ctx, button, args->groups);
    UI_APPLY_LAYOUT2(current, args);
    current->container->add(current->container, button);
    return button;
}


void ui_button_clicked(GtkWidget *widget, UiEventData *event) {
    UiEvent e;
    e.obj = event->obj;
    e.window = event->obj->window;
    e.document = event->obj->ctx->document;
    e.eventdata = NULL;
    e.eventdatatype = 0;
    e.intval = event->value;
    e.set = ui_get_setop();
    event->callback(&e, event->userdata);
}

void ui_button_set_label(UIWIDGET button, const char *label) {
    gtk_button_set_label(GTK_BUTTON(button), label);
}

void ui_button_set_icon(UIWIDGET button, const char *icon) {
    ui_button_set_icon_name(button, icon);
}

int64_t ui_toggle_button_get(UiInteger *integer) {
    GtkToggleButton *button = integer->obj;
    integer->value = (int)gtk_toggle_button_get_active(button);
    return integer->value;
}

void ui_toggle_button_set(UiInteger *integer, int64_t value) {
    GtkToggleButton *button = integer->obj;
    integer->value = value;
    gtk_toggle_button_set_active(button, value != 0 ? TRUE : FALSE);
}

void ui_toggled_obs(void *widget, UiVarEventData *event) {
    UiInteger *i = event->var->value;
    UiEvent e;
    e.obj = event->obj;
    e.window = event->obj->window;
    e.document = event->obj->ctx->document;
    e.eventdata = event->var->value;
    e.eventdatatype = UI_EVENT_DATA_INTEGER_VALUE;
    e.intval = i->get(i);
    e.set = ui_get_setop();
    
    ui_notify_evt(i->observers, &e);
}

static void ui_toggled_callback(GtkToggleButton *widget, UiEventData *event) {
    UiEvent e;
    e.obj = event->obj;
    e.window = event->obj->window;
    e.document = event->obj->ctx->document;
    e.eventdata = NULL;
    e.eventdatatype = 0;
    e.intval = gtk_toggle_button_get_active(widget);
    e.set = ui_get_setop();
    event->callback(&e, event->userdata);    
}

static void ui_togglebutton_enable_state_callback(GtkToggleButton *widget, UiEventData *event) {
    if(gtk_toggle_button_get_active(widget)) {
        ui_set_group(event->obj->ctx, event->value);
    } else {
        ui_unset_group(event->obj->ctx, event->value);
    }
}

void ui_setup_togglebutton(
        UiObject *obj,
        GtkWidget *togglebutton,
        const char *label,
        const char *icon,
        const char *varname,
        UiInteger *value,
        ui_callback onchange,
        void *onchangedata,
        int enable_state)
{
    if(label) {
        gtk_button_set_label(GTK_BUTTON(togglebutton), label);
    }
    ui_button_set_icon_name(togglebutton, icon);
    
    ui_bind_togglebutton(
            obj,
            togglebutton,
            ui_toggle_button_get,
            ui_toggle_button_set,
            varname,
            value,
            (ui_toggled_func)ui_toggled_callback,
            onchange,
            onchangedata,
            (ui_toggled_func)ui_togglebutton_enable_state_callback,
            enable_state
            );
}

void ui_bind_togglebutton(
        UiObject *obj,
        GtkWidget *widget,
        int64_t (*getfunc)(UiInteger*),
        void (*setfunc)(UiInteger*, int64_t),
        const char *varname,
        UiInteger *value,
        void (*toggled_callback)(void*, void*),
        ui_callback onchange,
        void *onchangedata,
        void (*enable_state_func)(void*, void*),
        int enable_state)
{
    UiObject* current = uic_current_obj(obj);
    UiVar* var = uic_widget_var(obj->ctx, current->ctx, value, varname, UI_VAR_INTEGER);
    if (var) {
        UiInteger* value = (UiInteger*)var->value;
        value->obj = widget;
        value->get = getfunc;
        value->set = setfunc;
        
        UiVarEventData *event = malloc(sizeof(UiVarEventData));
        event->obj = obj;
        event->var = var;
        event->observers = NULL;
        event->callback = NULL;
        event->userdata = NULL;

        g_signal_connect(
                widget,
                "toggled",
                G_CALLBACK(ui_toggled_obs),
                event);
        g_signal_connect(
                widget,
                "destroy",
                G_CALLBACK(ui_destroy_vardata),
                event);
    }
    
    if(onchange) {
        UiEventData *event = malloc(sizeof(UiEventData));
        event->obj = obj;
        event->userdata = onchangedata;
        event->callback = onchange;
        event->value = 0;
        event->customdata = NULL;
        event->customint = 0;
        
        g_signal_connect(
                widget,
                "toggled",
                G_CALLBACK(toggled_callback),
                event);
        g_signal_connect(
                widget,
                "destroy",
                G_CALLBACK(ui_destroy_userdata),
                event);
    }
    
    if(enable_state > 0) {
        UiEventData *event = malloc(sizeof(UiEventData));
        event->obj = obj;
        event->userdata = NULL;
        event->callback = NULL;
        event->value = enable_state;
        event->customdata = NULL;
        event->customint = 0;
        
        g_signal_connect(
                widget,
                "toggled",
                G_CALLBACK(enable_state_func),
                event);
        g_signal_connect(
                widget,
                "destroy",
                G_CALLBACK(ui_destroy_userdata),
                event);
    }
}

static UIWIDGET togglebutton_create(UiObject *obj, GtkWidget *widget, UiToggleArgs *args) {
    UiObject* current = uic_current_obj(obj);
    
    ui_setup_togglebutton(
            obj,
            widget,
            args->label,
            args->icon,
            args->varname,
            args->value,
            args->onchange,
            args->onchangedata,
            args->enable_group);
    ui_set_name_and_style(widget, args->name, args->style_class);
    ui_set_widget_groups(obj->ctx, widget, args->groups);
    
    UI_APPLY_LAYOUT2(current, args);
    current->container->add(current->container, widget);
    
    return widget;
}

UIWIDGET ui_togglebutton_create(UiObject* obj, UiToggleArgs *args) {
    return togglebutton_create(obj, gtk_toggle_button_new(), args);
}

#if GTK_MAJOR_VERSION >= 4

int64_t ui_check_button_get(UiInteger *integer) {
    GtkCheckButton *button = integer->obj;
    integer->value = (int)gtk_check_button_get_active(button);
    return integer->value;
}

void ui_check_button_set(UiInteger *integer, int64_t value) {
    GtkCheckButton *button = integer->obj;
    integer->value = value;
    gtk_check_button_set_active(button, value != 0 ? TRUE : FALSE);
}

static void ui_checkbox_callback(GtkCheckButton *widget, UiEventData *event) {
    UiEvent e;
    e.obj = event->obj;
    e.window = event->obj->window;
    e.document = event->obj->ctx->document;
    e.eventdata = NULL;
    e.eventdatatype = 0;
    e.intval = gtk_check_button_get_active(widget);
    e.set = ui_get_setop();
    event->callback(&e, event->userdata);    
}

static void ui_checkbox_enable_state(GtkCheckButton *widget, UiEventData *event) {
    if(gtk_check_button_get_active(widget)) {
        ui_set_group(event->obj->ctx, event->value);
    } else {
        ui_unset_group(event->obj->ctx, event->value);
    }
}

UIWIDGET ui_checkbox_create(UiObject* obj, UiToggleArgs *args) {
    UiObject* current = uic_current_obj(obj);
    
    GtkWidget *widget = gtk_check_button_new_with_label(args->label); 
    ui_bind_togglebutton(
            obj,
            widget,
            ui_check_button_get,
            ui_check_button_set,
            args->varname,
            args->value,
            (ui_toggled_func)ui_checkbox_callback,
            args->onchange,
            args->onchangedata,
            (ui_toggled_func)ui_checkbox_enable_state,
            args->enable_group);
    
    ui_set_name_and_style(widget, args->name, args->style_class);
    ui_set_widget_groups(obj->ctx, widget, args->groups);
    
    UI_APPLY_LAYOUT2(current, args);
    current->container->add(current->container, widget);
    
    return widget;
}

#else
UIWIDGET ui_checkbox_create(UiObject* obj, UiToggleArgs *args) {
    return togglebutton_create(obj, gtk_check_button_new(), args);
}
#endif


#if GTK_MAJOR_VERSION >= 3

static void switch_changed(
        GObject *gobject,
        GParamSpec *pspec,
        UiVarEventData *event)
{
    GtkSwitch *sw = GTK_SWITCH (gobject);
    gboolean active = gtk_switch_get_active (sw);
    
    UiEvent e;
    e.obj = event->obj;
    e.document = e.obj->ctx->document;
    e.window = e.obj->window;
    e.eventdata = NULL;
    e.eventdatatype = 0;
    e.set = ui_get_setop();
    
    if(event->callback) {
        event->callback(&e, event->userdata);
    }
    if(event->var) {
        UiInteger *i = event->var->value;
        ui_notify_evt(i->observers, &e);
    }
}

UIWIDGET ui_switch_create(UiObject* obj, UiToggleArgs *args) {
    UiObject* current = uic_current_obj(obj);
    GtkWidget *widget = gtk_switch_new();
    ui_set_name_and_style(widget, args->name, args->style_class);
    ui_set_widget_groups(obj->ctx, widget, args->groups);
    
    UiVar* var = uic_widget_var(obj->ctx, current->ctx, args->value, args->varname, UI_VAR_INTEGER);
    if(var) {
        UiInteger *value = var->value;
        value->obj = widget;
        value->get = ui_switch_get;
        value->set = ui_switch_set;
        
        if(value->value) {
            gtk_switch_set_active(GTK_SWITCH(widget), TRUE);
        }
        
        
    }
    
    UiVarEventData *event = malloc(sizeof(UiVarEventData));
    event->obj = obj;
    event->callback = args->onchange;
    event->userdata = args->onchangedata;
    event->var = var;
    event->observers = NULL;
    
    g_signal_connect(
            widget,
            "notify::active",
            G_CALLBACK(switch_changed),
            event);
    
    g_signal_connect(
            widget,
            "destroy",
            G_CALLBACK(ui_destroy_vardata),
            event);
    
    UI_APPLY_LAYOUT2(current, args);
    current->container->add(current->container, widget);
    
    return widget;
}

int64_t ui_switch_get(UiInteger *value) {
    GtkSwitch *sw = GTK_SWITCH((GtkWidget*)value->obj);
    value->value = gtk_switch_get_active(sw);
    return value->value;
}

void ui_switch_set(UiInteger *value, int64_t i) {
    GtkSwitch *sw = GTK_SWITCH((GtkWidget*)value->obj);
    value->value = i;
    gtk_switch_set_active(sw, i);
}
    
#else

UIWIDGET ui_switch_create(UiObject* obj, UiToggleArgs *args) {
    return ui_checkbox_create(obj, args);
}

#endif

#if GTK_MAJOR_VERSION >= 4
#define RADIOBUTTON_NEW(group, label) gtk_check_button_new_with_label(label)
#define RADIOBUTTON_SET_GROUP(button, group) 
#define RADIOBUTTON_GET_GROUP(button) GTK_CHECK_BUTTON(button)
#define RADIOBUTTON_GET_ACTIVE(button) gtk_check_button_get_active(GTK_CHECK_BUTTON(button))
#else
#define RADIOBUTTON_NEW(group, label) gtk_radio_button_new_with_label(group, label)
#define RADIOBUTTON_SET_GROUP(button, group) /* noop */
#define RADIOBUTTON_GET_GROUP(button) gtk_radio_button_get_group(GTK_RADIO_BUTTON(button))
#define RADIOBUTTON_GET_ACTIVE(button) gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(button))
#endif

static void radiobutton_toggled(void *widget, UiEventData *event) {
    UiEvent e;
    e.obj = event->obj;
    e.window = event->obj->window;
    e.document = event->obj->ctx->document;
    e.eventdata = NULL;
    e.eventdatatype = 0;
    e.intval = RADIOBUTTON_GET_ACTIVE(widget);
    e.set = ui_get_setop();
    event->callback(&e, event->userdata);    
}

typedef struct UiRadioButtonData {
    UiInteger *value;
    UiVarEventData *eventdata;
    UiBool first;
} UiRadioButtonData;

static void destroy_radiobutton(GtkWidget *w, UiRadioButtonData *data) {
    if(data->first) {
        ui_destroy_vardata(w, data->eventdata);
        g_slist_free(data->value->obj);
        data->value->obj = NULL;
        data->value->get = NULL;
        data->value->set = NULL;
    } else {
        free(data->eventdata);
    }
    free(data);
}

UIWIDGET ui_radiobutton_create(UiObject *obj, UiToggleArgs *args) {
    UiObject* current = uic_current_obj(obj);
    
    GSList *rg = NULL;
    UiInteger *rgroup;
    
    UiVar* var = uic_widget_var(obj->ctx, current->ctx, args->value, args->varname, UI_VAR_INTEGER);
    
    UiBool first = FALSE;
    if(var) {
        rgroup = var->value;
        rg = rgroup->obj;
        if(!rg) {
            first = TRUE;
        }
    }
    
    GtkWidget *rbutton = RADIOBUTTON_NEW(rg, args->label); 
    ui_set_name_and_style(rbutton, args->name, args->style_class);
    ui_set_widget_groups(obj->ctx, rbutton, args->groups);
    if(rgroup) {
#if GTK_MAJOR_VERSION >= 4
        if(rg) {
            gtk_check_button_set_group(GTK_CHECK_BUTTON(rbutton), rg->data);
        }
        rg = g_slist_prepend(rg, rbutton);
#else
        gtk_radio_button_set_group(GTK_RADIO_BUTTON(rbutton), rg);
        rg = gtk_radio_button_get_group(GTK_RADIO_BUTTON(rbutton));
#endif
        
        rgroup->obj = rg;
        rgroup->get = ui_radiobutton_get;
        rgroup->set = ui_radiobutton_set;
        
        ui_radiobutton_set(rgroup, rgroup->value);
        
        UiVarEventData *event = malloc(sizeof(UiVarEventData));
        event->obj = obj;
        event->var = var;
        event->observers = NULL;
        event->callback = NULL;
        event->userdata = NULL;
        
        UiRadioButtonData *rbdata = malloc(sizeof(UiRadioButtonData));
        rbdata->value = rgroup;
        rbdata->eventdata = event;
        rbdata->first = first;
        
        g_signal_connect(
                rbutton,
                "toggled",
                G_CALLBACK(ui_radio_obs),
                event);
        g_signal_connect(
                rbutton,
                "destroy",
                G_CALLBACK(destroy_radiobutton),
                rbdata);
    }
    
    if(args->onchange) {
        UiEventData *event = malloc(sizeof(UiEventData));
        event->obj = obj;
        event->userdata = args->onchangedata;
        event->callback = args->onchange;
        event->value = 0;
        event->customdata = NULL;
        event->customint = 0;
        
        g_signal_connect(
                rbutton,
                "toggled",
                G_CALLBACK(radiobutton_toggled),
                event);
        g_signal_connect(
                rbutton,
                "destroy",
                G_CALLBACK(ui_destroy_userdata),
                event);
    }
    
    UI_APPLY_LAYOUT2(current, args);
    current->container->add(current->container, rbutton);
    
    return rbutton;
}

void ui_radio_obs(GtkToggleButton *widget, UiVarEventData *event) {
    UiInteger *i = event->var->value;
    
    UiEvent e;
    e.obj = event->obj;
    e.window = event->obj->window;
    e.document = event->obj->ctx->document;
    e.eventdata = NULL;
    e.eventdatatype = 0;
    e.intval = i->get(i);
    
    ui_notify_evt(i->observers, &e);
}

#if GTK_MAJOR_VERSION >= 4
int64_t ui_radiobutton_get(UiInteger *value) {
    int selection = 0;
    GSList *ls = value->obj;
    int i = 0;
    guint len = g_slist_length(ls);
    while(ls) {
        if(gtk_check_button_get_active(GTK_CHECK_BUTTON(ls->data))) {
            selection = len - i - 1;
            break;
        }
        ls = ls->next;
        i++;
    }
    
    value->value = selection;
    return selection;
}

void ui_radiobutton_set(UiInteger *value, int64_t i) {
    GSList *ls = value->obj;
    int s = g_slist_length(ls) - 1 - i;
    int j = 0;
    while(ls) {
        if(j == s) {
            gtk_check_button_set_active(GTK_CHECK_BUTTON(ls->data), TRUE);
            break;
        }
        ls = ls->next;
        j++;
    }
    
    value->value = i;
}
#else
int64_t ui_radiobutton_get(UiInteger *value) {
    int selection = 0;
    GSList *ls = value->obj;
    int i = 0;
    guint len = g_slist_length(ls);
    while(ls) {
        if(gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(ls->data))) {
            selection = len - i - 1;
            break;
        }
        ls = ls->next;
        i++;
    }
    
    value->value = selection;
    return selection;
}

void ui_radiobutton_set(UiInteger *value, int64_t i) {
    GSList *ls = value->obj;
    int s = g_slist_length(ls) - 1 - i;
    int j = 0;
    while(ls) {
        if(j == s) {
            gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(ls->data), TRUE);
            break;
        }
        ls = ls->next;
        j++;
    }
    
    value->value = i;
}
#endif


static void ui_destroy_linkbutton(GtkWidget *widget, UiLinkButton *data) {
    free(data->link);
    free(data);
}

static const char* linkbutton_get_uri(UiLinkButton *link) {
    if(link->type == UI_LINK_BUTTON) {
        return link->link;
    } else {
        return gtk_link_button_get_uri(GTK_LINK_BUTTON(link->widget));
    }
}

static void linkbutton_set_uri(UiLinkButton *link, const char *uri) {
    if(link->type == UI_LINK_BUTTON) {
        free(link->link);
        link->link = uri ? strdup(uri) : NULL;
    } else {
        gtk_link_button_set_uri(GTK_LINK_BUTTON(link->widget), uri);
    }
}

static gboolean linkbutton_get_visited(UiLinkButton *link) {
    if(link->type == UI_LINK_BUTTON) {
        return FALSE;
    } else {
        gtk_link_button_get_visited(GTK_LINK_BUTTON(link->widget));
    }
}

static void linkbutton_set_visited(UiLinkButton *link, gboolean visited) {
    if(link->type != UI_LINK_BUTTON) {
        gtk_link_button_set_visited(GTK_LINK_BUTTON(link->widget), visited);
    }
}

/*
 * Apply linkbutton settings from json. Expects jsonvalue to be a valid
 * json object.
 * 
 * {
 *     "label": "label text",
 *     "uri": "http://example.com",
 *     "visited": true
 * }
 * 
 */
static void linkbutton_apply_value(UiLinkButton *link, const char *jsonvalue) {
    CxJson json;
    cxJsonInit(&json, NULL);
    cxJsonFill(&json, jsonvalue);
    
    CxJsonValue *value;
    if(cxJsonNext(&json, &value) == CX_JSON_NO_ERROR) {
        if(cxJsonIsObject(value)) {
            CxJsonValue *label = cxJsonObjGet(value, "label");
            CxJsonValue *uri = cxJsonObjGet(value, "uri");
            CxJsonValue *visited = cxJsonObjGet(value, "visited");
            if(label) {
                gtk_button_set_label(GTK_BUTTON(link->widget), cxJsonIsString(label) ? cxJsonAsString(label) : NULL);
            }
            if(uri) {
                linkbutton_set_uri(link, cxJsonIsString(uri) ? cxJsonAsString(uri) : NULL);
                
            }
            if(visited) {
                linkbutton_set_visited(link, cxJsonIsBool(visited) ? cxJsonAsBool(visited) : FALSE);
            }
        }        
        cxJsonValueFree(value);
    }
    cxJsonDestroy(&json);
}

static char* create_linkbutton_jsonvalue(const char *label, const char *uri, gboolean include_null, gboolean visited, gboolean set_visited) {
    CxJsonValue *obj = cxJsonCreateObj(NULL);
    if(label) {
        cxJsonObjPutString(obj, CX_STR("label"), label);
    } else if(include_null) {
        cxJsonObjPutLiteral(obj, CX_STR("label"), CX_JSON_NULL);
    }
    
    if(uri) {
        cxJsonObjPutString(obj, CX_STR("uri"), uri);
    } else if(include_null) {
        cxJsonObjPutLiteral(obj, CX_STR("uri"), CX_JSON_NULL);
    }
    
    if(set_visited) {
        cxJsonObjPutLiteral(obj, CX_STR("visited"), visited ? CX_JSON_TRUE : CX_JSON_FALSE);
    }
    
    CxJsonWriter writer = cxJsonWriterCompact();
    CxBuffer buf;
    cxBufferInit(&buf, NULL, 128, NULL, CX_BUFFER_AUTO_EXTEND);
    cxJsonWrite(&buf, obj, (cx_write_func)cxBufferWrite, &writer);
    cxJsonValueFree(obj);
    cxBufferTerminate(&buf);
    
    return buf.space;
}

static char* linkbutton_get_value(UiLinkButton *link) {
    const char *label = gtk_button_get_label(GTK_BUTTON(link->widget));
    const char *uri = linkbutton_get_uri(link);
    gboolean visited = linkbutton_get_visited(link);
    return create_linkbutton_jsonvalue(label, uri, TRUE, visited, TRUE);
}

static void linkbutton_clicked(GtkWidget *widget, UiLinkButton *data) {
    if(data->onclick) {
        UiEvent e;
        e.obj = data->obj;
        e.document = e.obj->ctx->document;
        e.window = e.obj->window;
        e.eventdata = (char*)linkbutton_get_uri(data);
        e.eventdatatype = UI_EVENT_DATA_STRING;
        e.intval = 0;
        e.set = ui_get_setop();
        data->onclick(&e, data->onclickdata);
    }
}

static gboolean linkbutton_activate_link(GtkLinkButton *self, UiLinkButton *data) {
    linkbutton_clicked(data->widget, data);
    return data->nofollow;
}

UIWIDGET ui_linkbutton_create(UiObject *obj, UiLinkButtonArgs *args) {
    UiLinkButton *data = malloc(sizeof(UiLinkButton));
    memset(data, 0, sizeof(UiLinkButton));
    data->obj = obj;
    data->type = args->type;
    data->nofollow = args->nofollow;
    data->onclick = args->onclick;
    data->onclickdata = args->onclickdata;
    
    GtkWidget *button;
    if(args->type == UI_LINK_BUTTON) {
        button = gtk_button_new();
        g_signal_connect(
                button,
                "clicked",
                G_CALLBACK(linkbutton_clicked),
                data);
    } else {
        button = gtk_link_button_new("file:///");
        g_signal_connect(
                button,
                "activate-link",
                G_CALLBACK(linkbutton_activate_link),
                data);
    }
    gtk_button_set_label(GTK_BUTTON(button), args->label);
#if GTK_CHECK_VERSION(4, 0, 0)
    gtk_button_set_can_shrink(GTK_BUTTON(button), TRUE);
#elif GTK_MAJOR_VERSION == 3
    GtkWidget *child = gtk_bin_get_child(GTK_BIN(button));
    gtk_label_set_ellipsize(GTK_LABEL(child), PANGO_ELLIPSIZE_END);
#endif
    g_object_set_data(G_OBJECT(button), "ui_linkbutton", data);
    g_signal_connect(
            button,
            "destroy",
            G_CALLBACK(ui_destroy_linkbutton),
            data);
    
    data->widget = button;
    
    UiObject* current = uic_current_obj(obj);
    UiVar *var = uic_widget_var(obj->ctx, current->ctx, args->value, args->varname, UI_VAR_STRING);
    if(var) {
        UiString *str = var->value;
        char *current_value = ui_get(str);
        if(current_value) {
            linkbutton_apply_value(data, current_value);
        }
        
        str->obj = data;
        str->get = ui_linkbutton_get;
        str->set = ui_linkbutton_set;
    }
    
    ui_set_name_and_style(button, args->name, args->style_class);
    ui_set_widget_groups(obj->ctx, button, args->groups);
    UI_APPLY_LAYOUT2(current, args);
    current->container->add(current->container, button);
    
    return button;
}

char* ui_linkbutton_get(UiString *s) {
    UiLinkButton *link = s->obj;
    if(s->value.free) {
        s->value.free(s->value.ptr);
    }
    s->value.ptr = linkbutton_get_value(link);
    s->value.free = free;
    return s->value.ptr;
}

void ui_linkbutton_set(UiString *s, const char *str) {
    linkbutton_apply_value(s->obj, str);
    if(s->value.free) {
        s->value.free(s->value.ptr);
    }
#if GTK_MAJOR_VERSION == 3
    UiLinkButton *data = s->obj;
    GtkWidget *child = gtk_bin_get_child(GTK_BIN(data->widget));
    gtk_label_set_ellipsize(GTK_LABEL(child), PANGO_ELLIPSIZE_END);
#endif
}


void ui_linkbutton_value_set(UiString *str, const char *label, const char *uri) {
    char *value = create_linkbutton_jsonvalue(label, uri, TRUE, FALSE, TRUE);
    ui_set(str, value);
    free(value);
}

void ui_linkbutton_value_set_label(UiString *str, const char *label) {
    char *value = create_linkbutton_jsonvalue(label, NULL, FALSE, FALSE, TRUE);
    ui_set(str, value);
    free(value);
}

void ui_linkbutton_value_set_uri(UiString *str, const char *uri) {
    char *value = create_linkbutton_jsonvalue(NULL, uri, FALSE, FALSE, TRUE);
    ui_set(str, value);
    free(value);
}

void ui_linkbutton_value_set_visited(UiString *str, UiBool visited) {
    char *value = create_linkbutton_jsonvalue(NULL, NULL, FALSE, visited, TRUE);
    ui_set(str, value);
    free(value);
}


void ui_linkbutton_set_label(UIWIDGET button, const char *label) {
    gtk_button_set_label(GTK_BUTTON(button), label);
}

void ui_linkbutton_set_uri(UIWIDGET button, const char *label) {
    UiLinkButton *link = g_object_get_data(G_OBJECT(button), "ui_linkbutton");
    if(link) {
        linkbutton_set_uri(link, label);
    } else {
        fprintf(stderr, "Error: ui_linkbutton_set_label: widget is not a linkbutton\n");
    }
}

void ui_linkbutton_set_visited(UIWIDGET button, UiBool visited) {
    UiLinkButton *link = g_object_get_data(G_OBJECT(button), "ui_linkbutton");
    if(link) {
        linkbutton_set_visited(link, visited);
    } else {
        fprintf(stderr, "Error: ui_linkbutton_set_label: widget is not a linkbutton\n");
    }
}

char* ui_linkbutton_get_label(UIWIDGET button) {
    const char *label = gtk_button_get_label(GTK_BUTTON(button));
    return label ? strdup(label) : NULL;
}

char* ui_linkbutton_get_uri(UIWIDGET button) {
    UiLinkButton *link = g_object_get_data(G_OBJECT(button), "ui_linkbutton");
    if(link) {
        const char *uri = linkbutton_get_uri(link);
        return uri ? strdup(uri) : NULL;
    } else {
        fprintf(stderr, "Error: ui_linkbutton_set_label: widget is not a linkbutton\n");
    }
    return NULL;
}

UiBool ui_linkbutton_get_visited(UIWIDGET button) {
    UiLinkButton *link = g_object_get_data(G_OBJECT(button), "ui_linkbutton");
    if(link) {
        return linkbutton_get_visited(link);
    } else {
        fprintf(stderr, "Error: ui_linkbutton_set_label: widget is not a linkbutton\n");
    }
    return FALSE;
}