/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 * Copyright (C) 2013 Intel Corporation
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU Lesser General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 * Author: Tristan Van Berkom <tristanvb@openismus.com>
 */
 
#include "cursor-navigator.h"

/* GObjectClass */
static void            cursor_navigator_constructed     (GObject              *object);
static void            cursor_navigator_finalize        (GObject              *object);

/* GtkScaleClass */
static gchar          *cursor_navigator_format_value    (GtkScale             *scale,
							 gdouble               value);

static void            cursor_navigator_changed         (GtkAdjustment        *adj,
							 GParamSpec           *pspec,
							 CursorNavigator      *navigator);


struct _CursorNavigatorPrivate {
	gchar **alphabet;
	gint    letters;
	gint    index;
};


enum {
	INDEX_CHANGED,
	LAST_SIGNAL
};

static guint signals[LAST_SIGNAL];

enum {
	PROP_0,
	PROP_INDEX,
};

G_DEFINE_TYPE (CursorNavigator, cursor_navigator, GTK_TYPE_SCALE);

/************************************************************************
 *                          GObjectClass                                *
 ************************************************************************/
static void
cursor_navigator_class_init (CursorNavigatorClass *klass)
{
	GObjectClass       *object_class;
	GtkScaleClass      *scale_class;

	object_class = G_OBJECT_CLASS (klass);
	object_class->constructed = cursor_navigator_constructed;
	object_class->finalize = cursor_navigator_finalize;

	scale_class = GTK_SCALE_CLASS (klass);
	scale_class->format_value = cursor_navigator_format_value;

	signals[INDEX_CHANGED] = g_signal_new ("index-changed",
					       G_OBJECT_CLASS_TYPE (object_class),
					       G_SIGNAL_RUN_LAST,
					       0, NULL, NULL, NULL,
					       G_TYPE_NONE, 0);

	g_type_class_add_private (object_class, sizeof (CursorNavigatorPrivate));
}

static void
cursor_navigator_init (CursorNavigator *navigator)
{
	CursorNavigatorPrivate *priv;

	navigator->priv = priv =
		G_TYPE_INSTANCE_GET_PRIVATE (navigator,
					     CURSOR_TYPE_NAVIGATOR,
					     CursorNavigatorPrivate);

	priv->letters = -1;
}

static void
cursor_navigator_constructed (GObject *object)
{
	CursorNavigator        *navigator = CURSOR_NAVIGATOR (object);
	GtkAdjustment          *adj = NULL;

	G_OBJECT_CLASS (cursor_navigator_parent_class)->constructed (object);

	adj = gtk_adjustment_new (0.0F, 0.0F, 1.0F, 1.0F, 1.0F, 0.0F);
	gtk_range_set_adjustment (GTK_RANGE (navigator), adj);

	g_signal_connect (adj, "notify::value",
			  G_CALLBACK (cursor_navigator_changed), navigator);
}

static void
cursor_navigator_finalize (GObject  *object)
{
	CursorNavigator        *navigator = CURSOR_NAVIGATOR (object);
	CursorNavigatorPrivate *priv = navigator->priv;

	g_strfreev (priv->alphabet);

	G_OBJECT_CLASS (cursor_navigator_parent_class)->finalize (object);
}

/************************************************************************
 *                          GtkScaleClass                               *
 ************************************************************************/
static gchar *
cursor_navigator_format_value (GtkScale  *scale,
			       gdouble    value)
{
	CursorNavigator        *navigator = CURSOR_NAVIGATOR (scale);
	CursorNavigatorPrivate *priv = navigator->priv;
	gint                    index;

	if (priv->letters < 0)
		return NULL;

	index = CLAMP ((gint)value, 0, priv->letters - 1);

	/* Return the letter for the gvoidiven value
	 */
	return g_strdup (priv->alphabet[index]);
}

static void
cursor_navigator_changed (GtkAdjustment        *adj,
			  GParamSpec           *pspec,
			  CursorNavigator      *navigator)
{
	gint index = gtk_adjustment_get_value (adj);

	cursor_navigator_set_index (navigator, index);
}

/************************************************************************
 *                                API                                   *
 ************************************************************************/
CursorNavigator *
cursor_navigator_new (void)
{
	return g_object_new (CURSOR_TYPE_NAVIGATOR, NULL);
}

static void
cursor_navigator_update_parameters (CursorNavigator     *navigator)
{
	CursorNavigatorPrivate *priv = navigator->priv;
	GtkScale               *scale = GTK_SCALE (navigator);
	GtkAdjustment          *adj;
	gint                    i;

	gtk_scale_clear_marks (scale);
	for (i = 0; i < priv->letters; i++) {
		gchar *letter;

		letter = g_strdup_printf ("<span size=\"x-small\">%s</span>", priv->alphabet[i]);

		gtk_scale_add_mark (scale, i, GTK_POS_LEFT, letter);
		g_free (letter);
	}

	adj = gtk_range_get_adjustment (GTK_RANGE (navigator));

	gtk_adjustment_set_upper (adj, priv->letters - 1);
}

void
cursor_navigator_set_alphabet (CursorNavigator     *navigator,
			       const gchar * const *alphabet)
{
	CursorNavigatorPrivate *priv;

	g_return_if_fail (CURSOR_IS_NAVIGATOR (navigator));
	g_return_if_fail (alphabet == NULL ||
			  g_strv_length ((gchar **)alphabet) > 0);

	priv = navigator->priv;

	g_free (priv->alphabet);
	if (alphabet) {
		priv->alphabet = g_strdupv ((gchar **)alphabet);
		priv->letters = g_strv_length ((gchar **)alphabet);
	} else {
		priv->alphabet = NULL;
		priv->letters = -1;
	}

	cursor_navigator_update_parameters (navigator);
	cursor_navigator_set_index (navigator, 0);
}

const gchar * const *
cursor_navigator_get_alphabet (CursorNavigator *navigator)
{
	CursorNavigatorPrivate *priv;

	g_return_val_if_fail (CURSOR_IS_NAVIGATOR (navigator), NULL);

	priv = navigator->priv;

	return (const gchar * const *)priv->alphabet;
}

void
cursor_navigator_set_index (CursorNavigator     *navigator,
			    gint                 index)
{
	CursorNavigatorPrivate *priv;
	GtkAdjustment          *adj;

	g_return_if_fail (CURSOR_IS_NAVIGATOR (navigator));

	priv = navigator->priv;
	adj  = gtk_range_get_adjustment (GTK_RANGE (navigator));

	index = CLAMP (index, 0, priv->letters);

	if (priv->index != index) {

		priv->index = index;

		g_signal_emit (navigator, signals[INDEX_CHANGED], 0);

		g_signal_handlers_block_by_func (adj, cursor_navigator_changed, navigator);
		gtk_adjustment_set_value (adj, priv->index);
		g_signal_handlers_unblock_by_func (adj, cursor_navigator_changed, navigator);
	}
}

gint
cursor_navigator_get_index (CursorNavigator     *navigator)
{
	CursorNavigatorPrivate *priv;

	g_return_val_if_fail (CURSOR_IS_NAVIGATOR (navigator), 0);

	priv = navigator->priv;

	return priv->index;
}