/* AspectBin - A GTK+ container for packing with consrained aspect ratio.
 * Copyright (C) 2009 Nick Bowler
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <stdio.h>
#include "aspectbin.h"

enum {
	PROP_0,
	PROP_RATIO,
	PROP_CONSTRAIN,
	PROP_FILL,
};

enum {
	CHILD_PROP_0,
	CHILD_PROP_ALIGN,
};

static void aspect_bin_size_request(GtkWidget *, GtkRequisition *);
static void aspect_bin_size_allocate(GtkWidget *, GtkAllocation *);
static void aspect_bin_add(GtkContainer *, GtkWidget *);
static void aspect_bin_remove(GtkContainer *, GtkWidget *);
static void aspect_bin_forall(GtkContainer *, gboolean, GtkCallback, gpointer);
static GType aspect_bin_child_type(GtkContainer *);

static void aspect_bin_get_property(GObject *, guint, GValue *, GParamSpec *);
static void aspect_bin_set_property(GObject *, guint, const GValue *,
                                                          GParamSpec *);
static void aspect_bin_set_child_property(GtkContainer *, GtkWidget *, guint,
                                                const GValue *, GParamSpec *);
static void aspect_bin_get_child_property(GtkContainer *, GtkWidget *, guint,
                                                      GValue *, GParamSpec *);

G_DEFINE_TYPE(AspectBin, aspect_bin, GTK_TYPE_CONTAINER)

static void aspect_bin_init(AspectBin *abin)
{
	GTK_WIDGET_SET_FLAGS(abin, GTK_NO_WINDOW);

	abin->body       = NULL;
	abin->side       = NULL;
	abin->ratio      = 1;
	abin->body_align = 0.5;
	abin->side_align = 0.5;
	abin->constrain  = FALSE;
	abin->fill       = TRUE;
}

static void aspect_bin_class_init(AspectBinClass *class)
{
	GObjectClass      *object_class    = G_OBJECT_CLASS(class);
	GtkWidgetClass    *widget_class    = GTK_WIDGET_CLASS(class);
	GtkContainerClass *container_class = GTK_CONTAINER_CLASS(class);

	widget_class->size_request  = aspect_bin_size_request;
	widget_class->size_allocate = aspect_bin_size_allocate;

	container_class->add        = aspect_bin_add;
	container_class->remove     = aspect_bin_remove;
	container_class->forall     = aspect_bin_forall;
	container_class->child_type = aspect_bin_child_type;

	container_class->set_child_property = aspect_bin_set_child_property;
	container_class->get_child_property = aspect_bin_get_child_property;

	object_class->set_property = aspect_bin_set_property;
	object_class->get_property = aspect_bin_get_property;

	g_object_class_install_property(object_class,
		PROP_RATIO,
		g_param_spec_float("ratio",
			"Aspect Ratio",
			"Width:height ratio of the body.",
			0.2, 5.0, 1.0,
			G_PARAM_READWRITE));
	g_object_class_install_property(object_class,
		PROP_FILL,
		g_param_spec_boolean("fill",
			"Fill",
			"Allocate all remaining space to the side.",
			TRUE,
			G_PARAM_READWRITE));
	g_object_class_install_property(object_class,
		PROP_CONSTRAIN,
		g_param_spec_boolean("constrain",
			"Constrain",
			"Try not to place the side beyond the body's edges.",
			FALSE,
			G_PARAM_READWRITE));
	gtk_container_class_install_child_property(container_class,
		CHILD_PROP_ALIGN,
		g_param_spec_float("align",
			"Alignment",
			"Alignment of the child within the available space.",
			0.0, 1.0, 0.5,
			G_PARAM_READWRITE));
}

GtkWidget *aspect_bin_new(void)
{
	return GTK_WIDGET(g_object_new(ASPECT_BIN_TYPE, NULL));
}

static void aspect_bin_set_property(GObject      *object,
                                    guint         prop_id,
                                    const GValue *value,
                                    GParamSpec   *pspec)
{
	AspectBin *abin = ASPECT_BIN(object);
	gfloat tmp;

	switch (prop_id) {
	case PROP_RATIO:
		tmp = abin->ratio;
		abin->ratio = g_value_get_float(value);
		if (tmp != abin->ratio)
			gtk_widget_queue_resize(GTK_WIDGET(abin));
		break;
	case PROP_CONSTRAIN:
		abin->constrain = g_value_get_boolean(value);
		gtk_widget_queue_resize(GTK_WIDGET(abin));
		break;
	case PROP_FILL:
		abin->fill = g_value_get_boolean(value);
		gtk_widget_queue_resize(GTK_WIDGET(abin));
		break;
	default:
		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
	}
}

static void aspect_bin_get_property(GObject    *object,
                                    guint       prop_id,
                                    GValue     *value,
                                    GParamSpec *pspec)
{
	AspectBin *abin = ASPECT_BIN(object);

	switch (prop_id) {
	case PROP_RATIO:
		g_value_set_float(value, abin->ratio);
		break;
	case PROP_CONSTRAIN:
		g_value_set_boolean(value, abin->constrain);
		break;
	case PROP_FILL:
		g_value_set_boolean(value, abin->fill);
		break;
	default:
		G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec);
	}
}

static void aspect_bin_set_child_property(GtkContainer *container,
                                          GtkWidget    *child,
                                          guint         prop_id,
                                          const GValue *value,
                                          GParamSpec   *pspec)
{
	AspectBin *abin = ASPECT_BIN(container);
	gfloat align;

	g_assert(child == abin->body || child == abin->side);

	switch (prop_id) {
	case CHILD_PROP_ALIGN:
		align = g_value_get_float(value);
		if (child == abin->body)
			abin->body_align = align;
		else if (child == abin->side)
			abin->side_align = align;
		gtk_widget_queue_resize(GTK_WIDGET(abin));
		break;
	default:
		GTK_CONTAINER_WARN_INVALID_CHILD_PROPERTY_ID(container,
		                                             prop_id, pspec);
	}
}

static void aspect_bin_get_child_property(GtkContainer *container,
                                          GtkWidget    *child,
                                          guint         prop_id,
                                          GValue       *value,
                                          GParamSpec   *pspec)
{
	AspectBin *abin = ASPECT_BIN(container);
	gfloat align = 0;

	g_assert(child == abin->body || child == abin->side);

	switch (prop_id) {
	case CHILD_PROP_ALIGN:
		if (child == abin->body)
			align = abin->body_align;
		else if (child == abin->side)
			align = abin->side_align;
		g_value_set_float(value, align);
		break;
	default:
		GTK_CONTAINER_WARN_INVALID_CHILD_PROPERTY_ID(container,
		                                             prop_id, pspec);
	}
}

static void aspect_bin_add(GtkContainer *container, GtkWidget *widget)
{
	AspectBin *abin;
	g_return_if_fail(IS_ASPECT_BIN(container));
	abin = ASPECT_BIN(container);

	if (!abin->body)
		aspect_bin_set_body(abin, widget, 1);
	else if (!abin->side)
		aspect_bin_set_side(abin, widget);
	else
		g_warning("AspectBin cannot have more than 2 children.\n");
}

static void aspect_bin_remove(GtkContainer *container, GtkWidget *child)
{
	AspectBin *abin = ASPECT_BIN(container);

	if (abin->body == child) {
		aspect_bin_set_body(abin, NULL, 1);
	} else if (abin->side == child) {
		aspect_bin_set_side(abin, NULL);
	}
}

static void aspect_bin_forall(GtkContainer *container,
                              gboolean      include_internals,
                              GtkCallback   callback,
                              gpointer      callback_data)
{
	AspectBin *abin = ASPECT_BIN(container);
	g_return_if_fail(callback != NULL);

	if (abin->body)
		callback(abin->body, callback_data);
	if (abin->side)
		callback(abin->side, callback_data);
}

static GType aspect_bin_child_type(GtkContainer *container)
{
	if (!ASPECT_BIN(container)->body || !ASPECT_BIN(container)->side)
		return GTK_TYPE_WIDGET;
	return G_TYPE_NONE;
}

static void
aspect_bin_size_request(GtkWidget *widget, GtkRequisition *requisition)
{
	AspectBin *abin = ASPECT_BIN(widget);
	GtkRequisition creq = {0}, areq = {0};

	if (abin->side && GTK_WIDGET_VISIBLE(abin->side)) {
		gtk_widget_size_request(abin->side, &creq);
	}

	if (abin->body && GTK_WIDGET_VISIBLE(abin->body)) {
		int wtmp, htmp;
		gtk_widget_size_request(abin->body, &areq);
		wtmp = areq.height * abin->ratio + 0.5;
		htmp = areq.width  / abin->ratio + 0.5;

		if (wtmp > areq.width) {
			areq.width  = wtmp;
		} else {
			areq.height = htmp;
		}
	}

	requisition->width  = areq.width + creq.width;
	requisition->height = MAX(areq.height, creq.height);
}

static void
aspect_bin_size_allocate(GtkWidget *widget, GtkAllocation *allocation)
{
	AspectBin *abin = ASPECT_BIN(widget);
	GtkRequisition creq = {0};
	GtkAllocation csize = {0}, asize = {0};

	/* First find the best fit for the body. */
	if (abin->body && GTK_WIDGET_VISIBLE(abin->body)) {
		asize.height = allocation->height;
		asize.width  = asize.height * abin->ratio + 0.5;

		if (asize.width > allocation->width) {
			asize.width  = allocation->width;
			asize.height = asize.width / abin->ratio + 0.5;
		}
	}

	/* Now try to fit the side. */
	if (abin->side && GTK_WIDGET_VISIBLE(abin->side)) {
		gtk_widget_get_child_requisition(abin->side, &creq);

		if (allocation->width - asize.width < creq.width) {
			/* It didn't fit, squish the constrained guy. */
			asize.width  = allocation->width - creq.width;
			asize.height = asize.width / abin->ratio + 0.5;
		}

		csize.width  = allocation->width - asize.width;
		csize.x = asize.width;

		if (abin->fill && abin->constrain) {
			csize.height = asize.height;
		} else if (abin->fill) {
			csize.height = allocation->height;
		} else {
			csize.height = MIN(creq.height, allocation->height);
		}
	}

	asize.y = (allocation->height - asize.height) * abin->body_align + 0.5;

	if (abin->constrain && csize.height <= asize.height) {
		csize.y = asize.y + (asize.height-csize.height)
		        * abin->side_align + 0.5;
	} else if (abin->constrain) {
		csize.y = (allocation->height - csize.height)
		        * abin->body_align + 0.5;
	} else {
		csize.y = (allocation->height - csize.height)
		        * abin->side_align + 0.5;
	}

	if (abin->body)
		gtk_widget_size_allocate(abin->body, &asize);
	if (abin->side)
		gtk_widget_size_allocate(abin->side, &csize);
}

static gboolean
set_widget(GtkWidget **dest, GtkWidget *parent, GtkWidget *widget)
{
	gboolean need_resize = FALSE;

	if (*dest == widget)
		return FALSE;

	if (*dest) {
		need_resize |= GTK_WIDGET_VISIBLE(*dest);
		gtk_widget_unparent(*dest);
	}

	*dest = widget;
	if (widget) {
		gtk_widget_set_parent(widget, parent);
		need_resize |= GTK_WIDGET_VISIBLE(widget);
	}

	return GTK_WIDGET_VISIBLE(parent) && need_resize;
}

void aspect_bin_set_body(AspectBin *abin, GtkWidget *widget, gfloat ratio)
{
	g_return_if_fail(IS_ASPECT_BIN(abin));
	g_return_if_fail(widget == NULL || GTK_IS_WIDGET(widget));
	g_return_if_fail(widget == NULL || widget->parent == NULL);

	if (set_widget(&abin->body, GTK_WIDGET(abin), widget))
		gtk_widget_queue_resize(GTK_WIDGET(abin));
}

void aspect_bin_set_side(AspectBin *abin, GtkWidget *widget)
{
	g_return_if_fail(IS_ASPECT_BIN(abin));
	g_return_if_fail(widget == NULL || GTK_IS_WIDGET(widget));
	g_return_if_fail(widget == NULL || widget->parent == NULL);

	if (set_widget(&abin->side, GTK_WIDGET(abin), widget))
		gtk_widget_queue_resize(GTK_WIDGET(abin));
}

GtkWidget *aspect_bin_get_body(AspectBin *abin)
{
	g_return_val_if_fail(IS_ASPECT_BIN(abin), NULL);
	return abin->body;
}

GtkWidget *aspect_bin_get_side(AspectBin *abin)
{
	g_return_val_if_fail(IS_ASPECT_BIN(abin), NULL);
	return abin->side;
}