/* -*- Mode: C; indent-tabs-mode:nil; c-basic-offset: 8-*- */

/*
 * This file is part of The Croco Library
 *
 * Copyright (C) 2002-2003 Dodji Seketeli <dodji@seketeli.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2.1 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */

/*
 *$Id$
 */

#include <string.h>
#include "cr-cascade.h"

#define PRIVATE(a_this) ((a_this)->priv)

struct _CRCascadePriv
{
	/**
	 *the 3 style sheets of the cascade:
	 *author, user, and useragent sheet.
	 *Intended to be addressed by
	 *sheets[ORIGIN_AUTHOR] or sheets[ORIGIN_USER]
	 *of sheets[ORIGIN_UA] ;
	 */
	CRStyleSheet *sheets[3] ;
        guint ref_count ;
} ;


/**
 *Constructor of the #CRCascade class.
 *Note that all three parameters of this
 *method are ref counted and their refcount is increased.
 *Their refcount will be decreased at the destruction of
 *the instance of #CRCascade.
 *So the caller should not call their destructor. The caller
 *should call their ref/unref method instead if it wants
 *@param a_author_sheet the autor origin style sheet
 *@param a_user_sheet the user origin style sheet.
 *@param a_ua_sheet the user agent origin style sheet.
 *@return the newly built instance of CRCascade or NULL if
 *an error arose during constrution.
 */
CRCascade *
cr_cascade_new (CRStyleSheet *a_author_sheet,
		CRStyleSheet *a_user_sheet,
		CRStyleSheet *a_ua_sheet)
{
	CRCascade *result = NULL ;

	result = g_try_malloc (sizeof (CRCascade)) ;
	if (!result)
	{
		cr_utils_trace_info ("Out of memory") ;
		return NULL ;
	}
	memset (result, 0, sizeof (CRCascade)) ;

	PRIVATE (result) = g_try_malloc (sizeof (CRCascadePriv)) ;
	if (!PRIVATE (result))
	{
		cr_utils_trace_info ("Out of memory") ;
		return NULL ;
	}
	memset (PRIVATE (result), 0, sizeof (CRCascadePriv)) ;

	if (a_author_sheet)
	{
                cr_cascade_set_sheet (result, a_author_sheet,
                                      ORIGIN_AUTHOR) ;
	}
	if (a_user_sheet)
	{
                cr_cascade_set_sheet (result, a_user_sheet,
                                      ORIGIN_USER) ;
	}
	if (a_ua_sheet)
	{
                cr_cascade_set_sheet (result, a_ua_sheet,
                                      ORIGIN_UA) ;
	}

	return result ;
}

/**
 *Gets a given origin sheet.
 *Note that the returned stylesheet
 *is refcounted so if the caller wants
 *to manage it's lifecycle, it must use
 *cr_stylesheet_ref()/cr_stylesheet_unref() instead
 *of the cr_stylesheet_destroy() method.
 *@param a_this the current instance of #CRCascade.
 *@param a_origin the origin of the style sheet as
 *defined in the css2 spec in chapter 6.4.
 *@return the style sheet, or NULL if it does not
 *exist.
 */
CRStyleSheet *
cr_cascade_get_sheet (CRCascade *a_this,
                      enum CRStyleOrigin a_origin)
{
	g_return_val_if_fail (a_this
			      && a_origin >= ORIGIN_UA
			      && a_origin < NB_ORIGINS,
			      NULL) ;

	return PRIVATE (a_this)->sheets[a_origin] ;
}


/**
 *Sets a stylesheet in the cascade
 *@param a_this the current instance of #CRCascade.
 *@param a_sheet the stylesheet to set.
 *@param a_origin the origin of the stylesheet.
 *@return CR_OK upon successfull completion, an error
 *code otherwise.
 */
enum CRStatus
cr_cascade_set_sheet (CRCascade *a_this,
                      CRStyleSheet *a_sheet,
                      enum CRStyleOrigin a_origin)
{
	g_return_val_if_fail (a_this
			      && a_sheet
			      && a_origin >= ORIGIN_UA
			      && a_origin < NB_ORIGINS,
			      CR_BAD_PARAM_ERROR) ;

	if (PRIVATE (a_this)->sheets[a_origin])
		cr_stylesheet_unref 
			(PRIVATE (a_this)->sheets[a_origin]) ;
	PRIVATE (a_this)->sheets[a_origin] = a_sheet ;
	cr_stylesheet_ref (a_sheet) ;
        a_sheet->origin = a_origin ;
	return CR_OK ;
}

/**
 *Increases the reference counter of the current instance
 *of #CRCascade.
 *@param a_this the current instance of #CRCascade
 *
 */
void
cr_cascade_ref (CRCascade *a_this)
{
        g_return_if_fail (a_this && PRIVATE (a_this)) ;
        
        PRIVATE (a_this)->ref_count++ ;
}

/**
 *Decrements the reference counter associated
 *to this instance of #CRCascade. If the reference
 *counter reaches zero, the instance is destroyed 
 *using cr_cascade_destroy()
 *@param a_this the current instance of 
 *#CRCascade.
 */
void 
cr_cascade_unref (CRCascade *a_this)
{
        g_return_if_fail (a_this && PRIVATE (a_this)) ;

        if (PRIVATE (a_this)->ref_count)
                PRIVATE (a_this)->ref_count -- ;
        if (!PRIVATE (a_this)->ref_count) 
        {
                cr_cascade_destroy (a_this) ;
        }
}

/**
 *Destructor of #CRCascade.
 */
void
cr_cascade_destroy (CRCascade *a_this)
{
	g_return_if_fail (a_this) ;

	if (PRIVATE (a_this))
	{
		gulong i = 0 ;

		for (i = 0 ; 
		     PRIVATE (a_this)->sheets
			     && i < NB_ORIGINS ; 
		     i++)
		{
			if (PRIVATE (a_this)->sheets[i])
			{
				if (cr_stylesheet_unref 
				    (PRIVATE (a_this)->sheets[i]) 
				    == TRUE)
				{
					PRIVATE (a_this)->sheets[i] = 
						NULL ;
				}
			}
		}
		g_free (PRIVATE (a_this)) ;
		PRIVATE (a_this) = NULL ;
	}
	g_free (a_this) ;
}