/**
 *############################################################################
 * A component of the Greenstone Librarian Interface, part of the Greenstone
 * digital library suite from the New Zealand Digital Library Project at the
 * University of Waikato, New Zealand.
 *
 * Author: Michael Dewsnip, NZDL Project, University of Waikato, NZ
 *
 * Copyright (C) 2004 New Zealand Digital Library Project
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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 General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *############################################################################
 */

package org.greenstone.gatherer.metadata;


/** This class is a static class containing useful metadata functions */
public class MetadataTools
{
    static final public String NAMESPACE_SEPARATOR = ".";


    static public String getDisplayNameForMetadataElementWithName(String metadata_element_name_full)
    {
	MetadataElement metadata_element = getMetadataElementWithName(metadata_element_name_full);
	if (metadata_element != null) {
	    return metadata_element.getDisplayName();
	}

	return metadata_element_name_full;
    }


    static public String getMetadataElementAttribute(MetadataElement metadata_element, String attribute_name, String language_code, String fallback_language_code)
    {
	String metadata_element_attribute = metadata_element.getAttribute(attribute_name, language_code);

	// If the attribute isn't defined in the desired language, resort to the fallback
	if (metadata_element_attribute == null && !language_code.equals(fallback_language_code)) {
	    metadata_element_attribute = metadata_element.getAttribute(attribute_name, fallback_language_code);
	}

	return metadata_element_attribute;
    }


    static public String getMetadataElementName(String metadata_element_name_full)
    {
	// Full element name contains namespace
	if (metadata_element_name_full.indexOf(NAMESPACE_SEPARATOR) != -1) {
	    return metadata_element_name_full.substring(metadata_element_name_full.indexOf(NAMESPACE_SEPARATOR) + 1);
	}

	// No namespace
	return metadata_element_name_full;      
    }


    static public MetadataElement getMetadataElementWithDisplayName(String metadata_element_display_name_full)
    {
	String metadata_set_namespace = getMetadataSetNamespace(metadata_element_display_name_full);
	MetadataSet metadata_set = MetadataSetManager.getMetadataSet(metadata_set_namespace);
	if (metadata_set == null) {
	    return null;
	}

	return metadata_set.getMetadataElementWithDisplayName(metadata_element_display_name_full);
    }


    static public MetadataElement getMetadataElementWithName(String metadata_element_name_full)
    {
	String metadata_set_namespace = getMetadataSetNamespace(metadata_element_name_full);
	MetadataSet metadata_set = MetadataSetManager.getMetadataSet(metadata_set_namespace);
	if (metadata_set == null) {
	    return null;
	}

	String metadata_element_name = getMetadataElementName(metadata_element_name_full);
	return metadata_set.getMetadataElementWithName(metadata_element_name);
    }


    static public String getMetadataSetAttribute(MetadataSet metadata_set, String attribute_name, String language_code, String fallback_language_code)
    {
	String metadata_set_attribute = metadata_set.getAttribute(attribute_name, language_code);

	// If the attribute isn't defined in the desired language, resort to the fallback
	if (metadata_set_attribute == null && !language_code.equals(fallback_language_code)) {
	    metadata_set_attribute = metadata_set.getAttribute(attribute_name, fallback_language_code);
	}

	return metadata_set_attribute;
    }


    static public String getMetadataSetNamespace(String metadata_element_name_full)
    {
	// Full element name contains namespace
	if (metadata_element_name_full.indexOf(NAMESPACE_SEPARATOR) != -1) {
	    return metadata_element_name_full.substring(0, metadata_element_name_full.indexOf(NAMESPACE_SEPARATOR));
	}

	// No namespace
	return "";
    }
}