/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2017, Open Source Geospatial Foundation (OSGeo)
 *
 *    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;
 *    version 2.1 of the License.
 *
 *    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.
 */
package org.geotools.data.complex.spi;

import org.geotools.data.complex.FeatureTypeMapping;
import org.geotools.data.complex.NestedAttributeMapping;
import org.geotools.data.complex.config.AppSchemaDataAccessConfigurator;
import org.geotools.data.complex.filter.XPathUtil;
import org.opengis.feature.type.Name;
import org.opengis.filter.expression.Expression;
import org.xml.sax.helpers.NamespaceSupport;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.ServiceLoader;

/**
 * Helper class used to find implementations for extensions points.
 */
public final class CustomImplementationsFinder {

    private static List<CustomMappingFactory> mappingsFactories = new ArrayList<>();
    private static List<CustomAttributeExpressionFactory> attributesFactories = new ArrayList<>();

    static {
        mappingsFactories = initFactories(CustomMappingFactory.class);
        attributesFactories = initFactories(CustomAttributeExpressionFactory.class);
    }

    private CustomImplementationsFinder() {
    }

    private static <T> List<T> initFactories(Class<T> type) {
        ServiceLoader<T> loader = ServiceLoader.load(type);
        loader.reload();
        List<T> factories = new ArrayList<>();
        for (T aLoader : loader) {
            factories.add(aLoader);
        }
        return factories;
    }

    public static NestedAttributeMapping find(AppSchemaDataAccessConfigurator configuration,
                                              Expression idExpression, Expression parentExpression,
                                              XPathUtil.StepList targetXPath, boolean isMultiValued,
                                              Map<Name, Expression> clientProperties, Expression sourceElement,
                                              XPathUtil.StepList sourcePath, NamespaceSupport namespaces) {
        for (CustomMappingFactory factory : mappingsFactories) {
            NestedAttributeMapping mapping = factory.createNestedAttributeMapping(configuration, idExpression,
                    parentExpression, targetXPath, isMultiValued, clientProperties,
                    sourceElement, sourcePath, namespaces);
            if (mapping != null) {
                return mapping;
            }
        }
        return null;
    }

    public static Expression find(FeatureTypeMapping mappings, XPathUtil.StepList xpath,
                                  NestedAttributeMapping nestedMapping) {
        for (CustomAttributeExpressionFactory factory : attributesFactories) {
            Expression attributeExpression = factory.createNestedAttributeExpression(mappings, xpath, nestedMapping);
            if (attributeExpression != null) {
                return attributeExpression;
            }
        }
        return null;
    }
}