/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.apache.bval.xml;

import org.apache.bval.MetaBeanManager;
import org.apache.bval.model.MetaBean;
import org.apache.bval.model.MetaProperty;
import org.apache.bval.util.PrivilegedActions;

import java.util.Map;

import static org.apache.bval.model.Features.Property.REF_BEAN_ID;

/**
 * Description: internal implementation class to construct metabeans with
 * factories and from xstream xml files. You can register different
 * XMLMetaBeanLoaders (see addLoader()) to register xstream-xml-files that
 * contain meta-data. You can merge + unify meta data with method
 * enrichCopies(). <br/>
 * User: roman.stumm<br>
 * Date: 17.06.2010<br>
 * Time: 09:47:14<br>
 */
public class XMLMetaBeanManager extends MetaBeanManager implements XMLMetaBeanRegistry, MetaBeanEnricher {
    public XMLMetaBeanManager() {
        this(new XMLMetaBeanBuilder());
    }

    public XMLMetaBeanManager(XMLMetaBeanBuilder builder) {
        super(builder);
    }

    public void addResourceLoader(String resource) {
        addLoader(new XMLMetaBeanURLLoader(PrivilegedActions.getClassLoader(getClass()).getResource(resource)));
    }

    public synchronized void addLoader(XMLMetaBeanLoader loader) {
        ((XMLMetaBeanBuilder) builder).addLoader(loader);
        cache.clear(); // clear because new loaders can affect ALL MetaBeans
                       // already created!
        complete = false;
    }

    /**
     * @param infos
     *            - the patches to apply
     * @return all MetaBeans for classes that have a xml descriptor and
     *         additional the MetaBeans loaded by the given loaders. The given
     *         loaders may also return patches for MetaBeans that have also been
     *         returned by other loaders. The beans with patches for references
     *         to patched beans will be copied.
     */
    public Map<String, MetaBean> enrichCopies(XMLMetaBeanInfos... infos) {
        Map<String, MetaBean> cached = findAll();
        try {
            Map<String, MetaBean> patched = ((XMLMetaBeanBuilder) builder).enrichCopies(cached, infos);
            for (Object entry : patched.values()) {
                MetaBean meta = (MetaBean) entry;
                computeRelationships(meta, patched);
            }
            return patched;
        } catch (RuntimeException e) {
            throw e; // do not wrap runtime exceptions
        } catch (Exception e) {
            throw new IllegalArgumentException("error enriching beanInfos", e);
        }
    }

    /**
     * 
     * @return all MetaBeans for classes that have a xml descriptor: key =
     *         bean.id, value = MetaBean
     */
    public Map<String, MetaBean> findAll() {
        if (!complete) {
            try {
                Map<String, MetaBean> allBuilt = builder.buildAll();
                for (MetaBean meta : allBuilt.values()) {
                    MetaBean cached = cache.findForId(meta.getId());
                    if (cached == null) {
                        cache.cache(meta);
                    }
                }
                Map<String, MetaBean> map = cache.findAll();
                for (Object oentry : map.values()) {
                    MetaBean meta = (MetaBean) oentry;
                    computeRelationships(meta, map);
                }
                complete = true;
                return map;
            } catch (RuntimeException e) {
                throw e; // do not wrap runtime exceptions
            } catch (Exception e) {
                throw new IllegalArgumentException("error creating beanInfos", e);
            }
        } else {
            return cache.findAll();
        }
    }

    protected void computeRelationships(MetaBean beanInfo, Map<String, MetaBean> cached) {
        for (MetaProperty prop : beanInfo.getProperties()) {
            String beanRef = (String) prop.getFeature(REF_BEAN_ID);
            if (beanRef != null) {
                prop.setMetaBean(cached.get(beanRef));
            }
        }
    }

    protected void computeRelatedMetaBean(MetaProperty prop, String beanRef) {
        if (beanRef != null) {
            prop.setMetaBean(findForId(beanRef));
        } else {
            super.computeRelatedMetaBean(prop, beanRef);
        }
    }
}