/*
 * Copyright 2011-2013 the original author or authors.
 * 
 * Licensed 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.springframework.data.hadoop.config.namespace;

import java.util.Collection;
import java.util.Collections;

import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.beans.factory.support.ManagedList;
import org.springframework.beans.factory.xml.ParserContext;
import org.springframework.core.io.ByteArrayResource;
import org.springframework.core.io.Resource;
import org.springframework.data.hadoop.hive.HiveRunner;
import org.springframework.data.hadoop.hive.HiveScript;
import org.springframework.util.CollectionUtils;
import org.springframework.util.StringUtils;
import org.springframework.util.xml.DomUtils;
import org.w3c.dom.Element;

/**
 * @author Costin Leau
 */
public class HiveRunnerParser extends AbstractImprovedSimpleBeanDefinitionParser {

	@Override
	protected Class<?> getBeanClass(Element element) {
		return HiveRunner.class;
	}

	@Override
	protected boolean isEligibleAttribute(String attributeName) {
		return !("pre-action".equals(attributeName) || "post-action".equals(attributeName))
				&& super.isEligibleAttribute(attributeName);
	}

	@Override
	protected void doParse(Element element, ParserContext parserContext, BeanDefinitionBuilder builder) {
		// parse attributes using conventions
		super.doParse(element, parserContext, builder);

		NamespaceUtils.setCSVReferenceProperty(element, builder, "pre-action", "preAction");
		NamespaceUtils.setCSVReferenceProperty(element, builder, "post-action", "postAction");

		// parse scripts
		Collection<Object> scripts = parseScripts(parserContext, element);
		if (!CollectionUtils.isEmpty(scripts)) {
			builder.addPropertyValue("scripts", scripts);
		}
	}

    public static Collection<Object> parseScripts(ParserContext context, Element element) {
        Collection<Element> children = DomUtils.getChildElementsByTagName(element, "script");

        if (!children.isEmpty()) {
            Collection<Object> defs = new ManagedList<Object>(children.size());

            for (Element child : children) {
                // parse source
                String location = child.getAttribute("location");
                String inline = DomUtils.getTextValue(child);
                boolean hasScriptInlined = StringUtils.hasText(inline);

                GenericBeanDefinition def = new GenericBeanDefinition();
                def.setSource(child);
                def.setBeanClass(HiveScript.class);

                Object resource = null;

                if (StringUtils.hasText(location)) {
                    if (hasScriptInlined) {
                        context.getReaderContext().error("cannot specify both 'location' and a nested script; use only one", element);
                    }
                    resource = location;
                }
                else {
                    if (!hasScriptInlined) {
                        context.getReaderContext().error("no 'location' or nested script specified", element);
                    }

                    resource = BeanDefinitionBuilder.genericBeanDefinition(ByteArrayResource.class).
                            addConstructorArgValue(inline).
                            addConstructorArgValue("resource for inlined script").getBeanDefinition();
                }

                def.getConstructorArgumentValues().addIndexedArgumentValue(0, resource, Resource.class.getName());
                String args = DomUtils.getChildElementValueByTagName(child, "arguments");

                if (args != null) {
                    BeanDefinition params = BeanDefinitionBuilder.genericBeanDefinition(LinkedProperties.class).addConstructorArgValue(args).getBeanDefinition();
                    def.getConstructorArgumentValues().addIndexedArgumentValue(1, params);
                }
                defs.add(def);

            }

            return defs;
        }

        return Collections.emptyList();
    }

    @Override
	protected boolean shouldGenerateIdAsFallback() {
		return true;
	}
}