/*-
 * ============LICENSE_START=======================================================
 * org.openecomp.aai
 * ================================================================================
 * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * 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.
 * ============LICENSE_END=========================================================
 */

package org.openecomp.aai.introspection;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.xml.bind.JAXBException;

import org.eclipse.persistence.dynamic.DynamicType;
import org.eclipse.persistence.jaxb.JAXBContextProperties;
import org.eclipse.persistence.jaxb.dynamic.DynamicJAXBContext;
import org.eclipse.persistence.jaxb.dynamic.DynamicJAXBContextFactory;

import org.openecomp.aai.util.AAIConstants;


public class ModelInjestor {
	
	private Map<Version, DynamicJAXBContext> versionContextMap = new HashMap<>();
	private static final Pattern classNamePattern = Pattern.compile("\\.(v\\d+)\\.");
	private static final Pattern uriPattern = 	Pattern.compile("(v\\d+)\\/");

	
	/**
	 * Instantiates a new model injestor.
	 */
	private ModelInjestor() {
		try {
			injestModels();
		} catch (FileNotFoundException | JAXBException e) {
			throw new RuntimeException(e);
		}
	}
	
	private static class Helper {
		private static final ModelInjestor INSTANCE = new ModelInjestor();
	}
	
	/**
	 * Gets the single instance of ModelInjestor.
	 *
	 * @return single instance of ModelInjestor
	 */
	public synchronized static ModelInjestor getInstance() {
		return Helper.INSTANCE;
	}
	
	/**
	 * Injest models.
	 *
	 * @throws FileNotFoundException the file not found exception
	 * @throws JAXBException the JAXB exception
	 */
	private void injestModels() throws FileNotFoundException, JAXBException {
		
		for (Version version : Version.values()) {
			this.injestModel(version);
		}
	}
	
	/**
	 * Injest model.
	 *
	 * @param version the version
	 * @throws JAXBException the JAXB exception
	 * @throws FileNotFoundException the file not found exception
	 */
	private void injestModel (Version version) throws JAXBException, FileNotFoundException {
		String fileName = this.getOXMFileName(version);
		InputStream iStream = new FileInputStream(new File(fileName));
		Map<String, Object> properties = new HashMap<String, Object>(); 
		properties.put(JAXBContextProperties.OXM_METADATA_SOURCE, iStream);
		final DynamicJAXBContext jaxbContext = DynamicJAXBContextFactory.createContextFromOXM(this.getClass().getClassLoader(), properties);
		versionContextMap.put(version, jaxbContext);
	}
	
	/**
	 * Gets the version from class name.
	 *
	 * @param classname the classname
	 * @return the version from class name
	 */
	public Version getVersionFromClassName (String classname) {
		Matcher m = classNamePattern.matcher(classname);
		String version = "v2"; //for the OXM, only the v2 ones don't include a model name, hence this default
		if (m.find()) {
			version = m.group(1);
		}
		
		return Version.valueOf(version);
	}
	
	/**
	 * Gets the context for URI.
	 *
	 * @param uri the uri
	 * @return the context for URI
	 */
	public DynamicJAXBContext getContextForURI(String uri) {
		DynamicJAXBContext result = null;
		Matcher m = uriPattern.matcher(uri);
		Version version = null;
		if (m.find()) {
			version = Version.valueOf(m.group(1));
			result = versionContextMap.get(version);
		}
		
		return result;
	}
	
	/**
	 * Gets the context for version.
	 *
	 * @param version the version
	 * @return the context for version
	 */
	public DynamicJAXBContext getContextForVersion(Version version) {
		DynamicJAXBContext result = null;
		
		result = versionContextMap.get(version);
		
		
		return result;
	}
	
	/**
	 * Gets the dynamic type for class name.
	 *
	 * @param classname the classname
	 * @return the dynamic type for class name
	 */
	public DynamicType getDynamicTypeForClassName(String classname) {
		DynamicType result = null;
		DynamicJAXBContext context = null;

		Version version = this.getVersionFromClassName(classname);

		context = versionContextMap.get(version);
		
		if (context != null) {
			result = context.getDynamicType(classname);
		}
		
		return result;
	}
	
	public String getOXMFileName(Version v) {
		return 	AAIConstants.AAI_HOME_ETC_OXM + "aai_oxm_" + v.toString() + ".xml";
	}
	
}