/**
 * ============LICENSE_START=======================================================
 * org.onap.aai
 * ================================================================================
 * Copyright © 2017-2018 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.onap.aai.introspection;

import com.att.eelf.configuration.EELFLogger;
import com.att.eelf.configuration.EELFManager;
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.onap.aai.util.AAIConstants;

import javax.xml.bind.JAXBException;
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;

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+)\\/");
	private static final EELFLogger LOGGER = EELFManager.getInstance().getLogger(ModelInjestor.class);

	
	/**
	 * 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);

		File oxmFile = new File(AAIConstants.AAI_HOME_ETC + fileName);

		// Check if the file exists on the path and if it doesn't exist then
		// Using classloader makes it easy to have a different oxm file
		// for unit testing the oxm files otherwise, you will be
		// stuck with using the main oxm for even the testing

		InputStream iStream;
		if(oxmFile.exists()){
			LOGGER.info("Oxm file exists on the system {}", oxmFile);
		    iStream = new FileInputStream(oxmFile);
		} else {
			LOGGER.warn("Unable to find oxm file {} on the system so using classloader", oxmFile);
			iStream = getClass().getClassLoader().getResourceAsStream(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 = "v12";
		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) {
		// Changed the /oxm/aai_oxm_*.xml to oxm/aai_oxm_*.xml
		// Modified to load from input stream using getClass().getClassLoader()
		// As this will be able to relatively get the oxm if the oxm file is there
		// So if there is a src/main/resources/oxm/ and src/test/resources/oxm, the
		// test oxm will end up being used for tests and src oxm for source files
		// Don't change this unless you understand the details specified
		return 	"oxm/aai_oxm_" + v.toString() + ".xml";
	}
	
}