/*
 * Copyright (c) 2010-2013 Evolveum
 *
 * 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 com.evolveum.midpoint.prism.schema;

import java.io.IOException;
import java.text.MessageFormat;

import org.xml.sax.EntityResolver;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

import com.evolveum.midpoint.util.logging.Trace;
import com.evolveum.midpoint.util.logging.TraceManager;

/**
 * Implements {@link EntityResolver} and {@link ErrorHandler} that reports sax
 * errors to log.
 * 
 * @author Vilo Repan
 * 
 */
public class SchemaHandler implements ErrorHandler, EntityResolver {

	private static final Trace LOGGER = TraceManager.getTrace(SchemaHandler.class);

	private EntityResolver entityResolver;

	public SchemaHandler(EntityResolver entityResolver) {
		super();
		this.entityResolver = entityResolver;
	}

	@Override
	public void warning(SAXParseException e) throws SAXException {
		print("[Warning]", e);
	}

	@Override
	public void error(SAXParseException e) throws SAXException {
		print("[Error]", e);
		throw e;
	}

	@Override
	public void fatalError(SAXParseException e) throws SAXException {
		print("[Fatal]", e);
		throw e;
	}

	private void print(String header, SAXParseException e) {
		StringBuilder builder = new StringBuilder();
		builder.append("Error occured during schema parsing: ");
		builder.append(header);
		builder.append(" ");
		builder.append(MessageFormat.format("on line {0} at {1}, {2}",
				new Object[] { Integer.toString(e.getLineNumber()), e.getSystemId(), e.getPublicId() }));
		builder.append(" ");
		builder.append(e.getMessage());

		LOGGER.error(builder.toString());
		LOGGER.trace(builder.toString(), e);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.xml.sax.EntityResolver#resolveEntity(java.lang.String,
	 * java.lang.String)
	 */
	@Override
	public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException {
		if (entityResolver == null) {
			throw new IllegalStateException("Entity resolver is not set");
		}
		try {
			InputSource source = entityResolver.resolveEntity(publicId, systemId);
			LOGGER.trace("Resolved entity '{}', '{}': '{}' (resolver: {})", new Object[] { publicId, systemId, source, entityResolver});
			return source;
		} catch (SAXException e) {
			LOGGER.error("XML error resolving entity '{}', '{}': '{}'",
					new Object[] { publicId, systemId, e.getMessage(), e });
			throw e;
		} catch (IOException e) {
			LOGGER.error("IO error resolving entity '{}', '{}': '{}'",
					new Object[] { publicId, systemId, e.getMessage(), e });
			throw e;
		}
	}
}