/*******************************************************************************
 * Copyright 2017 Graz University of Technology
 * EAAF-Core Components has been developed in a cooperation between EGIZ,  
 * A-SIT Plus, A-SIT, and Graz University of Technology.
 *
 * Licensed under the EUPL, Version 1.2 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * https://joinup.ec.europa.eu/news/understanding-eupl-v12
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *  
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 *******************************************************************************/
/*******************************************************************************
 *******************************************************************************/
/*******************************************************************************
 *******************************************************************************/
package at.gv.egiz.eaaf.core.impl.idp.conf;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.Map;
import java.util.Properties;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import at.gv.egiz.eaaf.core.api.idp.IExtendedConfiguration;
import at.gv.egiz.eaaf.core.exceptions.EAAFConfigurationException;
import at.gv.egiz.eaaf.core.impl.utils.KeyValueUtils;

public abstract class AbstractConfigurationImpl implements IExtendedConfiguration {
	private static final Logger log = LoggerFactory.getLogger(AbstractConfigurationImpl.class);
	
	private static final String URI_SCHEME_CLASSPATH = "classpath";
	private static final String URI_SCHEME_FILESYSTEM = "file";
	
	private final URI internalConfigPath;
	private final URI configRootDirectory;
	private final Properties properties;
			
	public AbstractConfigurationImpl(final String configPath) throws EAAFConfigurationException {
		InputStream is = null;
		try {
			log.debug("Starting EAAFCore initialization process .... ");
			
			if (StringUtils.isEmpty(configPath)) {
				log.debug("Primary configuration is empty. Search for backup configuration .... ");
				final String backupConfigPath = getBackupConfigPath();
				if (StringUtils.isEmpty(backupConfigPath)) {
					log.error("No configuration file found.");					
					throw new EAAFConfigurationException("config.01", null);
					
				}
				
				internalConfigPath = new URI(getBackupConfigPath());
							
			} else
				internalConfigPath = new URI(configPath);
									
			log.info("Load EAAFCore configuration from " + internalConfigPath);
			
			
			//extract configuration root directory
			//TODO: check if it works with classpath
			final File propertiesFile = new File(internalConfigPath);			
			if (!propertiesFile.exists()) {
				log.error("Configuration file: " + internalConfigPath + " is NOT found on filesystem");
				throw new EAAFConfigurationException("config.18", null);
				
			}
			
			final String configDir = propertiesFile.getParent();
			configRootDirectory = new File(configDir).toURI();			
			log.debug("Set EAAFCore configuration root directory to " + configRootDirectory.toString());
			
			
			//get input stream from configuration path 			
			if (internalConfigPath.getScheme().equals(URI_SCHEME_FILESYSTEM)) {
				log.trace("Load config from filesystem");
				is = new FileInputStream(propertiesFile);
				
			} else if (internalConfigPath.getScheme().equals(URI_SCHEME_CLASSPATH)) {
				log.trace("Load config from classpath");
				is = this.getClass().getResourceAsStream(internalConfigPath.toString());
				
			} else {
				log.error("Can not load EAAFCore configuration. Unsupported prefix! (Only 'file:' and 'classpath:')  ");
				throw new EAAFConfigurationException("config.24", new Object[] {internalConfigPath, "'file:'"});
				
			}
			
			if (is == null) {
				log.error("Can NOT load EAAFCore configuration from file " +  internalConfigPath.toString());
				throw new EAAFConfigurationException("config.03", 
						new Object[] {internalConfigPath.toString()});
				
			}
			
			
			//load EAAF core configuration into properties object
			properties = new Properties();
			properties.load(is);
			
			log.info("EAAFCore configuration loaded");
						
		} catch (URISyntaxException | IOException e) {
			log.error("Can not parse configuration path " + configPath + " or " + getBackupConfigPath());
			throw new EAAFConfigurationException("config.03", new Object[]{configPath + " or " + getBackupConfigPath()}, e);
			
		} finally {
			if (is != null) {
				try {
					is.close();
					
				} catch (final IOException e) {
					log.warn("Can not close inputstream from configuration loader!");
					
				}
			}
		}
		
	}
	
	@Override
	public String getBasicConfiguration(String key) {
		if (StringUtils.isNotEmpty(key)) {
			final String value = properties.getProperty(addPrefixToKey(key));
			if (value != null)
				return value.trim();
		}
		
		return null;
	}

	@Override
	public String getBasicConfiguration(String key, String defaultValue) {
		if (StringUtils.isNotEmpty(key)) {
			final String value = properties.getProperty(addPrefixToKey(key), defaultValue);
			if (value != null)
				return value.trim();
		}
		
		return defaultValue;
	}

	
	@Override
	public Boolean getBasicConfigurationBoolean(String key) {
		final String value = getBasicConfiguration(key);
		if (value != null)
			return Boolean.parseBoolean(value);
		else
			return null;
		
	}


	@Override
	public boolean getBasicConfigurationBoolean(String key, boolean defaultValue) {
		final Boolean result = getBasicConfigurationBoolean(key);
		if (result != null)
			return result;
		else
			return defaultValue;
		
	}
	
	@Override
	public Map<String, String> getBasicConfigurationWithPrefix(String prefix) {
		return KeyValueUtils.getSubSetWithPrefix(KeyValueUtils.convertPropertiesToMap(properties), addPrefixToKey(prefix));
		
	}
	
	@Override
	public Properties getFullConfigurationProperties() {
		return properties;
		
	}

	@Override
	public URI getConfigurationRootDirectory() {
		return configRootDirectory;
		
	}
	
	@Override
	public URI getConfigurationFilePath() {
		return internalConfigPath;
		
	}
	
	/**
	 * Get the path to backup configuration
	 * 
	 * @return A filepath file: or a classpath classpath:
	 */
	abstract protected String getBackupConfigPath();
	
	/**
	 * Get a specific configuration-key prefix for this software implementation
	 * 
	 * @return
	 */
	abstract public String getApplicationSpecificKeyPrefix();

	
	private String addPrefixToKey(String key) {
		if (StringUtils.isNotEmpty(getApplicationSpecificKeyPrefix())) {
			if (getApplicationSpecificKeyPrefix().endsWith(KeyValueUtils.KEY_DELIMITER))
				return getApplicationSpecificKeyPrefix() + key;
			else
				return getApplicationSpecificKeyPrefix() + KeyValueUtils.KEY_DELIMITER + key;
			
		}
		
		return key;
		
	}
}