/*******************************************************************************
 * 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.net.URI;
import java.net.URISyntaxException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import javax.annotation.PostConstruct;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.env.CompositePropertySource;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.EnumerablePropertySource;
import org.springframework.core.env.Environment;
import org.springframework.core.env.PropertySource;

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

public abstract class AbstractSpringBootConfigurationImpl implements IConfiguration {
	private static final Logger log = LoggerFactory.getLogger(AbstractSpringBootConfigurationImpl.class);	

	@Autowired private Environment env;

	public static final String PROP_CONFIG_ROOT_DIR = "core.configRootDir";
	
	@PostConstruct
	private void initialize() throws EAAFConfigurationException {
		if (getConfigurationRootDirectory() == null) {
			throw new EAAFConfigurationException("config.08", new Object[] {addPrefixToKey(PROP_CONFIG_ROOT_DIR)});
			
		}
		
	}
	
	@Override
	public String getBasicConfiguration(String key) {
		if (StringUtils.isNotEmpty(key)) {
			final String value = env.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 = env.getProperty(addPrefixToKey(key), defaultValue);
			if (value != null)
				return value.trim();
		}
		
		return defaultValue;
	}

	@Override
	public Map<String, String> getBasicConfigurationWithPrefix(String prefix) {				
		final Map<String, String> configProps = getPropertiesStartingWith((ConfigurableEnvironment) env, addPrefixToKey(prefix));
		return KeyValueUtils.removePrefixFromKeys(configProps, addPrefixToKey(prefix) + ".");

		
	}

	@Override
	public Boolean getBasicConfigurationBoolean(String key) {
		final String value = getBasicConfiguration(key);
		if (StringUtils.isNotEmpty(value))
			return Boolean.valueOf(value.trim());
		else
			return null;
	}

	@Override
	public boolean getBasicConfigurationBoolean(String key, boolean defaultValue) {
		final Boolean value = getBasicConfigurationBoolean(key);		
		if (value != null)
			return value;
		else
			return defaultValue;
	}
	
	@Override
	public URI getConfigurationRootDirectory() {
		try {
			return new URI(env.getRequiredProperty(addPrefixToKey(PROP_CONFIG_ROOT_DIR)));
			
		} catch (IllegalStateException | URISyntaxException e) {
			log.warn("ConfigRootDirectory is NOT set");
			return null;
			
		}
		
	}
	
	
	/**
	 * 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;
		
	}
	
	private static Map<String, String> getPropertiesStartingWith( ConfigurableEnvironment aEnv, String aKeyPrefix ) {
		final Map<String,String> result = new HashMap<>();
		final Map<String,Object> map = getAllProperties(aEnv);
		
		for (final Entry<String, Object> entry : map.entrySet())	{
			final String key = entry.getKey();

			if ( key.startsWith( aKeyPrefix ) )
			{
				result.put( key, (String) entry.getValue() );
			}
		}

		return result;
	}
	
	private static Map<String,Object> getAllProperties( ConfigurableEnvironment aEnv ) {
	    final Map<String,Object> result = new HashMap<>();
	    aEnv.getPropertySources().forEach( ps -> addAll( result, getAllProperties( ps ) ) );
	    return result;
	    
	}
	
	private static Map<String,Object> getAllProperties( PropertySource<?> aPropSource ) {
	    final Map<String,Object> result = new HashMap<>();

	    if ( aPropSource instanceof CompositePropertySource)
	    {
	        final CompositePropertySource cps = (CompositePropertySource) aPropSource;
	        cps.getPropertySources().forEach( ps -> addAll( result, getAllProperties( ps ) ) );
	        return result;
	    }

	    if ( aPropSource instanceof EnumerablePropertySource<?> )
	    {
	        final EnumerablePropertySource<?> ps = (EnumerablePropertySource<?>) aPropSource;
	        Arrays.asList( ps.getPropertyNames() ).forEach( key -> result.put( key, ps.getProperty( key ) ) );
	        return result;
	    }

	    // note: Most descendants of PropertySource are EnumerablePropertySource. There are some
	    // few others like JndiPropertySource or StubPropertySource
	    log.debug( "Given PropertySource is instanceof " + aPropSource.getClass().getName()
	                 + " and cannot be iterated" );

	    return result;

	}
	
	private static void addAll( Map<String, Object> aBase, Map<String, Object> aToBeAdded )
	{
	    for (final Entry<String, Object> entry : aToBeAdded.entrySet())
	    {
	        if ( aBase.containsKey( entry.getKey() ) )
	        {
	            continue;
	        }

	        aBase.put( entry.getKey(), entry.getValue() );
	    }
	}
}