/*
 * Copyright 2012-2017 the original author or authors.
 *
 * 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 org.springframework.boot.autoconfigure.ldap.embedded;

import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;

import javax.annotation.PreDestroy;

import com.unboundid.ldap.listener.InMemoryDirectoryServer;
import com.unboundid.ldap.listener.InMemoryDirectoryServerConfig;
import com.unboundid.ldap.listener.InMemoryListenerConfig;
import com.unboundid.ldap.sdk.LDAPException;
import com.unboundid.ldap.sdk.schema.Schema;
import com.unboundid.ldif.LDIFReader;

import org.springframework.boot.autoconfigure.AutoConfigureBefore;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.autoconfigure.ldap.LdapAutoConfiguration;
import org.springframework.boot.autoconfigure.ldap.LdapProperties;
import org.springframework.boot.autoconfigure.ldap.embedded.EmbeddedLdapProperties.Credential;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.DependsOn;
import org.springframework.core.env.Environment;
import org.springframework.core.env.MapPropertySource;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource;
import org.springframework.core.io.Resource;
import org.springframework.ldap.core.ContextSource;
import org.springframework.ldap.core.support.LdapContextSource;
import org.springframework.util.StringUtils;

/**
 * {@link EnableAutoConfiguration Auto-configuration} for Embedded LDAP.
 *
 * @author Eddú Meléndez
 * @author Mathieu Ouellet
 * @since 1.5.0
 */
@Configuration
@EnableConfigurationProperties({ LdapProperties.class, EmbeddedLdapProperties.class })
@AutoConfigureBefore(LdapAutoConfiguration.class)
@ConditionalOnClass(InMemoryDirectoryServer.class)
@ConditionalOnProperty(prefix = "spring.ldap.embedded", name = "base-dn")
public class EmbeddedLdapAutoConfiguration {

	private static final String PROPERTY_SOURCE_NAME = "ldap.ports";

	private final EmbeddedLdapProperties embeddedProperties;

	private final LdapProperties properties;

	private final ConfigurableApplicationContext applicationContext;

	private final Environment environment;

	private InMemoryDirectoryServer server;

	public EmbeddedLdapAutoConfiguration(EmbeddedLdapProperties embeddedProperties,
			LdapProperties properties, ConfigurableApplicationContext applicationContext,
			Environment environment) {
		this.embeddedProperties = embeddedProperties;
		this.properties = properties;
		this.applicationContext = applicationContext;
		this.environment = environment;
	}

	@Bean
	@DependsOn("directoryServer")
	@ConditionalOnMissingBean
	public ContextSource ldapContextSource() {
		LdapContextSource source = new LdapContextSource();
		if (hasCredentials(this.embeddedProperties.getCredential())) {
			source.setUserDn(this.embeddedProperties.getCredential().getUsername());
			source.setPassword(this.embeddedProperties.getCredential().getPassword());
		}
		source.setUrls(this.properties.determineUrls(this.environment));
		return source;
	}

	@Bean
	public InMemoryDirectoryServer directoryServer() throws LDAPException {
		InMemoryDirectoryServerConfig config = new InMemoryDirectoryServerConfig(
				this.embeddedProperties.getBaseDn());
		if (hasCredentials(this.embeddedProperties.getCredential())) {
			config.addAdditionalBindCredentials(
					this.embeddedProperties.getCredential().getUsername(),
					this.embeddedProperties.getCredential().getPassword());
		}
		setSchema(config);
		InMemoryListenerConfig listenerConfig = InMemoryListenerConfig
				.createLDAPConfig("LDAP", this.embeddedProperties.getPort());
		config.setListenerConfigs(listenerConfig);
		this.server = new InMemoryDirectoryServer(config);
		importLdif();
		this.server.startListening();
		setPortProperty(this.applicationContext, this.server.getListenPort());
		return this.server;
	}

	private void setSchema(InMemoryDirectoryServerConfig config) {
		if (!this.embeddedProperties.getValidation().isEnabled()) {
			config.setSchema(null);
			return;
		}
		Resource schema = this.embeddedProperties.getValidation().getSchema();
		if (schema != null) {
			setSchema(config, schema);
		}
	}

	private void setSchema(InMemoryDirectoryServerConfig config, Resource resource) {
		try {
			Schema defaultSchema = Schema.getDefaultStandardSchema();
			Schema schema = Schema.getSchema(resource.getInputStream());
			config.setSchema(Schema.mergeSchemas(defaultSchema, schema));
		}
		catch (Exception ex) {
			throw new IllegalStateException(
					"Unable to load schema " + resource.getDescription(), ex);
		}
	}

	private boolean hasCredentials(Credential credential) {
		return StringUtils.hasText(credential.getUsername())
				&& StringUtils.hasText(credential.getPassword());
	}

	private void importLdif() throws LDAPException {
		String location = this.embeddedProperties.getLdif();
		if (StringUtils.hasText(location)) {
			try {
				Resource resource = this.applicationContext.getResource(location);
				if (resource.exists()) {
					InputStream inputStream = resource.getInputStream();
					try {
						this.server.importFromLDIF(true, new LDIFReader(inputStream));
					}
					finally {
						inputStream.close();
					}
				}
			}
			catch (Exception ex) {
				throw new IllegalStateException("Unable to load LDIF " + location, ex);
			}
		}
	}

	private void setPortProperty(ApplicationContext context, int port) {
		if (context instanceof ConfigurableApplicationContext) {
			MutablePropertySources sources = ((ConfigurableApplicationContext) context)
					.getEnvironment().getPropertySources();
			getLdapPorts(sources).put("local.ldap.port", port);
		}
		if (context.getParent() != null) {
			setPortProperty(context.getParent(), port);
		}
	}

	@SuppressWarnings("unchecked")
	private Map<String, Object> getLdapPorts(MutablePropertySources sources) {
		PropertySource<?> propertySource = sources.get(PROPERTY_SOURCE_NAME);
		if (propertySource == null) {
			propertySource = new MapPropertySource(PROPERTY_SOURCE_NAME,
					new HashMap<String, Object>());
			sources.addFirst(propertySource);
		}
		return (Map<String, Object>) propertySource.getSource();
	}

	@PreDestroy
	public void close() {
		if (this.server != null) {
			this.server.shutDown(true);
		}
	}

}
