/*-
 * ============LICENSE_START=======================================================
 * ONAP : CCSDK
 * ================================================================================
 * Copyright (C) 2017 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.ccsdk.sli.core.slipluginutils;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Strings;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Optional;
import java.util.Properties;
import java.util.Vector;

import org.onap.ccsdk.sli.core.utils.JREFileResolver;
import org.onap.ccsdk.sli.core.utils.KarafRootFileResolver;
import org.onap.ccsdk.sli.core.utils.PropertiesFileResolver;
import org.onap.ccsdk.sli.core.utils.common.CoreDefaultFileResolver;
import org.onap.ccsdk.sli.core.utils.common.SdncConfigEnvVarFileResolver;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Immutable properties container for dme2 properties. Since the initial design
 * decision was made to utilize <code>Properties</code> instead of an OSGi
 * <code>ManagedService</code>, it was decided to make these properties
 * immutable.
 */
public final class Dme2PropertiesProvider {

	private static final Logger LOG = LoggerFactory.getLogger(Dme2PropertiesProvider.class);

	/**
	 * The name of the environment variable to specify the configuration directory.
	 */
	private static final String SDNC_ROOT_DIR_ENV_VAR_KEY = "SDNC_CONFIG_DIR";

	/**
	 * the dme2 properties file name.
	 */
	private static final String DME2_PROPERTIES_FILE_NAME = "dme2.properties";

	/**
	 * the key for <code>proxyUrl</code>, which represents a CSV list of urls
	 */
	static final String PROXY_URL_KEY = "proxyUrl";

	/**
	 * indicates that proxy urls are separated by commas
	 */
	private static final String PROXY_URLS_VALUE_SEPARATOR = ",";

	/**
	 * the key for <code>aafUserName</code>
	 */
	static final String AAF_USERNAME_KEY = "aafUserName";

	/**
	 * the key for <code>aafPassword</code>
	 */
	static final String AAF_PASSWORD_KEY = "aafPassword";

	/**
	 * the key for <code>envContext</code>
	 */
	static final String ENV_CONTEXT_KEY = "envContext";

	/**
	 * the key for <code>routeOffer</code>
	 */
	static final String ROUTE_OFFER_KEY = "routeOffer";

	/**
	 * the key for <code>commonServiceVersion</code>
	 */
	static final String COMMON_SERVICE_VERSION_KEY = "commonServiceVersion";

	/**
	 * the key for <code>partner</code>
	 */
	static final String PARTNER_KEY = "partner";

	private Optional<String[]> proxyUrls = Optional.empty();

	private Optional<String> aafUsername = Optional.empty();

	private Optional<String> aafPassword = Optional.empty();

	private Optional<String> envContext = Optional.empty();

	private Optional<String> routeOffer = Optional.empty();

	private Optional<String> commonServiceVersion = Optional.empty();

	private Optional<String> partner = Optional.empty();

	/**
	 * A prioritized list of strategies for resolving dme2 properties files.
	 */
	private Vector<PropertiesFileResolver> dme2PropertiesFileResolvers = new Vector<>();

	/**
	 * Instantiates the properties provider, which involves loading the appropriate
	 * properties for dme2.
	 */
	public Dme2PropertiesProvider() {
		this(DME2_PROPERTIES_FILE_NAME);
	}

	/**
	 * Instantiates the properties provider, which involves loading the appropriate
	 * properties for dme2.
	 *
	 * @param dme2Path
	 *            location of the dme2.properties file
	 */
	@VisibleForTesting
	Dme2PropertiesProvider(final String dme2FileName) {
		dme2PropertiesFileResolvers
				.add(new SdncConfigEnvVarFileResolver("Using property file (1) from environment variable"));
		dme2PropertiesFileResolvers.add(new CoreDefaultFileResolver("Using property file (2) from default directory"));

		dme2PropertiesFileResolvers
				.add(new JREFileResolver("Using property file (3) from JRE argument", Dme2PropertiesProvider.class));
		dme2PropertiesFileResolvers.add(new KarafRootFileResolver("Using property file (4) from karaf root", this));

		File dme2File = getDme2File(dme2FileName);

		init(dme2File);
	}

	private void init(final File dme2Path) {
		final Properties properties;
		try {
			properties = getProperties(dme2Path);
			this.proxyUrls = getProxyUrls(properties);
			this.aafUsername = getAafUsername(properties);
			this.aafPassword = getAafPassword(properties);
			this.envContext = getEnvContext(properties);
			this.routeOffer = getRouteOffer(properties);
			this.commonServiceVersion = getCommonServiceVersion(properties);
			this.partner = getPartner(properties);
		} catch (final FileNotFoundException e) {

			LOG.error("dme2.properties file could not be found at path: {}", dme2Path, e);
		} catch (final IOException e) {
			LOG.error("fatal error reading dme2.properties at path: {}", dme2Path, e);
		}
	}

	/**
	 * Reports the method chosen for properties resolution to the
	 * <code>Logger</code>.
	 *
	 * @param message
	 *            Some user friendly message
	 * @param fileOptional
	 *            The file location of the chosen properties file
	 * @return the file location of the chosen properties file
	 */
	private static File reportSuccess(final String message, final Optional<File> fileOptional) {
		if (fileOptional.isPresent()) {
			final File file = fileOptional.get();
			LOG.info("{} {}", message, file.getPath());
			return file;
		}
		return null;
	}

	private File getDme2File(final String dme2Filename) {

		for (final PropertiesFileResolver dblibPropertiesFileResolver : dme2PropertiesFileResolvers) {
			final Optional<File> fileOptional = dblibPropertiesFileResolver.resolveFile(dme2Filename);
			if (fileOptional.isPresent()) {
				return reportSuccess(dblibPropertiesFileResolver.getSuccessfulResolutionMessage(), fileOptional);
			}
		}
		return (new File(dme2Filename));
	}

	private static Properties getProperties(final File dme2File) throws IOException {

		final Properties properties = new Properties();
		properties.load(new FileReader(dme2File));
		return properties;
	}

	private String getProxyUrl(final Properties properties) {
		return properties.getProperty(PROXY_URL_KEY);
	}

	private Optional<String[]> getProxyUrls(final Properties properties) {
		final String proxyUrlsValue = getProxyUrl(properties);
		if (!Strings.isNullOrEmpty(proxyUrlsValue)) {
			return Optional.ofNullable(proxyUrlsValue.split(PROXY_URLS_VALUE_SEPARATOR));
		}
		return Optional.empty();
	}

	public Optional<String[]> getProxyUrls() {
		return this.proxyUrls;
	}

	private Optional<String> getAafUsername(final Properties properties) {
		final String aafUsernameValue = properties.getProperty(AAF_USERNAME_KEY);
		return Optional.ofNullable(aafUsernameValue);
	}

	Optional<String> getAafUsername() {
		return this.aafUsername;
	}

	private Optional<String> getAafPassword(final Properties properties) {
		final String aafPassword = properties.getProperty(AAF_PASSWORD_KEY);
		return Optional.ofNullable(aafPassword);
	}

	Optional<String> getAafPassword() {
		return this.aafPassword;
	}

	private Optional<String> getEnvContext(final Properties properties) {
		final String envContext = properties.getProperty(ENV_CONTEXT_KEY);
		return Optional.ofNullable(envContext);
	}

	Optional<String> getEnvContext() {
		return this.envContext;
	}

	private Optional<String> getRouteOffer(final Properties properties) {
		final String routeOffer = properties.getProperty(ROUTE_OFFER_KEY);
		return Optional.ofNullable(routeOffer);
	}

	Optional<String> getRouteOffer() {
		return this.routeOffer;
	}

	private Optional<String> getCommonServiceVersion(final Properties properties) {
		final String commonServiceVersion = properties.getProperty(COMMON_SERVICE_VERSION_KEY);
		return Optional.ofNullable(commonServiceVersion);
	}

	Optional<String> getCommonServiceVersion() {
		return this.commonServiceVersion;
	}

	private Optional<String> getPartner(final Properties properties) {
		final String partner = properties.getProperty(PARTNER_KEY);
		return Optional.ofNullable(partner);
	}

	Optional<String> getPartner() {
		return this.partner;
	}
}