/*******************************************************************************
 * Copyright (c) 2008, 2011 Attensity Europe GmbH and brox IT Solutions GmbH. All rights reserved. This program and the
 * accompanying materials are made available under the terms of the Eclipse Public License v1.0 which accompanies this
 * distribution, and is available at http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Andreas Schank (Attensity Europe GmbH) - initial implementation
 **********************************************************************************************************************/
package org.eclipse.smila.clusterconfig.simple;

import java.io.IOException;
import java.io.InputStream;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Locale;
import java.util.Map.Entry;

import org.apache.commons.io.IOUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.eclipse.smila.clusterconfig.ClusterConfigService;
import org.eclipse.smila.datamodel.Any;
import org.eclipse.smila.datamodel.AnyMap;
import org.eclipse.smila.datamodel.AnySeq;
import org.eclipse.smila.datamodel.DataFactory;
import org.eclipse.smila.datamodel.Value;
import org.eclipse.smila.datamodel.ipc.IpcAnyReader;
import org.eclipse.smila.utils.config.ConfigUtils;
import org.osgi.service.component.ComponentContext;

/**
 * Simple Cluster Configuration Service implementation.
 *
 * @see ClusterConfigService
 */
public class SimpleClusterConfigService implements ClusterConfigService {

  /** bundle id. */
  public static final String BUNDLE_ID = "org.eclipse.smila.clusterconfig.simple";

  // ---- default values ----
  /** default zookeeper garbage collection interval. */
  public static final long DEFAULT_ZK_GC_INTERVAL = 60;

  /** default number of nodes that may fail until zookeeper stops to work. */
  public static final long DEFAULT_FAILSAFETY_LEVEL = 0;

  /** default max scale up is -1 which means: unlimited. */
  public static final long DEFAULT_MAX_SCALE_UP = -1;

  /** default max retries for a task. */
  public static final long DEFAULT_MAX_RETRIES = 10;

  /** default time to live for a task. */
  public static final long DEFAULT_TIME_TO_LIVE = 300;

  /** default resumeJobs. */
  public static final boolean DEFAULT_RESUME_JOBS = false;

  // ---- other constants ----

  /** properties file name. */
  private static final String CONFIG_FILE_NAME = "clusterconfig.json";

  // ---- keys ----
  /** key for cluster nodes. */
  private static final String KEY_CLUSTER_NODES = "clusterNodes";

  /** key for specified local host name. */
  private static final String KEY_LOCAL_HOST_NAME = "localHost";

  /** key for Zookeeper garbage collection interval. */
  private static final String KEY_ZK_GC_INTERVAL = "zkGcInterval";

  /** key for Zookeeper garbage collection interval. */
  private static final String KEY_FAILSAFETY_LEVEL = "failsafetyLevel";

  /** key for maximum scale up. */
  private static final String KEY_MAX_SCALE_UP = "maxScaleUp";

  /** key for workers section. */
  private static final String KEY_WORKERS = "workers";

  /** key for services section. */
  private static final String KEY_SERVICES = "services";

  /** key for httpPort. */
  private static final String KEY_HTTP_PORT = "httpPort";

  /** key for httpSecurePort. */
  private static final String KEY_HTTP_SECURE_PORT = "httpSecurePort";

  /** key for taskmanager section. */
  private static final String KEY_TASKMANAGER = "taskmanager";

  /** key for timeToLive. */
  private static final String KEY_TIME_TO_LIVE = "timeToLive";

  /** key for maxRetries section. */
  private static final String KEY_MAX_RETRIES = "maxRetries";

  /** key for resumeJobs. */
  private static final String KEY_RESUME_JOBS = "resumeJobs";

  /** key for httpAuthUser. */
  private static final String KEY_HTTP_AUTH_USER = "httpAuthUser";

  /** key for httpAuthPasswordHash. */
  private static final String KEY_HTTP_AUTH_PWD_HASH = "httpAuthPasswordHash";

  // ---- other fields ----
  /** private log. */
  private final Log _log = LogFactory.getLog(getClass());

  /** properties from file. */
  private AnyMap _properties = DataFactory.DEFAULT.createAnyMap();

  /** could we read the configuration? */
  private boolean _isConfigured;

  /**
   * Default Constructor for OSGi DS.
   */
  public SimpleClusterConfigService() {
  }

  /**
   * OSGi Declarative Services service activation method.
   *
   * @param context
   *          OSGi service component context.
   */
  protected void activate(final ComponentContext context) {
    try {
      readConfiguration();

      if (_log.isDebugEnabled()) {
        _log.debug("successfully activated");
      }
    } catch (final Throwable e) {
      final String msg = "Error while activating " + BUNDLE_ID;
      if (_log.isErrorEnabled()) {
        _log.error(msg, e);
      }
      throw new RuntimeException(msg, e);
    }
  }

  /**
   * OSGi Declarative Services service deactivation method.
   *
   * @param context
   *          OSGi service component context.
   */
  protected void deactivate(final ComponentContext context) {
    if (_log.isDebugEnabled()) {
      _log.debug("deactivate");
    }
  }

  @Override
  public AnyMap getAllProperties() {
    return _properties;
  }

  /**
   * {@inheritDoc}
   *
   * <p>
   * If no cluster nodes are specified, the returned cluster consists of the local host only (as returned by
   * {@link #getLocalHost()}.
   * </p>
   */
  @Override
  public List<String> getClusterNodes() {
    final AnySeq clusterNodes;
    if (_properties.containsKey(KEY_CLUSTER_NODES)) {
      if (_properties.get(KEY_CLUSTER_NODES).isSeq()) {
        clusterNodes = _properties.getSeq(KEY_CLUSTER_NODES);
      } else {
        clusterNodes = DataFactory.DEFAULT.createAnySeq();
        clusterNodes.add(_properties.getStringValue(KEY_CLUSTER_NODES));
      }
    } else {
      clusterNodes = DataFactory.DEFAULT.createAnySeq();
      clusterNodes.add(getLocalHost());
      _properties.put(KEY_CLUSTER_NODES, clusterNodes);
    }
    // convert all nodes to lower case
    final AnySeq clusterNodesLowerCase = DataFactory.DEFAULT.createAnySeq();
    for (final Any node : clusterNodes) {
      clusterNodesLowerCase.add(((Value) node).asString().toLowerCase(Locale.ENGLISH));
    }
    return clusterNodesLowerCase.asStrings();
  }

  /**
   * {@inheritDoc}
   *
   * <p>
   * If no name is specified in the configuration, the host name determined by the local {@link InetAddress} is
   * returned.
   * </p>
   */
  @Override
  public String getLocalHost() {
    final String localHost;
    if (_properties.containsKey(KEY_LOCAL_HOST_NAME)) {
      localHost = _properties.getStringValue(KEY_LOCAL_HOST_NAME);
    } else {
      String hostName = "localhost";
      try {
        final InetAddress address = InetAddress.getLocalHost();
        hostName = address.getHostName();
      } catch (final UnknownHostException e) {
        _log.warn("Could not retrieve local host name. Using " + hostName);
      }
      localHost = hostName;
      _properties.put(KEY_LOCAL_HOST_NAME, localHost);
    }
    return localHost.toLowerCase(Locale.ENGLISH);
  }

  /**
   * {@inheritDoc}
   *
   * <p>
   * If no value is specified, the default value of 60 is returned.
   * </p>
   */
  @Override
  public long getZkGcInterval() {
    return getLongPropertyOrSetDefault(KEY_ZK_GC_INTERVAL, DEFAULT_ZK_GC_INTERVAL);
  }

  /** {@inheritDoc} */
  @Override
  public long getFailSafetyLevel() {
    return getLongPropertyOrSetDefault(KEY_FAILSAFETY_LEVEL, DEFAULT_FAILSAFETY_LEVEL);
  }

  /** {@inheritDoc} */
  @Override
  public boolean isConfigured() {
    return _isConfigured;
  }

  /**
   * {@inheritDoc}
   *
   * <p>
   * If no limit is configured, -1 is returned.
   * </p>
   */
  @Override
  public long getMaxScaleUp() {
    final AnyMap taskManagerSection;
    if (_properties.containsKey(KEY_TASKMANAGER)) {
      taskManagerSection = _properties.getMap(KEY_TASKMANAGER);
    } else {
      taskManagerSection = DataFactory.DEFAULT.createAnyMap();
      _properties.put(KEY_TASKMANAGER, taskManagerSection);
    }
    return getLongPropertyOrSetDefault(taskManagerSection, KEY_MAX_SCALE_UP, DEFAULT_MAX_SCALE_UP);
  }

  @Override
  public boolean isResumeJobs() {
    final AnyMap taskManagerSection;
    if (_properties.containsKey(KEY_TASKMANAGER)) {
      taskManagerSection = _properties.getMap(KEY_TASKMANAGER);
    } else {
      taskManagerSection = DataFactory.DEFAULT.createAnyMap();
      _properties.put(KEY_TASKMANAGER, taskManagerSection);
    }
    return getBooleanPropertyOrSetDefault(taskManagerSection, KEY_RESUME_JOBS, DEFAULT_RESUME_JOBS);
  }

  /** {@inheritDoc} */
  @Override
  public long getWorkerScaleUp(final String worker) {
    final AnyMap workersSection;
    if (_properties.containsKey(KEY_WORKERS)) {
      workersSection = _properties.getMap(KEY_WORKERS);
    } else {
      workersSection = DataFactory.DEFAULT.createAnyMap();
      _properties.put(KEY_WORKERS, workersSection);
    }
    final AnyMap workerProperties;
    if (workersSection.containsKey(worker)) {
      workerProperties = workersSection.getMap(worker);
    } else {
      workerProperties = DataFactory.DEFAULT.createAnyMap();
      workersSection.put(worker, workerProperties);
    }
    return getLongPropertyOrSetDefault(workerProperties, KEY_MAX_SCALE_UP, DEFAULT_MAX_SCALE_UP);
  }

  /** {@inheritDoc} */
  @Override
  public Collection<String> getWorkersWithScaleUp() {
    final Collection<String> workers = new ArrayList<String>();
    if (_properties.containsKey(KEY_WORKERS)) {
      for (final Entry<String, Any> entry : _properties.getMap(KEY_WORKERS).entrySet()) {
        final AnyMap workerMap = (AnyMap) entry.getValue();
        if (getLongPropertyOrSetDefault(workerMap, KEY_MAX_SCALE_UP, DEFAULT_MAX_SCALE_UP) >= 0) {
          workers.add(entry.getKey());
        }
      }
    }
    return workers;
  }

  /** {@inheritDoc} */
  @Override
  public int getHttpPort(final String serviceName) {
    return getIntegerServiceProperty(serviceName, KEY_HTTP_PORT);
  }

  @Override
  public int getSecureHttpPort(final String serviceName) {
    return getIntegerServiceProperty(serviceName, KEY_HTTP_SECURE_PORT);
  }

  @Override
  public String getHttpAuthUser() {
    return _properties.getStringValue(KEY_HTTP_AUTH_USER);
  };

  @Override
  public String getHttpAuthPasswordHash() {
    return _properties.getStringValue(KEY_HTTP_AUTH_PWD_HASH);
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public long getMaxRetries() {
    final AnyMap taskManagerSection;
    if (_properties.containsKey(KEY_TASKMANAGER)) {
      taskManagerSection = _properties.getMap(KEY_TASKMANAGER);
    } else {
      taskManagerSection = DataFactory.DEFAULT.createAnyMap();
      _properties.put(KEY_TASKMANAGER, taskManagerSection);
    }
    return getLongPropertyOrSetDefault(taskManagerSection, KEY_MAX_RETRIES, DEFAULT_MAX_RETRIES);
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public long getTimeToLive() {
    final AnyMap taskManagerSection;
    if (_properties.containsKey(KEY_TASKMANAGER)) {
      taskManagerSection = _properties.getMap(KEY_TASKMANAGER);
    } else {
      taskManagerSection = DataFactory.DEFAULT.createAnyMap();
      _properties.put(KEY_TASKMANAGER, taskManagerSection);
    }
    return getLongPropertyOrSetDefault(taskManagerSection, KEY_TIME_TO_LIVE, DEFAULT_TIME_TO_LIVE);
  }

  /**
   * Looks up the long value with the given key, if this value is not set, the given defaultvalue will be set.
   *
   * @param key
   *          the key of the property
   * @param defaultValueToSet
   *          the default value
   * @return the value from the properties or the default value if not set.
   */
  protected long getLongPropertyOrSetDefault(final String key, final long defaultValueToSet) {
    return getLongPropertyOrSetDefault(_properties, key, defaultValueToSet);
  }

  /**
   * Looks up the long value with the given key in the givent properties map, if this value is not set, the given
   * defaultvalue will be set.
   *
   * @param key
   *          the key of the property
   * @param defaultValueToSet
   *          the default value
   * @return the value from the properties or the default value if not set.
   */
  protected long getLongPropertyOrSetDefault(final AnyMap properties, final String key, final long defaultValueToSet) {
    final long value;
    if (properties.containsKey(key)) {
      value = properties.getLongValue(key);
    } else {
      value = defaultValueToSet;
      properties.put(key, value);
    }
    return value;
  }

  /**
   * Looks up the long value with the given key, if this value is not set, the given defaultvalue will be set.
   *
   * @param key
   *          the key of the property
   * @param defaultValueToSet
   *          the default value
   * @return the value from the properties or the default value if not set.
   */
  protected boolean getBooleanPropertyOrSetDefault(final String key, final boolean defaultValueToSet) {
    return getBooleanPropertyOrSetDefault(_properties, key, defaultValueToSet);
  }

  /**
   * Looks up the long value with the given key in the given properties map, if this value is not set, the given
   * defaultvalue will be set.
   *
   * @param key
   *          the key of the property
   * @param defaultValueToSet
   *          the default value
   * @return the value from the properties or the default value if not set.
   */
  protected boolean getBooleanPropertyOrSetDefault(final AnyMap properties, final String key,
    final boolean defaultValueToSet) {
    final boolean value;
    if (properties.containsKey(key)) {
      value = properties.getBooleanValue(key);
    } else {
      value = defaultValueToSet;
      properties.put(key, value);
    }
    return value;
  }

  /**
   * Gets integer property from a service section. return -1 if not set.
   *
   * @param serviceName
   *          name of service section
   * @param property
   *          property name
   * @return value of property or -1, if not defined.
   */
  protected int getIntegerServiceProperty(final String serviceName, final String property) {
    final AnyMap servicesSectionMap = _properties.getMap(KEY_SERVICES);
    if (servicesSectionMap != null && servicesSectionMap.containsKey(serviceName)) {
      final AnyMap serviceMap = servicesSectionMap.getMap(serviceName);
      if (serviceMap.containsKey(property)) {
        return serviceMap.getLongValue(property).intValue();
      }
    }
    if (_log.isInfoEnabled()) {
      _log.info("'" + property + "' for service '" + serviceName + "' is not defined.");
    }
    return -1;
  }

  /**
   * Read the configuration from the configuration file.
   *
   * @throws IOException
   *           error during loading of configuration file.
   */
  protected void readConfiguration() throws IOException {
    final IpcAnyReader anyReader = new IpcAnyReader();
    InputStream configurationFileStream = null;
    try {
      configurationFileStream = ConfigUtils.getConfigStream(BUNDLE_ID, CONFIG_FILE_NAME);
      _properties = (AnyMap) anyReader.readJsonStream(configurationFileStream);
      _isConfigured = true;
    } catch (final IOException ex) {
      throw new IOException("Could not read configuration property file " + CONFIG_FILE_NAME + ": " + ex.toString());
    } finally {
      IOUtils.closeQuietly(configurationFileStream);
    }
  }

}