package org.apache.solr.core;

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

import org.apache.solr.common.SolrException;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.util.DOMUtil;

import com.google.common.base.Function;
import com.google.common.base.Functions;

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.util.Locale;


/**
 *
 */
public class ConfigSolrXml extends ConfigSolr {

  protected static Logger log = LoggerFactory.getLogger(ConfigSolrXml.class);

  private final CoresLocator coresLocator;

  public ConfigSolrXml(Config config) {
    super(config);
    try {
      checkForIllegalConfig();
      fillPropMap();
      coresLocator = new CorePropertiesLocator(getCoreRootDirectory());
    } catch (IOException e) {
      throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, e);
    }
  }

  private void checkForIllegalConfig() throws IOException {

    // Do sanity checks - we don't want to find old style config
    failIfFound("solr/@coreLoadThreads");
    failIfFound("solr/@persistent");
    failIfFound("solr/@sharedLib");
    failIfFound("solr/@zkHost");

    failIfFound("solr/logging/@class");
    failIfFound("solr/logging/@enabled");
    failIfFound("solr/logging/watcher/@size");
    failIfFound("solr/logging/watcher/@threshold");

    failIfFound("solr/cores/@adminHandler");
    failIfFound("solr/cores/@distribUpdateConnTimeout");
    failIfFound("solr/cores/@distribUpdateSoTimeout");
    failIfFound("solr/cores/@host");
    failIfFound("solr/cores/@hostContext");
    failIfFound("solr/cores/@hostPort");
    failIfFound("solr/cores/@leaderVoteWait");
    failIfFound("solr/cores/@leaderConflictResolveWait");
    failIfFound("solr/cores/@genericCoreNodeNames");
    failIfFound("solr/cores/@managementPath");
    failIfFound("solr/cores/@shareSchema");
    failIfFound("solr/cores/@transientCacheSize");
    failIfFound("solr/cores/@zkClientTimeout");

    // These have no counterpart in 5.0, asking for any of these in Solr 5.0
    // will result in an error being
    // thrown.
    failIfFound("solr/cores/@defaultCoreName");
    failIfFound("solr/@persistent");
    failIfFound("solr/cores/@adminPath");

  }

  private void failIfFound(String xPath) {

    if (config.getVal(xPath, false) != null) {
      throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, "Should not have found " + xPath +
          " solr.xml may be a mix of old and new style formats.");
    }
  }

  private NamedList<Object> readNodeListAsNamedList(String path) {
    NodeList nodes = config.getNodeList(path, false);
    if (nodes != null) {
      NamedList<Object> namedList = DOMUtil.nodesToNamedList(nodes);
      return namedList;
    }
    return new NamedList<>();
  }

  private void fillPropMap() {
    NamedList<Object> unknownConfigParams = new NamedList<>();

    // shardHandlerFactory is parsed differently in the base class as a plugin, so we're excluding this node from the node list
    fillSolrSection(readNodeListAsNamedList("solr/*[@name][not(name()='shardHandlerFactory')]"));

    thereCanBeOnlyOne("solr/solrcloud","<solrcloud>");
    fillSolrCloudSection(readNodeListAsNamedList("solr/solrcloud/*[@name]"));

    thereCanBeOnlyOne("solr/logging","<logging>");
    thereCanBeOnlyOne("solr/logging/watcher","Logging <watcher>");
    fillLoggingSection(readNodeListAsNamedList("solr/logging/*[@name]"), 
                       readNodeListAsNamedList("solr/logging/watcher/*[@name]"));
  }

  private void fillSolrSection(NamedList<Object> nl) {
    String s = "Main";
    storeConfigPropertyAsString(s, nl, CfgProp.SOLR_ADMINHANDLER, "adminHandler");
    storeConfigPropertyAsString(s, nl, CfgProp.SOLR_COLLECTIONSHANDLER, "collectionsHandler");
    storeConfigPropertyAsString(s, nl, CfgProp.SOLR_INFOHANDLER, "infoHandler");
    storeConfigPropertyAsString(s, nl, CfgProp.SOLR_COREROOTDIRECTORY, "coreRootDirectory");
    storeConfigPropertyAsString(s, nl, CfgProp.SOLR_MANAGEMENTPATH, "managementPath");
    storeConfigPropertyAsString(s, nl, CfgProp.SOLR_SHAREDLIB, "sharedLib");
    storeConfigPropertyAsString(s, nl, CfgProp.SOLR_CONFIGSETBASEDIR, "configSetBaseDir");

    storeConfigPropertyAsBoolean(s, nl, CfgProp.SOLR_SHARESCHEMA, "shareSchema");

    storeConfigPropertyAsInt(s, nl, CfgProp.SOLR_CORELOADTHREADS, "coreLoadThreads");
    storeConfigPropertyAsInt(s, nl, CfgProp.SOLR_TRANSIENTCACHESIZE, "transientCacheSize");

    errorOnLeftOvers(s, nl);
  }

  private void fillSolrCloudSection(NamedList<Object> nl) {
    
    String s = "<solrcloud>";
    storeConfigPropertyAsInt(s, nl, CfgProp.SOLR_DISTRIBUPDATECONNTIMEOUT, "distribUpdateConnTimeout");
    storeConfigPropertyAsInt(s, nl, CfgProp.SOLR_DISTRIBUPDATESOTIMEOUT, "distribUpdateSoTimeout");
    storeConfigPropertyAsInt(s, nl, CfgProp.SOLR_MAXUPDATECONNECTIONS, "maxUpdateConnections");
    storeConfigPropertyAsInt(s, nl, CfgProp.SOLR_MAXUPDATECONNECTIONSPERHOST, "maxUpdateConnectionsPerHost");
    storeConfigPropertyAsInt(s, nl, CfgProp.SOLR_LEADERVOTEWAIT, "leaderVoteWait");
    storeConfigPropertyAsInt(s, nl, CfgProp.SOLR_LEADERCONFLICTRESOLVEWAIT, "leaderConflictResolveWait");
    storeConfigPropertyAsInt(s, nl, CfgProp.SOLR_ZKCLIENTTIMEOUT, "zkClientTimeout");
    storeConfigPropertyAsInt(s, nl, CfgProp.SOLR_AUTOREPLICAFAILOVERBADNODEEXPIRATION, "autoReplicaFailoverBadNodeExpiration");
    storeConfigPropertyAsInt(s, nl, CfgProp.SOLR_AUTOREPLICAFAILOVERWAITAFTEREXPIRATION, "autoReplicaFailoverWaitAfterExpiration");
    storeConfigPropertyAsInt(s, nl, CfgProp.SOLR_AUTOREPLICAFAILOVERWORKLOOPDELAY, "autoReplicaFailoverWorkLoopDelay");
    
    storeConfigPropertyAsString(s, nl, CfgProp.SOLR_HOST, "host");
    storeConfigPropertyAsString(s, nl, CfgProp.SOLR_HOSTCONTEXT, "hostContext");
    storeConfigPropertyAsString(s, nl, CfgProp.SOLR_HOSTPORT, "hostPort");
    storeConfigPropertyAsString(s, nl, CfgProp.SOLR_ZKHOST, "zkHost");

    storeConfigPropertyAsBoolean(s, nl, CfgProp.SOLR_GENERICCORENODENAMES, "genericCoreNodeNames");
    
    errorOnLeftOvers(s, nl);
  }

  private void fillLoggingSection(NamedList<Object> loggingConfig, 
                                  NamedList<Object> loggingWatcherConfig) {
    
    String s = "<logging>";
    storeConfigPropertyAsString(s, loggingConfig, CfgProp.SOLR_LOGGING_CLASS, "class");
    storeConfigPropertyAsBoolean(s, loggingConfig, CfgProp.SOLR_LOGGING_ENABLED, "enabled");

    errorOnLeftOvers(s, loggingConfig);

    s = "Logging <watcher>";
    storeConfigPropertyAsInt(s, loggingWatcherConfig, CfgProp.SOLR_LOGGING_WATCHER_SIZE, "size");
    storeConfigPropertyAsString(s, loggingWatcherConfig, CfgProp.SOLR_LOGGING_WATCHER_THRESHOLD, "threshold");

    errorOnLeftOvers(s, loggingWatcherConfig);
  }


  private <T> void storeConfigProperty(String section, NamedList<Object> config, CfgProp propertyKey, String name, Function<Object, T> valueTransformer, Class<T> clazz) {
    List<Object> values = config.removeAll(name); 
    if (null != values && 0 != values.size()) {
      if (1 < values.size()) {
        throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,
                                String.format(Locale.ROOT, 
                                              "%s section of solr.xml contains duplicated '%s'"+
                                              " in solr.xml: %s", section, name, values));
      } else {
        Object value = values.get(0);
        if (value != null) {
          if (value.getClass().isAssignableFrom(clazz)) {
            propMap.put(propertyKey, value);
          } else {
            propMap.put(propertyKey, valueTransformer.apply(value));
          }
        } else {
          propMap.put(propertyKey, null);
        }
      }
    }
  }

  private void storeConfigPropertyAsString(String section, NamedList<Object> config, CfgProp propertyKey, String name) {
    storeConfigProperty(section, config, propertyKey, name, Functions.toStringFunction(), String.class);
  }

  private void storeConfigPropertyAsInt(String section, NamedList<Object> config, CfgProp propertyKey, String xmlElementName) {
    storeConfigProperty(section, config, propertyKey, xmlElementName, TO_INT_FUNCTION, Integer.class);
  }

  private void storeConfigPropertyAsBoolean(String section, NamedList<Object> config, CfgProp propertyKey, String name) {
    storeConfigProperty(section, config, propertyKey, name, TO_BOOLEAN_FUNCTION, Boolean.class);
  }

  /** throws an error if more then one element matching the xpath */
  private void thereCanBeOnlyOne(String xpath, String section) {
    NodeList lst = config.getNodeList(xpath, false);
    if (1 < lst.getLength())
      throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,
                              lst.getLength() + " instances of " + section + " found in solr.xml");
  }

  /** logs each item in leftovers and then throws an exception with a summary */
  private void errorOnLeftOvers(String section, NamedList<Object> leftovers) {

    if (null == leftovers || 0 == leftovers.size()) return;

    List<String> unknownElements = new ArrayList<String>(leftovers.size());
    for (Map.Entry<String, Object> unknownElement : leftovers) {
      log.error("Unknown config parameter in {} section of solr.xml: {} -> {}", 
                section, unknownElement.getKey(), unknownElement.getValue());
      unknownElements.add(unknownElement.getKey());
    }
    if (! unknownElements.isEmpty() ) {
      throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,
                              String.format(Locale.ROOT, "%s section of solr.xml contains %d unknown config parameter(s): %s", section, unknownElements.size(), unknownElements));
    }
  }

  @Override
  public String getDefaultCoreName() {
    return "collection1";
  }

  @Override
  public boolean isPersistent() {
    return true;
  }

  @Override
  protected String getShardHandlerFactoryConfigPath() {
    return "solr/shardHandlerFactory";
  }

  @Override
  public String getAdminPath() {
    return DEFAULT_CORE_ADMIN_PATH;
  }

  @Override
  public CoresLocator getCoresLocator() {
    return coresLocator;
  }

  private static final Function<Map.Entry<String, Object>, String> GET_KEY_FUNCTION = new Function<Map.Entry<String, Object>, String>() {
    @Override
    public String apply(Map.Entry<String, Object> input) {
      return input.getKey();
    }
  };

  private static final Function<Object, Integer> TO_INT_FUNCTION = new Function<Object, Integer>() {
    @Override
    public Integer apply(Object input) {
      try {
        return Integer.parseInt(String.valueOf(input));
      } catch (NumberFormatException exc) {
        throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, 
                                String.format(Locale.ROOT, 
                                              "Value of '%s' can not be parsed as 'int'", input));
      }
    }
  };

  private static final Function<Object, Boolean> TO_BOOLEAN_FUNCTION = new Function<Object, Boolean>() {
    @Override
    public Boolean apply(Object input) {
      if (input instanceof String) {
        return Boolean.valueOf(String.valueOf(input));
      }
      throw new SolrException(SolrException.ErrorCode.SERVER_ERROR, String.format(Locale.ROOT, "Value of '%s' can not be parsed as 'bool'", input));
    }
  };
}