/*
 * 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.
 */
package org.apache.solr.client.solrj.io.stream;


import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;

import org.apache.solr.client.solrj.io.stream.expr.Expressible;
import org.apache.solr.client.solrj.io.stream.expr.StreamExpression;
import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionNamedParameter;
import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionValue;
import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;
import org.apache.solr.common.params.CommonParams;
import org.apache.solr.common.params.ModifiableSolrParams;


public class ShuffleStream extends CloudSolrStream implements Expressible {

  public ShuffleStream(StreamExpression expression, StreamFactory factory) throws IOException {
    // grab all parameters out
    String collectionName = factory.getValueOperand(expression, 0);
    List<StreamExpressionNamedParameter> namedParams = factory.getNamedOperands(expression);
    StreamExpressionNamedParameter aliasExpression = factory.getNamedOperand(expression, "aliases");
    StreamExpressionNamedParameter zkHostExpression = factory.getNamedOperand(expression, "zkHost");

    // Collection Name
    if(null == collectionName){
      throw new IOException(String.format(Locale.ROOT,"invalid expression %s - collectionName expected as first operand",expression));
    }

    // Validate there are no unknown parameters - zkHost and alias are namedParameter so we don't need to count it twice
    if(expression.getParameters().size() != 1 + namedParams.size()){
      throw new IOException(String.format(Locale.ROOT,"invalid expression %s - unknown operands found",expression));
    }

    // Named parameters - passed directly to solr as solrparams
    if(0 == namedParams.size()){
      throw new IOException(String.format(Locale.ROOT,"invalid expression %s - at least one named parameter expected. eg. 'q=*:*'",expression));
    }

    ModifiableSolrParams mParams = new ModifiableSolrParams();
    for(StreamExpressionNamedParameter namedParam : namedParams){
      if(!namedParam.getName().equals("zkHost") && !namedParam.getName().equals("aliases")){
        mParams.add(namedParam.getName(), namedParam.getParameter().toString().trim());
      }
    }

    // Aliases, optional, if provided then need to split
    if(null != aliasExpression && aliasExpression.getParameter() instanceof StreamExpressionValue){
      fieldMappings = new HashMap<>();
      for(String mapping : ((StreamExpressionValue)aliasExpression.getParameter()).getValue().split(",")){
        String[] parts = mapping.trim().split("=");
        if(2 == parts.length){
          fieldMappings.put(parts[0], parts[1]);
        }
        else{
          throw new IOException(String.format(Locale.ROOT,"invalid expression %s - alias expected of the format origName=newName",expression));
        }
      }
    }

    // zkHost, optional - if not provided then will look into factory list to get
    String zkHost = null;
    if(null == zkHostExpression){
      zkHost = factory.getCollectionZkHost(collectionName);
      if(zkHost == null) {
        zkHost = factory.getDefaultZkHost();
      }
    }
    else if(zkHostExpression.getParameter() instanceof StreamExpressionValue){
      zkHost = ((StreamExpressionValue)zkHostExpression.getParameter()).getValue();
    }
    if(null == zkHost){
      throw new IOException(String.format(Locale.ROOT,"invalid expression %s - zkHost not found for collection '%s'",expression,collectionName));
    }

    // We've got all the required items
    init(collectionName, zkHost, mParams);
  }

  public ModifiableSolrParams adjustParams(ModifiableSolrParams mParams) {
    mParams.set(CommonParams.QT, "/export");
    return mParams;
  }

}