/**
 * ============LICENSE_START=======================================================
 * org.onap.aai
 * ================================================================================
 * Copyright © 2017-2018 AT&T Intellectual Property. All rights reserved.
 * Copyright © 2017-2018 Amdocs
 * ================================================================================
 * 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.aai.sa.searchdbabstraction.util;

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.List;
import java.util.concurrent.atomic.AtomicBoolean;
import org.apache.commons.io.IOUtils;
import org.onap.aai.sa.rest.DocumentFieldSchema;
import org.onap.aai.sa.rest.DocumentSchema;

public class DocumentSchemaUtil {

  private static String dynamicCustomMapping = null;
  private static final String DYNAMIC_CUSTOM_TEMPALTE_FILE = System.getProperty("CONFIG_HOME") + File.separator 
		  + "dynamic-custom-template.json";
  
  public static String generateDocumentMappings(String documentSchema)
      throws JsonParseException, JsonMappingException, IOException {

    // Unmarshal the json content into a document schema object.
    ObjectMapper mapper = new ObjectMapper();
    DocumentSchema schema = mapper.readValue(documentSchema, DocumentSchema.class);

    return generateDocumentMappings(schema);
  }

  public static String generateDocumentMappings(DocumentSchema schema) throws IOException {
	  
	// Adding dynamic template to add fielddata=true to dynamic fields of type "string"  
	// in order to avoid aggregation queries breaking in ESv6.1.2
	if(dynamicCustomMapping == null) {
		try {
			dynamicCustomMapping = IOUtils.toString(new FileInputStream(DYNAMIC_CUSTOM_TEMPALTE_FILE), "UTF-8").replaceAll("\\s+", "");
		} catch (IOException e) {
			throw new IOException("Dynamic Custom template configuration went wrong! Please check for the correct template file.", e);
		}
	}

    // Now, generate the Elastic Search mapping json and return it.
    StringBuilder sb = new StringBuilder();
    sb.append("{");
    // Adding custom mapping which adds fielddata=true to dynamic fields of type "string"
    sb.append(dynamicCustomMapping != null ? dynamicCustomMapping : "");
    sb.append("\"properties\": {");

    generateFieldMappings(schema.getFields(), sb);

    sb.append("}");
    sb.append("}");

    return sb.toString();
  }


  private static void generateFieldMappings(List<DocumentFieldSchema> fields, StringBuilder sb) {

    AtomicBoolean firstField = new AtomicBoolean(true);

    for (DocumentFieldSchema field : fields) {

      // If this isn't the first field in the list, prepend it with a ','
      if (!firstField.compareAndSet(true, false)) {
        sb.append(", ");
      }

      // Now, append the translated field contents.
      generateFieldMapping(field, sb);
    }
  }

  private static void generateFieldMapping(DocumentFieldSchema fieldSchema, StringBuilder sb) {

    sb.append("\"").append(fieldSchema.getName()).append("\": {");

    // The field type is mandatory.
    sb.append("\"type\": \"").append(fieldSchema.getDataType()).append("\"");

    // For date type fields we may optionally supply a format specifier.
    if (fieldSchema.getDataType().equals("date")) {
      if (fieldSchema.getFormat() != null) {
        sb.append(", \"format\": \"").append(fieldSchema.getFormat()).append("\"");
      }
    }

    // If the index field was specified, then append it.
    if (fieldSchema.getSearchable() != null) {
      sb.append(", \"index\": \"").append(fieldSchema.getSearchable()
          ? "analyzed" : "not_analyzed").append("\"");
    }

    // If a search analyzer was specified, then append it.
    if (fieldSchema.getSearchAnalyzer() != null) {
      sb.append(", \"search_analyzer\": \"").append(fieldSchema.getSearchAnalyzer()).append("\"");
    }

    // If an indexing analyzer was specified, then append it.
    if (fieldSchema.getIndexAnalyzer() != null) {
      sb.append(", \"analyzer\": \"").append(fieldSchema.getIndexAnalyzer()).append("\"");
    }


    if (fieldSchema.getDataType().equals("nested")) {

      sb.append(", \"properties\": {");
      generateFieldMappings(fieldSchema.getSubFields(), sb);
      sb.append("}");
    }

    sb.append("}");
  }

}