package org.neo4j.talend;
   
   import org.apache.commons.lang3.StringUtils;
   import org.apache.log4j.Logger;
   import org.neo4j.tooling.ImportTool;
   
   import java.io.BufferedWriter;
   import java.io.FileWriter;
   import java.io.IOException;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  
  public class Neo4jImportTool {
  
      /**
       * The logger
       */
      private final static Logger log = Logger.getLogger(Neo4jImportTool.class);
  
      protected final static String HEADERS_KEY = "HEADERS";
      protected final static String FILE_KEY = "FILE";
  
      private String dbPath;
      private Map<String, String> neo4jConfiguration;
      private Map<String, String> importConfiguration;
      private List<Map<String, String>> nodes;
      private List<Map<String, String>> relationships;
  
      /**
       * Constructor.
       *
       * @param dbPath
       * @param neo4jConfiguration
       * @param importConfiguration
       * @param nodes
       * @param relationships
       */
      public Neo4jImportTool(String dbPath, Map<String, String> neo4jConfiguration, Map<String, String> importConfiguration, List<Map<String, String>> nodes, List<Map<String, String>> relationships) {
          this.dbPath = dbPath;
          this.neo4jConfiguration = neo4jConfiguration;
          this.importConfiguration = importConfiguration;
          this.nodes = nodes;
          this.relationships = relationships;
      }
  
      /**
       * Execute the import.
       *
       * @throws IOException
       */
      public void execute() throws IOException {
          List<String> params = new ArrayList<>();
  
          // Adding dbPath
          params.add("--into");
          params.add(dbPath);
  
          // Adding neo4j config file
          params.add("--db-config");
          params.add(this.createNeo4jConfigFile());
  
          // Adding advanced configuration
          for (Map.Entry<String, String> entry : importConfiguration.entrySet()) {
              params.add("--" + entry.getKey());
              params.add(entry.getValue());
          }
  
          // Adding node files
          for (Map<String, String> node : nodes) {
              params.add("--nodes");
              params.add(this.createHeaderFile(node.get(HEADERS_KEY)) + "," + node.get(FILE_KEY));
          }
  
          // Adding relationships files
          for (Map<String, String> relationship : relationships) {
              params.add("--relationships");
              params.add(this.createHeaderFile(relationship.get(HEADERS_KEY)) + "," + relationship.get(FILE_KEY));
          }
  
          log.trace("Launch import tool with args : " + StringUtils.join(params, " "));
  
          // execute the import tool
          ImportTool.main(params.toArray(new String[params.size()]));
      }
  
      /**
       * Create the specified header file.
       *
       * @param header Content of the file
       * @return Full path of the generated file
       * @throws IOException
       */
      protected String createHeaderFile(String header) throws IOException {
          // create file
          Path path = Files.createTempFile("importToolHeader", ".csv");
  
         // write header into it
         BufferedWriter bw = new BufferedWriter(new FileWriter(path.toFile()));
         bw.write(header);
         bw.close();
 
 
         return path.toFile().getAbsolutePath();
     }
 
     /**
      * Create Neo4j configuration file.
      *
      * @return Full path of the generated file
      * @throws IOException
      */
     protected String createNeo4jConfigFile() throws IOException {
         // create file
         Path path = Files.createTempFile("neo4jConfig", ".properties");
 
         // write header into it
         BufferedWriter bw = new BufferedWriter(new FileWriter(path.toFile()));
         for (Map.Entry<String, String> entry : neo4jConfiguration.entrySet()) {
             bw.write(entry.getKey() + "=" + entry.getValue());
             bw.newLine();
         }
         bw.close();
 
         return path.toFile().getAbsolutePath();
     }
 }