import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import org.neo4j.graphdb.Direction;
import org.neo4j.graphdb.DynamicLabel;
import org.neo4j.graphdb.DynamicRelationshipType;
import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Label;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.RelationshipType;
import org.neo4j.graphdb.Transaction;
import org.neo4j.graphdb.factory.GraphDatabaseFactory;
import org.neo4j.unsafe.batchinsert.BatchInserter;
import org.neo4j.unsafe.batchinsert.BatchInserters;
import org.neo4j.io.fs.DefaultFileSystemAbstraction;
import org.neo4j.io.fs.FileUtils;

/**
 * 
 * In this program a separate inserter is used for each file; This is not
 * required for small datasets like this sample program But larger datasets
 * might result in memory overruns if a single inserter is used for the entire
 * dataset
 *
 */
public class LoadData {

  BufferedReader breader;

  Map<String, Long> movieMap = new HashMap<String, Long>();
  Map<String, Long> theaterMap = new HashMap<String, Long>();
  Map<String, Long> screenMap = new HashMap<String, Long>();

  public void loadDB() throws IOException {

    deleteDataDir(new File(CONSTANTS.dbPath));

    loadMovies();

    loadTheaters();

    loadScreens();

    loadTheaterScreenRel();

    loadScreenShowsRel();

    System.out.println("Done loading..Shutting down....");
  }

  public void loadMovies() throws IOException {

    BatchInserter inserter = null;
    try {
      inserter = BatchInserters.inserter(CONSTANTS.dbPath);

      // indexes are only creatred for the id attribute of the movie.
      // Indexes are dependent on the query.
      // So create as many indexes as the queries demand
      inserter.createDeferredSchemaIndex(MyLabels.MOVIE).on("id").create();

      Map<String, Object> properties = new HashMap<>();

      String line;
      // read movies
      breader = new BufferedReader(
                      new FileReader(CONSTANTS.inputPath + CONSTANTS.movieFile));
      while ((line = breader.readLine()) != null) {
        String[] parts = line.split(":");

        properties.put("id", parts[0]);
        properties.put("name", parts[1]);
        properties.put("country", parts[2]);
        properties.put("year", parts[3]);

        long node = inserter.createNode(properties, MyLabels.MOVIE);
        movieMap.put(parts[0], node);
      }
    } finally {
      if (inserter != null) {
        inserter.shutdown();
      }
    }
  }

  public void loadTheaters() throws IOException {
    BatchInserter inserter = null;
    try {
      inserter = BatchInserters.inserter(CONSTANTS.dbPath);

      // here an index is not created for the city attribute even though
      // it is required forn the query
      // experiment query times with and without indexes

      Map<String, Object> properties = new HashMap<>();

      breader = new BufferedReader(
                      new FileReader(CONSTANTS.inputPath + CONSTANTS.theaterFile));
      String line;
      while ((line = breader.readLine()) != null) {
        String[] parts = line.split(":");

        properties.put("id", parts[0]);
        properties.put("name", parts[1]);
        properties.put("city", parts[2]);

        long node = inserter.createNode(properties, MyLabels.THEATER);
        theaterMap.put(parts[0], node);
      }
    } finally {
      if (inserter != null) {
        inserter.shutdown();
      }
    }
  }

  public void loadScreens() throws IOException {

    BatchInserter inserter = null;
    try {
      inserter = BatchInserters.inserter(CONSTANTS.dbPath);

      Map<String, Object> properties = new HashMap<>();

      breader = new BufferedReader(
                      new FileReader(CONSTANTS.inputPath + CONSTANTS.screensFile));
      String line;
      while ((line = breader.readLine()) != null) {
        String[] parts = line.split(":");

        properties.put("id", parts[0]);
        properties.put("name", parts[1]);

        long node = inserter.createNode(properties, MyLabels.SCREEN); 
        screenMap.put(parts[0], node);
      }
    } finally {
      if (inserter != null) {
        inserter.shutdown();
      }
    }
  }

  public void loadTheaterScreenRel() throws IOException {
    BatchInserter inserter = null;
    try {
      inserter = BatchInserters.inserter(CONSTANTS.dbPath);

      breader = new BufferedReader(
                      new FileReader(CONSTANTS.inputPath + CONSTANTS.theaterscreensFile));
      String line;
      while ((line = breader.readLine()) != null) {
        String[] parts = line.split(":");

        Long theater = theaterMap.get(parts[0]);
        Long screen = screenMap.get(parts[1]);
        inserter.createRelationship(theater, screen, RelTypes.HAS_SCREEN, null);
      }
    } finally {
      if (inserter != null) {
        inserter.shutdown();
      }
    }
  }

  public void loadScreenShowsRel() throws IOException {

    BatchInserter inserter = null;
    try {
      inserter = BatchInserters.inserter(CONSTANTS.dbPath);

      breader = new BufferedReader(
                      new FileReader(CONSTANTS.inputPath + CONSTANTS.showsFile));
      String line;
      while ((line = breader.readLine()) != null) {
        Map<String, Object> properties = new HashMap<String, Object>();
        String[] parts = line.split(":");

        Long screen = screenMap.get(parts[0]);
        Long movie = movieMap.get(parts[1]);
        properties.put("date", parts[2]);
        properties.put("time", parts[3]);
        properties.put("numOfTkts", Integer.parseInt(parts[4]));
        properties.put("price", Integer.parseInt(parts[5]));

        inserter.createRelationship(screen, movie, RelTypes.PLAYS_MOVIE, properties);
      }
    } finally {
      if (inserter != null) {
        inserter.shutdown();
      }
    }
  }

  public void deleteDataDir(File dir) {
    for (File file : dir.listFiles())
      file.delete();
  }

}