/*
 * DbaseClean
 *   Drop a database, if exists, and create a new empty one.
 *   Collect database info from a resource file.
 *
 * When using embeded in an application must be called outside a transaction
 * (@Atomic) or connection to the same database server!
 *
 * javac DbaseClean.java
 * java -cp mysql-connector-java-5.1.38.jar:.  DbaseClean
 *
 * Maven (do not use in the fenix-framework):
 * <dependency>
 *   <groupId>mysql</groupId>
 *   <artifactId>mysql-connector-java</artifactId>
 *   <version>5.1.38</version>
 * </dependency>
 */
import java.io.*;
import java.sql.*;
import java.util.Scanner;

public class DbaseClean {
  static final String driver = "com.mysql.jdbc.Driver";
  static final String url = "jdbc:mysql://localhost/";

  private String dbase, user, passwd; // dbase params from resource file
  // resource file in current-dir ou src/main/resources maven-dir
  private static String res = "fenix-framework-jvstm-ojb.properties";
  private Connection conn = null;

  public DbaseClean() { getDbase(res); }
  public DbaseClean(String resource) { getDbase(res = resource); }
  public DbaseClean(String db, String user, String pw) {
    dbase = db;
    this.user = user;
    passwd = pw;
  }

  public void connect() throws SQLException {
    conn = DriverManager.getConnection(url, user, passwd);
  }
  public void disconnect() throws SQLException {
    if (conn != null) conn.close();
    conn = null;
  }

  public String name() { return dbase; }
  public String user() { return user; }
  protected String passwd() { return passwd; }
  public void name(String s) { dbase = s; }
  public void user(String s) { user = s; }
  public void passwd(String s) { passwd = s; }

  public static void main(String[] args) {
    try {
      DbaseClean db;
      if (args.length == 3) db = new DbaseClean(args[0], args[1], args[2]);
      else {
	if (args.length > 3) {
	    System.err.println("DbaseClean [dbase [user [passwd]]]");
	    return;
	}
        db = new DbaseClean();
        if (args.length > 0) db.name(args[0]);
        if (args.length > 1) db.user(args[1]);
        if (args.length > 2) db.passwd(args[2]);
      }
      db.cleanup();
      System.out.println("Database created successfully...");
    } catch(Exception e) { e.printStackTrace(); }
  }

  public void cleanup() throws Exception {
    Class.forName(driver);
    System.err.println(user()+"@"+url+user()); // debug
    connect();
    System.err.println("Connected..."); // debug
    try { sql("DROP DATABASE " + name());
    } catch (SQLException e) { System.err.println(e); }
    sql("CREATE DATABASE " + name());
    disconnect();
  }

  public void sql(String com) throws SQLException {
    Statement stmt = conn.createStatement();
    stmt.executeUpdate(com);
    stmt.close();
  }

  /* read database information from resource file */
  private void getDbase(String fileName) {
    ClassLoader classLoader = getClass().getClassLoader();
    File file = new File(classLoader.getResource(fileName).getFile());

    try (Scanner scanner = new Scanner(file)) {
      while (scanner.hasNextLine()) {
	String line = scanner.nextLine().trim();
	if (line.length() == 0) continue;
	if (line.charAt(0) == '#') continue;
	String[] attr = line.split("=");
	if (attr[0].equals("dbUsername")) user = attr[1].trim();
	if (attr[0].equals("dbPassword")) passwd = attr[1].trim();
	if (attr[0].equals("dbAlias")) {
	  int i = attr[1].trim().lastIndexOf('/');
	  int j = attr[1].trim().lastIndexOf('?');
	  dbase = attr[1].trim().substring(i+1,j);
	}
      }
      scanner.close();
    } catch (IOException e) { e.printStackTrace(); }
  }
}