package uk.ac.ebi.intenz.mapper;
   
   import java.sql.Connection;
   import java.sql.PreparedStatement;
   import java.sql.ResultSet;
   import java.sql.SQLException;
   import java.sql.Statement;
   import java.util.ArrayList;
   import java.util.List;
  
  import org.apache.log4j.Logger;
  
  import uk.ac.ebi.intenz.domain.enzyme.EnzymeClass;
  import uk.ac.ebi.intenz.domain.enzyme.EnzymeCommissionNumber;
  import uk.ac.ebi.intenz.domain.enzyme.EnzymeSubclass;
  import uk.ac.ebi.intenz.domain.exceptions.DomainException;
  import uk.ac.ebi.intenz.domain.exceptions.EcException;
  
  /**
   * Maps enzyme class information to the corresponding database tables.
   *
   * @author Michael Darsow
   * @version $Revision: 1.3 $ $Date: 2009/05/26 14:59:09 $
   */
  public class EnzymeClassMapper {
  
    private static final String COLUMNS = "ec1, name, description";
    
    private static final String SELECT_ALL = "SELECT " + COLUMNS + " FROM classes";
  
    private static final Logger LOGGER =
  	  Logger.getLogger(EnzymeClassMapper.class.getName());
  
    public EnzymeClassMapper() {
    }
  
    private String findStatement() {
      return "SELECT " + COLUMNS + " FROM classes WHERE ec1 = ?";
    }
  
    private String findNumberOfClassesStatement() {
      return "SELECT count(*) AS count FROM classes";
    }
  
    /**
     * Tries to find Class information about an enzyme.
     *
     * @param ec1 Number of class to search for.
     * @param con The logical connection.
     * @return an <code>EnzymeClass</code> instance or <code>null</code> if nothing has been found.
     * @throws NullPointerException if any of the parameters is <code>null</code>.
     * @throws SQLException         if a database error occurs.
     * @throws DomainException      if any error related to domain information occurs (e.g. <code>ec1</code> is invalid).
     */
    public EnzymeClass find(String ec1, Connection con) throws SQLException, DomainException {
      if (ec1 == null) throw new NullPointerException("Parameter 'ec1' must not be null.");
      if (con == null) throw new NullPointerException("Parameter 'con' must not be null.");
      PreparedStatement findStatement = null;
      ResultSet rs = null;
      EnzymeClass result = null;
      List<EnzymeSubclass> subclasses;
  
      // Get subclasses.
      EnzymeSubclassMapper subclassMapper = new EnzymeSubclassMapper();
      subclasses = subclassMapper.findList(ec1, con);
  
      try {
        findStatement = con.prepareStatement(findStatement());
        findStatement.setString(1, ec1);
        rs = findStatement.executeQuery();
        if (rs.next()) {
          result = doLoad(rs, subclasses);
        } else {
          LOGGER.warn("No class information found for EC " + ec1);
        }
      } finally {
      	if (rs != null) rs.close();
        if (findStatement != null) findStatement.close();
      }
  
      return result;
    }
    
    /**
     * 
     * @param con
     * @return A <code>List</code> of all the <code>EnzymeClass</code>es
     *    (without subclass information)
   * @throws SQLException 
   * @throws EcException 
     */
    public List<EnzymeClass> findAll(Connection con) throws SQLException, DomainException{
        List<EnzymeClass> result = new ArrayList<EnzymeClass>();
        Statement stm = null;
        ResultSet rs = null;
        try {
            stm = con.createStatement();
            rs = stm.executeQuery("SELECT ec1 FROM classes");
            while (rs.next()){
               result.add(find(rs.getString(1), con));
           }
       } finally {
       	if (rs != null) rs.close();
           if (stm != null) stm.close();
       }
       return result;
   }
 
   /**
    * Finds the number of classes.
    *
    * @param con The logical connection.
    * @return the number of classes.
    * @throws SQLException
    */
   public int findNumberOfClasses(Connection con) throws SQLException {
     if (con == null) throw new NullPointerException("Parameter 'con' must not be null.");
     PreparedStatement findStatement = null;
     ResultSet rs = null;
     int number = 0;
 
     try {
       findStatement = con.prepareStatement(findNumberOfClassesStatement());
       rs = findStatement.executeQuery();
       if (rs.next()) {
         number = Integer.parseInt(rs.getString("count"));
       }
     } finally {
       	if (rs != null) rs.close();
       	if (findStatement != null) findStatement.close();
     }
 
     return number;
   }
 
   /**
    * Checks if the given class number is valid.
    *
    * @param ec1 The class number.
    * @param con The connection.
    * @return <code>true</code> if the class exists.
    * @throws SQLException
    */
   public boolean classExists(String ec1, Connection con) throws SQLException {
     if (ec1 == null) throw new NullPointerException("Parameter 'ec1' must not be null.");
     if (con == null) throw new NullPointerException("Parameter 'con' must not be null.");
     PreparedStatement findStatement = null;
     ResultSet rs = null;
     try {
       findStatement = con.prepareStatement(findStatement());
       findStatement.setString(1, ec1);
       rs = findStatement.executeQuery();
       if (rs.next()) {
         return true;
       }
     } finally {
       	if (rs != null) rs.close();
       	if (findStatement != null) findStatement.close();
     }
 
     return false;
   }
 
   // ------------------- PRIVATE METHODS ------------------------
 
   /**
    * Creates the <code>EnzymeClass</code> object.
    *
    * @param rs The result set object.
    * @return an <code>EnzymeClass</code> instance.
    * @throws SQLException
    */
   private EnzymeClass doLoad(ResultSet rs, List<EnzymeSubclass> subclasses)
   throws SQLException, EcException {
     assert rs != null;
     
     int ec1 = 0;
     String name = "";
     String description = "";
 
     if (rs.getInt("ec1") > 0) ec1 = rs.getInt("ec1");
     if (rs.getString("name") != null) name = rs.getString("name");
     if (rs.getString("description") != null) description = rs.getString("description");
 
     EnzymeCommissionNumber ec = EnzymeCommissionNumber.valueOf(ec1);
     return EnzymeClass.valueOf(ec, name, description, subclasses);
   }
 }