package liquibase.ext.spatial.datatype;
   
   import liquibase.database.Database;
   import liquibase.database.core.DerbyDatabase;
   import liquibase.database.core.H2Database;
   import liquibase.database.core.OracleDatabase;
   import liquibase.database.core.PostgresDatabase;
   import liquibase.datatype.DataTypeInfo;
   import liquibase.datatype.DatabaseDataType;
  import liquibase.datatype.LiquibaseDataType;
  import liquibase.exception.UnexpectedLiquibaseException;
  import liquibase.statement.DatabaseFunction;
  
  import com.vividsolutions.jts.geom.Geometry;
  import com.vividsolutions.jts.io.ParseException;
  import com.vividsolutions.jts.io.WKTReader;
  
  /**
   * The <code>GeometryType</code> assists in defining database-specific geometry types and converting
   * SQL representations of geometries.
   */
  @DataTypeInfo(name = "geometry", aliases = { "com.vividsolutions.jts.geom.Geometry" }, minParameters = 0, maxParameters = 2, priority = LiquibaseDataType.PRIORITY_DEFAULT)
  public class GeometryType extends LiquibaseDataType {
     /**
      * Returns the value geometry type parameter.
      * 
      * @return the geometry type or <code>null</code> if not present.
      */
     public String getGeometryType() {
        String geometryType = null;
        if (getParameters().length > 0 && getParameters()[0] != null) {
           geometryType = getParameters()[0].toString();
        }
        return geometryType;
     }
  
     /**
      * Returns the value SRID parameter.
      * 
      * @return the SRID or <code>null</code> if not present.
      */
     public Integer getSRID() {
        Integer srid = null;
        if (getParameters().length > 1 && getParameters()[1] != null) {
           srid = Integer.valueOf(getParameters()[1].toString());
        }
        return srid;
     }
  
     /**
      * Creates the appropriate Geometry <code>DatabaseDataType</code>.
      */
     @Override
     public DatabaseDataType toDatabaseDataType(final Database database) {
        final DatabaseDataType databaseDataType;
        if (database instanceof DerbyDatabase) {
           databaseDataType = new DatabaseDataType("VARCHAR(32672) FOR BIT DATA");
        } else if (database instanceof H2Database) {
           // User's wanting to use a BLOB can use modifySql.
           databaseDataType = new DatabaseDataType("BINARY");
        } else if (database instanceof OracleDatabase) {
           databaseDataType = new DatabaseDataType("SDO_GEOMETRY");
        } else if (database instanceof PostgresDatabase) {
           databaseDataType = new DatabaseDataType(getName(), getParameters());
        } else {
           databaseDataType = new DatabaseDataType("GEOMETRY");
        }
        return databaseDataType;
     }
  
     /**
      * @see liquibase.datatype.LiquibaseDataType#objectToSql(java.lang.Object,
      *      liquibase.database.Database)
      */
     @Override
     public String objectToSql(final Object value, final Database database) {
        final String returnValue;
        if (value instanceof Geometry) {
           // TODO: Tailor the output for the database.
           returnValue = ((Geometry) value).toText();
        } else if (value instanceof String) {
           returnValue = value.toString();
        } else if (value instanceof DatabaseFunction) {
           returnValue = value.toString();
        } else if (value == null || value.toString().equalsIgnoreCase("null")) {
           returnValue = null;
        } else {
           throw new UnexpectedLiquibaseException("Cannot convert type " + value.getClass()
                 + " to a Geometry value");
        }
        return returnValue;
     }
  
     /**
      * @see liquibase.datatype.LiquibaseDataType#sqlToObject(java.lang.String,
      *      liquibase.database.Database)
      */
     @Override
     public Object sqlToObject(final String value, final Database database) {
       final Geometry returnValue;
       if (value == null || value.equalsIgnoreCase("null")) {
          returnValue = null;
       } else {
          final WKTReader reader = new WKTReader();
          try {
             // TODO: Check for SRID.
             returnValue = reader.read(value);
          } catch (final ParseException e) {
             throw new UnexpectedLiquibaseException("Cannot parse " + value + " to a Geometry", e);
          }
       }
       return returnValue;
    }
 }