package nl.beesting.beangenerator.generator;

 import java.lang.reflect.Constructor;

 import nl.beesting.beangenerator.TypeNotSupportedException;

 import nl.beesting.beangenerator.util.ParameterDescriptor;

 import nl.beesting.beangenerator.util.ParameterPair;

 import nl.beesting.beangenerator.util.RandomUtil;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 /**

  * Instance generator for String types: <code>Character</code>, <code>String</code> and <code>StringBuffer</code>

  */

 public class StringInstanceGenerator extends AbstractInstanceGenerator {

    /** The <code>logger</code> for this class. */

    private static final Log logger = LogFactory.getLog(PhoneticalNameGenerator.class);

    private static final int DEFAULT_LENGTH = 30;

    private static final String LENGTH_PARAMETER = "length";

    private int length = DEFAULT_LENGTH;

    private int from;

    private int until;

    public StringInstanceGenerator() {

       // set the suppported types

       addSupportedTypes(new Class[]{String.class, StringBuffer.class});

       // set the supported parameters

       setSupportedParameterDescriptors(new ParameterDescriptor[]{

          new ParameterDescriptor(LENGTH_PARAMETER, String.class, "Fixed length of generated text."),

          new ParameterDescriptor(FROM_PARAMETER, String.class, "From. variable length left boundry."),

          new ParameterDescriptor(UNTIL_PARAMETER, String.class, "Until. variable length right boundry.")

       });

    }

    /**

     * Initializes the instnce generator with the given array of objects.

     */

    public void init(ParameterPair[] initParams) {

       if (initParams != null) {

          length = initParameter(initParams, LENGTH_PARAMETER, DEFAULT_LENGTH);

          from = initParameter(initParams, FROM_PARAMETER, 0);

          until = initParameter(initParams, UNTIL_PARAMETER, 0);

       }

    }

    /**

     * Create an instance for the given class. The returned object is of the given class.

     */

    public Object generateInstance(Class<?> type) throws TypeNotSupportedException {

       // preconditions

       if (type == null) {

          throw new IllegalArgumentException("Input parameter type cannot be null.");

       }

       if (!checkSupport(type)) {

          throw new TypeNotSupportedException(type.getName(), "generateInstance");

       }

       if (type.equals(Character.class)) {

          return instantiateCharacter();

       }

       String result = instantiateString();

       try {

          Constructor<?> c = type.getConstructor(String.class);

          return c.newInstance(result);

       } catch (Exception e) {

          logger.warn("Could not construct Object of type " + type + " . Returning null.", e);

       }

       return null;

    }

    /**

     * Create an instance for the given class with an instance generator specific modus. The returned object is of the given

     * class.

     */

    public Object generateInstance(Class<?> type, int modus) throws TypeNotSupportedException {

       if (!checkSupport(type)) {

          throw new TypeNotSupportedException(type.getName(), "generateInstance");

       }

       return generateInstance(type);

    }

    // ///////////// INSTANCE METHODS ////////////////

    /**

     * Instantiates random Character

     * @return

     */

    private Character instantiateCharacter() {

       return RandomUtil.initRandomChar();

    }

    /**

     * Instantiates random String value.

     * @return

     */

    private String instantiateString() {

       int stringSize = 0;

       if (from == 0) {

          stringSize = length;

       } else {

          stringSize = RandomUtil.initRandomIntBetween(from, until);

       }

       StringBuffer returnStringBuf = new StringBuffer();

       for (int i = 0; i < stringSize; i++) {

          char randomChar = RandomUtil.initRandomChar();

          returnStringBuf.append(randomChar);

       }

       return returnStringBuf.toString();

    }

    /* For testing */

    protected Object getFromValue() {

       return from;

    }

    protected Object getUntilValue() {

       return until;

    }

    protected Object getDefaultFromValue() {

       return 0;

    }

    protected Object getDefaultUntilValue() {

       return 0;

    }

 }