package org.supercsv.cellprocessor.time;
   
   import java.time.DateTimeException;
   import java.time.format.DateTimeFormatter;
   import java.time.temporal.TemporalAccessor;
   import java.util.Objects;
   
   import org.supercsv.cellprocessor.CellProcessorAdaptor;
   import org.supercsv.cellprocessor.ift.CellProcessor;
  import org.supercsv.exception.SuperCsvCellProcessorException;
  import org.supercsv.util.CsvContext;
  
  /**
   * Abstract base class for cell processors converting {@link TemporalAccessor} types to Strings.
   *
   * @author Ludovico Fischer
   * @since 2.4.0
   */
  public abstract class AbstractTemporalAccessorFormattingProcessor<T extends TemporalAccessor>
  	extends CellProcessorAdaptor {
  
  	private final DateTimeFormatter formatter;
  
  	/**
  	 * Constructs a new <tt>AbstractTemporalAccessorFormattingProcessor</tt> processor,
  	 * which formats the type as a String.
  	 */
  	public AbstractTemporalAccessorFormattingProcessor() {
  		this.formatter = null;
  
  	}
  
  	/**
  	 * Constructs a new <tt>AbstractTemporalAccessorFormattingProcessor</tt> processor,
  	 * which formats the type as a String, then calls the next processor in
  	 * the chain.
  	 *
  	 * @param next next processor in the chain
  	 * @throws NullPointerException if temporalAccessor or next is null
  	 */
  	public AbstractTemporalAccessorFormattingProcessor(final CellProcessor next) {
  		super(next);
  		this.formatter = null;
  
  	}
  
  	/**
  	 * Constructs a new <tt>AbstractTemporalAccessorFormattingProcessor</tt> processor,
  	 * which formats the type as a String using the supplied formatter.
  	 *
  	 * @param formatter the formatter to use
  	 * @throws NullPointerException if temporalAccessor or formatter is null
  	 */
  	public AbstractTemporalAccessorFormattingProcessor(final DateTimeFormatter formatter) {
  		checkPreconditions(formatter);
  		this.formatter = formatter;
  	}
  
  	/**
  	 * Constructs a new <tt>AbstractTemporalAccessorFormattingProcessor</tt> processor,
  	 * which formats the type as a String using the supplied formatter,
  	 * then calls the next processor in the chain.
  	 *
  	 * @param formatter the formatter to use
  	 * @param next      the next processor in the chain
  	 * @throws NullPointerException if temporalAccessor, formatter or next is null
  	 */
  	public AbstractTemporalAccessorFormattingProcessor(final DateTimeFormatter formatter, final CellProcessor next) {
  		super(next);
  		checkPreconditions(formatter);
  		this.formatter = formatter;
  	}
  
  	/**
  	 * Checks the preconditions for creating a new
  	 * AbstractTemporalAccessorFormattingProcessor processor.
  	 *
  	 * @param formatter the formatter
  	 * @throws NullPointerException if temporalAccessor or formatter is null
  	 */
  	private static void checkPreconditions(final DateTimeFormatter formatter) {
  		Objects.requireNonNull(formatter, "formatter should not be null");
  	}
  
  	/**
  	 * {@inheritDoc}
  	 *
  	 * @throws SuperCsvCellProcessorException if value is null, not the correct type, or can't be formatted
  	 */
  	public Object execute(final Object value, final CsvContext context) {
  		validateInputNotNull(value, context);
  		final Class<T> ourType = getType();
  		if( !(value.getClass().equals(ourType)) ) {
  			throw new SuperCsvCellProcessorException(ourType, value, context, this);
  		}
  		final TemporalAccessor timeType = ourType.cast(value);
  		try {
  			if( formatter != null ) {
  				return formatter.format(timeType);
 			} else {
 				return timeType.toString();
 			}
 		}
 		catch(DateTimeException | IllegalArgumentException e) {
 			throw new SuperCsvCellProcessorException(
 				String.format("Failed to format value as a %s", ourType.getSimpleName()), context, this, e);
 		}
 	}
 
 	/**
 	 * @return the type formatted by this subclass
 	 */
 	protected abstract Class<T> getType();
 
 }