/*
 *  RapidMiner
 *
 *  Copyright (C) 2001-2014 by RapidMiner and the contributors
 *
 *  Complete list of developers available at our web site:
 *
 *       http://rapidminer.com
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
 */
package com.rapidminer.datatable;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Vector;

/**
 * A view on a parent DataTable which maps values from the parent table to other values.
 * Can e.g. be used to change the mapping of nominal values.
 * 
 * @author Marius Helf
 */
public class ValueMappingDataTableView extends AbstractDataTable implements DataTableListener {

	public static interface MappedDataTableListener {
		/**
		 * This method is called by a datatable, if its content is changed.
		 */
		public void informDataTableChange(DataTable dataTable);
	}

	private List<MappedDataTableListener> listeners = new LinkedList<MappedDataTableListener>();
	
	private DataTable parentTable;
	private Vector<DataTableMappingProvider> mappings;
	
	public ValueMappingDataTableView(DataTable parentDataTable) {
		super(parentDataTable.getName());
		this.parentTable = parentDataTable;
		
		// init mappings with nulls
		int columnCount = parentTable.getColumnNumber();
		mappings = new Vector<DataTableMappingProvider>(columnCount);
		for (int i = 0; i < columnCount; ++i) {
			mappings.add(null);
		}
		
		parentTable.addDataTableListener(this);
	}
	
	double mapValue(double originalValue, int columnIdx) {
		double mappedValue = originalValue;
		
		if (mappings.elementAt(columnIdx) != null) {
			mappedValue = mappings.elementAt(columnIdx).mapFromParentValue(originalValue);
		}
		
		return mappedValue;
	}

	@Override
	public Iterator<DataTableRow> iterator() {
		return new Iterator<DataTableRow>() {
			int nextRow = 0;
			@Override
			public boolean hasNext() {
				return nextRow < getNumberOfRows();
			}

			@Override
			public DataTableRow next() {
				DataTableRow row = getRow(nextRow);
				nextRow++;
				return row;
			}

			@Override
			public void remove() {
				throw new UnsupportedOperationException("remove() not suppported by FilterDataTable");
			}
		};
	}

	@Override
	public DataTableRow getRow(int index) {
		return new ValueMappingDataTableRow(parentTable.getRow(index), this);
	}

	@Override
	public int getNumberOfRows() {
		return parentTable.getNumberOfRows();
	}

	
	public void setMappingProvider(int columnIdx, DataTableMappingProvider mapping) {
		if (mapping != mappings.elementAt(columnIdx)) {
			mappings.set(columnIdx, mapping);
			informMappedDataTableListeners();
			fireEvent();
		}
	}
	
	/*
	 * Listener Methods
	 */
	public void addMappedDataTableListener(MappedDataTableListener listener) {
		this.listeners.add(listener);
	}
	
	public void removeMappedDataTableListewner(MappedDataTableListener listener) {
		this.listeners.remove(listener);
	}
	
	private void informMappedDataTableListeners() {
		for (MappedDataTableListener listener: listeners) {
			listener.informDataTableChange(this);
		}
	}
	/*
	 *  Delegating methods
	 */

	@Override
	public void add(DataTableRow row) {
		parentTable.add(row);
	}

	@Override
	public int getColumnIndex(String name) {
		return parentTable.getColumnIndex(name);
	}

	@Override
	public String getColumnName(int i) {
		return parentTable.getColumnName(i);
	}

	@Override
	public double getColumnWeight(int i) {
		return parentTable.getColumnWeight(i);
	}

	@Override
	public int getNumberOfColumns() {
		return parentTable.getNumberOfColumns();
	}

	@Override
	public int getNumberOfSpecialColumns() {
		return parentTable.getNumberOfSpecialColumns();
	}

	@Override
	public int getNumberOfValues(int column) {
		return parentTable.getNumberOfValues(column);
	}

	@Override
	public boolean isDate(int index) {
		return parentTable.isDate(index);
	}

	@Override
	public boolean isDateTime(int index) {
		return parentTable.isDateTime(index);
	}

	@Override
	public boolean isNominal(int index) {
		return parentTable.isNominal(index);
	}

	@Override
	public boolean isNumerical(int index) {
		return parentTable.isNumerical(index);
	}

	@Override
	public boolean isSpecial(int column) {
		return parentTable.isSpecial(column);
	}

	@Override
	public boolean isSupportingColumnWeights() {
		return parentTable.isSupportingColumnWeights();
	}

	@Override
	public boolean isTime(int index) {
		return parentTable.isTime(index);
	}

	@Override
	public String mapIndex(int column, int index) {
		int parentIdx = index;
		DataTableMappingProvider mapping = mappings.elementAt(column);
		if (mapping != null) {
			if (mapping instanceof BidirectionalMappingProvider) {
				BidirectionalMappingProvider bidiMapping = (BidirectionalMappingProvider)mapping;
				parentIdx = (int)bidiMapping.mapToParentValue(index);	
			} else {
				return null;
			}
		}
		return parentTable.mapIndex(column, parentIdx);
	}

	@Override
	public int mapString(int column, String value) {
		int index = parentTable.mapString(column, value);

		return (int)mapValue(index, column);
	}

	@Override
	public DataTable sample(int newSize) {
//		return parentTable.sample(newSize);
		return this;
	}

	@Override
	public void dataTableUpdated(DataTable source) {
		fireEvent();
	}
	
	public DataTable getParent() {
		return parentTable;
	}
}