/**

 * SQL-DK

 * Copyright © 2013 František Kučera (frantovo.cz)

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 *

 * 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program. If not, see <http://www.gnu.org/licenses/>.

 */

package info.globalcode.sql.dk.formatting;

import java.util.ArrayList;

import java.util.List;

/**

 * <p>

 * Prefetches whole result set and computes column widths. Whole table is flushed at once in

 * {@linkplain #writeEndResultSet()}.

 * </p>

 *

 * <p>

 * Long values will not overflow the cells, but whole result set must be loaded into the memory.

 * </p>

 *

 * @author Ing. František Kučera (frantovo.cz)

 */

public class TabularPrefetchingFormatter extends TabularFormatter {

	public static final String NAME = "tabular-prefetching"; // bash-completion:formatter

	private ColumnsHeader currentHeader;

	private List<Object[]> currentResultSet;

	private Object[] currentRow;

	private int currentColumnsCount;

	private boolean prefetchDone = false;

	public TabularPrefetchingFormatter(FormatterContext formatterContext) {

		super(formatterContext);

	}

	@Override

	protected int getCurrentColumnsCount() {

		if (prefetchDone) {

			return super.getCurrentColumnsCount();

		} else {

			return currentColumnsCount;

		}

	}

	@Override

	public void writeStartResultSet(ColumnsHeader header) {

		currentResultSet = new ArrayList<>();

		currentHeader = header;

		initColumnWidths(header.getColumnCount());

	}

	@Override

	public void writeStartRow() {

		currentRow = new Object[currentHeader.getColumnCount()];

		currentResultSet.add(currentRow);

		currentColumnsCount = 0;

	}

	@Override

	public void writeColumnValue(Object value) {

		currentRow[currentColumnsCount] = value;

		currentColumnsCount++;

		String textRepresentation = toString(value);

		/** TODO: count only printable characters (currently not an issue) */

		updateColumnWidth(currentColumnsCount, textRepresentation.length());

	}

	@Override

	public void writeEndRow() {

		// do nothing

	}

	@Override

	public void writeEndResultSet() {

		prefetchDone = true;

		postprocessPrefetchedResultSet(currentHeader, currentResultSet);

		super.writeStartResultSet(currentHeader);

		for (Object[] row : currentResultSet) {

			super.writeStartRow();

			for (Object cell : row) {

				super.writeColumnValue(cell);

			}

			super.writeEndRow();

		}

		currentColumnsCount = 0;

		currentHeader = null;

		currentRow = null;

		currentResultSet = null;

		super.writeEndResultSet();

		prefetchDone = false;

	}

	/**

	 * Optional post-processing – override in sub-classes if needed.

	 * Don't forget to {@linkplain #updateColumnWidth(int, int)}

	 *

	 * @param currentHeader

	 * @param currentResultSet

	 */

	protected void postprocessPrefetchedResultSet(ColumnsHeader currentHeader, List<Object[]> currentResultSet) {

	}

}