/*
 * The Kuali Financial System, a comprehensive financial management system for higher education.
 * 
 * Copyright 2005-2014 The Kuali Foundation
 * 
 * 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 org.kuali.kfs.sys.document.service.impl;

import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.kuali.kfs.sys.document.service.AccountingLineTableTransformation;
import org.kuali.kfs.sys.document.web.AccountingLineTableCell;
import org.kuali.kfs.sys.document.web.AccountingLineTableRow;
import org.kuali.kfs.sys.document.web.RenderableElement;

/**
 * A transformation which takes all of the non-visible hidden fields of the accounting line and moves them
 * to the first possible position
 */
public class HiddenFieldRearrangementAccountingLineRenderingTransformationImpl implements AccountingLineTableTransformation {

    public void transformRows(List<AccountingLineTableRow> rows) {
        // 1. find the first top-level container element with non-hidden variables
        AccountingLineTableCell cell = findFirstNonHiddenCell(rows);
        // 2. move all the hidden fields
        for (AccountingLineTableRow row : rows) {
            moveHiddenFields(row, cell);
        }
    }
    
    /**
     * Finds the first top-level non-hidden container from the given list of elements
     * @param elements the elements to find the first non-hidden container from
     * @return the first top-level non-hidden container
     */
    protected AccountingLineTableCell findFirstNonHiddenCell(List<AccountingLineTableRow> rows) {
        for (AccountingLineTableRow row : rows) {
            for (AccountingLineTableCell cell : row.getCells()) {
                if (!cell.isHidden()) {
                    return cell;
                }
            }
        }
        throw new IllegalArgumentException("The renderable element tree specified does not seem to have any elements that will display as non-hidden specified");
    }
    
    /**
     * Moves any hidden fields in the source container to the target container 
     * @param sourceContainer the container which may have hidden fields
     * @param targetContainer the container which should be carrying all hidden fields
     */
    protected void moveHiddenFields(AccountingLineTableRow sourceRow, AccountingLineTableCell targetCell) {
        for (AccountingLineTableCell cell : sourceRow.getCells()) {
            moveHiddenFields(cell, targetCell);
        }
    }
    
    /**
     * Moves any hidden renderable fields in the source cell to the target cell
     * @param sourceCell the source cell to move hidden elements from
     * @param targetCell the target cell to move hidden elements to
     */
    protected void moveHiddenFields(AccountingLineTableCell sourceCell, AccountingLineTableCell targetCell) {
        Set<RenderableElement> renderableElementsToRemove = new HashSet<RenderableElement>();
        for (RenderableElement element : sourceCell.getRenderableElement()) {
            if (element.isHidden()) {
                renderableElementsToRemove.add(element);
            }
        }
        sourceCell.getRenderableElement().removeAll(renderableElementsToRemove);
        targetCell.getRenderableElement().addAll(renderableElementsToRemove);
    }
}