HtmlTable

/*
 * Copyright (c) 2002-2025 Gargoyle Software Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.htmlunit.html;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;

import org.htmlunit.ElementNotFoundException;
import org.htmlunit.SgmlPage;

/**
 * Wrapper for the HTML element "table".
 *
 * @author Mike Bowler
 * @author David K. Taylor
 * @author Christian Sell
 * @author Ahmed Ashour
 * @author Ronald Brill
 * @author Frank Danek
 */
public class HtmlTable extends HtmlElement {

    /** The HTML tag represented by this element. */
    public static final String TAG_NAME = "table";

    /**
     * Creates an instance.
     *
     * @param qualifiedName the qualified name of the element type to instantiate
     * @param page the page that contains this element
     * @param attributes the initial attributes
     */
    HtmlTable(final String qualifiedName, final SgmlPage page,
            final Map<String, DomAttr> attributes) {
        super(qualifiedName, page, attributes);
    }

    /**
     * Returns the first cell that matches the specified row and column, searching left to right, top to bottom.
     * <p>This method returns different values than getRow(rowIndex).getCell(cellIndex) because this takes cellspan
     * and rowspan into account.<br>
     * This means, a cell with colspan='2' consumes two columns; a cell with rowspan='3' consumes three rows. The
     * index is based on the 'background' model of the table; if you have a row like<br>
     * &lt;td&gt;cell1&lt;/td&gt; &lt;td colspan='2'&gt;cell2&lt;/td&gt; then this row is treated as a row with
     * three cells.<br>
     * <p>
     * <code>
     * getCellAt(rowIndex, 0).asText() returns "cell1";<br>
     * getCellAt(rowIndex, 1).asText() returns "cell2";<br>
     * getCellAt(rowIndex, 2).asText() returns "cell2"; and<br>
     * getCellAt(rowIndex, 3).asText() returns null;
     * </code>
     * </p>
     *
     * @param rowIndex the row index
     * @param columnIndex the column index
     * @return the HtmlTableCell at that location or null if there are no cells at that location
     */
    public final HtmlTableCell getCellAt(final int rowIndex, final int columnIndex) {
        final RowIterator rowIterator = getRowIterator();
        final HashSet<Position> occupied = new HashSet<>();
        int row = 0;
        for (final HtmlTableRow htmlTableRow : rowIterator) {
            final HtmlTableRow.CellIterator cellIterator = htmlTableRow.getCellIterator();
            int col = 0;
            for (final HtmlTableCell cell : cellIterator) {
                while (occupied.contains(new Position(row, col))) {
                    col++;
                }
                final int nextRow = row + cell.getRowSpan();
                if (row <= rowIndex && nextRow > rowIndex) {
                    final int nextCol = col + cell.getColumnSpan();
                    if (col <= columnIndex && nextCol > columnIndex) {
                        return cell;
                    }
                }
                final int rowSpan = cell.getRowSpan();
                final int columnSpan = cell.getColumnSpan();
                if (rowSpan > 1 || columnSpan > 1) {
                    for (int i = 0; i < rowSpan; i++) {
                        for (int j = 0; j < columnSpan; j++) {
                            occupied.add(new Position(row + i, col + j));
                        }
                    }
                }
                col++;
            }
            row++;
        }
        return null;
    }

    /**
     * @return an iterator over all the HtmlTableRow objects
     */
    private RowIterator getRowIterator() {
        return new RowIterator();
    }

    /**
     * @return an immutable list containing all the HtmlTableRow objects
     * @see #getRowIterator
     */
    public List<HtmlTableRow> getRows() {
        final List<HtmlTableRow> result = new ArrayList<>();
        for (final HtmlTableRow row : getRowIterator()) {
            result.add(row);
        }
        return Collections.unmodifiableList(result);
    }

    /**
     * @param index the 0-based index of the row
     * @return the HtmlTableRow at the given index
     * @throws IndexOutOfBoundsException if there is no row at the given index
     * @see #getRowIterator
     */
    public HtmlTableRow getRow(final int index) throws IndexOutOfBoundsException {
        int count = 0;
        for (final HtmlTableRow row : getRowIterator()) {
            if (count == index) {
                return row;
            }
            count++;
        }
        throw new IndexOutOfBoundsException("No row found for index " + index + ".");
    }

    /**
     * Computes the number of rows in this table. Note that the count is computed dynamically
     * by iterating over all rows.
     *
     * @return the number of rows in this table
     */
    public final int getRowCount() {
        int count = 0;
        for (final RowIterator iterator = getRowIterator(); iterator.hasNext(); iterator.next()) {
            count++;
        }
        return count;
    }

    /**
     * Finds and return the row with the specified id.
     *
     * @param id the id of the row
     * @return the row with the specified id
     * @exception ElementNotFoundException If the row cannot be found.
     */
    public final HtmlTableRow getRowById(final String id) throws ElementNotFoundException {
        for (final HtmlTableRow row : getRowIterator()) {
            if (row.getId().equals(id)) {
                return row;
            }
        }
        throw new ElementNotFoundException("tr", DomElement.ID_ATTRIBUTE, id);
    }

    /**
     * Returns the table caption text or an empty string if a caption wasn't specified.
     *
     * @return the caption text
     */
    public String getCaptionText() {
        for (final DomElement element : getChildElements()) {
            if (element instanceof HtmlCaption) {
                return element.asNormalizedText();
            }
        }
        return null;
    }

    /**
     * Returns the table header or null if a header wasn't specified.
     *
     * @return the table header
     */
    public HtmlTableHeader getHeader() {
        for (final DomElement element : getChildElements()) {
            if (element instanceof HtmlTableHeader) {
                return (HtmlTableHeader) element;
            }
        }
        return null;
    }

    /**
     * Returns the table footer or null if a footer wasn't specified.
     *
     * @return the table footer
     */
    public HtmlTableFooter getFooter() {
        for (final DomElement element : getChildElements()) {
            if (element instanceof HtmlTableFooter) {
                return (HtmlTableFooter) element;
            }
        }
        return null;
    }

    /**
     * Returns a list of tables bodies defined in this table. If no bodies were defined
     * then an empty list will be returned.
     *
     * @return a list of {@link HtmlTableBody} objects
     */
    public List<HtmlTableBody> getBodies() {
        final List<HtmlTableBody> bodies = new ArrayList<>();
        for (final DomElement element : getChildElements()) {
            if (element instanceof HtmlTableBody) {
                bodies.add((HtmlTableBody) element);
            }
        }
        return bodies;
    }

    /**
     * Returns the value of the attribute {@code summary}. Refer to the
     * <a href="http://www.w3.org/TR/html401/">HTML 4.01</a>
     * documentation for details on the use of this attribute.
     *
     * @return the value of the attribute {@code summary}
     *         or an empty string if that attribute isn't defined.
     */
    public final String getSummaryAttribute() {
        return getAttributeDirect("summary");
    }

    /**
     * Returns the value of the attribute {@code width}. Refer to the
     * <a href="http://www.w3.org/TR/html401/">HTML 4.01</a>
     * documentation for details on the use of this attribute.
     *
     * @return the value of the attribute {@code width}
     *         or an empty string if that attribute isn't defined.
     */
    public final String getWidthAttribute() {
        return getAttributeDirect("width");
    }

    /**
     * Returns the value of the attribute {@code border}. Refer to the
     * <a href="http://www.w3.org/TR/html401/">HTML 4.01</a>
     * documentation for details on the use of this attribute.
     *
     * @return the value of the attribute {@code border}
     *         or an empty string if that attribute isn't defined.
     */
    public final String getBorderAttribute() {
        return getAttributeDirect("border");
    }

    /**
     * Returns the value of the attribute {@code frame}. Refer to the
     * <a href="http://www.w3.org/TR/html401/">HTML 4.01</a>
     * documentation for details on the use of this attribute.
     *
     * @return the value of the attribute {@code frame}
     *         or an empty string if that attribute isn't defined.
     */
    public final String getFrameAttribute() {
        return getAttributeDirect("frame");
    }

    /**
     * Returns the value of the attribute {@code rules}. Refer to the
     * <a href="http://www.w3.org/TR/html401/">HTML 4.01</a>
     * documentation for details on the use of this attribute.
     *
     * @return the value of the attribute {@code rules}
     *         or an empty string if that attribute isn't defined.
     */
    public final String getRulesAttribute() {
        return getAttributeDirect("rules");
    }

    /**
     * Returns the value of the attribute {@code cellspacing}. Refer to the
     * <a href="http://www.w3.org/TR/html401/">HTML 4.01</a>
     * documentation for details on the use of this attribute.
     *
     * @return the value of the attribute {@code cellspacing}
     *         or an empty string if that attribute isn't defined.
     */
    public final String getCellSpacingAttribute() {
        return getAttributeDirect("cellspacing");
    }

    /**
     * Returns the value of the attribute {@code cellpadding}. Refer to the
     * <a href="http://www.w3.org/TR/html401/">HTML 4.01</a>
     * documentation for details on the use of this attribute.
     *
     * @return the value of the attribute {@code cellpadding}
     *         or an empty string if that attribute isn't defined.
     */
    public final String getCellPaddingAttribute() {
        return getAttributeDirect("cellpadding");
    }

    /**
     * Returns the value of the attribute {@code align}. Refer to the
     * <a href="http://www.w3.org/TR/html401/">HTML 4.01</a>
     * documentation for details on the use of this attribute.
     *
     * @return the value of the attribute {@code align}
     *         or an empty string if that attribute isn't defined.
     */
    public final String getAlignAttribute() {
        return getAttributeDirect("align");
    }

    /**
     * Returns the value of the attribute {@code bgcolor}. Refer to the
     * <a href="http://www.w3.org/TR/html401/">HTML 4.01</a>
     * documentation for details on the use of this attribute.
     *
     * @return the value of the attribute {@code bgcolor}
     *         or an empty string if that attribute isn't defined.
     */
    public final String getBgcolorAttribute() {
        return getAttributeDirect("bgcolor");
    }

    /**
     * An iterator that moves over all rows in this table. The iterator will also
     * enter into nested row group elements (header, footer and body).
     */
    private class RowIterator implements Iterator<HtmlTableRow>, Iterable<HtmlTableRow> {
        private HtmlTableRow nextRow_;
        private TableRowGroup currentGroup_;

        /** Creates a new instance. */
        RowIterator() {
            setNextRow(getFirstChild());
        }

        /**
         * @return {@code true} if there are more rows available
         */
        @Override
        public boolean hasNext() {
            return nextRow_ != null;
        }

        /**
         * @return the next row from this iterator
         * @throws NoSuchElementException if no more rows are available
         */
        @Override
        public HtmlTableRow next() throws NoSuchElementException {
            return nextRow();
        }

        /**
         * Removes the current row from the underlying table.
         */
        @Override
        public void remove() {
            if (nextRow_ == null) {
                throw new IllegalStateException();
            }
            final DomNode sibling = nextRow_.getPreviousSibling();
            if (sibling != null) {
                sibling.remove();
            }
        }

        /**
         * @return the next row from this iterator
         * @throws NoSuchElementException if no more rows are available
         */
        public HtmlTableRow nextRow() throws NoSuchElementException {
            if (nextRow_ != null) {
                final HtmlTableRow result = nextRow_;
                setNextRow(nextRow_.getNextSibling());
                return result;
            }
            throw new NoSuchElementException();
        }

        /**
         * Sets the internal position to the next row, starting at the given node.
         * @param node the node to mark as the next row; if this is not a row, the
         *        next reachable row will be marked.
         */
        private void setNextRow(final DomNode node) {
            nextRow_ = null;
            for (DomNode next = node; next != null; next = next.getNextSibling()) {
                if (next instanceof HtmlTableRow) {
                    nextRow_ = (HtmlTableRow) next;
                    return;
                }
                else if (currentGroup_ == null && next instanceof TableRowGroup) {
                    currentGroup_ = (TableRowGroup) next;
                    setNextRow(next.getFirstChild());
                    return;
                }
            }
            if (currentGroup_ != null) {
                final DomNode group = currentGroup_;
                currentGroup_ = null;
                setNextRow(group.getNextSibling());
            }
        }

        @Override
        public Iterator<HtmlTableRow> iterator() {
            return this;
        }
    }

    /**
     * {@inheritDoc}
     * @return {@code true} as browsers ignore self closing <code>table</code> tags.
     */
    @Override
    protected boolean isEmptyXmlTagExpanded() {
        return true;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public DisplayStyle getDefaultStyleDisplay() {
        return DisplayStyle.TABLE;
    }

    private static final class Position {

        private final int posX_;
        private final int posY_;

        Position(final int x, final int y) {
            posX_ = x;
            posY_ = y;
        }

        @Override
        public int hashCode() {
            final int prime = 31;
            int result = 1;
            result = prime * result + posX_;
            result = prime * result + posY_;
            return result;
        }

        @Override
        public boolean equals(final Object obj) {
            if (this == obj) {
                return true;
            }
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }

            final Position other = (Position) obj;
            if (posX_ != other.posX_) {
                return false;
            }
            if (posY_ != other.posY_) {
                return false;
            }

            return true;
        }
    }
}