/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
 *
 *      http://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.
 */

/* $Id: RowPainter.java 1761021 2016-09-16 11:40:57Z ssteiner $ */

package org.apache.fop.layoutmgr.table;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.ListIterator;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.apache.fop.area.Block;
import org.apache.fop.area.Trait;
import org.apache.fop.fo.flow.table.ConditionalBorder;
import org.apache.fop.fo.flow.table.EffRow;
import org.apache.fop.fo.flow.table.EmptyGridUnit;
import org.apache.fop.fo.flow.table.GridUnit;
import org.apache.fop.fo.flow.table.PrimaryGridUnit;
import org.apache.fop.fo.flow.table.Table;
import org.apache.fop.fo.flow.table.TableColumn;
import org.apache.fop.fo.flow.table.TablePart;
import org.apache.fop.fo.properties.CommonBorderPaddingBackground;
import org.apache.fop.fo.properties.CommonBorderPaddingBackground.BorderInfo;
import org.apache.fop.layoutmgr.ElementListUtils;
import org.apache.fop.layoutmgr.KnuthElement;
import org.apache.fop.layoutmgr.KnuthPossPosIter;
import org.apache.fop.layoutmgr.LayoutContext;
import org.apache.fop.layoutmgr.SpaceResolver;
import org.apache.fop.layoutmgr.TraitSetter;

class RowPainter {
    private static Log log = LogFactory.getLog(RowPainter.class);
    private int colCount;
    private int currentRowOffset;
    
Currently handled row (= last encountered row). /** Currently handled row (= last encountered row). */
    private EffRow currentRow;
    private LayoutContext layoutContext;
    
Index of the first row of the current part present on the current page.
/**
     * Index of the first row of the current part present on the current page.
     */
    private int firstRowIndex;

    
Index of the very first row on the current page. Needed to properly handle COLLAPSE_OUTER.COLLAPSE_OUTER. This is not the same as firstRowIndex when the table has headers! /**
     * Index of the very first row on the current page. Needed to properly handle
     * {@link BorderProps#COLLAPSE_OUTER}. This is not the same as {@link #firstRowIndex}
     * when the table has headers!
     */
    private int firstRowOnPageIndex;

    
Keeps track of the y-offsets of each row on a page.
This is particularly needed for spanned cells where you need to know the y-offset
of the starting row when the area is generated at the time the cell is closed.
/**
     * Keeps track of the y-offsets of each row on a page.
     * This is particularly needed for spanned cells where you need to know the y-offset
     * of the starting row when the area is generated at the time the cell is closed.
     */
    private List rowOffsets = new ArrayList();

    private int[] cellHeights;
    private boolean[] firstCellOnPage;
    private CellPart[] firstCellParts;
    private CellPart[] lastCellParts;

    
y-offset of the current table part. /** y-offset of the current table part. */
    private int tablePartOffset;
    
See registerPartBackgroundArea(Block). /** See {@link RowPainter#registerPartBackgroundArea(Block)}. */
    private CommonBorderPaddingBackground tablePartBackground;
    
See registerPartBackgroundArea(Block). /** See {@link RowPainter#registerPartBackgroundArea(Block)}. */
    private List tablePartBackgroundAreas;

    private TableContentLayoutManager tclm;

    RowPainter(TableContentLayoutManager tclm, LayoutContext layoutContext) {
        this.tclm = tclm;
        this.layoutContext = layoutContext;
        this.colCount = tclm.getColumns().getColumnCount();
        this.cellHeights = new int[colCount];
        this.firstCellOnPage = new boolean[colCount];
        this.firstCellParts = new CellPart[colCount];
        this.lastCellParts = new CellPart[colCount];
        this.firstRowIndex = -1;
        this.firstRowOnPageIndex = -1;
    }

    void startTablePart(TablePart tablePart) {
        CommonBorderPaddingBackground background = tablePart.getCommonBorderPaddingBackground();
        if (background.hasBackground()) {
            tablePartBackground = background;
            if (tablePartBackgroundAreas == null) {
                tablePartBackgroundAreas = new ArrayList();
            }
        }
        tablePartOffset = currentRowOffset;
    }

    
Signals that the end of the current table part is reached.
Params:
lastInBody – true if the part is the last table-body element to be displayed
on the current page. In which case all the cells must be flushed even if they
aren't finished, plus the proper collapsed borders must be selected (trailing
instead of normal, or rest if the cell is unfinished)
lastOnPage – true if the part is the last to be displayed on the current page.
In which case collapsed after borders for the cells on the last row must be drawn
in the outer mode/**
     * Signals that the end of the current table part is reached.
     *
     * @param lastInBody true if the part is the last table-body element to be displayed
     * on the current page. In which case all the cells must be flushed even if they
     * aren't finished, plus the proper collapsed borders must be selected (trailing
     * instead of normal, or rest if the cell is unfinished)
     * @param lastOnPage true if the part is the last to be displayed on the current page.
     * In which case collapsed after borders for the cells on the last row must be drawn
     * in the outer mode
     */
    void endTablePart(boolean lastInBody, boolean lastOnPage) {
        addAreasAndFlushRow(lastInBody, lastOnPage);

        if (tablePartBackground != null) {
            TableLayoutManager tableLM = tclm.getTableLM();
            for (Object tablePartBackgroundArea : tablePartBackgroundAreas) {
                Block backgroundArea = (Block) tablePartBackgroundArea;
                TraitSetter.addBackground(backgroundArea, tablePartBackground, tableLM,
                        -backgroundArea.getXOffset(), tablePartOffset - backgroundArea.getYOffset(),
                        tableLM.getContentAreaIPD(), currentRowOffset - tablePartOffset);
            }
            tablePartBackground = null;
            tablePartBackgroundAreas.clear();
        }
    }

    int getAccumulatedBPD() {
        return currentRowOffset;
    }

    
Records the fragment of row represented by the given position. If it belongs to
another (grid) row than the current one, that latter is painted and flushed first.
Params:
tcpos – a position representing the row fragment/**
     * Records the fragment of row represented by the given position. If it belongs to
     * another (grid) row than the current one, that latter is painted and flushed first.
     *
     * @param tcpos a position representing the row fragment
     */
    void handleTableContentPosition(TableContentPosition tcpos) {
        if (log.isDebugEnabled()) {
            log.debug("===handleTableContentPosition(" + tcpos);
        }
        if (currentRow == null) {
            currentRow = tcpos.getNewPageRow();
        } else {
            EffRow row = tcpos.getRow();
            if (row.getIndex() > currentRow.getIndex()) {
                addAreasAndFlushRow(false, false);
                currentRow = row;
            }
        }
        if (firstRowIndex < 0) {
            firstRowIndex = currentRow.getIndex();
            if (firstRowOnPageIndex < 0) {
                firstRowOnPageIndex = firstRowIndex;
            }
        }
        //Iterate over all grid units in the current step
        for (Object cellPart1 : tcpos.cellParts) {
            CellPart cellPart = (CellPart) cellPart1;
            if (log.isDebugEnabled()) {
                log.debug(">" + cellPart);
            }
            int colIndex = cellPart.pgu.getColIndex();
            if (firstCellParts[colIndex] == null) {
                firstCellParts[colIndex] = cellPart;
                cellHeights[colIndex] = cellPart.getBorderPaddingBefore(firstCellOnPage[colIndex]);
            } else {
                assert firstCellParts[colIndex].pgu == cellPart.pgu;
                cellHeights[colIndex] += cellPart.getConditionalBeforeContentLength();
            }
            cellHeights[colIndex] += cellPart.getLength();
            lastCellParts[colIndex] = cellPart;
        }
    }

    
Creates the areas corresponding to the last row. That is, an area with background
for the row, plus areas for all the cells that finish on the row (not spanning over
further rows).
Params:
lastInPart – true if the row is the last from its table part to be displayed
on the current page. In which case all the cells must be flushed even if they
aren't finished, plus the proper collapsed borders must be selected (trailing
instead of normal, or rest if the cell is unfinished)
lastOnPage – true if the row is the very last row of the table that will be
displayed on the current page. In which case collapsed after borders must be drawn
in the outer mode/**
     * Creates the areas corresponding to the last row. That is, an area with background
     * for the row, plus areas for all the cells that finish on the row (not spanning over
     * further rows).
     *
     * @param lastInPart true if the row is the last from its table part to be displayed
     * on the current page. In which case all the cells must be flushed even if they
     * aren't finished, plus the proper collapsed borders must be selected (trailing
     * instead of normal, or rest if the cell is unfinished)
     * @param lastOnPage true if the row is the very last row of the table that will be
     * displayed on the current page. In which case collapsed after borders must be drawn
     * in the outer mode
     */
    private void addAreasAndFlushRow(boolean lastInPart, boolean lastOnPage) {
        if (log.isDebugEnabled()) {
            log.debug("Remembering yoffset for row " + currentRow.getIndex() + ": "
                    + currentRowOffset);
        }
        recordRowOffset(currentRow.getIndex(), currentRowOffset);

        // Need to compute the actual row height first
        // and determine border behaviour for empty cells
        boolean firstCellPart = true;
        boolean lastCellPart = true;
        int actualRowHeight = 0;
        for (int i = 0; i < colCount; i++) {
            GridUnit currentGU = currentRow.getGridUnit(i);
            if (currentGU.isEmpty()) {
                continue;
            }
            if (currentGU.getColSpanIndex() == 0
                    && (lastInPart || currentGU.isLastGridUnitRowSpan())
                    && firstCellParts[i] != null) {
                // TODO
                // The last test above is a workaround for the stepping algorithm's
                // fundamental flaw making it unable to produce the right element list for
                // multiple breaks inside a same row group.
                // (see http://wiki.apache.org/xmlgraphics-fop/TableLayout/KnownProblems)
                // In some extremely rare cases (forced breaks, very small page height), a
                // TableContentPosition produced during row delaying may end up alone on a
                // page. It will not contain the CellPart instances for the cells starting
                // the next row, so firstCellParts[i] will still be null for those ones.
                int cellHeight = cellHeights[i];
                cellHeight += lastCellParts[i].getConditionalAfterContentLength();
                cellHeight += lastCellParts[i].getBorderPaddingAfter(lastInPart);
                int cellOffset = getRowOffset(Math.max(firstCellParts[i].pgu.getRowIndex(),
                        firstRowIndex));
                actualRowHeight = Math.max(actualRowHeight, cellOffset + cellHeight
                        - currentRowOffset);
            }

            if (firstCellParts[i] != null && !firstCellParts[i].isFirstPart()) {
                firstCellPart = false;
            }
            if (lastCellParts[i] != null && !lastCellParts[i].isLastPart()) {
                lastCellPart = false;
            }
        }

        // Then add areas for cells finishing on the current row
        for (int i = 0; i < colCount; i++) {
            GridUnit currentGU = currentRow.getGridUnit(i);
            if (currentGU.isEmpty() && !tclm.isSeparateBorderModel()) {
                int borderBeforeWhich;
                if (firstCellPart) {
                    if (firstCellOnPage[i]) {
                        borderBeforeWhich = ConditionalBorder.LEADING_TRAILING;
                    } else {
                        borderBeforeWhich = ConditionalBorder.NORMAL;
                    }
                } else {
                    borderBeforeWhich = ConditionalBorder.REST;
                }
                int borderAfterWhich;
                if (lastCellPart) {
                    if (lastInPart) {
                        borderAfterWhich = ConditionalBorder.LEADING_TRAILING;
                    } else {
                        borderAfterWhich = ConditionalBorder.NORMAL;
                    }
                } else {
                    borderAfterWhich = ConditionalBorder.REST;
                }
                assert (currentGU instanceof EmptyGridUnit);
                addAreaForEmptyGridUnit((EmptyGridUnit)currentGU,
                        currentRow.getIndex(), i,
                        actualRowHeight,
                        borderBeforeWhich, borderAfterWhich,
                        lastOnPage);

                firstCellOnPage[i] = false;
            } else if (currentGU.getColSpanIndex() == 0
                    && (lastInPart || currentGU.isLastGridUnitRowSpan())
                    && firstCellParts[i] != null) {
                assert firstCellParts[i].pgu == currentGU.getPrimary();

                int borderBeforeWhich;
                if (firstCellParts[i].isFirstPart()) {
                    if (firstCellOnPage[i]) {
                        borderBeforeWhich = ConditionalBorder.LEADING_TRAILING;
                    } else {
                        borderBeforeWhich = ConditionalBorder.NORMAL;
                    }
                } else {
                    assert firstCellOnPage[i];
                    borderBeforeWhich = ConditionalBorder.REST;
                }
                int borderAfterWhich;
                if (lastCellParts[i].isLastPart()) {
                    if (lastInPart) {
                        borderAfterWhich = ConditionalBorder.LEADING_TRAILING;
                    } else {
                        borderAfterWhich = ConditionalBorder.NORMAL;
                    }
                } else {
                    borderAfterWhich = ConditionalBorder.REST;
                }

                // when adding the areas for the TableCellLayoutManager this helps with the isLast trait
                // if, say, the first cell of a row has content that fits in the page, but the content of
                // the second cell does not fit this will assure that the isLast trait for the first cell
                // will also be false
                lastCellParts[i].pgu.getCellLM().setLastTrait(lastCellParts[i].isLastPart());
                addAreasForCell(firstCellParts[i].pgu,
                        firstCellParts[i].start, lastCellParts[i].end,
                        actualRowHeight, borderBeforeWhich, borderAfterWhich,
                        lastOnPage);
                firstCellParts[i] = null; // why? what about the lastCellParts[i]?
                Arrays.fill(firstCellOnPage, i, i + currentGU.getCell().getNumberColumnsSpanned(),
                        false);
            }
        }
        currentRowOffset += actualRowHeight;
        if (lastInPart) {
            /*
             * Either the end of the page is reached, then this was the last call of this
             * method and we no longer care about currentRow; or the end of a table-part
             * (header, footer, body) has been reached, and the next row will anyway be
             * different from the current one, and this is unnecessary to call this method
             * again in the first lines of handleTableContentPosition, so we may reset the
             * following variables.
             */
            currentRow = null;
            firstRowIndex = -1;
            rowOffsets.clear();
            /*
             * The current table part has just been handled. Be it the first one or not,
             * the header or the body, in any case the borders-before of the next row
             * (i.e., the first row of the next part if any) must be painted in
             * COLLAPSE_INNER mode. So the firstRowOnPageIndex indicator must be kept
             * disabled. The following way is not the most elegant one but will be good
             * enough.
             */
            firstRowOnPageIndex = Integer.MAX_VALUE;
        }
    }

    // TODO this is not very efficient and should probably be done another way
    // this method is only necessary when display-align = center or after, in which case
    // the exact content length is needed to compute the size of the empty block that will
    // be used as padding.
    // This should be handled automatically by a proper use of Knuth elements
    private int computeContentLength(PrimaryGridUnit pgu, int startIndex, int endIndex) {
        if (startIndex > endIndex) {
             // May happen if the cell contributes no content on the current page (empty
             // cell, in most cases)
            return 0;
        } else {
            ListIterator iter = pgu.getElements().listIterator(startIndex);
            // Skip from the content length calculation glues and penalties occurring at the
            // beginning of the page
            boolean nextIsBox = false;
            while (iter.nextIndex() <= endIndex && !nextIsBox) {
                nextIsBox = ((KnuthElement) iter.next()).isBox();
            }
            int len = 0;
            if (((KnuthElement) iter.previous()).isBox()) {
                while (iter.nextIndex() < endIndex) {
                    KnuthElement el = (KnuthElement) iter.next();
                    if (el.isBox() || el.isGlue()) {
                        len += el.getWidth();
                    }
                }
                len += ActiveCell.getElementContentLength((KnuthElement) iter.next());
            }
            return len;
        }
    }

    private void addAreasForCell(PrimaryGridUnit pgu, int startPos, int endPos,
            int rowHeight, int borderBeforeWhich, int borderAfterWhich, boolean lastOnPage) {
        /*
         * Determine the index of the first row of this cell that will be displayed on the
         * current page.
         */
        int currentRowIndex = currentRow.getIndex();
        int startRowIndex;
        int firstRowHeight;
        if (pgu.getRowIndex() >= firstRowIndex) {
            startRowIndex = pgu.getRowIndex();
            if (startRowIndex < currentRowIndex) {
                firstRowHeight = getRowOffset(startRowIndex + 1) - getRowOffset(startRowIndex);
            } else {
                firstRowHeight = rowHeight;
            }
        } else {
            startRowIndex = firstRowIndex;
            firstRowHeight = 0;
        }

        /*
         * In collapsing-border model, if the cell spans over several columns/rows then
         * dedicated areas will be created for each grid unit to hold the corresponding
         * borders. For that we need to know the height of each grid unit, that is of each
         * grid row spanned over by the cell
         */
        int[] spannedGridRowHeights = null;
        if (!tclm.getTableLM().getTable().isSeparateBorderModel() && pgu.hasSpanning()) {
            spannedGridRowHeights = new int[currentRowIndex - startRowIndex + 1];
            int prevOffset = getRowOffset(startRowIndex);
            for (int i = 0; i < currentRowIndex - startRowIndex; i++) {
                int newOffset = getRowOffset(startRowIndex + i + 1);
                spannedGridRowHeights[i] = newOffset - prevOffset;
                prevOffset = newOffset;
            }
            spannedGridRowHeights[currentRowIndex - startRowIndex] = rowHeight;
        }
        int cellOffset = getRowOffset(startRowIndex);
        int cellTotalHeight = rowHeight + currentRowOffset - cellOffset;
        if (log.isDebugEnabled()) {
            log.debug("Creating area for cell:");
            log.debug("  start row: " + pgu.getRowIndex() + " " + currentRowOffset + " "
                    + cellOffset);
            log.debug(" rowHeight=" + rowHeight + " cellTotalHeight=" + cellTotalHeight);
        }
        TableCellLayoutManager cellLM = pgu.getCellLM();
        cellLM.setXOffset(tclm.getXOffsetOfGridUnit(pgu));
        cellLM.setYOffset(cellOffset);
        cellLM.setContentHeight(computeContentLength(pgu, startPos, endPos));
        cellLM.setTotalHeight(cellTotalHeight);
        int prevBreak = ElementListUtils.determinePreviousBreak(pgu.getElements(), startPos);
        if (endPos >= 0) {
            SpaceResolver.performConditionalsNotification(pgu.getElements(),
                    startPos, endPos, prevBreak);
        }
        cellLM.addAreas(new KnuthPossPosIter(pgu.getElements(), startPos, endPos + 1),
                layoutContext, spannedGridRowHeights, startRowIndex - pgu.getRowIndex(),
                currentRowIndex - pgu.getRowIndex(), borderBeforeWhich, borderAfterWhich,
                startRowIndex == firstRowOnPageIndex, lastOnPage, this, firstRowHeight);
    }

    private void addAreaForEmptyGridUnit(EmptyGridUnit gu, int rowIndex, int colIndex,
            int actualRowHeight,
            int borderBeforeWhich, int borderAfterWhich, boolean lastOnPage) {

        //get effective borders
        BorderInfo borderBefore = gu.getBorderBefore(borderBeforeWhich);
        BorderInfo borderAfter = gu.getBorderAfter(borderAfterWhich);
        BorderInfo borderStart = gu.getBorderStart();
        BorderInfo borderEnd = gu.getBorderEnd();
        if (borderBefore.getRetainedWidth() == 0
                && borderAfter.getRetainedWidth() == 0
                && borderStart.getRetainedWidth() == 0
                && borderEnd.getRetainedWidth() == 0) {
            return; //no borders, no area necessary
        }

        TableLayoutManager tableLM = tclm.getTableLM();
        Table table = tableLM.getTable();
        TableColumn col = tclm.getColumns().getColumn(colIndex + 1);

        //position information
        boolean firstOnPage = (rowIndex == firstRowOnPageIndex);
        boolean inFirstColumn = (colIndex == 0);
        boolean inLastColumn = (colIndex == table.getNumberOfColumns() - 1);

        //determine the block area's size
        int ipd = col.getColumnWidth().getValue(tableLM);
        ipd -= (borderStart.getRetainedWidth() + borderEnd.getRetainedWidth()) / 2;
        int bpd = actualRowHeight;
        bpd -= (borderBefore.getRetainedWidth() + borderAfter.getRetainedWidth()) / 2;

        //generate the block area
        Block block = new Block();
        block.setPositioning(Block.ABSOLUTE);
        block.addTrait(Trait.IS_REFERENCE_AREA, Boolean.TRUE);
        block.setIPD(ipd);
        block.setBPD(bpd);
        block.setXOffset(tclm.getXOffsetOfGridUnit(colIndex, 1)
                + (borderStart.getRetainedWidth() / 2));
        block.setYOffset(getRowOffset(rowIndex)
                - (borderBefore.getRetainedWidth() / 2));
        boolean[] outer = new boolean[] {firstOnPage, lastOnPage, inFirstColumn,
                inLastColumn};
        TraitSetter.addCollapsingBorders(block,
                borderBefore,
                borderAfter,
                borderStart,
                borderEnd, outer);
        tableLM.addChildArea(block);
    }

    
Registers the given area, that will be used to render the part of table-header/footer/body background covered by a table-cell. If percentages are used to place the background image, the final bpd of the (fraction of) table part that will be rendered on the current page must be known. The traits can't then be set when the areas for the cell are created since at that moment this bpd is yet unknown. So they will instead be set in addAreasAndFlushRow(boolean, boolean). 
Params:
backgroundArea – the block of the cell's dimensions that will hold the part
background/**
     * Registers the given area, that will be used to render the part of
     * table-header/footer/body background covered by a table-cell. If percentages are
     * used to place the background image, the final bpd of the (fraction of) table part
     * that will be rendered on the current page must be known. The traits can't then be
     * set when the areas for the cell are created since at that moment this bpd is yet
     * unknown. So they will instead be set in
     * {@link #addAreasAndFlushRow(boolean, boolean)}.
     *
     * @param backgroundArea the block of the cell's dimensions that will hold the part
     * background
     */
    void registerPartBackgroundArea(Block backgroundArea) {
        tclm.getTableLM().addBackgroundArea(backgroundArea);
        tablePartBackgroundAreas.add(backgroundArea);
    }

    
Records the y-offset of the row with the given index.
Params:
rowIndex – index of the row
offset – y-offset of the row on the page/**
     * Records the y-offset of the row with the given index.
     *
     * @param rowIndex index of the row
     * @param offset y-offset of the row on the page
     */
    private void recordRowOffset(int rowIndex, int offset) {
        /*
         * In some very rare cases a row may be skipped. See for example Bugzilla #43633:
         * in a two-column table, a row contains a row-spanning cell and a missing cell.
         * In TableStepper#goToNextRowIfCurrentFinished this row will immediately be
         * considered as finished, since it contains no cell ending on this row. Thus no
         * TableContentPosition will be created for this row. Thus its index will never be
         * recorded by the #handleTableContentPosition method.
         *
         * The offset of such a row is the same as the next non-empty row. It's needed
         * to correctly offset blocks for cells starting on this row. Hence the loop
         * below.
         */
        for (int i = rowOffsets.size(); i <= rowIndex - firstRowIndex; i++) {
            rowOffsets.add(offset);
        }
    }

    
Returns the offset of the row with the given index.
Params:
rowIndex – index of the row
Returns:
its y-offset on the page/**
     * Returns the offset of the row with the given index.
     *
     * @param rowIndex index of the row
     * @return its y-offset on the page
     */
    private int getRowOffset(int rowIndex) {
        return (Integer) rowOffsets.get(rowIndex - firstRowIndex);
    }

    // TODO get rid of that
    
Signals that the first table-body instance has started. /** Signals that the first table-body instance has started. */
    void startBody() {
        Arrays.fill(firstCellOnPage, true);
    }

    // TODO get rid of that
    
Signals that the last table-body instance has ended. /** Signals that the last table-body instance has ended. */
    void endBody() {
        Arrays.fill(firstCellOnPage, false);
    }
}