/*

 * This file is part of the HTML rendering engine for KDE.

 *

 * Copyright (C) 2002 Lars Knoll (knoll@kde.org)

 *           (C) 2002 Dirk Mueller (mueller@kde.org)

 * Copyright (C) 2003, 2006 Apple Computer, Inc.

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Library General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License.

 *

 * This library 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

 * Library General Public License for more details.

 *

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

 * along with this library; see the file COPYING.LIB.  If not, write to

 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,

 * Boston, MA 02110-1301, USA.

 */

#include "config.h"

#include "AutoTableLayout.h"

#include "RenderTable.h"

#include "RenderTableCell.h"

#include "RenderTableCol.h"

#include "RenderTableSection.h"

using namespace std;

namespace WebCore {

AutoTableLayout::AutoTableLayout(RenderTable* table)

    : TableLayout(table)

    , m_hasPercent(false)

    , m_percentagesDirty(true)

    , m_effWidthDirty(true)

    , m_totalPercent(0)

{

}

AutoTableLayout::~AutoTableLayout()

{

}

/* recalculates the full structure needed to do layouting and minmax calculations.

   This is usually calculated on the fly, but needs to be done fully when table cells change

   dynamically

*/

void AutoTableLayout::recalcColumn(int effCol)

{

    Layout &l = m_layoutStruct[effCol];

    RenderObject* child = m_table->firstChild();

    // first we iterate over all rows.

    RenderTableCell* fixedContributor = 0;

    RenderTableCell* maxContributor = 0;

    while (child) {

        if (child->isTableSection()) {

            RenderTableSection* section = static_cast<RenderTableSection*>(child);

            int numRows = section->numRows();

            RenderTableCell* last = 0;

            for (int i = 0; i < numRows; i++) {

                RenderTableSection::CellStruct current = section->cellAt(i, effCol);

                RenderTableCell* cell = current.cell;

                bool cellHasContent = cell && (cell->firstChild() || m_table->cellPadding() || cell->style()->hasBorder() || cell->style()->hasPadding());

                if (cellHasContent)

                    l.emptyCellsOnly = false;

                if (current.inColSpan)

                    continue;

                if (cell && cell->colSpan() == 1) {

                    // A cell originates in this column.  Ensure we have

                    // a min/max width of at least 1px for this column now.

                    l.minWidth = max(l.minWidth, cellHasContent ? 1 : 0);

                    l.maxWidth = max(l.maxWidth, 1);

                    if (cell->prefWidthsDirty())

                        cell->calcPrefWidths();

                    l.minWidth = max(cell->minPrefWidth(), l.minWidth);

                    if (cell->maxPrefWidth() > l.maxWidth) {

                        l.maxWidth = cell->maxPrefWidth();

                        maxContributor = cell;

                    }

                    Length w = cell->styleOrColWidth();

                    // FIXME: What is this arbitrary value?

                    if (w.rawValue() > 32760)

                        w.setRawValue(32760);

                    if (w.isNegative())

                        w.setValue(0);

                    switch(w.type()) {

                    case Fixed:

                        // ignore width=0

                        if (w.value() > 0 && (int)l.width.type() != Percent) {

                            int wval = cell->calcBorderBoxWidth(w.value());

                            if (l.width.isFixed()) {

                                // Nav/IE weirdness

                                if ((wval > l.width.value()) ||

                                    ((l.width.value() == wval) && (maxContributor == cell))) {

                                    l.width.setValue(wval);

                                    fixedContributor = cell;

                                }

                            } else {

                                l.width.setValue(Fixed, wval);

                                fixedContributor = cell;

                            }

                        }

                        break;

                    case Percent:

                        m_hasPercent = true;

                        if (w.isPositive() && (!l.width.isPercent() || w.rawValue() > l.width.rawValue()))

                            l.width = w;

                        break;

                    case Relative:

                        // FIXME: Need to understand this case and whether it makes sense to compare values

                        // which are not necessarily of the same type.

                        if (w.isAuto() || (w.isRelative() && w.value() > l.width.rawValue()))

                            l.width = w;

                    default:

                        break;

                    }

                } else {

                    if (cell && (!effCol || section->cellAt(i, effCol-1).cell != cell)) {

                        // This spanning cell originates in this column.  Ensure we have

                        // a min/max width of at least 1px for this column now.

                        l.minWidth = max(l.minWidth, cellHasContent ? 1 : 0);

                        l.maxWidth = max(l.maxWidth, 1);

                        insertSpanCell(cell);

                    }

                    last = cell;

                }

            }

        }

        child = child->nextSibling();

    }

    // Nav/IE weirdness

    if (l.width.isFixed()) {

        if (m_table->style()->htmlHacks() && l.maxWidth > l.width.value() && fixedContributor != maxContributor) {

            l.width = Length();

            fixedContributor = 0;

        }

    }

    l.maxWidth = max(l.maxWidth, l.minWidth);

#ifdef DEBUG_LAYOUT

    qDebug("col %d, final min=%d, max=%d, width=%d(%d)", effCol, l.minWidth, l.maxWidth, l.width.value,  l.width.type);

#endif

    // ### we need to add col elements as well

}

void AutoTableLayout::fullRecalc()

{

    m_percentagesDirty = true;

    m_hasPercent = false;

    m_effWidthDirty = true;

    int nEffCols = m_table->numEffCols();

    m_layoutStruct.resize(nEffCols);

    m_layoutStruct.fill(Layout());

    m_spanCells.fill(0);

    RenderObject *child = m_table->firstChild();

    Length grpWidth;

    int cCol = 0;

    while (child) {

        if (child->isTableCol()) {

            RenderTableCol *col = static_cast<RenderTableCol*>(child);

            int span = col->span();

            if (col->firstChild()) {

                grpWidth = col->style()->width();

            } else {

                Length w = col->style()->width();

                if (w.isAuto())

                    w = grpWidth;

                if ((w.isFixed() || w.isPercent()) && w.isZero())

                    w = Length();

                int cEffCol = m_table->colToEffCol(cCol);

#ifdef DEBUG_LAYOUT

                qDebug("    col element %d (eff=%d): Length=%d(%d), span=%d, effColSpan=%d",  cCol, cEffCol, w.value, w.type, span, m_table->spanOfEffCol(cEffCol));

#endif

                if (!w.isAuto() && span == 1 && cEffCol < nEffCols) {

                    if (m_table->spanOfEffCol(cEffCol) == 1) {

                        m_layoutStruct[cEffCol].width = w;

                        if (w.isFixed() && m_layoutStruct[cEffCol].maxWidth < w.value())

                            m_layoutStruct[cEffCol].maxWidth = w.value();

                    }

                }

                cCol += span;

            }

        } else {

            break;

        }

        RenderObject *next = child->firstChild();

        if (!next)

            next = child->nextSibling();

        if (!next && child->parent()->isTableCol()) {

            next = child->parent()->nextSibling();

            grpWidth = Length();

        }

        child = next;

    }

    for (int i = 0; i < nEffCols; i++)

        recalcColumn(i);

}

static bool shouldScaleColumns(RenderTable* table)

{

    // A special case.  If this table is not fixed width and contained inside

    // a cell, then don't bloat the maxwidth by examining percentage growth.

    bool scale = true;

    while (table) {

        Length tw = table->style()->width();

        if ((tw.isAuto() || tw.isPercent()) && !table->isPositioned()) {

            RenderBlock* cb = table->containingBlock();

            while (cb && !cb->isRenderView() && !cb->isTableCell() &&

                cb->style()->width().isAuto() && !cb->isPositioned())

                cb = cb->containingBlock();

            table = 0;

            if (cb && cb->isTableCell() &&

                (cb->style()->width().isAuto() || cb->style()->width().isPercent())) {

                if (tw.isPercent())

                    scale = false;

                else {

                    RenderTableCell* cell = static_cast<RenderTableCell*>(cb);

                    if (cell->colSpan() > 1 || cell->table()->style()->width().isAuto())

                        scale = false;

                    else

                        table = cell->table();

                }

            }

        }

        else

            table = 0;

    }

    return scale;

}

void AutoTableLayout::calcPrefWidths(int& minWidth, int& maxWidth)

{

    fullRecalc();

    int spanMaxWidth = calcEffectiveWidth();

    minWidth = 0;

    maxWidth = 0;

    float maxPercent = 0;

    float maxNonPercent = 0;

    bool scaleColumns = shouldScaleColumns(m_table);

    // We substitute 0 percent by (epsilon / percentScaleFactor) percent in two places below to avoid division by zero.

    // FIXME: Handle the 0% cases properly.

    const int epsilon = 1;

    int remainingPercent = 100 * percentScaleFactor;

    for (unsigned int i = 0; i < m_layoutStruct.size(); i++) {

        minWidth += m_layoutStruct[i].effMinWidth;

        maxWidth += m_layoutStruct[i].effMaxWidth;

        if (scaleColumns) {

            if (m_layoutStruct[i].effWidth.isPercent()) {

                int percent = min(m_layoutStruct[i].effWidth.rawValue(), remainingPercent);

                float pw = static_cast<float>(m_layoutStruct[i].effMaxWidth) * 100 * percentScaleFactor / max(percent, epsilon);

                maxPercent = max(pw,  maxPercent);

                remainingPercent -= percent;

            } else

                maxNonPercent += m_layoutStruct[i].effMaxWidth;

        }

    }

    if (scaleColumns) {

        maxNonPercent = maxNonPercent * 100 * percentScaleFactor / max(remainingPercent, epsilon);

        maxWidth = max(maxWidth, static_cast<int>(min(maxNonPercent, INT_MAX / 2.0f)));

        maxWidth = max(maxWidth, static_cast<int>(min(maxPercent, INT_MAX / 2.0f)));

    }

    maxWidth = max(maxWidth, spanMaxWidth);

    int bs = m_table->bordersPaddingAndSpacing();

    minWidth += bs;

    maxWidth += bs;

    Length tw = m_table->style()->width();

    if (tw.isFixed() && tw.value() > 0) {

        minWidth = max(minWidth, tw.value());

        maxWidth = minWidth;

    }

}

/*

  This method takes care of colspans.

  effWidth is the same as width for cells without colspans. If we have colspans, they get modified.

 */

int AutoTableLayout::calcEffectiveWidth()

{

    float tMaxWidth = 0;

    unsigned int nEffCols = m_layoutStruct.size();

    int hspacing = m_table->hBorderSpacing();

#ifdef DEBUG_LAYOUT

    qDebug("AutoTableLayout::calcEffectiveWidth for %d cols", nEffCols);

#endif

    for (unsigned int i = 0; i < nEffCols; i++) {

        m_layoutStruct[i].effWidth = m_layoutStruct[i].width;

        m_layoutStruct[i].effMinWidth = m_layoutStruct[i].minWidth;

        m_layoutStruct[i].effMaxWidth = m_layoutStruct[i].maxWidth;

    }

    for (unsigned int i = 0; i < m_spanCells.size(); i++) {

        RenderTableCell *cell = m_spanCells[i];

        if (!cell)

            break;

        int span = cell->colSpan();

        Length w = cell->styleOrColWidth();

        if (!w.isRelative() && w.isZero())

            w = Length(); // make it Auto

        int col = m_table->colToEffCol(cell->col());

        unsigned int lastCol = col;

        int cMinWidth = cell->minPrefWidth() + hspacing;

        float cMaxWidth = cell->maxPrefWidth() + hspacing;

        int totalPercent = 0;

        int minWidth = 0;

        float maxWidth = 0;

        bool allColsArePercent = true;

        bool allColsAreFixed = true;

        bool haveAuto = false;

        bool spanHasEmptyCellsOnly = true;

        int fixedWidth = 0;

        while (lastCol < nEffCols && span > 0) {

            switch (m_layoutStruct[lastCol].width.type()) {

            case Percent:

                totalPercent += m_layoutStruct[lastCol].width.rawValue();

                allColsAreFixed = false;

                break;

            case Fixed:

                if (m_layoutStruct[lastCol].width.value() > 0) {

                    fixedWidth += m_layoutStruct[lastCol].width.value();

                    allColsArePercent = false;

                    // IE resets effWidth to Auto here, but this breaks the konqueror about page and seems to be some bad

                    // legacy behaviour anyway. mozilla doesn't do this so I decided we don't neither.

                    break;

                }

                // fall through

            case Auto:

                haveAuto = true;

                // fall through

            default:

                // If the column is a percentage width, do not let the spanning cell overwrite the

                // width value.  This caused a mis-rendering on amazon.com.

                // Sample snippet:

                // <table border=2 width=100%><

                //   <tr><td>1</td><td colspan=2>2-3</tr>

                //   <tr><td>1</td><td colspan=2 width=100%>2-3</td></tr>

                // </table>

                if (!m_layoutStruct[lastCol].effWidth.isPercent()) {

                    m_layoutStruct[lastCol].effWidth = Length();

                    allColsArePercent = false;

                }

                else

                    totalPercent += m_layoutStruct[lastCol].effWidth.rawValue();

                allColsAreFixed = false;

            }

            if (!m_layoutStruct[lastCol].emptyCellsOnly)

                spanHasEmptyCellsOnly = false;

            span -= m_table->spanOfEffCol(lastCol);

            minWidth += m_layoutStruct[lastCol].effMinWidth;

            maxWidth += m_layoutStruct[lastCol].effMaxWidth;

            lastCol++;

            cMinWidth -= hspacing;

            cMaxWidth -= hspacing;

        }

        // adjust table max width if needed

        if (w.isPercent()) {

            if (totalPercent > w.rawValue() || allColsArePercent) {

                // can't satify this condition, treat as variable

                w = Length();

            } else {

                float spanMax = max(maxWidth, cMaxWidth);

                tMaxWidth = max(tMaxWidth, spanMax * 100 * percentScaleFactor / w.rawValue());

                // all non percent columns in the span get percent vlaues to sum up correctly.

                int percentMissing = w.rawValue() - totalPercent;

                float totalWidth = 0;

                for (unsigned int pos = col; pos < lastCol; pos++) {

                    if (!(m_layoutStruct[pos].effWidth.isPercent()))

                        totalWidth += m_layoutStruct[pos].effMaxWidth;

                }

                for (unsigned int pos = col; pos < lastCol && totalWidth > 0; pos++) {

                    if (!(m_layoutStruct[pos].effWidth.isPercent())) {

                        int percent = static_cast<int>(percentMissing * static_cast<float>(m_layoutStruct[pos].effMaxWidth) / totalWidth);

                        totalWidth -= m_layoutStruct[pos].effMaxWidth;

                        percentMissing -= percent;

                        if (percent > 0)

                            m_layoutStruct[pos].effWidth.setRawValue(Percent, percent);

                        else

                            m_layoutStruct[pos].effWidth = Length();

                    }

                }

            }

        }

        // make sure minWidth and maxWidth of the spanning cell are honoured

        if (cMinWidth > minWidth) {

            if (allColsAreFixed) {

                for (unsigned int pos = col; fixedWidth > 0 && pos < lastCol; pos++) {

                    int w = max(m_layoutStruct[pos].effMinWidth, cMinWidth * m_layoutStruct[pos].width.value() / fixedWidth);

                    fixedWidth -= m_layoutStruct[pos].width.value();

                    cMinWidth -= w;

                    m_layoutStruct[pos].effMinWidth = w;

                }

            } else {

                float maxw = maxWidth;

                int minw = minWidth;

                // Give min to variable first, to fixed second, and to others third.

                for (unsigned int pos = col; maxw >= 0 && pos < lastCol; pos++) {

                    if (m_layoutStruct[pos].width.isFixed() && haveAuto && fixedWidth <= cMinWidth) {

                        int w = max(m_layoutStruct[pos].effMinWidth, m_layoutStruct[pos].width.value());

                        fixedWidth -= m_layoutStruct[pos].width.value();

                        minw -= m_layoutStruct[pos].effMinWidth;

                        maxw -= m_layoutStruct[pos].effMaxWidth;

                        cMinWidth -= w;

                        m_layoutStruct[pos].effMinWidth = w;

                    }

                }

                for (unsigned int pos = col; maxw >= 0 && pos < lastCol && minw < cMinWidth; pos++) {

                    if (!(m_layoutStruct[pos].width.isFixed() && haveAuto && fixedWidth <= cMinWidth)) {

                        int w = max(m_layoutStruct[pos].effMinWidth, static_cast<int>(maxw ? cMinWidth * static_cast<float>(m_layoutStruct[pos].effMaxWidth) / maxw : cMinWidth));

                        w = min(m_layoutStruct[pos].effMinWidth+(cMinWidth-minw), w);

                        maxw -= m_layoutStruct[pos].effMaxWidth;

                        minw -= m_layoutStruct[pos].effMinWidth;

                        cMinWidth -= w;

                        m_layoutStruct[pos].effMinWidth = w;

                    }

                }

            }

        }

        if (!(w.isPercent())) {

            if (cMaxWidth > maxWidth) {

                for (unsigned int pos = col; maxWidth >= 0 && pos < lastCol; pos++) {

                    int w = max(m_layoutStruct[pos].effMaxWidth, static_cast<int>(maxWidth ? cMaxWidth * static_cast<float>(m_layoutStruct[pos].effMaxWidth) / maxWidth : cMaxWidth));

                    maxWidth -= m_layoutStruct[pos].effMaxWidth;

                    cMaxWidth -= w;

                    m_layoutStruct[pos].effMaxWidth = w;

                }

            }

        } else {

            for (unsigned int pos = col; pos < lastCol; pos++)

                m_layoutStruct[pos].maxWidth = max(m_layoutStruct[pos].maxWidth, m_layoutStruct[pos].minWidth);

        }

        // treat span ranges consisting of empty cells only as if they had content

        if (spanHasEmptyCellsOnly)

            for (unsigned int pos = col; pos < lastCol; pos++)

                m_layoutStruct[pos].emptyCellsOnly = false;

    }

    m_effWidthDirty = false;

    return static_cast<int>(min(tMaxWidth, INT_MAX / 2.0f));

}

/* gets all cells that originate in a column and have a cellspan > 1

   Sorts them by increasing cellspan

*/

void AutoTableLayout::insertSpanCell(RenderTableCell *cell)

{

    if (!cell || cell->colSpan() == 1)

        return;

    int size = m_spanCells.size();

    if (!size || m_spanCells[size-1] != 0) {

        m_spanCells.resize(size + 10);

        for (int i = 0; i < 10; i++)

            m_spanCells[size+i] = 0;

        size += 10;

    }

    // add them in sort. This is a slow algorithm, and a binary search or a fast sorting after collection would be better

    unsigned int pos = 0;

    int span = cell->colSpan();

    while (pos < m_spanCells.size() && m_spanCells[pos] && span > m_spanCells[pos]->colSpan())

        pos++;

    memmove(m_spanCells.data()+pos+1, m_spanCells.data()+pos, (size-pos-1)*sizeof(RenderTableCell *));

    m_spanCells[pos] = cell;

}

void AutoTableLayout::layout()

{

    // table layout based on the values collected in the layout structure.

    int tableWidth = m_table->width() - m_table->bordersPaddingAndSpacing();

    int available = tableWidth;

    int nEffCols = m_table->numEffCols();

    if (nEffCols != (int)m_layoutStruct.size()) {

        fullRecalc();

        nEffCols = m_table->numEffCols();

    }

#ifdef DEBUG_LAYOUT

    qDebug("AutoTableLayout::layout()");

#endif

    if (m_effWidthDirty)

        calcEffectiveWidth();

#ifdef DEBUG_LAYOUT

    qDebug("    tableWidth=%d,  nEffCols=%d", tableWidth,  nEffCols);

    for (int i = 0; i < nEffCols; i++) {

        qDebug("    effcol %d is of type %d value %d, minWidth=%d, maxWidth=%d",

               i, m_layoutStruct[i].width.type, m_layoutStruct[i].width.value,

               m_layoutStruct[i].minWidth, m_layoutStruct[i].maxWidth);

        qDebug("        effective: type %d value %d, minWidth=%d, maxWidth=%d",

               m_layoutStruct[i].effWidth.type, m_layoutStruct[i].effWidth.value,