/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "GridLines.h"

#include "GridDimension.h"

#include "GridLine.h"

#include "mozilla/dom/GridBinding.h"

#include "nsGridContainerFrame.h"

namespace mozilla {

namespace dom {

NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(GridLines, mParent, mLines)

NS_IMPL_CYCLE_COLLECTING_ADDREF(GridLines)

NS_IMPL_CYCLE_COLLECTING_RELEASE(GridLines)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(GridLines)

  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY

  NS_INTERFACE_MAP_ENTRY(nsISupports)

NS_INTERFACE_MAP_END

GridLines::GridLines(GridDimension* aParent)

  : mParent(aParent)

{

  MOZ_ASSERT(aParent,

    "Should never be instantiated with a null GridDimension");

}

GridLines::~GridLines()

{

}

JSObject*

GridLines::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)

{

  return GridLines_Binding::Wrap(aCx, this, aGivenProto);

}

uint32_t

GridLines::Length() const

{

  return mLines.Length();

}

GridLine*

GridLines::Item(uint32_t aIndex)

{

  return mLines.SafeElementAt(aIndex);

}

GridLine*

GridLines::IndexedGetter(uint32_t aIndex,

                         bool& aFound)

{

  aFound = aIndex < mLines.Length();

  if (!aFound) {

    return nullptr;

  }

  return mLines[aIndex];

}

static void AddLineNameIfNotPresent(nsTArray<nsString>& aLineNames,

                             const nsString& aName)

{

  if (!aLineNames.Contains(aName)) {

    aLineNames.AppendElement(aName);

  }

}

static void AddLineNamesIfNotPresent(nsTArray<nsString>& aLineNames,

                              const nsTArray<nsString>& aNames)

{

  for (const auto& name : aNames) {

    AddLineNameIfNotPresent(aLineNames, name);

  }

}

void

GridLines::SetLineInfo(const ComputedGridTrackInfo* aTrackInfo,

                       const ComputedGridLineInfo* aLineInfo,

                       const nsTArray<RefPtr<GridArea>>& aAreas,

                       bool aIsRow)

{

  MOZ_ASSERT(aLineInfo);

  mLines.Clear();

  if (!aTrackInfo) {

    return;

  }

  uint32_t lineCount = aTrackInfo->mEndFragmentTrack -

                       aTrackInfo->mStartFragmentTrack +

                       1;

  // If there is at least one track, line count is one more

  // than the number of tracks.

  if (lineCount > 0) {

    nscoord lastTrackEdge = 0;

    nscoord startOfNextTrack;

    uint32_t repeatIndex = 0;

    uint32_t numRepeatTracks = aTrackInfo->mRemovedRepeatTracks.Length();

    uint32_t numAddedLines = 0;

    // For the calculation of negative line numbers, we need to know

    // the total number of leading implicit and explicit tracks.

    // This might be different from the number of tracks sizes in

    // aTrackInfo, because some of those tracks may be auto-fits that

    // have been removed.

    uint32_t leadingTrackCount = aTrackInfo->mNumLeadingImplicitTracks +

                                 aTrackInfo->mNumExplicitTracks;

    if (numRepeatTracks > 0) {

      for (auto& removedTrack : aTrackInfo->mRemovedRepeatTracks) {

        if (removedTrack) {

          ++leadingTrackCount;

        }

      }

    }

    for (uint32_t i = aTrackInfo->mStartFragmentTrack;

         i < aTrackInfo->mEndFragmentTrack + 1;

         i++) {

      // Since line indexes are 1-based, calculate a 1-based value

      // for this track to simplify some calculations.

      const uint32_t line1Index = i + 1;

      startOfNextTrack = (i < aTrackInfo->mEndFragmentTrack) ?

                         aTrackInfo->mPositions[i] :

                         lastTrackEdge;

      // Get the line names for the current line. aLineInfo->mNames

      // may contain duplicate names. This is intentional, since grid

      // layout works fine with duplicate names, and we don't want to

      // detect and remove duplicates in layout since it is an O(n^2)

      // problem. We do the work here since this is only run when

      // requested by devtools, and slowness here will not affect

      // normal browsing.

      const nsTArray<nsString>& possiblyDuplicateLineNames(

        aLineInfo->mNames.SafeElementAt(i, nsTArray<nsString>()));

      nsTArray<nsString> lineNames;

      AddLineNamesIfNotPresent(lineNames, possiblyDuplicateLineNames);

      // Add in names from grid areas where this line is used as a boundary.

      for (auto area : aAreas) {

        // We specifically ignore line names from implicitly named areas,

        // because it can be confusing for designers who might naturally use

        // a named line of "-start" or "-end" and create an implicit named

        // area without meaning to.

        if (area->Type() == GridDeclaration::Implicit) {

          continue;

        }

        bool haveNameToAdd = false;

        nsAutoString nameToAdd;

        area->GetName(nameToAdd);

        if (aIsRow) {

          if (area->RowStart() == line1Index) {

            haveNameToAdd = true;

            nameToAdd.AppendLiteral("-start");

          } else if (area->RowEnd() == line1Index) {

            haveNameToAdd = true;

            nameToAdd.AppendLiteral("-end");

          }

        } else {

          if (area->ColumnStart() == line1Index) {

            haveNameToAdd = true;

            nameToAdd.AppendLiteral("-start");

          } else if (area->ColumnEnd() == line1Index) {

            haveNameToAdd = true;

            nameToAdd.AppendLiteral("-end");

          }

        }

        if (haveNameToAdd) {

          AddLineNameIfNotPresent(lineNames, nameToAdd);

        }

      }

      if (i >= (aTrackInfo->mRepeatFirstTrack +

                aTrackInfo->mNumLeadingImplicitTracks) &&

          repeatIndex < numRepeatTracks) {

        numAddedLines += AppendRemovedAutoFits(aTrackInfo,

                                               aLineInfo,

                                               lastTrackEdge,

                                               repeatIndex,

                                               numRepeatTracks,

                                               leadingTrackCount,

                                               lineNames);

      }

      // If this line is the one that ends a repeat, then add

      // in the mNamesFollowingRepeat names from aLineInfo.

      if (numRepeatTracks > 0 &&

          i == (aTrackInfo->mRepeatFirstTrack +

                aTrackInfo->mNumLeadingImplicitTracks +

                numRepeatTracks - numAddedLines)) {

        AddLineNamesIfNotPresent(lineNames,

                                 aLineInfo->mNamesFollowingRepeat);

      }

      RefPtr<GridLine> line = new GridLine(this);

      mLines.AppendElement(line);

      MOZ_ASSERT(line1Index > 0, "line1Index must be positive.");

      bool isBeforeFirstExplicit =

        (line1Index <= aTrackInfo->mNumLeadingImplicitTracks);

      bool isAfterLastExplicit = line1Index > (leadingTrackCount + 1);

      // Calculate an actionable line number for this line, that could be used

      // in a css grid property to align a grid item or area at that line.

      // For implicit lines that appear before line 1, report a number of 0.

      // We can't report negative indexes, because those have a different

      // meaning in the css grid spec (negative indexes are negative-1-based

      // from the end of the grid decreasing towards the front).

      uint32_t lineNumber = isBeforeFirstExplicit ? 0 :

        (line1Index + numAddedLines - aTrackInfo->mNumLeadingImplicitTracks);

      // The negativeNumber is counted back from the leadingTrackCount.

      int32_t lineNegativeNumber = isAfterLastExplicit ? 0 :

        (line1Index + numAddedLines - (leadingTrackCount + 2));

      GridDeclaration lineType =

        (isBeforeFirstExplicit || isAfterLastExplicit)

         ? GridDeclaration::Implicit

         : GridDeclaration::Explicit;

      line->SetLineValues(

        lineNames,

        nsPresContext::AppUnitsToDoubleCSSPixels(lastTrackEdge),

        nsPresContext::AppUnitsToDoubleCSSPixels(startOfNextTrack -

                                                 lastTrackEdge),

        lineNumber,

        lineNegativeNumber,

        lineType

      );

      if (i < aTrackInfo->mEndFragmentTrack) {

        lastTrackEdge = aTrackInfo->mPositions[i] + aTrackInfo->mSizes[i];

      }

    }

  }

}

uint32_t

GridLines::AppendRemovedAutoFits(const ComputedGridTrackInfo* aTrackInfo,

                                 const ComputedGridLineInfo* aLineInfo,

                                 nscoord aLastTrackEdge,

                                 uint32_t& aRepeatIndex,

                                 uint32_t aNumRepeatTracks,

                                 uint32_t aNumLeadingTracks,

                                 nsTArray<nsString>& aLineNames)

{

  // Check to see if lineNames contains ALL of the before line names.

  bool alreadyHasBeforeLineNames = true;

  for (const auto& beforeName : aLineInfo->mNamesBefore) {

    if (!aLineNames.Contains(beforeName)) {

      alreadyHasBeforeLineNames = false;

      break;

    }

  }

  bool extractedExplicitLineNames = false;

  nsTArray<nsString> explicitLineNames;

  uint32_t linesAdded = 0;

  while (aRepeatIndex < aNumRepeatTracks &&

         aTrackInfo->mRemovedRepeatTracks[aRepeatIndex]) {

    // If this is not the very first call to this function, and if we

    // haven't already added a line this call, pull all the explicit

    // names to pass along to the next line that will be added after

    // this function completes.

    if (aRepeatIndex > 0 &&

        linesAdded == 0) {

      // Find the names that didn't match the before or after names,

      // and extract them.

      for (const auto& name : aLineNames) {

        if (!aLineInfo->mNamesBefore.Contains(name) &&

            !aLineInfo->mNamesAfter.Contains(name)) {

          explicitLineNames.AppendElement(name);

        }

      }

      for (const auto& extractedName : explicitLineNames) {

        aLineNames.RemoveElement(extractedName);

      }

      extractedExplicitLineNames = true;

    }

    // If this is the second or later time through, or didn't already

    // have before names, add them.

    if (linesAdded > 0 || !alreadyHasBeforeLineNames) {

      AddLineNamesIfNotPresent(aLineNames, aLineInfo->mNamesBefore);

    }

    RefPtr<GridLine> line = new GridLine(this);

    mLines.AppendElement(line);

    // Time to calculate the line numbers. For the positive numbers

    // we count with a 1-based index from mRepeatFirstTrack. Although

    // this number is the index of the first repeat track AFTER all

    // the leading implicit tracks, that's still what we want since

    // all those leading implicit tracks have line number 0.

    uint32_t lineNumber = aTrackInfo->mRepeatFirstTrack +

                          aRepeatIndex + 1;

    // The negative number does have to account for the leading

    // implicit tracks. We've been passed aNumLeadingTracks which is

    // the total of the leading implicit tracks plus the explicit

    // tracks. So all we have to do is subtract that number plus one

    // from the 0-based index of this track.

    int32_t lineNegativeNumber = (aTrackInfo->mNumLeadingImplicitTracks +

                                  aTrackInfo->mRepeatFirstTrack +

                                  aRepeatIndex) - (aNumLeadingTracks + 1);

    line->SetLineValues(

      aLineNames,

      nsPresContext::AppUnitsToDoubleCSSPixels(aLastTrackEdge),

      nsPresContext::AppUnitsToDoubleCSSPixels(0),

      lineNumber,

      lineNegativeNumber,

      GridDeclaration::Explicit

    );

    // No matter what, the next line should have the after names associated

    // with it. If we go through the loop again, the before names will also

    // be added.

    aLineNames = aLineInfo->mNamesAfter;

    aRepeatIndex++;

    linesAdded++;

  }

  aRepeatIndex++;

  if (extractedExplicitLineNames) {

    // Pass on the explicit names we saved to the next explicit line.

    AddLineNamesIfNotPresent(aLineNames, explicitLineNames);

  }

  if (alreadyHasBeforeLineNames && linesAdded > 0) {

    // If we started with before names, pass them on to the next explicit

    // line.

    AddLineNamesIfNotPresent(aLineNames, aLineInfo->mNamesBefore);

  }

  return linesAdded;

}

} // namespace dom

} // namespace mozilla