/* 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 "mozilla/dom/CrossShadowBoundaryRange.h"

#include "nsContentUtils.h"
#include "nsIContentInlines.h"
#include "nsINode.h"
#include "nsRange.h"

namespace mozilla::dom {
template already_AddRefed<CrossShadowBoundaryRange>
CrossShadowBoundaryRange::Create(const RangeBoundary& aStartBoundary,
                                 const RangeBoundary& aEndBoundary,
                                 nsRange* aOwner);
template already_AddRefed<CrossShadowBoundaryRange>
CrossShadowBoundaryRange::Create(const RangeBoundary& aStartBoundary,
                                 const RawRangeBoundary& aEndBoundary,
                                 nsRange* aOwner);
template already_AddRefed<CrossShadowBoundaryRange>
CrossShadowBoundaryRange::Create(const RawRangeBoundary& aStartBoundary,
                                 const RangeBoundary& aEndBoundary,
                                 nsRange* aOwner);
template already_AddRefed<CrossShadowBoundaryRange>
CrossShadowBoundaryRange::Create(const RawRangeBoundary& aStartBoundary,
                                 const RawRangeBoundary& aEndBoundary,
                                 nsRange* aOwner);

template nsresult CrossShadowBoundaryRange::SetStartAndEnd(
    const RangeBoundary& aStartBoundary, const RangeBoundary& aEndBoundary);
template nsresult CrossShadowBoundaryRange::SetStartAndEnd(
    const RangeBoundary& aStartBoundary, const RawRangeBoundary& aEndBoundary);
template nsresult CrossShadowBoundaryRange::SetStartAndEnd(
    const RawRangeBoundary& aStartBoundary, const RangeBoundary& aEndBoundary);
template nsresult CrossShadowBoundaryRange::SetStartAndEnd(
    const RawRangeBoundary& aStartBoundary,
    const RawRangeBoundary& aEndBoundary);

nsTArray<RefPtr<CrossShadowBoundaryRange>>*
    CrossShadowBoundaryRange::sCachedRanges = nullptr;

NS_IMPL_CYCLE_COLLECTING_ADDREF(CrossShadowBoundaryRange)

NS_IMPL_CYCLE_COLLECTING_RELEASE_WITH_INTERRUPTABLE_LAST_RELEASE(
    CrossShadowBoundaryRange, ResetToReuse(),
    AbstractRange::MaybeCacheToReuse(*this))

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CrossShadowBoundaryRange)
NS_INTERFACE_MAP_END_INHERITING(CrossShadowBoundaryRange)

NS_IMPL_CYCLE_COLLECTION_CLASS(CrossShadowBoundaryRange)

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(CrossShadowBoundaryRange,
                                                StaticRange)
  if (tmp->mCommonAncestor) {
    tmp->mCommonAncestor->RemoveMutationObserver(tmp);
  }
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mCommonAncestor)
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(CrossShadowBoundaryRange,
                                                  StaticRange)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCommonAncestor)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(CrossShadowBoundaryRange,
                                               StaticRange)
NS_IMPL_CYCLE_COLLECTION_TRACE_END

/* static */
template <typename SPT, typename SRT, typename EPT, typename ERT>
already_AddRefed<CrossShadowBoundaryRange> CrossShadowBoundaryRange::Create(
    const RangeBoundaryBase<SPT, SRT>& aStartBoundary,
    const RangeBoundaryBase<EPT, ERT>& aEndBoundary, nsRange* aOwner) {
  RefPtr<CrossShadowBoundaryRange> range;
  if (!sCachedRanges || sCachedRanges->IsEmpty()) {
    range = new CrossShadowBoundaryRange(aStartBoundary.GetContainer(), aOwner);
  } else {
    range = sCachedRanges->PopLastElement().forget();
  }

  // mOwner is fixed for the lifetime of the range; set it here so it is also
  // re-established on the cache-reuse path, where the constructor doesn't run.
  range->mOwner = aOwner;
  range->Init(aStartBoundary.GetContainer());
  range->DoSetRange(aStartBoundary, aEndBoundary, nullptr);
  return range.forget();
}

void CrossShadowBoundaryRange::ResetToReuse() {
  DoSetRange(RawRangeBoundary(TreeKind::FlatForSelection),
             RawRangeBoundary(TreeKind::FlatForSelection), nullptr);
  mOwner = nullptr;
}

void CrossShadowBoundaryRange::UpdateCommonAncestor() {
  nsINode* startRoot = RangeUtils::ComputeRootNode(mStart.GetContainer());
  nsINode* endRoot = RangeUtils::ComputeRootNode(mEnd.GetContainer());

  nsINode* previousCommonAncestor = mCommonAncestor;
  mCommonAncestor =
      startRoot == endRoot
          ? startRoot
          : nsContentUtils::GetClosestCommonShadowIncludingInclusiveAncestor(
                mStart.GetContainer(), mEnd.GetContainer());

  if (previousCommonAncestor != mCommonAncestor) {
    if (previousCommonAncestor) {
      previousCommonAncestor->RemoveMutationObserver(this);
    }
    if (mCommonAncestor) {
      mCommonAncestor->AddMutationObserver(this);
    }
  }
}

void CrossShadowBoundaryRange::ContentWillBeRemoved(nsIContent* aChild,
                                                    const ContentRemoveInfo&) {
  // It's unclear from the spec about what should the selection be after
  // DOM mutation. See https://github.com/w3c/selection-api/issues/168
  //
  // For now, we just clear the selection if the removed node is related
  // to mStart or mEnd.
  MOZ_DIAGNOSTIC_ASSERT(mOwner);
  MOZ_DIAGNOSTIC_ASSERT(mOwner->GetCrossShadowBoundaryRange() == this);

  RefPtr<CrossShadowBoundaryRange> kungFuDeathGrip(this);

  const nsINode* startContainer = mStart.GetContainer();
  const nsINode* endContainer = mEnd.GetContainer();
  MOZ_ASSERT(startContainer && endContainer);

  if (startContainer == aChild || endContainer == aChild) {
    mOwner->ResetCrossShadowBoundaryRange(
        ResetCommonAncestorIfInAnySelection::Yes);
    return;
  }

  // This is a special case that the startContainer and endContainer could
  // anonymous contents created by the frame of aChild, and they are
  // unbounded from the document now.
  if (!startContainer->IsInComposedDoc() || !endContainer->IsInComposedDoc()) {
    mOwner->ResetCrossShadowBoundaryRange(
        ResetCommonAncestorIfInAnySelection::Yes);
    return;
  }

  if (const auto* shadowRoot = aChild->GetShadowRoot()) {
    if (startContainer == shadowRoot || endContainer == shadowRoot) {
      mOwner->ResetCrossShadowBoundaryRange(
          ResetCommonAncestorIfInAnySelection::Yes);
      return;
    }
  }

  if (startContainer->IsShadowIncludingInclusiveDescendantOf(aChild) ||
      endContainer->IsShadowIncludingInclusiveDescendantOf(aChild)) {
    mOwner->ResetCrossShadowBoundaryRange(
        ResetCommonAncestorIfInAnySelection::Yes);
    return;
  }

  nsINode* container = aChild->GetParentNode();

  auto MaybeCreateNewBoundary =
      [container, aChild](
          const nsINode* aContainer,
          const RangeBoundary& aBoundary) -> Maybe<RawRangeBoundary> {
    if (container == aContainer) {
      // We're only interested if our boundary reference was removed, otherwise
      // we can just invalidate the offset.
      if (aChild == aBoundary.Ref()) {
        return Some(
            RawRangeBoundary::FromChild(*aChild, TreeKind::FlatForSelection));
      }
      RawRangeBoundary newBoundary(TreeKind::FlatForSelection);
      newBoundary.CopyFrom(aBoundary, RangeBoundarySetBy::Ref);
      newBoundary.InvalidateOffset();
      return Some(newBoundary);
    }
    return Nothing();
  };

  const Maybe<RawRangeBoundary> newStartBoundary =
      MaybeCreateNewBoundary(startContainer, mStart);
  const Maybe<RawRangeBoundary> newEndBoundary =
      MaybeCreateNewBoundary(endContainer, mEnd);

  if (newStartBoundary || newEndBoundary) {
    DoSetRange(newStartBoundary ? newStartBoundary.ref() : mStart.AsRaw(),
               newEndBoundary ? newEndBoundary.ref() : mEnd.AsRaw(), nullptr);
  }
}

void CrossShadowBoundaryRange::CharacterDataChanged(
    nsIContent* aContent, const CharacterDataChangeInfo& aInfo) {
  // DOM mutation for cross-shadow-boundary selections is not specified.
  // (https://github.com/w3c/selection-api/issues/168)
  //
  // When aInfo.mDetails is present, it means the character data was changed
  // due to splitText() or normalize(). Only reset the cross-shadow-boundary
  // range if the split/normalize affects the start or end container.
  if (aInfo.mDetails) {
    if (aContent == mStart.GetContainer() || aContent == mEnd.GetContainer()) {
      mOwner->ResetCrossShadowBoundaryRange(
          ResetCommonAncestorIfInAnySelection::Yes);
    }
    return;
  }
  MOZ_ASSERT(aContent);
  MOZ_ASSERT(mIsPositioned);

  auto MaybeCreateNewBoundary =
      [aContent, &aInfo](const RangeBoundary& aBoundary,
                         RangeBoundaryFor aFor) -> Maybe<RawRangeBoundary> {
    // If the changed node contains our start boundary and the change starts
    // before the boundary we'll need to adjust the offset.
    if (aContent == aBoundary.GetContainer() &&
        // aInfo.mChangeStart is the offset where the change starts, if it's
        // smaller than the offset of aBoundary, it means the characters
        // before the selected content is changed (i.e, removed), so the
        // offset of aBoundary needs to be adjusted.
        aInfo.mChangeStart <
            *aBoundary.Offset(
                RangeBoundary::OffsetFilter::kValidOrInvalidOffsets)) {
      RawRangeBoundary newStart =
          nsRange::ComputeNewBoundaryWhenBoundaryInsideChangedText(
              aInfo, aBoundary.AsRaw());
      return Some(newStart.AsRangeBoundaryInFlatTreeOrNonFlattenedNode(aFor));
    }
    return Nothing();
  };

  const bool collapsed = mStart == mEnd;
  const Maybe<RawRangeBoundary> newStartBoundary =
      MaybeCreateNewBoundary(mStart, collapsed ? RangeBoundaryFor::Collapsed
                                               : RangeBoundaryFor::Start);
  const Maybe<RawRangeBoundary> newEndBoundary = MaybeCreateNewBoundary(
      mEnd, collapsed ? RangeBoundaryFor::Collapsed : RangeBoundaryFor::End);

  if (newStartBoundary || newEndBoundary) {
    DoSetRange(newStartBoundary ? newStartBoundary.ref() : mStart.AsRaw(),
               newEndBoundary ? newEndBoundary.ref() : mEnd.AsRaw(), nullptr);
  }
}

// DOM mutation for shadow-crossing selection is not specified.
// Spec issue: https://github.com/w3c/selection-api/issues/168
void CrossShadowBoundaryRange::ParentChainChanged(nsIContent* aContent) {
  MOZ_DIAGNOSTIC_ASSERT(mCommonAncestor == aContent,
                        "Wrong ParentChainChanged notification");
  MOZ_DIAGNOSTIC_ASSERT(mOwner);
  mOwner->ResetCrossShadowBoundaryRange(
      ResetCommonAncestorIfInAnySelection::Yes);
}
}  // namespace mozilla::dom