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

/* 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 "DeleteTextTransaction.h"

#include "mozilla/Assertions.h"

#include "mozilla/EditorBase.h"

#include "mozilla/EditorDOMPoint.h"

#include "mozilla/SelectionState.h"

#include "mozilla/dom/Selection.h"

#include "nsDebug.h"

#include "nsError.h"

#include "nsIEditor.h"

#include "nsISupportsImpl.h"

#include "nsAString.h"

namespace mozilla {

using namespace dom;

// static

already_AddRefed<DeleteTextTransaction>

DeleteTextTransaction::MaybeCreate(EditorBase& aEditorBase,

                                   CharacterData& aCharData,

                                   uint32_t aOffset,

                                   uint32_t aLengthToDelete)

{

  RefPtr<DeleteTextTransaction> transaction =

    new DeleteTextTransaction(aEditorBase, aCharData, aOffset, aLengthToDelete);

  return transaction.forget();

}

// static

already_AddRefed<DeleteTextTransaction>

DeleteTextTransaction::MaybeCreateForPreviousCharacter(

                         EditorBase& aEditorBase,

                         CharacterData& aCharData,

                         uint32_t aOffset)

{

  if (NS_WARN_IF(!aOffset)) {

    return nullptr;

  }

  nsAutoString data;

  aCharData.GetData(data);

  if (NS_WARN_IF(data.IsEmpty())) {

    return nullptr;

  }

  uint32_t length = 1;

  uint32_t offset = aOffset - 1;

  if (offset &&

      NS_IS_LOW_SURROGATE(data[offset]) &&

      NS_IS_HIGH_SURROGATE(data[offset - 1])) {

    ++length;

    --offset;

  }

  return DeleteTextTransaction::MaybeCreate(aEditorBase, aCharData,

                                            offset, length);

}

// static

already_AddRefed<DeleteTextTransaction>

DeleteTextTransaction::MaybeCreateForNextCharacter(

                         EditorBase& aEditorBase,

                         CharacterData& aCharData,

                         uint32_t aOffset)

{

  nsAutoString data;

  aCharData.GetData(data);

  if (NS_WARN_IF(aOffset >= data.Length()) ||

      NS_WARN_IF(data.IsEmpty())) {

    return nullptr;

  }

  uint32_t length = 1;

  if (aOffset + 1 < data.Length() &&

      NS_IS_HIGH_SURROGATE(data[aOffset]) &&

      NS_IS_LOW_SURROGATE(data[aOffset + 1])) {

    ++length;

  }

  return DeleteTextTransaction::MaybeCreate(aEditorBase, aCharData,

                                            aOffset, length);

}

DeleteTextTransaction::DeleteTextTransaction(

                         EditorBase& aEditorBase,

                         CharacterData& aCharData,

                         uint32_t aOffset,

                         uint32_t aLengthToDelete)

  : mEditorBase(&aEditorBase)

  , mCharData(&aCharData)

  , mOffset(aOffset)

  , mLengthToDelete(aLengthToDelete)

{

  NS_ASSERTION(mCharData->Length() >= aOffset + aLengthToDelete,

               "Trying to delete more characters than in node");

}

NS_IMPL_CYCLE_COLLECTION_INHERITED(DeleteTextTransaction, EditTransactionBase,

                                   mEditorBase,

                                   mCharData)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DeleteTextTransaction)

NS_INTERFACE_MAP_END_INHERITING(EditTransactionBase)

bool

DeleteTextTransaction::CanDoIt() const

{

  if (NS_WARN_IF(!mCharData) || NS_WARN_IF(!mEditorBase)) {

    return false;

  }

  return mEditorBase->IsModifiableNode(*mCharData);

}

NS_IMETHODIMP

DeleteTextTransaction::DoTransaction()

{

  if (NS_WARN_IF(!mEditorBase) || NS_WARN_IF(!mCharData)) {

    return NS_ERROR_NOT_AVAILABLE;

  }

  // Get the text that we're about to delete

  ErrorResult err;

  mCharData->SubstringData(mOffset, mLengthToDelete, mDeletedText, err);

  if (NS_WARN_IF(err.Failed())) {

    return err.StealNSResult();

  }

  mCharData->DeleteData(mOffset, mLengthToDelete, err);

  if (NS_WARN_IF(err.Failed())) {

    return err.StealNSResult();

  }

  mEditorBase->RangeUpdaterRef().

                 SelAdjDeleteText(mCharData, mOffset, mLengthToDelete);

  if (!mEditorBase->AllowsTransactionsToChangeSelection()) {

    return NS_OK;

  }

  RefPtr<Selection> selection = mEditorBase->GetSelection();

  if (NS_WARN_IF(!selection)) {

    return NS_ERROR_FAILURE;

  }

  ErrorResult error;

  selection->Collapse(EditorRawDOMPoint(mCharData, mOffset), error);

  if (NS_WARN_IF(error.Failed())) {

    return error.StealNSResult();

  }

  return NS_OK;

}

//XXX: We may want to store the selection state and restore it properly.  Was

//     it an insertion point or an extended selection?

NS_IMETHODIMP

DeleteTextTransaction::UndoTransaction()

{

  if (NS_WARN_IF(!mCharData)) {

    return NS_ERROR_NOT_INITIALIZED;

  }

  ErrorResult rv;

  mCharData->InsertData(mOffset, mDeletedText, rv);

  return rv.StealNSResult();

}

} // namespace mozilla