/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 sw=2 et tw=80: */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Mozilla Japan.
 * Portions created by the Initial Developer are Copyright (C) 2008
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Masayuki Nakano <masayuki@d-toybox.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsQueryContentEventHandler.h"
#include "nsCOMPtr.h"
#include "nsPresContext.h"
#include "nsIPresShell.h"
#include "nsISelection.h"
#include "nsIDOMText.h"
#include "nsIDOMRange.h"
#include "nsRange.h"
#include "nsGUIEvent.h"
#include "nsICaret.h"
#include "nsFrameSelection.h"
#include "nsIFrame.h"
#include "nsIView.h"
#include "nsIContentIterator.h"
#include "nsTextFragment.h"
#include "nsTextFrame.h"

nsresult NS_NewContentIterator(nsIContentIterator** aInstancePtrResult);

/******************************************************************/
/* nsQueryContentEventHandler                                     */
/******************************************************************/

nsQueryContentEventHandler::nsQueryContentEventHandler(
                              nsPresContext* aPresContext) :
  mPresContext(aPresContext),
  mPresShell(aPresContext->GetPresShell()), mSelection(nsnull),
  mFirstSelectedRange(nsnull), mRootContent(nsnull)
{
}

nsresult
nsQueryContentEventHandler::Init(nsQueryContentEvent* aEvent)
{
  NS_ASSERTION(aEvent, "aEvent must not be null");

  if (mSelection)
    return NS_OK;

  aEvent->mSucceeded = PR_FALSE;

  if (!mPresShell)
    return NS_ERROR_NOT_AVAILABLE;

  nsresult rv = mPresShell->GetSelectionForCopy(getter_AddRefs(mSelection));
  NS_ENSURE_SUCCESS(rv, rv);
  NS_ASSERTION(mSelection,
               "GetSelectionForCopy succeeded, but the result is null");

  nsCOMPtr<nsIDOMRange> firstRange;
  rv = mSelection->GetRangeAt(0, getter_AddRefs(firstRange));
  // This shell doesn't support selection.
  if (NS_FAILED(rv))
    return NS_ERROR_NOT_AVAILABLE;
  mFirstSelectedRange = do_QueryInterface(firstRange);
  NS_ENSURE_TRUE(mFirstSelectedRange, NS_ERROR_FAILURE);

  nsINode* startNode = mFirstSelectedRange->GetStartParent();
  NS_ENSURE_TRUE(startNode, NS_ERROR_FAILURE);
  mRootContent = startNode->GetSelectionRootContent(mPresShell);
  NS_ENSURE_TRUE(mRootContent, NS_ERROR_FAILURE);

  aEvent->mReply.mContentsRoot = mRootContent.get();

  return NS_OK;
}

static void ConvertToNativeNewlines(nsAFlatString& aString)
{
#if defined(XP_MACOSX)
  aString.ReplaceSubstring(NS_LITERAL_STRING("\n"), NS_LITERAL_STRING("\r"));
#elif defined(XP_WIN)
  aString.ReplaceSubstring(NS_LITERAL_STRING("\n"), NS_LITERAL_STRING("\r\n"));
#endif
}

static void ConvertToXPNewlines(nsAFlatString& aString)
{
#if defined(XP_MACOSX)
  aString.ReplaceSubstring(NS_LITERAL_STRING("\r"), NS_LITERAL_STRING("\n"));
#elif defined(XP_WIN)
  aString.ReplaceSubstring(NS_LITERAL_STRING("\r\n"), NS_LITERAL_STRING("\n"));
#endif
}

static void AppendString(nsAString& aString, nsIContent* aContent)
{
  NS_ASSERTION(aContent->IsNodeOfType(nsINode::eTEXT),
               "aContent is not a text node!");
  const nsTextFragment* text = aContent->GetText();
  if (!text)
    return;
  text->AppendTo(aString);
}

static void AppendSubString(nsAString& aString, nsIContent* aContent,
                            PRUint32 aXPOffset, PRUint32 aXPLength)
{
  NS_ASSERTION(aContent->IsNodeOfType(nsINode::eTEXT),
               "aContent is not a text node!");
  const nsTextFragment* text = aContent->GetText();
  if (!text)
    return;
  text->AppendTo(aString, PRInt32(aXPOffset), PRInt32(aXPLength));
}

static PRUint32 GetNativeTextLength(nsIContent* aContent)
{
  nsAutoString str;
  if (aContent->IsNodeOfType(nsINode::eTEXT))
    AppendString(str, aContent);
  else if (aContent->IsNodeOfType(nsINode::eHTML) &&
           aContent->Tag() == nsGkAtoms::br)
    str.Assign(PRUnichar('\n'));
  ConvertToNativeNewlines(str);
  return str.Length();
}

static PRUint32 ConvertToXPOffset(nsIContent* aContent, PRUint32 aNativeOffset)
{

  nsAutoString str;
  AppendString(str, aContent);
  ConvertToNativeNewlines(str);
  NS_ASSERTION(aNativeOffset <= str.Length(),
               "aOffsetForNativeLF is too large!");
  str.Truncate(aNativeOffset);
  ConvertToXPNewlines(str);
  return str.Length();
}

nsresult
nsQueryContentEventHandler::GenerateFlatTextContent(nsIRange* aRange,
                                                    nsAFlatString& aString)
{
  nsCOMPtr<nsIContentIterator> iter;
  nsresult rv = NS_NewContentIterator(getter_AddRefs(iter));
  NS_ENSURE_SUCCESS(rv, rv);
  NS_ASSERTION(iter, "NS_NewContentIterator succeeded, but the result is null");
  nsCOMPtr<nsIDOMRange> domRange(do_QueryInterface(aRange));
  NS_ASSERTION(domRange, "aRange doesn't have nsIDOMRange!");
  iter->Init(domRange);

  NS_ASSERTION(aString.IsEmpty(), "aString must be empty string");

  nsINode* startNode = aRange->GetStartParent();
  nsINode* endNode = aRange->GetEndParent();

  if (startNode == endNode && startNode->IsNodeOfType(nsINode::eTEXT)) {
    nsIContent* content = static_cast<nsIContent*>(startNode);
    AppendSubString(aString, content, aRange->StartOffset(),
                    aRange->EndOffset() - aRange->StartOffset());
    ConvertToNativeNewlines(aString);
    return NS_OK;
  }

  nsAutoString tmpStr;
  for (; !iter->IsDone(); iter->Next()) {
    nsIContent* content = iter->GetCurrentNode();
    if (!content)
      continue;

    if (content->IsNodeOfType(nsINode::eTEXT)) {
      if (content == startNode)
        AppendSubString(aString, content, aRange->StartOffset(),
                        content->TextLength() - aRange->StartOffset());
      else if (content == endNode)
        AppendSubString(aString, content, 0, aRange->EndOffset());
      else
        AppendString(aString, content);
    } else if (content->IsNodeOfType(nsINode::eHTML) &&
               content->Tag() == nsGkAtoms::br)
        aString.Append(PRUnichar('\n'));
  }
  ConvertToNativeNewlines(aString);
  return NS_OK;
}

nsresult
nsQueryContentEventHandler::ExpandToClusterBoundary(nsIContent* aContent,
                                                    PRBool aForward,
                                                    PRUint32* aXPOffset)
{
  NS_ASSERTION(*aXPOffset >= 0 && *aXPOffset <= aContent->TextLength(),
               "offset is out of range.");

  // XXX This method assumes that the frame boundaries must be cluster
  // boundaries. It's false, but no problem now, maybe.
  if (!aContent->IsNodeOfType(nsINode::eTEXT) ||
      *aXPOffset == 0 || *aXPOffset == aContent->TextLength())
    return NS_OK;
  nsCOMPtr<nsFrameSelection> fs = mPresShell->FrameSelection();
  PRInt32 offsetInFrame;
  nsFrameSelection::HINT hint =
    aForward ? nsFrameSelection::HINTLEFT : nsFrameSelection::HINTRIGHT;
  nsIFrame* frame = fs->GetFrameForNodeOffset(aContent, PRInt32(*aXPOffset),
                                              hint, &offsetInFrame);
  if (!frame) {
    // This content doesn't have any frames, we only can check surrogate pair...
    const nsTextFragment* text = aContent->GetText();
    NS_ENSURE_TRUE(text, NS_ERROR_FAILURE);
    if (NS_IS_LOW_SURROGATE(text->CharAt(*aXPOffset)) &&
        NS_IS_HIGH_SURROGATE(text->CharAt(*aXPOffset - 1)))
      *aXPOffset += aForward ? 1 : -1;
    return NS_OK;
  }
  PRInt32 startOffset, endOffset;
  nsresult rv = frame->GetOffsets(startOffset, endOffset);
  NS_ENSURE_SUCCESS(rv, rv);
  if (*aXPOffset == PRUint32(startOffset) || *aXPOffset == PRUint32(endOffset))
    return NS_OK;
  if (frame->GetType() != nsGkAtoms::textFrame)
    return NS_ERROR_FAILURE;
  nsTextFrame* textFrame = static_cast<nsTextFrame*>(frame);
  PRInt32 newOffsetInFrame = offsetInFrame;
  newOffsetInFrame += aForward ? -1 : 1;
  textFrame->PeekOffsetCharacter(aForward, &newOffsetInFrame);
  *aXPOffset = startOffset + newOffsetInFrame;
  return NS_OK;
}

nsresult
nsQueryContentEventHandler::SetRangeFromFlatTextOffset(
                              nsIRange* aRange,
                              PRUint32 aNativeOffset,
                              PRUint32 aNativeLength,
                              PRBool aExpandToClusterBoundaries)
{
  nsCOMPtr<nsIContentIterator> iter;
  nsresult rv = NS_NewContentIterator(getter_AddRefs(iter));
  NS_ENSURE_SUCCESS(rv, rv);
  NS_ASSERTION(iter, "NS_NewContentIterator succeeded, but the result is null");
  rv = iter->Init(mRootContent);
  NS_ENSURE_SUCCESS(rv, rv);
  nsCOMPtr<nsIDOMRange> domRange(do_QueryInterface(aRange));
  NS_ASSERTION(domRange, "aRange doesn't have nsIDOMRange!");

  PRUint32 nativeOffset = 0;
  PRUint32 nativeEndOffset = aNativeOffset + aNativeLength;
  nsIContent* content = nsnull;
  for (; !iter->IsDone(); iter->Next()) {
    content = iter->GetCurrentNode();
    if (!content)
      continue;

    PRUint32 nativeTextLength;
    nativeTextLength = GetNativeTextLength(content);
    if (nativeTextLength == 0)
      continue;

    if (nativeOffset <= aNativeOffset &&
        aNativeOffset < nativeOffset + nativeTextLength) {
      nsCOMPtr<nsIDOMNode> domNode(do_QueryInterface(content));
      NS_ASSERTION(domNode, "aContent doesn't have nsIDOMNode!");

      PRUint32 xpOffset =
        content->IsNodeOfType(nsINode::eTEXT) ?
          ConvertToXPOffset(content, aNativeOffset - nativeOffset) : 0;

      if (aExpandToClusterBoundaries) {
        rv = ExpandToClusterBoundary(content, PR_FALSE, &xpOffset);
        NS_ENSURE_SUCCESS(rv, rv);
      }

      rv = domRange->SetStart(domNode, PRInt32(xpOffset));
      NS_ENSURE_SUCCESS(rv, rv);
      if (aNativeLength == 0) {
        // Ensure that the end offset and the start offset are same.
        rv = domRange->SetEnd(domNode, PRInt32(xpOffset));
        NS_ENSURE_SUCCESS(rv, rv);
        return NS_OK;
      }
    }
    if (nativeEndOffset <= nativeOffset + nativeTextLength) {
      nsCOMPtr<nsIDOMNode> domNode(do_QueryInterface(content));
      NS_ASSERTION(domNode, "aContent doesn't have nsIDOMNode!");

      PRUint32 xpOffset;
      if (content->IsNodeOfType(nsINode::eTEXT)) {
        xpOffset = ConvertToXPOffset(content, nativeEndOffset - nativeOffset);
        if (aExpandToClusterBoundaries) {
          rv = ExpandToClusterBoundary(content, PR_TRUE, &xpOffset);
          NS_ENSURE_SUCCESS(rv, rv);
        }
      } else {
        // Use first position of next node, because the end node is ignored
        // by ContentIterator when the offset is zero.
        xpOffset = 0;
        iter->Next();
        if (iter->IsDone())
          break;
        domNode = do_QueryInterface(iter->GetCurrentNode());
      }

      rv = domRange->SetEnd(domNode, PRInt32(xpOffset));
      NS_ENSURE_SUCCESS(rv, rv);
      return NS_OK;
    }

    nativeOffset += nativeTextLength;
  }

  if (nativeOffset < aNativeOffset)
    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIDOMNode> domNode(do_QueryInterface(mRootContent));
  NS_ASSERTION(domNode, "lastContent doesn't have nsIDOMNode!");
  if (!content) {
    rv = domRange->SetStart(domNode, 0);
    NS_ENSURE_SUCCESS(rv, rv);
  }
  rv = domRange->SetEnd(domNode, PRInt32(mRootContent->GetChildCount()));
  NS_ASSERTION(NS_SUCCEEDED(rv), "nsIDOMRange::SetEnd failed");
  return rv;
}

nsresult
nsQueryContentEventHandler::OnQuerySelectedText(nsQueryContentEvent* aEvent)
{
  nsresult rv = Init(aEvent);
  if (NS_FAILED(rv))
    return rv;

  NS_ASSERTION(aEvent->mReply.mString.IsEmpty(),
               "The reply string must be empty");

  rv = GetFlatTextOffsetOfRange(mFirstSelectedRange, &aEvent->mReply.mOffset);
  NS_ENSURE_SUCCESS(rv, rv);

  PRBool isCollapsed;
  rv = mSelection->GetIsCollapsed(&isCollapsed);
  NS_ENSURE_SUCCESS(rv, rv);

  if (!isCollapsed) {
    nsCOMPtr<nsIDOMRange> domRange;
    rv = mSelection->GetRangeAt(0, getter_AddRefs(domRange));
    NS_ENSURE_SUCCESS(rv, rv);
    NS_ASSERTION(domRange, "GetRangeAt succeeded, but the result is null");

    nsCOMPtr<nsIRange> range(do_QueryInterface(domRange));
    NS_ENSURE_TRUE(range, NS_ERROR_FAILURE);
    rv = GenerateFlatTextContent(range, aEvent->mReply.mString);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  aEvent->mSucceeded = PR_TRUE;
  return NS_OK;
}

nsresult
nsQueryContentEventHandler::OnQueryTextContent(nsQueryContentEvent* aEvent)
{
  nsresult rv = Init(aEvent);
  if (NS_FAILED(rv))
    return rv;

  NS_ASSERTION(aEvent->mReply.mString.IsEmpty(),
               "The reply string must be empty");

  nsCOMPtr<nsIRange> range = new nsRange();
  NS_ENSURE_TRUE(range, NS_ERROR_OUT_OF_MEMORY);
  rv = SetRangeFromFlatTextOffset(range, aEvent->mInput.mOffset,
                                  aEvent->mInput.mLength, PR_FALSE);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = GenerateFlatTextContent(range, aEvent->mReply.mString);
  NS_ENSURE_SUCCESS(rv, rv);

  aEvent->mSucceeded = PR_TRUE;

  return NS_OK;
}

nsresult
nsQueryContentEventHandler::QueryRectFor(nsQueryContentEvent* aEvent,
                                         nsIRange* aRange,
                                         nsICaret* aCaret)
{
  PRInt32 offsetInFrame;
  nsIFrame* frame;
  nsresult rv = GetStartFrameAndOffset(aRange, &frame, &offsetInFrame);
  NS_ENSURE_SUCCESS(rv, rv);

  nsPoint posInFrame;
  rv = frame->GetPointFromOffset(aRange->StartOffset(), &posInFrame);
  NS_ENSURE_SUCCESS(rv, rv);

  aEvent->mReply.mRect.y = posInFrame.y;
  aEvent->mReply.mRect.height = frame->GetSize().height;

  if (aEvent->message == NS_QUERY_CHARACTER_RECT) {
    nsPoint nextPos;
    rv = frame->GetPointFromOffset(aRange->EndOffset(), &nextPos);
    NS_ENSURE_SUCCESS(rv, rv);
    aEvent->mReply.mRect.x = PR_MIN(posInFrame.x, nextPos.x);
    aEvent->mReply.mRect.width = PR_ABS(posInFrame.x - nextPos.x);
  } else {
    aEvent->mReply.mRect.x = posInFrame.x;
    aEvent->mReply.mRect.width = aCaret->GetCaretRect().width;
  }

  // The coordinates are app units here, they will be converted to system
  // coordinates by view manager.
  rv = ConvertToRootViewRelativeOffset(frame, aEvent->mReply.mRect);
  NS_ENSURE_SUCCESS(rv, rv);

  aEvent->mSucceeded = PR_TRUE;
  return NS_OK;
}

nsresult
nsQueryContentEventHandler::OnQueryCharacterRect(nsQueryContentEvent* aEvent)
{
  nsresult rv = Init(aEvent);
  if (NS_FAILED(rv))
    return rv;

  nsCOMPtr<nsIRange> range = new nsRange();
  NS_ENSURE_TRUE(range, NS_ERROR_OUT_OF_MEMORY);
  rv = SetRangeFromFlatTextOffset(range, aEvent->mInput.mOffset, 1, PR_TRUE);
  NS_ENSURE_SUCCESS(rv, rv);

  if (range->Collapsed()) {
    // There is no character at the offset.
    return NS_OK;
  }

  return QueryRectFor(aEvent, range, nsnull);
}

nsresult
nsQueryContentEventHandler::OnQueryCaretRect(nsQueryContentEvent* aEvent)
{
  nsresult rv = Init(aEvent);
  if (NS_FAILED(rv))
    return rv;

  nsCOMPtr<nsICaret> caret;
  rv = mPresShell->GetCaret(getter_AddRefs(caret));
  NS_ENSURE_SUCCESS(rv, rv);
  NS_ASSERTION(caret, "GetCaret succeeded, but the result is null");

  // When the selection is collapsed and the queried offset is current caret
  // position, we should return the "real" caret rect.
  PRBool selectionIsCollapsed;
  rv = mSelection->GetIsCollapsed(&selectionIsCollapsed);
  NS_ENSURE_SUCCESS(rv, rv);

  if (selectionIsCollapsed) {
    PRUint32 offset;
    rv = GetFlatTextOffsetOfRange(mFirstSelectedRange, &offset);
    NS_ENSURE_SUCCESS(rv, rv);
    if (offset == aEvent->mInput.mOffset) {
      PRBool isCollapsed;
      rv = caret->GetCaretCoordinates(nsICaret::eTopLevelWindowCoordinates,
                                      mSelection, &aEvent->mReply.mRect,
                                      &isCollapsed, nsnull);
      NS_ENSURE_SUCCESS(rv, rv);
      aEvent->mSucceeded = PR_TRUE;
      return NS_OK;
    }
  }

  // Otherwise, we should set the guessed caret rect.
  nsCOMPtr<nsIRange> range = new nsRange();
  NS_ENSURE_TRUE(range, NS_ERROR_OUT_OF_MEMORY);
  rv = SetRangeFromFlatTextOffset(range, aEvent->mInput.mOffset, 0, PR_TRUE);
  NS_ENSURE_SUCCESS(rv, rv);

  return QueryRectFor(aEvent, range, caret);
}

nsresult
nsQueryContentEventHandler::GetFlatTextOffsetOfRange(nsIRange* aRange,
                                                     PRUint32* aNativeOffset)
{
  NS_ASSERTION(aNativeOffset, "param is invalid");

  nsCOMPtr<nsIRange> prev = new nsRange();
  NS_ENSURE_TRUE(prev, NS_ERROR_OUT_OF_MEMORY);
  nsCOMPtr<nsIDOMRange> domPrev(do_QueryInterface(prev));
  NS_ASSERTION(domPrev, "nsRange doesn't have nsIDOMRange??");
  nsCOMPtr<nsIDOMNode> rootDOMNode(do_QueryInterface(mRootContent));
  domPrev->SetStart(rootDOMNode, 0);

  nsINode* startNode = aRange->GetStartParent();
  NS_ENSURE_TRUE(startNode, NS_ERROR_FAILURE);

  PRInt32 startOffset = aRange->StartOffset();
  nsCOMPtr<nsIDOMNode> startDOMNode(do_QueryInterface(startNode));
  NS_ASSERTION(startDOMNode, "startNode doesn't have nsIDOMNode");
  domPrev->SetEnd(startDOMNode, startOffset);

  nsAutoString prevStr;
  nsresult rv = GenerateFlatTextContent(prev, prevStr);
  NS_ENSURE_SUCCESS(rv, rv);
  *aNativeOffset = prevStr.Length();
  return NS_OK;
}

nsresult
nsQueryContentEventHandler::GetStartFrameAndOffset(nsIRange* aRange,
                                                   nsIFrame** aFrame,
                                                   PRInt32* aOffsetInFrame)
{
  NS_ASSERTION(aRange && aFrame && aOffsetInFrame, "params are invalid");

  nsIContent* content = nsnull;
  nsINode* node = aRange->GetStartParent();
  if (node && node->IsNodeOfType(nsINode::eCONTENT))
    content = static_cast<nsIContent*>(node);
  NS_ASSERTION(content, "the start node doesn't have nsIContent!");

  nsCOMPtr<nsFrameSelection> fs = mPresShell->FrameSelection();
  *aFrame = fs->GetFrameForNodeOffset(content, aRange->StartOffset(),
                                      fs->GetHint(), aOffsetInFrame);
  NS_ENSURE_TRUE((*aFrame), NS_ERROR_FAILURE);
  NS_ASSERTION((*aFrame)->GetType() == nsGkAtoms::textFrame,
               "The frame is not textframe");
  return NS_OK;
}

nsresult
nsQueryContentEventHandler::ConvertToRootViewRelativeOffset(nsIFrame* aFrame,
                                                            nsRect& aRect)
{
  NS_ASSERTION(aFrame, "aFrame must not be null");

  nsIView* view = nsnull;
  nsPoint posInView;
  aFrame->GetOffsetFromView(posInView, &view);
  if (!view)
    return NS_ERROR_FAILURE;
  aRect += posInView + view->GetOffsetTo(nsnull);
  return NS_OK;
}