/*
 * 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 MathML Project.
 *
 * The Initial Developer of the Original Code is The University Of
 * Queensland.  Portions created by The University Of Queensland are
 * Copyright (C) 1999 The University Of Queensland.  All Rights Reserved.
 *
 * Contributor(s):
 *   Roger B. Sidje <rbs@maths.uq.edu.au>
 *   David J. Fiddes <D.J.Fiddes@hw.ac.uk>
 */


#include "nsCOMPtr.h"
#include "nsHTMLParts.h"
#include "nsIHTMLContent.h"
#include "nsFrame.h"
#include "nsLineLayout.h"
#include "nsHTMLIIDs.h"
#include "nsIPresContext.h"
#include "nsHTMLAtoms.h"
#include "nsUnitConversion.h"
#include "nsIStyleContext.h"
#include "nsStyleConsts.h"
#include "nsINameSpaceManager.h"
#include "nsIRenderingContext.h"
#include "nsIFontMetrics.h"
#include "nsStyleUtil.h"

#include "nsMathMLmsubFrame.h"

//
// <msub> -- attach a subscript to a base - implementation
//

nsresult
NS_NewMathMLmsubFrame(nsIPresShell* aPresShell, nsIFrame** aNewFrame)
{
  NS_PRECONDITION(aNewFrame, "null OUT ptr");
  if (nsnull == aNewFrame) {
    return NS_ERROR_NULL_POINTER;
  }
  nsMathMLmsubFrame* it = new (aPresShell) nsMathMLmsubFrame;
  if (nsnull == it) {
    return NS_ERROR_OUT_OF_MEMORY;
  }
  *aNewFrame = it;
  return NS_OK;
}

nsMathMLmsubFrame::nsMathMLmsubFrame()
{
}

nsMathMLmsubFrame::~nsMathMLmsubFrame()
{
}

NS_IMETHODIMP
nsMathMLmsubFrame::Place(nsIPresContext*      aPresContext,
                         nsIRenderingContext& aRenderingContext,
                         PRBool               aPlaceOrigin,
                         nsHTMLReflowMetrics& aDesiredSize)
{
  nscoord count = 0;
  nsRect rect[2];
  nsIFrame* child[2];
  nsIFrame* childFrame = mFrames.FirstChild();
  while (childFrame) {
    if (!IsOnlyWhitespace(childFrame) && 2 > count) {
      childFrame->GetRect(rect[count]);
      child[count] = childFrame;
      count++;
    }
    childFrame->GetNextSibling(&childFrame);
  }
  aDesiredSize.ascent = rect[0].y;

  // Get the subscript offset
  nscoord subscriptOffset, leading;
  nsCOMPtr<nsIFontMetrics> fm;
  const nsStyleFont* aFont =
    (const nsStyleFont*)mStyleContext->GetStyleData(eStyleStruct_Font);
  aPresContext->GetMetricsFor(aFont->mFont, getter_AddRefs(fm));
  fm->GetSubscriptOffset(subscriptOffset);
  fm->GetLeading(leading);

// XXX temporary hack pending bug http://bugzilla.mozilla.org/show_bug.cgi?id=9640
//#if 0
nscoord fmAscent, xHeight;
fm->GetMaxAscent(fmAscent);
fm->GetXHeight(xHeight);
subscriptOffset = PR_MAX(subscriptOffset,fmAscent-(xHeight*4)/5);
//#endif

//for (int i=0; i<100; i++) {
//printf("Ascent:%d   xHeight:%d  subscriptOffset:%d leading: %d ",
//fmAscent, xHeight, subscriptOffset, leading);
//}

  subscriptOffset += leading;

  // logic derived after examining the boxes on three cases: h0==h1, h0>h1, h0<h1
  aDesiredSize.height = rect[0].height + rect[1].height - subscriptOffset;
  aDesiredSize.width = rect[0].width + rect[1].width;
  rect[0].x = 0;
  rect[0].y = 0;
  rect[1].x = rect[0].width;
  rect[1].y = aDesiredSize.height - rect[1].height;
  aDesiredSize.descent = aDesiredSize.height - aDesiredSize.ascent;

  if (aPlaceOrigin) {
    // child[0]->SetRect(aPresContext, rect[0]);
    // child[1]->SetRect(aPresContext, rect[1]);
    nsHTMLReflowMetrics childSize(nsnull);
    for (PRInt32 i=0; i<count; i++) {
      childSize.width = rect[i].width;
      childSize.height = rect[i].height;
      FinishReflowChild(child[i], aPresContext, childSize, rect[i].x, rect[i].y, 0);
    }
  }
  return NS_OK;
}
