/*
 * 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>
 *   Vilya Harvey <vilya@nag.co.uk>
 *   Shyjan Mahamud <mahamud@cs.cmu.edu>
 */


#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 "nsMathMLmsqrtFrame.h"

//
// <msqrt> and <mroot> -- form a radical - implementation
//

//TODO:
//  The code assumes that TeX fonts are picked! Another separate version of
//  Reflow() is needed as a fall-back for cases where TeX fonts (CMSY/CMEX)
//  are not installed on the system, e.g., the fall-back could explicitly
//  draw the branches of the radical using th default rule thickness.

// additional style context to be used by our MathMLChar.
#define NS_SQR_CHAR_STYLE_CONTEXT_INDEX   0

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

nsMathMLmsqrtFrame::nsMathMLmsqrtFrame() :
  mSqrChar(),
  mBarRect()
{
}

nsMathMLmsqrtFrame::~nsMathMLmsqrtFrame()
{
}

NS_IMETHODIMP
nsMathMLmsqrtFrame::Init(nsIPresContext*  aPresContext,
                         nsIContent*      aContent,
                         nsIFrame*        aParent,
                         nsIStyleContext* aContext,
                         nsIFrame*        aPrevInFlow)
{
  nsresult rv = NS_OK;
  rv = nsMathMLContainerFrame::Init(aPresContext, aContent, aParent,
                                    aContext, aPrevInFlow);

  mEmbellishData.flags = NS_MATHML_STRETCH_ALL_CHILDREN_VERTICALLY;

  mSqrChar.SetEnum(aPresContext, eMathMLChar_Sqrt);
  ResolveMathMLCharStyle(aPresContext, mContent, mStyleContext, &mSqrChar);

#if defined(NS_DEBUG) && defined(SHOW_BOUNDING_BOX)
  mPresentationData.flags |= NS_MATHML_SHOW_BOUNDING_METRICS;
#endif
  return rv;
}

NS_IMETHODIMP
nsMathMLmsqrtFrame::Paint(nsIPresContext*      aPresContext,
                          nsIRenderingContext& aRenderingContext,
                          const nsRect&        aDirtyRect,
                          nsFramePaintLayer    aWhichLayer)
{
  nsresult rv = NS_OK;

  
  /////////////
  // paint the sqrt symbol
  if ((NS_FRAME_PAINT_LAYER_FOREGROUND == aWhichLayer) &&
      !NS_MATHML_HAS_ERROR(mPresentationData.flags))
  {
    mSqrChar.Paint(aPresContext, aRenderingContext,
                   aDirtyRect, aWhichLayer, this);
    // paint the overline bar
    nsStyleColor color;
    mStyleContext->GetStyle(eStyleStruct_Color, color);
    aRenderingContext.SetColor(color.mColor);
    aRenderingContext.FillRect(mBarRect.x, mBarRect.y, 
                               mBarRect.width, mBarRect.height);

#if defined(NS_DEBUG) && defined(SHOW_BOUNDING_BOX)
    // for visual debug
    if (NS_MATHML_PAINT_BOUNDING_METRICS(mPresentationData.flags))
    {
      nsRect rect;
      mSqrChar.GetRect(rect);

      nsBoundingMetrics bm;
      mSqrChar.GetBoundingMetrics(bm);

      aRenderingContext.SetColor(NS_RGB(255,0,0));
      nscoord x = rect.x + bm.leftBearing;
      nscoord y = rect.y;
      nscoord w = bm.rightBearing - bm.leftBearing;
      nscoord h = bm.ascent + bm.descent;
      aRenderingContext.DrawRect(x,y,w,h);
    }
#endif
  }

  /////////////
  // paint the content we are square-rooting
  rv = nsMathMLContainerFrame::Paint(aPresContext, aRenderingContext, 
                                     aDirtyRect, aWhichLayer);
  return rv;
}

NS_IMETHODIMP
nsMathMLmsqrtFrame::Reflow(nsIPresContext*          aPresContext,
                           nsHTMLReflowMetrics&     aDesiredSize,
                           const nsHTMLReflowState& aReflowState,
                           nsReflowStatus&          aStatus)
{
  nsresult rv = NS_OK;

  nsBoundingMetrics bmSqr, bmBase;

  ///////////////
  // Let the base class format our content like an inferred mrow
  nsHTMLReflowMetrics baseSize(aDesiredSize);
  rv = nsMathMLContainerFrame::Reflow(aPresContext, baseSize,
                                      aReflowState, aStatus);
  NS_ASSERTION(NS_FRAME_IS_COMPLETE(aStatus), "bad status");
  if (NS_FAILED(rv)) {
    return rv;
  }

  bmBase = baseSize.mBoundingMetrics;

  ////////////
  // Prepare the radical symbol and the overline bar

  nsIRenderingContext& renderingContext = *aReflowState.rendContext;
  nsStyleFont font;
  mStyleContext->GetStyle(eStyleStruct_Font, font);
  renderingContext.SetFont(font.mFont);
  nsCOMPtr<nsIFontMetrics> fm;
  renderingContext.GetFontMetrics(*getter_AddRefs(fm));

  nscoord ruleThickness;
  GetRuleThickness(renderingContext, fm, ruleThickness);

  // Rule 11, App. G, TeXbook
  // psi = clearance between rule and content
  nscoord phi = 0, psi = 0;
  if (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags))
    fm->GetXHeight(phi);
  else
    phi = ruleThickness;
  psi = ruleThickness + phi/4;
  
  // Stretch the radical symbol to the appropriate height if it is not big enough.
  nsBoundingMetrics contSize = bmBase;
  contSize.ascent = ruleThickness;
  contSize.descent = bmBase.ascent + bmBase.descent + psi;

  nsBoundingMetrics radicalSize;
  radicalSize.Clear(); // this tells Stretch() that we don't know the current size

  // height(radical) should be >= height(base) + psi + ruleThickness
  // however, nsMathMLChar will only try to meet this condition
  // with no guarantee.
  mSqrChar.Stretch(aPresContext, renderingContext,
                   NS_STRETCH_DIRECTION_VERTICAL, 
                   contSize, radicalSize,
                   NS_STRETCH_LARGER);
  // radicalSize have changed at this point, and should match with
  // the bounding metrics of the char
  mSqrChar.GetBoundingMetrics(bmSqr);

  // According to TeX, the ascent of the returned radical should be
  // the thickness of the overline
  ruleThickness = bmSqr.ascent;

  // adjust clearance psi to absorb any excess difference if any
  // in height between radical and content

  if (bmSqr.descent > (bmBase.ascent + bmBase.descent) + psi)
    psi = (psi + bmSqr.descent - (bmBase.ascent + bmBase.descent))/2;

  nscoord dx = 0, dy = 0;
  // place the radical symbol
  dy = ruleThickness; // leave a kern=ruleThickness at the top
  mSqrChar.SetRect(nsRect(dx, dy, bmSqr.width, bmSqr.ascent + bmSqr.descent));

  // place the radical bar
  dx = bmSqr.width;
  dy = ruleThickness; // leave a kern=ruleThickness at the top
  mBarRect.SetRect(dx, dy, bmBase.width, ruleThickness);

  // Update the desired size for the container.
  // the baseline will be that of the base.
  mBoundingMetrics.ascent = bmBase.ascent + psi + ruleThickness;
  mBoundingMetrics.descent = 
    PR_MAX(bmBase.descent, (bmSqr.descent - (bmBase.ascent + psi)));
  mBoundingMetrics.width = bmSqr.width + bmBase.width;
  mBoundingMetrics.leftBearing = bmSqr.leftBearing;
  mBoundingMetrics.rightBearing = bmSqr.width + 
    PR_MAX(bmBase.width, bmBase.rightBearing); // take also care of the rule

  aDesiredSize.ascent = bmBase.ascent + psi + 2*ruleThickness;
  aDesiredSize.descent =
    PR_MAX(baseSize.descent, (mBoundingMetrics.descent + ruleThickness));
  aDesiredSize.height = aDesiredSize.ascent + aDesiredSize.descent;
  aDesiredSize.width = mBoundingMetrics.width;

  mReference.x = 0;
  mReference.y = aDesiredSize.ascent;

  //////////////////
  // Adjust the origins to leave room for the sqrt char and the overline bar

  nsPoint origin;
  dx = radicalSize.width;
  dy = aDesiredSize.ascent - baseSize.ascent;
  nsIFrame* childFrame = mFrames.FirstChild();
  while (nsnull != childFrame) {
    if (!IsOnlyWhitespace(childFrame)) {
      childFrame->GetOrigin(origin);
      childFrame->MoveTo(aPresContext, origin.x + dx, origin.y + dy);
    }
    rv = childFrame->GetNextSibling(&childFrame);
    NS_ASSERTION(NS_SUCCEEDED(rv),"failed to get next child");
  }

  if (nsnull != aDesiredSize.maxElementSize) {
    aDesiredSize.maxElementSize->width = aDesiredSize.width;
    aDesiredSize.maxElementSize->height = aDesiredSize.height;
  }
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;
  aStatus = NS_FRAME_COMPLETE;
  return NS_OK;
}

// ----------------------
// the Style System will use these to pass the proper style context to our MathMLChar
NS_IMETHODIMP
nsMathMLmsqrtFrame::GetAdditionalStyleContext(PRInt32           aIndex, 
                                              nsIStyleContext** aStyleContext) const
{
  NS_PRECONDITION(aStyleContext, "null OUT ptr");
  if (aIndex < 0) {
    return NS_ERROR_INVALID_ARG;
  }
  *aStyleContext = nsnull;
  switch (aIndex) {
  case NS_SQR_CHAR_STYLE_CONTEXT_INDEX:
    mSqrChar.GetStyleContext(aStyleContext);
    break;
  default:
    return NS_ERROR_INVALID_ARG;
  }
  return NS_OK;
}

NS_IMETHODIMP
nsMathMLmsqrtFrame::SetAdditionalStyleContext(PRInt32          aIndex, 
                                              nsIStyleContext* aStyleContext)
{
  if (aIndex < 0) {
    return NS_ERROR_INVALID_ARG;
  }
  switch (aIndex) {
  case NS_SQR_CHAR_STYLE_CONTEXT_INDEX:
    mSqrChar.SetStyleContext(aStyleContext);
    break;
  }
  return NS_OK;
}