// Created on: 2013-01-29
// Created by: Kirill GAVRILOV
// Copyright (c) 2013-2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

#include <Font_TextFormatter.hxx>

#include <Font_FTFont.hxx>

#include <Precision.hxx>

IMPLEMENT_STANDARD_RTTIEXT (Font_TextFormatter, Standard_Transient)

namespace
{
  typedef NCollection_Vec2<Standard_ShortReal> Vec2f;

  //! Auxiliary function to translate corners by the vector.
  inline void move (NCollection_Vector< Vec2f >& theCorners,
                    const Vec2f&                 theMoveVec,
                    Standard_Integer             theCharLower,
                    const Standard_Integer       theCharUpper)
  {
    for(; theCharLower <= theCharUpper; ++theCharLower)
    {
      theCorners.ChangeValue (theCharLower) += theMoveVec;
    }
  }

  //! Auxiliary function to translate corners in vertical direction.
  inline void moveY (NCollection_Vector<Vec2f>& theCorners,
                     const Standard_ShortReal   theMoveVec,
                     Standard_Integer           theCharLower,
                     const Standard_Integer     theCharUpper)
  {
    for(; theCharLower <= theCharUpper; ++theCharLower)
    {
      theCorners.ChangeValue (theCharLower).y() += theMoveVec;
    }
  }

}

// =======================================================================
// function : Font_TextFormatter
// purpose  :
// =======================================================================
Font_TextFormatter::Font_TextFormatter()
: myAlignX (Graphic3d_HTA_LEFT),
  myAlignY (Graphic3d_VTA_TOP),
  myTabSize (8),
  myWrappingWidth (0.0f),
  myIsWordWrapping (true),
  myLastSymbolWidth (0.0f),
  myMaxSymbolWidth (0.0f),
  //
  myPen (0.0f, 0.0f),
  myLineSpacing (0.0f),
  myAscender (0.0f),
  myIsFormatted (false),
  //
  myLinesNb (0),
  myRectLineStart (0),
  myNewLineNb(0),
  myPenCurrLine (0.0f),
  myBndTop   (0.0f),
  myBndWidth (0.0f),
  myMoveVec (0.0f, 0.0f)
{
  //
}

// =======================================================================
// function : SetupAlignment
// purpose  :
// =======================================================================
void Font_TextFormatter::SetupAlignment (const Graphic3d_HorizontalTextAlignment theAlignX,
                                         const Graphic3d_VerticalTextAlignment   theAlignY)
{
  myAlignX = theAlignX;
  myAlignY = theAlignY;
}

// =======================================================================
// function : Reset
// purpose  :
// =======================================================================
void Font_TextFormatter::Reset()
{
  myIsFormatted = false;
  myString.Clear();
  myPen.x() = myPen.y() = 0.0f;
  myLineSpacing = myAscender = 0.0f;
  myCorners.Clear();
  myNewLines.Clear();

  myLastSymbolWidth = 0.0f;
  myMaxSymbolWidth = 0.0f;
}

// =======================================================================
// function : Append
// purpose  :
// =======================================================================
void Font_TextFormatter::Append (const NCollection_String& theString,
                                 Font_FTFont&              theFont)
{
  if (theString.IsEmpty())
  {
    return;
  }

  myAscender    = Max (myAscender,    theFont.Ascender());
  myLineSpacing = Max (myLineSpacing, theFont.LineSpacing());
  myString     += theString;

  int aSymbolsCounter = 0; // special counter to process tabulation symbols

  // first pass - render all symbols using associated font on single ZERO baseline
  for (Font_TextFormatter::Iterator aFormatterIt (*this); aFormatterIt.More(); aFormatterIt.Next())
  {
    const Standard_Utf32Char aCharThis = aFormatterIt.Symbol();
    const Standard_Utf32Char aCharNext = aFormatterIt.SymbolNext();

    Standard_ShortReal anAdvanceX = 0;
    if (IsCommandSymbol (aCharThis))
    {
      continue; // skip unsupported carriage control codes
    }
    else if (aCharThis == '\x0A') // LF (line feed, new line)
    {
      aSymbolsCounter = 0;
      myNewLines.Append (myPen.x());
      anAdvanceX = 0; // the symbol has null width
    }
    else if (aCharThis == ' ')
    {
      anAdvanceX = theFont.AdvanceX (' ', aCharNext);
    }
    else if (aCharThis == '\t')
    {
      const Standard_Integer aSpacesNum = (myTabSize - (aSymbolsCounter - 1) % myTabSize);
      anAdvanceX = theFont.AdvanceX (' ', aCharNext) * Standard_ShortReal(aSpacesNum);
      aSymbolsCounter += aSpacesNum;
    }
    else
    {
      anAdvanceX = theFont.AdvanceX (aCharThis, aCharNext);
    }
    ++aSymbolsCounter;
    myCorners.Append (myPen);
    myPen.x() += anAdvanceX;
    myMaxSymbolWidth = Max (myMaxSymbolWidth, anAdvanceX);
  }
  myLastSymbolWidth = myPen.x() - myCorners.Last().x();
}

// =======================================================================
// function : newLine
// purpose  :
// =======================================================================
void Font_TextFormatter::newLine (const Standard_Integer theLastRect,
                                  const Standard_ShortReal theMaxLineWidth)
{
  Standard_Integer aFirstCornerId = myRectLineStart;
  Standard_Integer aLastCornerId = theLastRect;

  if (aFirstCornerId >= myCorners.Length())
  {
    ++myLinesNb;
    myPenCurrLine -= myLineSpacing;
    return;
  }

  Standard_ShortReal aXMin = BottomLeft (aFirstCornerId).x();
  Font_Rect aBndBox;
  GlyphBoundingBox (aLastCornerId, aBndBox);
  Standard_ShortReal aXMax = aBndBox.Right;

  myMoveVec.y() = myPenCurrLine;
  switch (myAlignX)
  {
    default:
    case Graphic3d_HTA_LEFT:   myMoveVec.x() = -aXMin;
      break;
    case Graphic3d_HTA_RIGHT:  myMoveVec.x() = -aXMin +        (theMaxLineWidth - (aXMax - aXMin)) -        theMaxLineWidth;
      break;
    case Graphic3d_HTA_CENTER: myMoveVec.x() = -aXMin + 0.5f * (theMaxLineWidth - (aXMax - aXMin)) - 0.5f * theMaxLineWidth;
      break;
  }

  move (myCorners, myMoveVec, myRectLineStart, theLastRect);

  ++myLinesNb;
  myPenCurrLine -= myLineSpacing;
  myRectLineStart = theLastRect + 1;
}

// =======================================================================
// function : Format
// purpose  :
// =======================================================================
void Font_TextFormatter::Format()
{
  if (myCorners.Length() == 0 || myIsFormatted)
  {
    return;
  }

  myIsFormatted = true;
  myLinesNb = myRectLineStart = 0;
  myBndTop     = 0.0f;
  myBndWidth   = 0.0f;
  myMoveVec.x() = myMoveVec.y() = 0.0f;

  // split text into lines and apply horizontal alignment
  myPenCurrLine = -myAscender;
  Standard_Integer aRectIter = 0;
  myNewLineNb = 0;

  Standard_ShortReal aMaxLineWidth = Wrapping();
  if (HasWrapping())
  {
    // it is not possible to wrap less than symbol width
    aMaxLineWidth = Max (aMaxLineWidth, MaximumSymbolWidth());
  }
  else
  {
    if (myNewLines.IsEmpty()) // If only one line
    {
      aMaxLineWidth = myPen.x();
    }
    else
    {
      for (int aLineIt = 0; aLineIt < myNewLines.Size(); aLineIt++)
      {
        aMaxLineWidth = Max (aMaxLineWidth, LineWidth (aLineIt));
      }
      aMaxLineWidth = Max (aMaxLineWidth, LineWidth (myNewLines.Size())); // processing the last line also
    }
  }

  Standard_Utf32Char aCharPrev = 0;
  for (Font_TextFormatter::Iterator aFormatterIt(*this);
       aFormatterIt.More(); aFormatterIt.Next())
  {
    const Standard_Utf32Char aCharThis = aFormatterIt.Symbol();
    aRectIter = aFormatterIt.SymbolPosition();

    if (aCharThis == '\x0A') // LF (line feed, new line)
    {
      const Standard_Integer aLastRect = aRectIter; // last rect on current line
      newLine (aLastRect, aMaxLineWidth);
      ++myNewLineNb;
      continue;
    }
    else if (HasWrapping()) // wrap lines longer than maximum width
    {
      Standard_Integer aFirstCornerId = myRectLineStart;

      Font_Rect aBndBox;
      GlyphBoundingBox (aRectIter, aBndBox);
      const Standard_ShortReal aNextXPos = aBndBox.Right - BottomLeft (aFirstCornerId).x();
      Standard_Boolean isCurWordFits = true;
      if(myIsWordWrapping && IsSeparatorSymbol(aCharPrev))
      {
        for (Font_TextFormatter::Iterator aWordIt = aFormatterIt; aWordIt.More(); aWordIt.Next())
        {
          if (IsSeparatorSymbol(aWordIt.Symbol()))
          {
            break;
          }
          float aWordWidthPx = myCorners[aWordIt.SymbolPosition()].x() - myCorners[aRectIter].x();
          if (aNextXPos + aWordWidthPx > aMaxLineWidth)
          {
            isCurWordFits = false;
            break;
          }
        }
      }
      if (aNextXPos > aMaxLineWidth || !isCurWordFits) // wrap the line and do processing of the symbol
      {
        const Standard_Integer aLastRect = aRectIter - 1; // last rect on current line
        newLine (aLastRect, aMaxLineWidth);
      }
    }
    aCharPrev = aCharThis;
  }

  myBndWidth = aMaxLineWidth;

  // move last line
  newLine (myCorners.Length() - 1, aMaxLineWidth);

  // apply vertical alignment style
  if (myAlignY == Graphic3d_VTA_BOTTOM)
  {
    myBndTop = -myLineSpacing - myPenCurrLine;
  }
  else if (myAlignY == Graphic3d_VTA_CENTER)
  {
    myBndTop = 0.5f * (myLineSpacing * Standard_ShortReal(myLinesNb));
  }
  else if (myAlignY == Graphic3d_VTA_TOPFIRSTLINE)
  {
    myBndTop = myAscender;
  }

  if (myAlignY != Graphic3d_VTA_TOP)
  {
    moveY (myCorners, myBndTop, 0, myCorners.Length() - 1);
  }
}

// =======================================================================
// function : GlyphBoundingBox
// purpose  :
// =======================================================================
Standard_Boolean Font_TextFormatter::GlyphBoundingBox (const Standard_Integer theIndex,
                                                       Font_Rect& theBndBox) const
{
  if (theIndex < 0 || theIndex >= Corners().Size())
  {
    return Standard_False;
  }

  const NCollection_Vec2<Standard_ShortReal>& aLeftCorner = BottomLeft (theIndex);
  theBndBox.Left = aLeftCorner.x();
  theBndBox.Right = aLeftCorner.x() + myLastSymbolWidth;
  theBndBox.Bottom = aLeftCorner.y();
  theBndBox.Top = theBndBox.Bottom + myLineSpacing;
  if (theIndex + 1 >= myCorners.Length())
  {
    // the last symbol
    return Standard_True;
  }

  const NCollection_Vec2<Standard_ShortReal>& aNextLeftCorner = BottomLeft (theIndex + 1);
  if (Abs (aLeftCorner.y() - aNextLeftCorner.y()) < Precision::Confusion()) // in the same row
  {
    theBndBox.Right = aNextLeftCorner.x();
  }
  else
  {
    // the next symbol is on the next row either by '\n' or by wrapping
    Standard_ShortReal aLineWidth = LineWidth (LineIndex (theIndex));
    theBndBox.Left = aLeftCorner.x();
    switch (myAlignX)
    {
      case Graphic3d_HTA_LEFT:   theBndBox.Right = aLineWidth; break;
      case Graphic3d_HTA_RIGHT:  theBndBox.Right = myBndWidth; break;
      case Graphic3d_HTA_CENTER: theBndBox.Right = 0.5f * (myBndWidth + aLineWidth); break;
    }
  }
  return Standard_True;
}


// =======================================================================
// function : IsLFSymbol
// purpose  :
// =======================================================================
Standard_Boolean Font_TextFormatter::IsLFSymbol (const Standard_Integer theIndex) const
{
  Font_Rect aBndBox;
  if (!GlyphBoundingBox (theIndex, aBndBox))
  {
    return Standard_False;
  }

  return Abs (aBndBox.Right - aBndBox.Left) < Precision::Confusion();
}

// =======================================================================
// function : FirstPosition
// purpose  :
// =======================================================================
Standard_ShortReal Font_TextFormatter::FirstPosition() const
{
  switch (myAlignX)
  {
    default:
    case Graphic3d_HTA_LEFT:   return 0;
    case Graphic3d_HTA_RIGHT:  return myBndWidth;
    case Graphic3d_HTA_CENTER: return 0.5f * myBndWidth;
  }
}

// =======================================================================
// function : LinePositionIndex
// purpose  :
// =======================================================================
Standard_Integer Font_TextFormatter::LinePositionIndex (const Standard_Integer theIndex) const
{
  Standard_Integer anIndex = 0;

  Standard_ShortReal anIndexHeight = BottomLeft (theIndex).y();
  for (Standard_Integer aPrevIndex = theIndex-1; aPrevIndex >= 0; aPrevIndex--)
  {
    if (BottomLeft (aPrevIndex).y() > anIndexHeight)
    {
      break;
    }
    anIndex++;
  }
  return anIndex;
}

// =======================================================================
// function : LineIndex
// purpose  :
// =======================================================================
Standard_Integer Font_TextFormatter::LineIndex (const Standard_Integer theIndex) const
{
  if (myLineSpacing < 0.0f)
  {
    return 0;
  }

  return (Standard_Integer)Abs((BottomLeft (theIndex).y() + myAscender) / myLineSpacing);
}

// =======================================================================
// function : LineWidth
// purpose  :
// =======================================================================
Standard_ShortReal Font_TextFormatter::LineWidth (const Standard_Integer theIndex) const
{
  if (theIndex < 0)
  {
    return 0;
  }

  if (theIndex < myNewLines.Length())
  {
    return theIndex == 0 ? myNewLines[0] : myNewLines[theIndex] - myNewLines[theIndex -1];
  }

  if (theIndex == myNewLines.Length()) // the last line
  {
    return theIndex == 0 ? myPen.x() : myPen.x() - myNewLines[theIndex -1];
  }

  return 0;
}