// character_manager.cpp: implementation of the TFont class
// for FreeType 2.
//
//////////////////////////////////////////////////////////////////////

#include <QStringList>
#include <QFont>
#include <QFontDatabase>
#include <QFontMetrics>
#include <QImage>
#include <QPainterPath>
#include <QPainter>
#include <QRawFont>

#include <vector>
#include <iostream>
#include <string>

#include "tpixelgr.h"
#include "tfont.h"
#include "tstroke.h"
#include "tcurves.h"
#include "traster.h"
#include "tmathutil.h"
#include "tvectorimage.h"
using namespace std;

//=============================================================================

struct TFont::Impl {
  bool m_hasKerning;
  int m_hasVertical;
  QFont m_font;
  // XXX:cache a QFontMetrics m_metrics; ?
  // XXX:cache a QRawFont m_raw; ?

  //  KerningPairs m_kerningPairs;

  Impl(const QString &family, const QString &style, int size);
  ~Impl();

  // void getChar();
};

//-----------------------------------------------------------------------------

TFont::TFont(const wstring family, const wstring face, int size) {
  m_pimpl = new Impl(QString::fromStdWString(family),
                     QString::fromStdWString(face), size);
}

//-----------------------------------------------------------------------------

TFont::~TFont() { delete m_pimpl; }

//-----------------------------------------------------------------------------

TFont::Impl::Impl(const QString &family, const QString &style, int size) {
  m_font = QFont(family, size);
  m_font.setBold(TFontManager::instance()->isBold(family, style));
  m_font.setItalic(TFontManager::instance()->isItalic(family, style));
}

//-----------------------------------------------------------------------------

TFont::Impl::~Impl() {}

//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// returns the offset (advance of the cursor) for the current character
TPoint TFont::drawChar(TVectorImageP &image, wchar_t charcode,
                       wchar_t nextCharCode) const {
  QRawFont raw(QRawFont::fromFont(m_pimpl->m_font));

  QChar chars[2] = {charcode, nextCharCode};
  quint32 indices[2];
  int count = 2;

  if (!raw.glyphIndexesForChars(chars, 2, indices, &count) || count < 1)
    return TPoint(0, 0);
  QPainterPath path = raw.pathForGlyph(indices[0]);

  // empty glyph, nothing to do
  if (path.elementCount() < 1) return getDistance(charcode, nextCharCode);

  // force closing the last path
  if (path.elementAt(path.elementCount() - 1).type !=
      QPainterPath::MoveToElement) {
    path.moveTo(0.0, 0.0);
  }

  int i, n = path.elementCount();
  int strokes = 0;
  std::vector<TThickPoint> points;

  TThickPoint pts[4];
  int nCubicPts = 0;

  for (i = 0; i < n; i++) {
    QPainterPath::Element e = path.elementAt(i);
    e.y                     = -e.y;

    switch (e.type) {
    case QPainterPath::MoveToElement:
      if (!points.empty()) {
        if (points.back() != points.front()) {
          points.push_back(0.5 * (points.back() + points.front()));
          points.push_back(points.front());
        }

        TStroke *stroke = new TStroke(points);
        stroke->setSelfLoop(true);
        image->addStroke(stroke);
        strokes++;
        points.clear();
      }
      points.push_back(TThickPoint(e.x, e.y, 0));
      break;
    case QPainterPath::LineToElement: {
      TThickPoint p0 = points.back();
      TThickPoint p1 = TThickPoint(e.x, e.y, 0);
      points.push_back((p0 + p1) * 0.5);
      points.push_back(p1);
      break;
    }
    case QPainterPath::CurveToElement:
      pts[0]    = points.back();
      pts[1]    = TThickPoint(e.x, e.y, 0);
      nCubicPts = 2;
      break;
    case QPainterPath::CurveToDataElement:
      pts[nCubicPts++] = TThickPoint(e.x, e.y, 0);
      if (nCubicPts == 4) {
        vector<TThickQuadratic *> chunkArray;
        computeQuadraticsFromCubic(pts[0], pts[1], pts[2], pts[3], 0.09,
                                   chunkArray);

        for (int j = 0; j < chunkArray.size(); j++) {
          points.push_back(chunkArray[j]->getP1());
          points.push_back(chunkArray[j]->getP2());
        }
        nCubicPts = 0;
      }
      break;
    }
  }

  if (strokes > 1) image->group(0, strokes);

  return getDistance(charcode, nextCharCode);
}

//-----------------------------------------------------------------------------

TPoint TFont::drawChar(QImage &outImage, TPoint &unused, wchar_t charcode,
                       wchar_t nextCharCode) const {
  QRawFont raw(QRawFont::fromFont(m_pimpl->m_font));

  QChar chars[2] = {charcode, nextCharCode};
  quint32 indices[2];
  int count = 2;

  if (!raw.glyphIndexesForChars(chars, 2, indices, &count) || count < 1) {
    return TPoint(0, 0);
  }

  // Workaround for unix when the user using the space character:
  // alphaMapForGlyph with a space character returns an invalid
  // QImage for some reason.
  // Bug 3604: https://github.com/opentoonz/opentoonz/issues/3604
  // (21/1/2022) Use this workaround for all platforms as the crash also
  // occurred in windows when the display is scaled up.
  if (chars[0].isSpace()) {
    int w = QFontMetrics(m_pimpl->m_font).horizontalAdvance(chars[0]);
    outImage =
        QImage(w, raw.ascent() + raw.descent(), QImage::Format_Grayscale8);
    outImage.fill(255);
    return getDistance(charcode, nextCharCode);
  }
  QImage image = raw.alphaMapForGlyph(indices[0], QRawFont::PixelAntialiasing);
  if (image.format() != QImage::Format_Indexed8 &&
      image.format() != QImage::Format_Alpha8)
    throw TException(L"bad QImage format " + image.format());

  QRectF boundingRect = raw.boundingRect(indices[0]);

  outImage = QImage(image.width(), raw.ascent() + raw.descent(),
                    QImage::Format_Grayscale8);
  outImage.fill(255);
  QPainter painter(&outImage);
  painter.drawImage(0, boundingRect.top() + raw.ascent(), image);

  return getDistance(charcode, nextCharCode);
}

//-----------------------------------------------------------------------------

TPoint TFont::drawChar(TRasterCM32P &outImage, TPoint &unused, int inkId,
                       wchar_t charcode, wchar_t nextCharCode) const {
  QImage grayAppImage;
  this->drawChar(grayAppImage, unused, charcode, nextCharCode);

  int lx = grayAppImage.width();
  int ly = grayAppImage.height();

  outImage = TRasterCM32P(lx, ly);
  outImage->lock();

  assert(TPixelCM32::getMaxTone() == 255);
  TPixelCM32 bgColor(0, 0, TPixelCM32::getMaxTone());
  int ty = 0;

  for (int gy = ly - 1; gy >= 0; --gy, ++ty) {
    uchar *srcPix      = grayAppImage.scanLine(gy);
    TPixelCM32 *tarPix = outImage->pixels(ty);
    for (int x = 0; x < lx; ++x) {
      int tone = (int)(*srcPix);

      if (tone == 255)
        *tarPix = bgColor;
      else
        *tarPix = TPixelCM32(inkId, 0, tone);

      ++srcPix;
      ++tarPix;
    }
  }
  outImage->unlock();

  return getDistance(charcode, nextCharCode);
}

//-----------------------------------------------------------------------------

TPoint TFont::getDistance(wchar_t firstChar, wchar_t secondChar) const {
  QFontMetrics metrics(m_pimpl->m_font);
  return TPoint(metrics.width(QChar(firstChar)), 0);
}

//-----------------------------------------------------------------------------

int TFont::getMaxWidth() const {
  QFontMetrics metrics(m_pimpl->m_font);
  return metrics.maxWidth();
}
//-----------------------------------------------------------------------------

int TFont::getLineAscender() const {
  QFontMetrics metrics(m_pimpl->m_font);
  return metrics.ascent();
}

//-----------------------------------------------------------------------------

int TFont::getLineDescender() const {
  QFontMetrics metrics(m_pimpl->m_font);
  return metrics.descent();
}

//-----------------------------------------------------------------------------

int TFont::getLineSpacing() const {
  QFontMetrics metrics(m_pimpl->m_font);
  return metrics.lineSpacing();
}

//-----------------------------------------------------------------------------

int TFont::getHeight() const {
  QFontMetrics metrics(m_pimpl->m_font);
  return metrics.height();
}

//-----------------------------------------------------------------------------

int TFont::getAverageCharWidth() const {
  QFontMetrics metrics(m_pimpl->m_font);
  return metrics.averageCharWidth();
}

//-----------------------------------------------------------------------------

bool TFont::hasKerning() const { return m_pimpl->m_font.kerning(); }

//-----------------------------------------------------------------------------

bool TFont::hasVertical() const {
  // FIXME
  return false;
}

//-----------------------------------------------------------------------------

//=============================================================================
//====================      TFontManager  =====================================
//=============================================================================

//---------------------------------------------------------

struct TFontManager::Impl {
  QFontDatabase *m_qfontdb;
  bool m_loaded;

  TFont *m_currentFont;
  wstring m_currentFamily;
  wstring m_currentTypeface;
  int m_size;

  // this option is set by library user when he wants to write vertically.
  // In this implementation, if m_vertical is true and the font
  // has the @-version, the library use it.
  bool m_vertical;

  Impl()
      : m_qfontdb(NULL)
      , m_loaded(false)
      , m_currentFont(0)
      , m_size(0)
      , m_vertical(false) {}
  ~Impl() { delete m_qfontdb; }
};

//---------------------------------------------------------

TFontManager::TFontManager() { m_pimpl = new TFontManager::Impl(); }

//---------------------------------------------------------

TFontManager::~TFontManager() { delete m_pimpl; }

//---------------------------------------------------------

TFontManager *TFontManager::instance() {
  static TFontManager theManager;
  return &theManager;
}

//---------------------------------------------------------

void TFontManager::loadFontNames() {
  if (m_pimpl->m_loaded) return;

  m_pimpl->m_qfontdb = new QFontDatabase;

  if (m_pimpl->m_qfontdb->families().empty()) throw TFontLibraryLoadingError();

  m_pimpl->m_loaded = true;
}

//---------------------------------------------------------

void TFontManager::setFamily(const wstring family) {
  if (m_pimpl->m_currentFamily == family) return;

  QString qFamily      = QString::fromStdWString(family);
  QStringList families = m_pimpl->m_qfontdb->families();
  if (!families.contains(qFamily)) throw TFontCreationError();

  m_pimpl->m_currentFamily = family;

// XXX: if current style is not valid for family, reset it?
// doing so asserts when choosing a font in the GUI
#if 0
  QStringList styles = m_pimpl->m_qfontdb->styles(qFamily);
  if (styles.contains(QString::fromStdWString(m_pimpl->m_currentTypeface))) {
    m_pimpl->m_currentTypeface = L"";
  }
#endif
  delete m_pimpl->m_currentFont;
  m_pimpl->m_currentFont = new TFont(
      m_pimpl->m_currentFamily, m_pimpl->m_currentTypeface, m_pimpl->m_size);
}

//---------------------------------------------------------

void TFontManager::setTypeface(const wstring typeface) {
  if (m_pimpl->m_currentTypeface == typeface) return;

  QString qTypeface  = QString::fromStdWString(typeface);
  QStringList styles = m_pimpl->m_qfontdb->styles(
      QString::fromStdWString(m_pimpl->m_currentFamily));
  if (!styles.contains(qTypeface)) {
    throw TFontCreationError();
  }

  m_pimpl->m_currentTypeface = typeface;

  delete m_pimpl->m_currentFont;
  m_pimpl->m_currentFont = new TFont(
      m_pimpl->m_currentFamily, m_pimpl->m_currentTypeface, m_pimpl->m_size);
}

//---------------------------------------------------------

void TFontManager::setSize(int size) {
  if (m_pimpl->m_size == size) return;
  m_pimpl->m_size = size;
  delete m_pimpl->m_currentFont;
  m_pimpl->m_currentFont = new TFont(
      m_pimpl->m_currentFamily, m_pimpl->m_currentTypeface, m_pimpl->m_size);
}

//---------------------------------------------------------

wstring TFontManager::getCurrentFamily() const {
  return m_pimpl->m_currentFamily;
}

//---------------------------------------------------------

wstring TFontManager::getCurrentTypeface() const {
  return m_pimpl->m_currentTypeface;
}

//---------------------------------------------------------

TFont *TFontManager::getCurrentFont() {
  if (m_pimpl->m_currentFont) {
    return m_pimpl->m_currentFont;
  }

  if (!m_pimpl->m_currentFont) {
    loadFontNames();
  }

  assert(!m_pimpl->m_qfontdb->families().empty());
  setFamily(m_pimpl->m_qfontdb->families().first().toStdWString());

  return m_pimpl->m_currentFont;
}

//---------------------------------------------------------

void TFontManager::getAllFamilies(vector<wstring> &families) const {
  QStringList qFamilies = m_pimpl->m_qfontdb->families();

  families.clear();
  families.reserve(qFamilies.count());

  QStringList::const_iterator it = qFamilies.begin();
  for (; it != qFamilies.end(); ++it) {
    if (!m_pimpl->m_qfontdb->isPrivateFamily(*it))
      families.push_back(it->toStdWString());
  }
}

//---------------------------------------------------------

void TFontManager::getAllTypefaces(vector<wstring> &typefaces) const {
  typefaces.clear();

  QStringList qStyles = m_pimpl->m_qfontdb->styles(
      QString::fromStdWString(m_pimpl->m_currentFamily));

  if (qStyles.empty()) return;

  typefaces.reserve(qStyles.count());
  QStringList::const_iterator it_typeface = qStyles.begin();
  for (; it_typeface != qStyles.end(); ++it_typeface) {
    typefaces.push_back(it_typeface->toStdWString());
  }
}

//---------------------------------------------------------

void TFontManager::setVertical(bool vertical) {}

//---------------------------------------------------------

bool TFontManager::isBold(const QString &family, const QString &style) {
  return m_pimpl->m_qfontdb->bold(family, style);
}

//---------------------------------------------------------

bool TFontManager::isItalic(const QString &family, const QString &style) {
  return m_pimpl->m_qfontdb->italic(family, style);
}