void pHexEdit::setColumns(unsigned columns) {
  update();
}

void pHexEdit::setLength(unsigned length) {
  //add one if last row is not equal to column length (eg only part of the row is present)
  bool indivisible = hexEdit.state.columns == 0 || (hexEdit.state.length % hexEdit.state.columns) != 0;
  qtScroll->setRange(0, hexEdit.state.length / hexEdit.state.columns + indivisible - hexEdit.state.rows);
  update();
}

void pHexEdit::setOffset(unsigned offset) {
  locked = true;
  qtScroll->setSliderPosition(hexEdit.state.offset / hexEdit.state.columns);
  locked = false;
  update();
}

void pHexEdit::setRows(unsigned rows) {
  qtScroll->setPageStep(hexEdit.state.rows);
  update();
}

void pHexEdit::update() {
  if(!hexEdit.onRead) {
    qtHexEdit->setPlainText("");
    return;
  }

  unsigned cursorPosition = qtHexEdit->textCursor().position();

  string output;
  unsigned offset = hexEdit.state.offset;
  for(unsigned row = 0; row < hexEdit.state.rows; row++) {
    output.append(hex<8>(offset));
    output.append("  ");

    string hexdata;
    string ansidata = " ";

    for(unsigned column = 0; column < hexEdit.state.columns; column++) {
      if(offset < hexEdit.state.length) {
        uint8_t data = hexEdit.onRead(offset++);
        hexdata.append(hex<2>(data));
        hexdata.append(" ");
        char buffer[2] = { data >= 0x20 && data <= 0x7e ? (char)data : '.', 0 };
        ansidata.append(buffer);
      } else {
        hexdata.append("   ");
        ansidata.append(" ");
      }
    }

    output.append(hexdata);
    output.append(ansidata);
    if(offset >= hexEdit.state.length) break;
    if(row != hexEdit.state.rows - 1) output.append("\n");
  }

  qtHexEdit->setPlainText(QString::fromUtf8(output));
  QTextCursor cursor = qtHexEdit->textCursor();
  cursor.setPosition(cursorPosition);
  qtHexEdit->setTextCursor(cursor);
}

void pHexEdit::constructor() {
  qtWidget = qtHexEdit = new QtHexEdit(*this);

  qtHexEdit->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
  qtHexEdit->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

  qtLayout = new QHBoxLayout;
  qtLayout->setAlignment(Qt::AlignRight);
  qtLayout->setMargin(0);
  qtLayout->setSpacing(0);
  qtHexEdit->setLayout(qtLayout);

  qtScroll = new QScrollBar(Qt::Vertical);
  qtScroll->setSingleStep(1);
  qtLayout->addWidget(qtScroll);

  connect(qtScroll, SIGNAL(actionTriggered(int)), SLOT(onScroll()));
}

void pHexEdit::keyPressEvent(QKeyEvent *event) {
  if(!hexEdit.onRead) return;

  QTextCursor cursor = qtHexEdit->textCursor();
  unsigned lineWidth = 10 + (hexEdit.state.columns * 3) + 1 + hexEdit.state.columns + 1;
  unsigned cursorY = cursor.position() / lineWidth;
  unsigned cursorX = cursor.position() % lineWidth;

  unsigned nibble;
  switch(event->key()) {
    case Qt::Key_0: nibble =  0; break;
    case Qt::Key_1: nibble =  1; break;
    case Qt::Key_2: nibble =  2; break;
    case Qt::Key_3: nibble =  3; break;
    case Qt::Key_4: nibble =  4; break;
    case Qt::Key_5: nibble =  5; break;
    case Qt::Key_6: nibble =  6; break;
    case Qt::Key_7: nibble =  7; break;
    case Qt::Key_8: nibble =  8; break;
    case Qt::Key_9: nibble =  9; break;
    case Qt::Key_A: nibble = 10; break;
    case Qt::Key_B: nibble = 11; break;
    case Qt::Key_C: nibble = 12; break;
    case Qt::Key_D: nibble = 13; break;
    case Qt::Key_E: nibble = 14; break;
    case Qt::Key_F: nibble = 15; break;
    default: {
      //allow navigation keys to move cursor, but block text input
      qtHexEdit->setTextInteractionFlags(Qt::TextInteractionFlags(
        Qt::TextSelectableByKeyboard | Qt::TextSelectableByMouse
      ));
      qtHexEdit->keyPressEventAcknowledge(event);
      qtHexEdit->setTextInteractionFlags(Qt::TextEditorInteraction);
      return;
    }
  }

  if(cursorX >= 10) {
    //not on an offset
    cursorX -= 10;
    if((cursorX % 3) != 2) {
      //not on a space
      bool cursorNibble = (cursorX % 3) == 1;  //0 = high, 1 = low
      cursorX /= 3;
      if(cursorX < hexEdit.state.columns) {
        //not in ANSI region
        unsigned offset = hexEdit.state.offset + (cursorY * hexEdit.state.columns + cursorX);

        if(offset >= hexEdit.state.length) return;  //do not edit past end of file
        uint8_t data = hexEdit.onRead(offset);

        //write modified value
        if(cursorNibble == 1) {
          data = (data & 0xf0) | (nibble << 0);
        } else {
          data = (data & 0x0f) | (nibble << 4);
        }
        if(hexEdit.onWrite) hexEdit.onWrite(offset, data);

        //auto-advance cursor to next nibble/byte
        unsigned step = 1;
        if(cursorNibble && cursorX != hexEdit.state.columns - 1) step = 2;
        cursor.setPosition(cursor.position() + step);
        qtHexEdit->setTextCursor(cursor);

        //refresh output to reflect modified data
        update();
      }
    }
  }
}

void pHexEdit::onScroll() {
  if(locked) return;
  unsigned offset = qtScroll->sliderPosition();
  hexEdit.state.offset = offset * hexEdit.state.columns;
  update();
}

void pHexEdit::QtHexEdit::keyPressEvent(QKeyEvent *event) {
  self.keyPressEvent(event);
}

void pHexEdit::QtHexEdit::keyPressEventAcknowledge(QKeyEvent *event) {
  QTextEdit::keyPressEvent(event);
}
