#include "DocumentItem.h"
#include "DocumentBuffer.h"
#include <QBrush>
#include <QPen>
#include <QPainter>
#include <QPainterPath>
#include <QKeyEvent>
#include <QGraphicsSceneWheelEvent>
#include <QDebug>

DocumentItem::DocumentItem(int lineCharacterCount, int lineCount, QGraphicsItem *parent) :
	QGraphicsObject(parent),
	m_buffer(new DocumentBuffer),
	m_lineCharacterCount(lineCharacterCount),
	m_lineCount(lineCount),
	m_currentRow(0),
	m_currentCol(0),
	m_scrollTop(0),
	m_editable(true)
{
	setFlag(ItemIsFocusable, true);
}
DocumentItem::~DocumentItem()
{
	delete m_buffer;
}
void DocumentItem::keyPressEvent(QKeyEvent *event)
{
	if (event->modifiers().testFlag(Qt::AltModifier) || event->modifiers().testFlag(Qt::ControlModifier))
		return;

	if ((event->key() == Qt::Key_Backspace && !event->isAutoRepeat()) || event->key() == Qt::Key_Left) {
		if (--m_currentCol == -1) {
			m_currentRow = m_currentRow - 1;
			if (m_currentRow == -1) {
				m_currentRow = 0;
				m_currentCol = 0;
			} else
				m_currentCol = qMin(m_lineCharacterCount - 1, m_buffer->lineSize(m_currentRow));
		}
	} else if (event->key() == Qt::Key_Return && !event->isAutoRepeat()) {
		m_buffer->insertCharacterAt(QLatin1Char('\n'), m_currentRow, m_currentCol);
		m_currentCol = 0;
		++m_currentRow;
	} else if (event->key() == Qt::Key_Down) {
		m_currentRow = qMin(m_currentRow + 1, m_buffer->linesCount() - 1);
		m_currentCol = qMin(m_currentCol, m_buffer->lineSize(m_currentRow));
	} else if (event->key() == Qt::Key_Right) {
		if (m_currentCol < m_buffer->lineSize(m_currentRow))
			++m_currentCol;
		else {
			m_currentRow = qMin(m_currentRow + 1, m_buffer->linesCount() - 1);
			if (m_currentRow != m_buffer->linesCount() - 1)
				m_currentCol = 0;
		}
	} else if (event->key() == Qt::Key_Up) {
		m_currentRow = qMax(0, m_currentRow - 1);
		m_currentCol = qMin(m_currentCol, m_buffer->lineSize(m_currentRow));
	} else if (event->key() == Qt::Key_PageUp)
		scroll(-m_lineCount * 3 / 4);
	else if (event->key() == Qt::Key_PageDown)
		scroll(m_lineCount * 3 / 4);
	else if (m_editable && !event->isAutoRepeat() && event->text().size() == 1 && event->text().at(0).isPrint()) {
		m_buffer->insertCharacterAt(event->text().at(0), m_currentRow, m_currentCol++);
		if (m_currentCol == m_lineCharacterCount) {
			m_currentCol = 0;
			++m_currentRow;
		}
	}
	if (m_currentRow - m_scrollTop >= m_lineCount)
		++m_scrollTop;

	update();
}
void DocumentItem::wheelEvent(QGraphicsSceneWheelEvent *event)
{
	if (event->orientation() != Qt::Vertical)
		return;
	if (m_buffer->linesCount() <= m_lineCount)
		return;
	scroll(-event->delta() / 50);
}
void DocumentItem::scroll(int lines)
{
	m_scrollTop += lines;
	if (m_scrollTop < 0)
		m_scrollTop = 0;
	else if (m_scrollTop >= m_buffer->linesCount())
		m_scrollTop = m_buffer->linesCount() - 1;

	m_currentRow = qBound(m_scrollTop, m_currentRow, m_scrollTop + m_lineCount - 1);
	m_currentCol = qMin(m_currentCol, m_buffer->lineSize(m_currentRow));

	update();
}
QRectF DocumentItem::boundingRect() const
{
	return QRectF(0, 0, m_lineCharacterCount * CHARACTER_WIDTH, m_lineCount * CHARACTER_HEIGHT);
}
void DocumentItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
	Q_UNUSED(option)
	Q_UNUSED(widget)

	// Draw background
	painter->save();
	if (hasFocus())
		painter->setBrush(QBrush(QColor(255, 255, 200)));
	else
		painter->setBrush(QBrush(QColor(255, 255, 220)));
	painter->drawRect(boundingRect());
	painter->restore();

	// Setup font
	QFont font;
	font.setFamily("CMU Typewriter Text");
	font.setKerning(false);
	font.setFixedPitch(true);

	// Draw scroll indication
	painter->save();
	font.setPixelSize(CHARACTER_WIDTH * 5);
	painter->setFont(font);
	painter->setBrush(QBrush(QColor(200, 200, 200)));
	painter->setOpacity(0.25);
	if (m_scrollTop + m_lineCount < m_buffer->linesCount())
		painter->drawText(boundingRect(), Qt::AlignBottom | Qt::AlignRight, QString::fromUtf8("\u2193"));
	if (m_scrollTop > 0)
		painter->drawText(boundingRect(), Qt::AlignTop | Qt::AlignRight, QString::fromUtf8("\u2191"));
	painter->restore();

	// Draw text
	painter->save();
	font.setPixelSize(CHARACTER_WIDTH * 1.5);
	painter->setFont(font);
	painter->setBrush(QBrush(QColor(30, 30, 30)));
	painter->setPen(QPen(QColor(30, 30, 30)));
	for (int row = m_scrollTop; row < m_lineCount + m_scrollTop; ++row) {
		const double y = (row - m_scrollTop) * CHARACTER_HEIGHT;
		if (row >= m_buffer->linesCount())
			break;
		for (int col = 0; col < m_buffer->lineSize(row); ++col) {
			const double x = col * CHARACTER_WIDTH;
			const QLinkedList<QChar> &characters = m_buffer->charactersAt(row, col);
			const int size = characters.size();
			int i = 0;
			foreach (const QChar &character, characters) {
				painter->setOpacity(qMin(1.0, 1.0 / static_cast<double>(size - i++) + 0.2));
				painter->drawText(x, y, CHARACTER_WIDTH, CHARACTER_HEIGHT, Qt::TextSingleLine | Qt::AlignHCenter | Qt::AlignVCenter, QString(character));
			}
		}
	}
	painter->restore();

	// Draw cursor
	if (hasFocus() && isEditable()) {
		painter->save();
		painter->setOpacity(0.5);
		painter->setBrush(QBrush(QColor(0, 0, 0)));
		painter->drawRect(m_currentCol * CHARACTER_WIDTH, (m_currentRow - m_scrollTop) * CHARACTER_HEIGHT, CHARACTER_WIDTH, CHARACTER_HEIGHT);
		painter->restore();
	}

	// Draw rule lines
	painter->save();
	QPen pen(QColor(190, 0, 0, isEditable() ? 64 : 32));
	pen.setCapStyle(Qt::FlatCap);
	pen.setWidth(1);
	pen.setCosmetic(true);
	painter->setPen(pen);
	for (int i = 1; i < m_lineCount; ++i) {
		const double height = i * CHARACTER_HEIGHT;
		painter->drawLine(QPointF(boundingRect().left(), height), QPointF(boundingRect().right(), height));
	}
	painter->restore();
}
const DocumentBuffer& DocumentItem::buffer() const
{
	return *m_buffer;
}
void DocumentItem::setBuffer(DocumentBuffer *buffer)
{
	if (m_buffer)
		delete m_buffer;
	m_buffer = buffer;
}
bool DocumentItem::isEditable() const
{
	return m_editable;
}
void DocumentItem::setEditable(bool on)
{
	m_editable = on;
}
void DocumentItem::setText(const QString &text)
{
	const QPair<int, int> place = m_buffer->setText(text, m_lineCharacterCount);
	m_currentRow = place.first;
	m_currentCol = place.second;
}
QPair<int, int> DocumentItem::cursorLocation() const
{
	return qMakePair(m_currentRow, m_currentCol);
}
void DocumentItem::setCursorLocation(const QPair<int, int> &location)
{
	m_currentRow = location.first;
	m_currentCol = location.second;
	update();
}
int DocumentItem::scrollTop() const
{
	return m_scrollTop;
}
void DocumentItem::setScrollTop(int top)
{
	m_scrollTop = top;
	update();
}