#include "tagwidget.h"
#include <QPair>
#include <QDebug>
#include <QAbstractItemView>

TagWidget::TagWidget(QWidget *parent) : GroupedLineEdit(parent), m_completer(NULL)
{
	connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(reparse()));
	connect(this, SIGNAL(textChanged()), this, SLOT(reparse()));

	addColor(QColor(0x00, 0xAE, 0xFF));
	addColor(QColor(0x00, 0x78, 0xB0));
}

void TagWidget::setCompleter(QCompleter *completer)
{
	m_completer = completer;
	m_completer->setWidget(this);
	connect(m_completer, SIGNAL(activated(QString)), this, SLOT(completionSelected(QString)));
	connect(m_completer, SIGNAL(highlighted(QString)), this, SLOT(completionSelected(QString)));
}

QPair<int,int> TagWidget::getCursorTagPosition() {
	int i = 0, start = 0, end = 0;
	/* Parse string near cursor */
	i = cursorPosition();
	while (--i > 0) {
		if (text().at(i) == ',') {
			if (i > 0 && text().at(i-1) != '\\') {
				i++;
				break;
			}
		}
	}
	start = i;
	while (++i < text().length()) {
		if (text().at(i) == ',') {
			if (i > 0 && text().at(i-1) != '\\')
				break;
		}
	}
	end = i;
	if (start < 0 || end < 0) {
		start = 0;
		end = 0;
	}
	return QPair<int,int>(start,end);
}

enum ParseState {FINDSTART, FINDEND};

void TagWidget::highlight() {
	int i = 0, start = 0, end = 0;
	ParseState state = FINDEND;
	removeAllBlocks();

	while(i < text().length()) {
		if (text().at(i) == ',') {
			if (state == FINDSTART) {
				/* Detect empty tags */
			} else if (state == FINDEND) {
				/* Found end of tag */
				if (i > 1) {
					if(text().at(i-1) != '\\') {
						addBlock(start, end);
						state = FINDSTART;
					}
				} else {
					state = FINDSTART;
				}
			}
		} else if (text().at(i) == ' ') {
			/* Handled */
		} else {
			/* Found start of tag */
			if (state == FINDSTART) {
				state = FINDEND;
				start = i;
			} else if (state == FINDEND) {
				end = i;
			}
		}
		i++;
	}
	if (state == FINDEND) {
		if (end < start)
			end = text().length()-1;
		if (text().length() > 0)
			addBlock(start, end);
	}
}

void TagWidget::reparse()
{
	highlight();
	QPair<int,int> pos = getCursorTagPosition();
	QString currentText;
	if (pos.first >= 0 && pos.second > 0)
		currentText = text().mid(pos.first, pos.second-pos.first).trimmed();
	else
		currentText = "";
	if (m_completer) {
		m_completer->setCompletionPrefix(currentText);
		if (m_completer->completionCount() == 1) {
			if (m_completer->currentCompletion() == currentText) {
				QAbstractItemView *popup = m_completer->popup();
				if (popup)
					popup->hide();
				}
			else
				m_completer->complete();

		} else {
			m_completer->complete();
		}
	}
}

void TagWidget::completionSelected(QString completion) {
	QPair <int,int> pos;
	pos = getCursorTagPosition();
	if (pos.first >= 0 && pos.second > 0) {
		setText(text().remove(pos.first, pos.second-pos.first).insert(pos.first, completion));
		setCursorPosition(pos.first+completion.length());
	}
	else {
		setText(completion.append(", "));
		setCursorPosition(text().length());
	}
}

void TagWidget::setCursorPosition(int position) {
	blockSignals(true);
	GroupedLineEdit::setCursorPosition(position);
	blockSignals(false);
}

void TagWidget::setText(QString text) {
	blockSignals(true);
	GroupedLineEdit::setText(text);
	blockSignals(false);
	highlight();
}

void TagWidget::clear() {
	blockSignals(true);
	GroupedLineEdit::clear();
	blockSignals(false);
}

void TagWidget::keyPressEvent(QKeyEvent *e) {
	switch (e->key()) {
	case Qt::Key_Return:
	case Qt::Key_Enter:
	case Qt::Key_Tab:
		/*
		 * Fake the QLineEdit behaviour by simply
		 * closing the QAbstractViewitem
		 */
		if (m_completer) {
			QAbstractItemView *popup = m_completer->popup();
			if (popup)
				popup->hide();
		}
	}
	if (e->key() == Qt::Key_Tab) { // let's pretend this is a comma instead
		QKeyEvent *fakeEvent = new QKeyEvent(e->type(), Qt::Key_Comma, e->modifiers(), QString(","));
		GroupedLineEdit::keyPressEvent(fakeEvent);
		delete fakeEvent;
	} else {
		GroupedLineEdit::keyPressEvent(e);
	}
}