#include <QtGui>
#include "editor.h"

Editor::Editor() : QPlainTextEdit(),
    folded(false)
{
    document()->setDocumentLayout(new EditorLayout(document()));

    setPlainText(
        "int main(int argc, char **args)\n"
        "{\n"
        "\tqDebug() << \"Folding Code Example\";\n"
        "\treturn 0;\n"
        "}\n"
        "\n"
        "#include main.moc"
    );
    connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(updateCursorPosition()));
}

void Editor::paintEvent(QPaintEvent *event)
{
    if (folded) {
        QTextBlock foldedBlock = document()->findBlockByNumber(1);
        if (!foldedBlock.isValid() || !foldedBlock.isVisible())
            return;

        qreal top = blockBoundingGeometry(foldedBlock).translated(contentOffset()).top();

        QTextLayout *layout = foldedBlock.layout();
        QTextLine line = layout->lineAt(layout->lineCount()-1);
        QRectF lineRect = line.naturalTextRect().translated(0, top);

        lineRect.adjust(0, 0, -1, -1);

        QRectF collapseRect(lineRect.right() + 12,
                            lineRect.top(),
                            fontMetrics().width(QLatin1String(" ...} ")),
                            lineRect.height());

        QPainter painter(viewport());
        painter.setRenderHint(QPainter::Antialiasing, true);
        painter.translate(.5, .5);
        painter.drawRoundedRect(collapseRect.adjusted(0, 0, 0, -1), 3, 3);
        painter.translate(-.5, -.5);
        painter.drawText(collapseRect, Qt::AlignCenter, "...}");
    }

    QPlainTextEdit::paintEvent(event);
}

QTextBlock Editor::foldedBlockAt(const QPoint &pos)
{
    QTextBlock block = firstVisibleBlock();
    qreal top = blockBoundingGeometry(block).translated(contentOffset()).top();
    qreal bottom = top + blockBoundingRect(block).height();

    int viewportHeight = viewport()->height();

    while (block.isValid() && top <= viewportHeight) {
        QTextBlock nextBlock = block.next();

        if (block.isVisible() && bottom >= 0) {
            if (nextBlock.isValid() && !nextBlock.isVisible()) {
                QTextLayout *layout = block.layout();
                QTextLine line = layout->lineAt(layout->lineCount()-1);
                QRectF lineRect = line.naturalTextRect().translated(0, top);
                lineRect.adjust(0, 0, -1, -1);

                QRectF collapseRect(lineRect.right() + 12,
                                    lineRect.top(),
                                    fontMetrics().width(QLatin1String(" ...} ")),
                                    lineRect.height());

                if (collapseRect.contains(pos)) {
                    QTextBlock result = block;
                    return result;
                } else {
                    block = nextBlock;
                    while (nextBlock.isValid() && !nextBlock.isVisible()) {
                        block = nextBlock;
                        nextBlock = block.next();
                    }
                }
            }
        }

        block = nextBlock;
        top = bottom;
        bottom = top + blockBoundingRect(block).height();
    }
    return QTextBlock();
}

void Editor::updateCursorPosition()
{
    QTextCursor cursor = textCursor();
    QTextBlock block = cursor.block();

    if (!block.isVisible()) {
        while (!block.isVisible() && block.previous().isValid()) {
            block.setVisible(true);
            block.setLineCount(qMax(1, block.layout()->lineCount()));
            block = block.previous();
        }
        EditorLayout *layout = static_cast<EditorLayout *>(document()->documentLayout());
        layout->requestUpdate();
        layout->emitDocumentSizeChanged();

        folded = false;
        QPlainTextEdit::ensureCursorVisible();
    }
}

void Editor::mousePressEvent(QMouseEvent *event)
{
    if (folded) {
        QTextBlock foldedBlock = foldedBlockAt(event->pos());
        if (!foldedBlock.isValid()) {
            QPlainTextEdit::mousePressEvent(event);
            return;
        }
    } else {
        QPlainTextEdit::mousePressEvent(event);
    }

    EditorLayout *layout = static_cast<EditorLayout *>(document()->documentLayout());

    folded = !folded;
    for (int i = 0; i < 3; ++i) {
        QTextBlock block = document()->findBlockByNumber(i + 2);
        block.setVisible(!folded);
        block.setLineCount(folded ? 0 : qMax(1, block.layout()->lineCount()));
    }

    QTextCursor cursor = textCursor();
    if (!cursor.block().isVisible()) {
        cursor.setVisualNavigation(true);
        cursor.movePosition(QTextCursor::Up);
        setTextCursor(cursor);
    }

    layout->requestUpdate();
    layout->emitDocumentSizeChanged();
}