#include "ui/TextLabel.h"

#include <QAbstractTextDocumentLayout>
#include <QDesktopServices>
#include <QEvent>
#include <QWheelEvent>

#include "Utils.h"

bool
ContextMenuFilter::eventFilter(QObject *obj, QEvent *event)
{
        if (event->type() == QEvent::MouseButtonPress) {
                emit contextMenuIsOpening();
                return true;
        }

        return QObject::eventFilter(obj, event);
}

TextLabel::TextLabel(QWidget *parent)
  : TextLabel(QString(), parent)
{}

TextLabel::TextLabel(const QString &text, QWidget *parent)
  : QTextBrowser(parent)
{
        document()->setDefaultStyleSheet(QString("a {color: %1; }").arg(utils::linkColor()));

        setText(text);
        setOpenExternalLinks(true);

        // Make it look and feel like an ordinary label.
        setReadOnly(true);
        setFrameStyle(QFrame::NoFrame);
        QPalette pal = palette();
        pal.setColor(QPalette::Base, Qt::transparent);
        setPalette(pal);

        // Wrap anywhere but prefer words, adjust minimum height on the fly.
        setLineWrapMode(QTextEdit::WidgetWidth);
        setWordWrapMode(QTextOption::WrapAtWordBoundaryOrAnywhere);
        connect(document()->documentLayout(),
                &QAbstractTextDocumentLayout::documentSizeChanged,
                this,
                &TextLabel::adjustHeight);
        document()->setDocumentMargin(0);

        setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
        setFixedHeight(0);

        connect(this, &TextLabel::linkActivated, this, &TextLabel::handleLinkActivation);

        auto filter = new ContextMenuFilter(this);
        installEventFilter(filter);
        connect(filter, &ContextMenuFilter::contextMenuIsOpening, this, [this]() {
                contextMenuRequested_ = true;
        });
}

void
TextLabel::focusOutEvent(QFocusEvent *e)
{
        QTextBrowser::focusOutEvent(e);

        // We keep the selection available for the context menu.
        if (contextMenuRequested_) {
                contextMenuRequested_ = false;
                return;
        }

        QTextCursor cursor = textCursor();
        cursor.clearSelection();
        setTextCursor(cursor);
}

void
TextLabel::mousePressEvent(QMouseEvent *e)
{
        link_ = (e->button() & Qt::LeftButton) ? anchorAt(e->pos()) : QString();
        QTextBrowser::mousePressEvent(e);
}

void
TextLabel::mouseReleaseEvent(QMouseEvent *e)
{
        if (e->button() & Qt::LeftButton && !link_.isEmpty() && anchorAt(e->pos()) == link_) {
                emit linkActivated(link_);
                return;
        }

        QTextBrowser::mouseReleaseEvent(e);
}

void
TextLabel::wheelEvent(QWheelEvent *event)
{
        event->ignore();
}

void
TextLabel::handleLinkActivation(const QUrl &url)
{
        auto parts          = url.toString().split('/');
        auto defaultHandler = [](const QUrl &url) { QDesktopServices::openUrl(url); };

        if (url.host() != "matrix.to" || parts.isEmpty())
                return defaultHandler(url);

        try {
                using namespace mtx::identifiers;
                parse<User>(parts.last().toStdString());
        } catch (const std::exception &) {
                return defaultHandler(url);
        }

        emit userProfileTriggered(parts.last());
}