#include "chatview.h"
#include "messagedelegate.h"
#include <QPainter>
#include <QClipboard>
#include <QApplication>
#include <QDebug>
#include <QMouseEvent>
#include <QKeyEvent>

ChatView::ChatView(QWidget *parent)
    : QListView(parent)
{
    setMouseTracking(true);
}

void ChatView::setBackgroundImage(const QString &path) {
    if (!m_background.load(path)) {
        qWarning() << "ChatView: failed to load background" << path;
        return;
    }
    viewport()->update();
}

void ChatView::resizeEvent(QResizeEvent *event) {
    QListView::resizeEvent(event);
    scheduleDelayedItemsLayout();
}

void ChatView::scrollContentsBy(int dx, int dy) {
    QListView::scrollContentsBy(dx, dy);
    viewport()->update();
}

void ChatView::paintEvent(QPaintEvent *event) {
    if (!m_background.isNull()) {
        QPainter p(viewport());
        p.drawTiledPixmap(viewport()->rect(), m_background);
    }
    QListView::paintEvent(event);
}

bool ChatView::isRowSelected(const QModelIndex &idx) const {
    if (!m_selStart.isValid() || !m_selEnd.isValid() || !idx.isValid())
        return false;
    int r = idx.row();
    int a = m_selStart.row();
    int b = m_selEnd.row();
    if (a > b) qSwap(a, b);
    return r >= a && r <= b;
}

void ChatView::mousePressEvent(QMouseEvent *event) {
    if (event->button() != Qt::LeftButton) {
        QListView::mousePressEvent(event);
        return;
    }
    if (hasSelection()) {
        m_selStart = QPersistentModelIndex();
        m_selEnd   = QPersistentModelIndex();
        m_textSel  = ChatTextSelection{};
        m_selecting = false;
        viewport()->update();
    }
    QModelIndex idx = indexAt(viewport()->mapFrom(this, event->pos()));
    m_pressIndex = QPersistentModelIndex(idx);
    m_pressPos = event->pos();
    event->accept();
}

void ChatView::mouseMoveEvent(QMouseEvent *event) {
    if (!m_selecting && m_pressIndex.isValid()) {
        int dx = event->pos().x() - m_pressPos.x();
        int dy = event->pos().y() - m_pressPos.y();
        if (dx * dx + dy * dy >= 25) {
            m_selStart = m_pressIndex;
            m_selEnd   = m_pressIndex;
            m_selecting = true;
            QRect r = visualRect(QModelIndex(m_pressIndex));
            m_textSel.index    = m_pressIndex;
            m_textSel.clickPos = m_pressPos - r.topLeft();
            m_textSel.dragPos  = m_textSel.clickPos;
            m_textSel.active   = true;
            viewport()->update();
        }
    }
    if (!m_selecting) {
        QModelIndex idx = indexAt(viewport()->mapFrom(this, event->pos()));
        if (idx != QModelIndex(m_lastHovered)) {
            m_lastHovered = idx;
            emit hoveredIndexChanged(idx);
        }
    }
    if (!m_selecting) {
        QListView::mouseMoveEvent(event);
        return;
    }
    QModelIndex idx = indexAt(viewport()->mapFrom(this, event->pos()));
    if (idx.isValid()) {
        m_selEnd = idx;
    }
    if (m_textSel.active) {
        QRect r = visualRect(QModelIndex(m_textSel.index));
        m_textSel.dragPos = event->pos() - r.topLeft();
    }
    viewport()->update();
    event->accept();
}

void ChatView::mouseReleaseEvent(QMouseEvent *event) {
    if (event->button() == Qt::LeftButton && m_selecting) {
        m_selecting = false;
        viewport()->update();
    }
    m_pressIndex = QPersistentModelIndex();
    QListView::mouseReleaseEvent(event);
}

void ChatView::keyPressEvent(QKeyEvent *event) {
    if (event == QKeySequence::Copy) {
        copySelection();
        return;
    }
    QListView::keyPressEvent(event);
}

void ChatView::copySelection() {
    if (!hasSelection()) return;
    auto *m = model();
    if (!m) return;

    if (selStart() == selEnd()) {
        QModelIndex idx(selStart());
        QString text = idx.data(MsgTextRole).toString();
        if (m_textSel.startChar >= 0 && m_textSel.endChar > m_textSel.startChar)
            text = text.mid(m_textSel.startChar, m_textSel.endChar - m_textSel.startChar);
        QApplication::clipboard()->setText(text);
    } else {
        QString r;
        int a = selStart().row(), b = selEnd().row();
        if (a > b) qSwap(a, b);
        for (int i = a; i <= b; ++i) {
            QModelIndex idx = m->index(i, 0);
            if (!r.isEmpty()) r += '\n';
            r += '[' + idx.data(MsgTimeRole).toString() + "] ";
            r += idx.data(MsgAuthorRole).toString() + ": ";
            r += idx.data(MsgTextRole).toString();
        }
        QApplication::clipboard()->setText(r);
    }
}