#include "chatlog.h"
#include "chatline.h"
#include "chatlinecontent.h"
#include "chatlinecontentproxy.h"
#include "content/text.h"
#include "content/filetransferwidget.h"
#include "content/spinner.h"

#include <QDebug>
#include <QScrollBar>
#include <QApplication>
#include <QMenu>
#include <QClipboard>

template<class T>
T clamp(T x, T min, T max)
{
    if(x > max)
        return max;
    if(x < min)
        return min;
    return x;
}

ChatLog::ChatLog(QWidget* parent)
    : QGraphicsView(parent)
{
    scene = new QGraphicsScene(this);
    scene->setItemIndexMethod(QGraphicsScene::NoIndex);
    setScene(scene);

    setInteractive(true);
    setAlignment(Qt::AlignTop | Qt::AlignLeft);
    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    setDragMode(QGraphicsView::NoDrag);
    setViewportUpdateMode(SmartViewportUpdate);
    //setRenderHint(QPainter::TextAntialiasing);

    // copy action
    copyAction = new QAction(this);
    copyAction->setShortcut(QKeySequence::Copy);
    addAction(copyAction);
    connect(copyAction, &QAction::triggered, this, [ = ](bool)
    {
        copySelectedText();
    });
}

ChatLog::~ChatLog()
{
    for(ChatLine* line : lines)
        delete line;
}

void ChatLog::addTextLine(const QString& sender, const QString& text, QDateTime timestamp)
{
    ChatLine* line = new ChatLine(scene);

    line->addColumn(new Text(sender, true), ColumnFormat(75.0, ColumnFormat::FixedSize, 1, ColumnFormat::Right));
    line->addColumn(new Text(text), ColumnFormat(1.0, ColumnFormat::VariableSize));
    line->addColumn(new Text(timestamp.toString("hh:mm")), ColumnFormat(50.0, ColumnFormat::FixedSize, 1));

    insertChatline(line);
}

void ChatLog::addWidgetLine(const QString& sender, QDateTime timestamp)
{
    ChatLine* line = new ChatLine(scene);

    line->addColumn(new Text(sender, true), ColumnFormat(75.0, ColumnFormat::FixedSize, 1));
    line->addColumn(new ChatLineContentProxy(new FileTransferWidget()), ColumnFormat(1.0, ColumnFormat::VariableSize));
    line->addColumn(new Spinner(QSizeF(16, 16)), ColumnFormat(50.0, ColumnFormat::FixedSize, 1, ColumnFormat::Right));

    insertChatline(line);
}

void ChatLog::clearSelection()
{
    if(selStartRow >= 0)
        for(int r = qMin(selStartRow, selLastRow); r <= qMax(selLastRow, selStartRow) && r < lines.size(); ++r)
            lines[r]->selectionCleared();

    selStartRow = -1;
    selStartCol = -1;
    selLastRow = -1;
    selLastCol = -1;
}

void ChatLog::dbgPopulate()
{
    for(int i = 0; i < 2000; i++)
        addTextLine("Jemp longlong name foo moth", "Line " + QString::number(i) +
                    " Lorem ipsum <b>Hello</b> dolor sit amet, "
                    "consectetur adipisicing elit, sed do eiusmod "
                    "tempor incididunt ut labore et dolore magna "
                    "aliqua. Ut enim ad minim veniam, quis nostrud "
                    "exercitation ullamco laboris nisi ut aliquip ex "
                    "ea commodo consequat. ");
}

QRect ChatLog::getVisibleRect() const
{
    return mapToScene(viewport()->rect()).boundingRect().toRect();
}

void ChatLog::updateSceneRect()
{
    setSceneRect(QRectF(0, 0, width(), lines.empty() ? 0.0 : lines.last()->boundingSceneRect().bottom()));
}

bool ChatLog::layout(int start, int end, qreal width)
{
    //qDebug() << "layout " << start << end;
    if(lines.empty())
        return false;

    start = clamp<int>(start, 0, lines.size() - 1);
    end = clamp<int>(end + 1, 0, lines.size());

    qreal h = lines[start]->boundingSceneRect().top();

    bool needsReposition = false;
    for(int i = start; i < end; ++i)
    {
        ChatLine* l = lines[i];

        qreal oldHeight = l->boundingSceneRect().height();
        l->layout(width, QPointF(0, h));

        if(oldHeight != l->boundingSceneRect().height())
            needsReposition = true;

        h += l->boundingSceneRect().height() + lineSpacing;
    }

    // move up
    if(needsReposition)
        reposition(end-1, end+10);

    return needsReposition;
}

void ChatLog::partialUpdate()
{
    checkVisibility();

    if(visibleLines.empty())
        return;

    auto oldUpdateMode = viewportUpdateMode();
    setViewportUpdateMode(NoViewportUpdate);

    static int count = 0;
    int count2 = 0;
    int lastNonDirty = visibleLines.first()->getRowIndex();
    bool repos;
    do
    {
        repos = false;
        if(!visibleLines.empty())
        {
            repos = layout(visibleLines.first()->getRowIndex(), visibleLines.last()->getRowIndex(), useableWidth());
            lastNonDirty = visibleLines.last()->getRowIndex();
        }

        checkVisibility();
        count2++;
    }
    while(repos);

    reposition(visibleLines.last()->getRowIndex(), lines.size());
    checkVisibility();

    count = qMax(count, count2);
    //qDebug() << "COUNT: " << count;

    setViewportUpdateMode(oldUpdateMode);
    updateSceneRect();
}

void ChatLog::fullUpdate()
{
    layout(0, lines.size(), useableWidth());
    checkVisibility();
    updateSceneRect();
}

void ChatLog::mousePressEvent(QMouseEvent* ev)
{
    QGraphicsView::mousePressEvent(ev);

    QPointF scenePos = mapToScene(ev->pos());

    if(ev->button() == Qt::LeftButton)
    {
        clickPos = ev->pos();
        clearSelection();
    }

    if(ev->button() == Qt::RightButton)
    {
        if(!isOverSelection(scenePos))
            clearSelection();

        showContextMenu(ev->globalPos(), scenePos);
    }
}

void ChatLog::mouseReleaseEvent(QMouseEvent* ev)
{
    QGraphicsView::mouseReleaseEvent(ev);

    if(ev->button() == Qt::LeftButton)
        selecting = false;
}

void ChatLog::mouseMoveEvent(QMouseEvent* ev)
{
    QGraphicsView::mouseMoveEvent(ev);

    QPointF scenePos = mapToScene(ev->pos());

    if(ev->buttons() & Qt::LeftButton)
    {
        if(!selecting && (clickPos - ev->pos()).manhattanLength() > QApplication::startDragDistance())
        {
            QPointF sceneClickPos = mapToScene(clickPos.toPoint());

            ChatLineContent* content = getContentFromPos(sceneClickPos);
            if(content)
            {
                selStartRow = content->getRow();
                selStartCol = content->getColumn();
                selLastRow = selStartRow;
                selLastCol = selStartCol;

                content->selectionStarted(sceneClickPos);

                selecting = true;

                // ungrab mouse grabber
                if(scene->mouseGrabberItem())
                    scene->mouseGrabberItem()->ungrabMouse();
            }
        }
    }

    if(selecting && ev->pos() != lastPos)
    {
        lastPos = ev->pos();

        ChatLineContent* content = getContentFromPos(scenePos);

        if(content)
        {
            // TODO: turn this into a sane algo.
            int row = content->getRow();
            int col = content->getColumn();
            int firstRow = selStartRow;

            // selection
            for(int r = qMin(firstRow, row + 1); r < qMax(row, firstRow); r++)
                lines[r]->selectAll();

            if(row != selStartRow)
                for(int c = 0; c < col; c++)
                    lines[selStartRow]->selectAll();

            if(row == selStartRow)
                content->selectionMouseMove(scenePos);
            else
            {
                lines[row]->selectAll();
                selStartCol = 0;
                selLastCol = lines[row]->getColumnCount();
            }

            // de-selection
            if(row < selStartRow)
                selLastRow = qMin(row, selLastRow);
            else
                selLastRow = qMax(row, selLastRow);

            if(col < selStartCol)
                selLastCol = qMin(col, selLastCol);
            else
                selLastCol = qMax(col, selLastCol);

            for(int r = qMin(row, selLastRow); r < qMax(row, selLastRow + 1) && r < lines.size(); ++r)
                if(r != row)
                    lines[r]->selectionCleared();

            if(row == selStartRow)
                for(int c = col + 1; c < lines[row]->getColumnCount() && c < selLastCol; ++c)
                    lines[row]->selectionCleared(c);

        }
    }
}

ChatLineContent* ChatLog::getContentFromPos(QPointF scenePos) const
{
    QGraphicsItem* item = scene->itemAt(scenePos, QTransform());

    if(item && item->type() == ChatLineContent::ChatLineContentType)
        return static_cast<ChatLineContent*>(item);

    return nullptr;
}

bool ChatLog::isOverSelection(QPointF scenePos)
{
    ChatLineContent* content = getContentFromPos(scenePos);

    if(content)
        return content->isOverSelection(scenePos);

    return false;
}

int ChatLog::useableWidth()
{
    return width() - verticalScrollBar()->sizeHint().width();
}

void ChatLog::reposition(int start, int end)
{
    if(lines.isEmpty())
        return;

    start = clamp<int>(start, 0, lines.size() - 1);
    end = clamp<int>(end + 1, 0, lines.size());

    qreal h = lines[start]->boundingSceneRect().bottom() + lineSpacing;

    for(int i = start + 1; i < end; ++i)
    {
        ChatLine* l = lines[i];
        l->layout(QPointF(0, h));
        h += l->boundingSceneRect().height() + lineSpacing;
    }
}

void ChatLog::repositionDownTo(int start, qreal end)
{
    if(lines.isEmpty())
        return;

    start = clamp<int>(start, 0, lines.size() - 1);

    qreal h = lines[start]->boundingSceneRect().bottom() + lineSpacing;

    for(int i = start + 1; i < lines.size(); ++i)
    {
        ChatLine* l = lines[i];
        l->layout(QPointF(0, h));
        h += l->boundingSceneRect().height() + lineSpacing;

        if(h > end)
            break;
    }
}

void ChatLog::insertChatline(ChatLine* l)
{
    stickToBtm = stickToBottom();

    l->setRowIndex(lines.size());
    lines.append(l);

    layout(lines.last()->getRowIndex() - 1, lines.size(), useableWidth());
    updateSceneRect();

    if(stickToBtm)
        scrollToBottom();

    checkVisibility();
}

bool ChatLog::stickToBottom()
{
    return verticalScrollBar()->value() == verticalScrollBar()->maximum();
}

void ChatLog::scrollToBottom()
{
    verticalScrollBar()->setValue(verticalScrollBar()->maximum());
    updateGeometry();
    checkVisibility();
}

QString ChatLog::getSelectedText() const
{
    QString ret;

    const int rowStart = qMin(selStartRow, selLastRow);
    const int rowLast = qMax(selStartRow, selLastRow);

    const int colStart = qMin(selStartCol, selLastCol);
    const int colLast = qMax(selStartCol, selLastCol);

    for(int r = rowStart; r <= rowLast && r < lines.size(); ++r)
        for(int c = colStart; c <= colLast && c < lines[r]->getColumnCount(); ++c)
            ret.append(lines[r]->content[c]->getSelectedText() + '\n');

    return ret;
}

void ChatLog::showContextMenu(const QPoint& globalPos, const QPointF& scenePos)
{
    QMenu menu;

    // populate
    QAction* copyAction = menu.addAction(QIcon::fromTheme("edit-copy"), "Copy");
    menu.addSeparator();
    QAction* clearAction = menu.addAction("Clear log");

    if(!isOverSelection(scenePos))
        copyAction->setDisabled(true);

    // show
    QAction* action = menu.exec(globalPos);

    if(action == copyAction)
        copySelectedText();

    if(action == clearAction)
        clear();
}

void ChatLog::clear()
{
    visibleLines.clear();
    clearSelection();

    for(ChatLine* line : lines)
        delete line;

    lines.clear();
    updateSceneRect();
}

void ChatLog::copySelectedText() const
{
    QString text = getSelectedText();

    QClipboard* clipboard = QApplication::clipboard();
    clipboard->setText(text);
}

void ChatLog::checkVisibility()
{
    // find first visible row
    QList<ChatLine*>::const_iterator upperBound;
    upperBound = std::upper_bound(lines.cbegin(), lines.cend(), getVisibleRect().top(), [](const qreal lhs, const ChatLine* rhs)
    {
        return lhs < rhs->boundingSceneRect().bottom();
    });

    if(upperBound == lines.end())
        upperBound = lines.begin();

    // find last visible row
    QList<ChatLine*>::const_iterator lowerBound;
    lowerBound = std::lower_bound(lines.cbegin(), lines.cend(), getVisibleRect().bottom(), [](const ChatLine* lhs, const qreal rhs)
    {
        return lhs->boundingSceneRect().bottom() < rhs;
    });

    if(lowerBound == lines.end())
        lowerBound = lines.end();

    // set visibilty
    QList<ChatLine*> newVisibleLines;
    for(auto itr = upperBound; itr <= lowerBound && itr != lines.end(); ++itr)
    {
        newVisibleLines.append(*itr);

        if(!visibleLines.contains(*itr))
            (*itr)->visibilityChanged(true);

        visibleLines.removeOne(*itr);
    }

    for(ChatLine* line : visibleLines)
        line->visibilityChanged(false);

    visibleLines = newVisibleLines;

    // assure order
    std::sort(visibleLines.begin(), visibleLines.end(), [](const ChatLine* lhs, const ChatLine* rhs)
    {
        return lhs->getRowIndex() < rhs->getRowIndex();
    });

    //if(!visibleLines.empty())
    //    qDebug() << "visible from " << visibleLines.first()->getRowIndex() << "to " << visibleLines.last()->getRowIndex() << " total " << visibleLines.size();
}

void ChatLog::scrollContentsBy(int dx, int dy)
{
    QGraphicsView::scrollContentsBy(dx, dy);
    partialUpdate();
}

void ChatLog::resizeEvent(QResizeEvent* ev)
{
    bool stb = stickToBottom();

    QGraphicsView::resizeEvent(ev);

    if(lines.count() > 300)
        partialUpdate();
    else
        fullUpdate();

    if(stb)
        scrollToBottom();
}