/**************************************************************************
 *                                                                        *
 * SPDX-FileCopyrightText: 2015 Felix Rohrbach <kde@fxrh.de>              *
 *                                                                        *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *                                                                        *
 **************************************************************************/

#include "chatroomwidget.h"

#include <QtWidgets/QVBoxLayout>
#include <QtWidgets/QLabel>
#include <QtWidgets/QToolButton>
#include <QtWidgets/QFileDialog>
#include <QtWidgets/QApplication>
#include <QtGui/QClipboard>
#include <QtGui/QTextCursor> // for last-minute message fixups before sending
#include <QtGui/QTextDocumentFragment> // to produce plain text from /html
#include <QtGui/QImageReader>

#if QT_VERSION_MAJOR < 6
#include <QtWidgets/QAction>
#else
#include <QtGui/QAction>
#endif

#include <QtCore/QRegularExpression>
#include <QtCore/QStringBuilder>
#include <QtCore/QLocale>
#include <QtCore/QTemporaryFile>
#include <QtCore/QMimeData>
#include <QtCore/QMimeDatabase>

#include <Quotient/events/roommessageevent.h>
#include <Quotient/user.h>
#include <Quotient/uri.h>
#include <Quotient/settings.h>

#include "mainwindow.h"
#include "timelinewidget.h"
#include "quaternionroom.h"
#include "chatedit.h"
#include "htmlfilter.h"
#include "logging_categories.h"

using namespace Qt::StringLiterals;

static auto DefaultPlaceholderText()
{
    return ChatRoomWidget::tr(
        "Choose a room to send messages or enter a command...");
}

static auto AttachedPlaceholderText()
{
    return ChatRoomWidget::tr(
        "Add a message to the file or just push Enter");
}

static constexpr auto MaxNamesToShow = 5;
static constexpr auto SampleSizeForHud = 3;
Q_STATIC_ASSERT(MaxNamesToShow > SampleSizeForHud);

ChatRoomWidget::ChatRoomWidget(MainWindow* parent)
    : QWidget(parent)
    , m_timelineWidget(new TimelineWidget(this))
    , m_uiSettings("UI")
{
    m_timelineWidget->setSizePolicy(QSizePolicy::Expanding,
                                    QSizePolicy::Expanding);

    m_hudCaption = new QLabel();
    m_hudCaption->setWordWrap(true);
    auto f = m_hudCaption->font();
    f.setItalic(true);
    m_hudCaption->setFont(f);
    m_hudCaption->setTextFormat(Qt::RichText);

    auto attachButton = new QToolButton();
    attachButton->setAutoRaise(true);
    m_attachAction = new QAction(QIcon::fromTheme("mail-attachment"),
                                 tr("Attach"), attachButton);
    m_attachAction->setCheckable(true);
    m_attachAction->setDisabled(true);
    connect(m_attachAction, &QAction::triggered, this, [this](bool checked) {
        auto statusMessage = tr("Attaching cancelled");
        if (checked) {
            if (const auto filePath =
                    QFileDialog::getOpenFileName(this, tr("Attach file"));
                !filePath.isEmpty()
                && (statusMessage  = attachFile(filePath)).isEmpty())
                return;
        }
        cancelAttaching();
        m_chatEdit->setPlaceholderText(DefaultPlaceholderText());
        mainWindow()->showStatusMessage(statusMessage , 3000);
    });
    attachButton->setDefaultAction(m_attachAction);

    m_chatEdit = new ChatEdit(this);
    m_chatEdit->setPlaceholderText(DefaultPlaceholderText());
    m_chatEdit->setAcceptRichText(true); // m_uiSettings.get("rich_text_editor", false);
    m_chatEdit->setMaximumHeight(maximumChatEditHeight());
    connect(m_chatEdit, &KChatEdit::returnPressed, this,
            &ChatRoomWidget::sendInput);
    connect(m_chatEdit, &KChatEdit::copyRequested, this, [this] {
        QApplication::clipboard()->setText(
            m_chatEdit->textCursor().hasSelection()
                ? m_chatEdit->textCursor().selectedText()
                : m_timelineWidget->selectedText());
    });
    // When completion is cancelled, revert to showing typing users, if any
    connect(m_chatEdit, &ChatEdit::cancelledCompletion,
            this, &ChatRoomWidget::typingChanged);

    {
        QString styleSheet;
        const auto& fontFamily =
            m_uiSettings.get<QString>("Fonts/timeline_family");
        if (!fontFamily.isEmpty())
            styleSheet += "font-family: " + fontFamily + ";";
        const auto& fontPointSize =
            m_uiSettings.value("Fonts/timeline_pointSize");
        if (fontPointSize.toReal() > 0.0)
            styleSheet += "font-size: " + fontPointSize.toString() + "pt;";
        if (!styleSheet.isEmpty())
            setStyleSheet(styleSheet);
    }
    setAcceptDrops(true); // see dragEnteredEvent(), dropEvent()

    auto* layout = new QVBoxLayout();
    layout->addWidget(m_timelineWidget);
    layout->addWidget(m_hudCaption);
    {
        auto inputLayout = new QHBoxLayout;
        inputLayout->addWidget(attachButton);
        inputLayout->addWidget(m_chatEdit);
        layout->addLayout(inputLayout);
    }
    setLayout(layout);
}

TimelineWidget* ChatRoomWidget::timelineWidget() const
{
    return m_timelineWidget;
}

MainWindow* ChatRoomWidget::mainWindow() const
{
    return static_cast<MainWindow*>(parent());
}

QuaternionRoom* ChatRoomWidget::currentRoom() const
{
    return m_timelineWidget->currentRoom();
}

Quotient::Connection* ChatRoomWidget::currentConnection() const
{
    return currentRoom()->connection();
}

void ChatRoomWidget::setRoom(QuaternionRoom* newRoom)
{
    if (currentRoom() == newRoom) {
        focusInput();
        return;
    }

    if (currentRoom()) {
        currentConnection()->disconnect(this);
        currentRoom()->disconnect(this);
    }
    cancelAttaching();

    m_timelineWidget->setRoom(newRoom);
    m_attachAction->setEnabled(newRoom != nullptr);
    m_chatEdit->switchContext(newRoom);
    if (newRoom) {
        using namespace Quotient;
        focusInput();
        connect(newRoom, &Room::typingChanged, //
                this, &ChatRoomWidget::typingChanged);
        connect(newRoom, &Room::encryption, //
                this, &ChatRoomWidget::encryptionChanged);
        connect(newRoom->connection(), &Connection::loggedOut, this, [this] {
            qCWarning(MSGINPUT) << "Logged out, escaping the room";
            setRoom(nullptr);
        });
    }
    typingChanged();
    encryptionChanged();
}

void ChatRoomWidget::typingChanged()
{
    if (!currentRoom() || currentRoom()->membersTyping().isEmpty())
    {
        setHudHtml({});
        return;
    }
    const auto& membersTyping = currentRoom()->membersTyping();
    const auto endIt = membersTyping.size() > MaxNamesToShow
                       ? membersTyping.cbegin() + SampleSizeForHud
                       : membersTyping.cend();
    QStringList typingNames;
    typingNames.reserve(MaxNamesToShow);
    std::transform(membersTyping.cbegin(), endIt, std::back_inserter(typingNames),
                   std::mem_fn(&Quotient::RoomMember::disambiguatedName));

    if (membersTyping.size() > MaxNamesToShow) {
        typingNames.push_back(
            //: The number of users in the typing or completion list
            tr("%L1 more").arg(membersTyping.size() - SampleSizeForHud));
    }
    setHudHtml(tr("Currently typing:"), typingNames);
}

void ChatRoomWidget::encryptionChanged()
{
    m_chatEdit->setPlaceholderText(
        currentRoom()
            ? tr("Send a message (over %1) or enter a command...",
                 "%1 is the protocol used by the server (usually HTTPS)")
                  .arg(currentConnection()->homeserver().scheme().toUpper())
            : DefaultPlaceholderText());
}

void ChatRoomWidget::setHudHtml(const QString& htmlCaption,
                                const QStringList& plainTextNames)
{
    if (htmlCaption.isEmpty()) { // Fast track
        m_hudCaption->clear();
        return;
    }

    auto hudText = htmlCaption;

    if (!plainTextNames.empty()) {
        QStringList namesToShow;
        namesToShow.reserve(plainTextNames.size());

        // Elide names that don't fit the HUD line width
        // NB: averageCharWidth() accounts for a list separator appended by
        // QLocale::createSeparatedList() appends. It would be ideal
        // to subtract the specific separator width but there's no way to get
        // the list separator from QLocale()
        // (https://bugreports.qt.io/browse/QTBUG-48510)
        const auto& fm = m_hudCaption->fontMetrics();
        for (const auto& name: plainTextNames) {
            auto elided =
                fm.elidedText(name, Qt::ElideMiddle,
                              m_hudCaption->width() - fm.averageCharWidth());
            // Make sure an elided name takes a new line
            namesToShow.push_back(
                (elided != name ? "<br/>" : "") + elided.toHtmlEscaped());
        }

        hudText += ' ' + namesToShow.join(", ");
    }
    m_hudCaption->setText(hudText);
}

void ChatRoomWidget::showStatusMessage(const QString& message, int timeout) const
{
    mainWindow()->showStatusMessage(message, timeout);
}

void ChatRoomWidget::showCompletions(QStringList matches, int pos)
{
    Q_ASSERT(pos >= 0 && pos < matches.size());
    // If the completion list is MaxNamesToShow or shorter, show all
    // of it; if it's longer, show SampleSizeForHud entries and
    // append how many more matches are there.
    // #344: in any case, drop the current match from the list
    // ("Next completion:" showing the current match looks wrong)

    switch (matches.size()) {
    case 0:
        setHudHtml(tr("No completions"));
        return;
    case 1:
        setHudHtml({}); // That one match is already in the text
        return;
    default:;
    }
    matches.removeAt(pos); // Drop the current match (#344)

           // Replenish the tail of the list from the beginning, if needed
    std::rotate(matches.begin(), matches.begin() + pos,
                matches.end());
    if (matches.size() > MaxNamesToShow) {
        matches[SampleSizeForHud] =
            tr("%Ln more completions", "", static_cast<int>(matches.size() - SampleSizeForHud));
        matches.resize(SampleSizeForHud);
    }
    setHudHtml(tr("Next completion:"), matches);
}

void ChatRoomWidget::insertMention(const QString& userId)
{
    Q_ASSERT(currentRoom() != nullptr);
    const auto member = currentRoom()->member(userId);
    m_chatEdit->insertMention(member.displayName(),
                              Quotient::Uri(member.id()).toUrl(Quotient::Uri::MatrixToUri));
    m_chatEdit->setFocus();
}

void ChatRoomWidget::attachImage(const QImage& img, const QList<QUrl>& sources)
{
    if (currentRoom() == nullptr)
        return;

    // TODO:
    // 3. If the URL is local, detect the MIME type and the suffix
    // 4. Otherwise, prepend "image/" to the format string in QImage
    //    and derive the suffix from this string
    const auto tempFileName = sources.size() == 1
                                      && sources.front().isLocalFile()
                                  ? sources.front().fileName()
                                  : QStringLiteral("image.XXXXXX.png");
    m_fileToAttach = std::make_unique<QTemporaryFile>(tempFileName);
    img.save(m_fileToAttach.get());

    m_attachAction->setChecked(true);
    m_chatEdit->setPlaceholderText(AttachedPlaceholderText());
    mainWindow()->showStatusMessage(tr("Attaching the pasted image"));
}

QString ChatRoomWidget::attachFile(const QString& localPath)
{
    if (QUO_ALARM(currentRoom() == nullptr))
        return tr("Can't attach a file without a selected room");

    qCDebug(MSGINPUT) << "Trying to attach" << localPath;
    m_fileToAttach = std::make_unique<QFile>(localPath);
    if (const auto error = checkAttachment(); !error.isEmpty())
        return error;

    m_chatEdit->setPlaceholderText(AttachedPlaceholderText());
    mainWindow()->showStatusMessage(
        tr("Attaching %1").arg(m_fileToAttach->fileName()));
    return {};
}

void ChatRoomWidget::dropFile(const QString& localPath)
{
    if (const auto error = attachFile(localPath); !error.isEmpty())
        mainWindow()->showStatusMessage(error, 3000);
    else
        m_attachAction->setChecked(true);
}

QString ChatRoomWidget::checkAttachment()
{
    Q_ASSERT(m_fileToAttach != nullptr);
    if (m_fileToAttach->isReadable() || m_fileToAttach->open(QIODevice::ReadOnly))
        return {};

    // Form the message in advance while the file name is still there
    const auto msg = tr("%1 is not readable or not a file").arg(m_fileToAttach->fileName());
    cancelAttaching();
    return msg;
}

void ChatRoomWidget::cancelAttaching()
{
    m_fileToAttach.reset();
    m_attachAction->setChecked(false);
}

void ChatRoomWidget::focusInput()
{
    m_chatEdit->setFocus();
}

/**
 * \brief Split the string into the specified number of parts
 * The function takes \p s and splits it into \p maxParts parts using \p sep
 * for the separator. Empty parts are skipped. If there are more than
 * \p maxParts parts in the string, the last returned part includes
 * the remainder of the string; if there are fewer parts, the missing parts
 * are filled with empty strings.
 * \return the vector of references to the original string, one reference for
 * each part.
 */
QVector<QString> lazySplitRef(const QString& s, QChar sep, int maxParts)
{
    QVector<QString> parts { maxParts };
    int pos = 0, nextPos = 0;
    for (; maxParts > 1 && (nextPos = s.indexOf(sep, pos)) > -1; --maxParts)
    {
        parts[parts.size() - maxParts] = s.mid(pos, nextPos - pos);
        while (s[++nextPos] == sep)
            ;
        pos = nextPos;
    }
    parts[parts.size() - maxParts] = s.mid(pos);
    return parts;
}

std::unique_ptr<Quotient::EventContent::FileContentBase> contentFromFile(const QFileInfo& file)
{
    using namespace Quotient::EventContent;
    using namespace Quotient::Literals;
    auto filePath = file.absoluteFilePath();
    auto localUrl = QUrl::fromLocalFile(filePath);
    auto mimeType = QMimeDatabase().mimeTypeForFile(file);

    auto mimeTypeName = mimeType.name();
    if (mimeTypeName.startsWith("image/"_L1))
        return std::make_unique<ImageContent>(localUrl, file.size(), mimeType,
                                              QImageReader(filePath).size(), file.fileName());

    if (mimeTypeName.startsWith("audio/"_L1))
        return std::make_unique<AudioContent>(localUrl, file.size(), mimeType, file.fileName());

    // TODO: video files support

    return std::make_unique<FileContent>(localUrl, file.size(), mimeType, file.fileName());
}

QString ChatRoomWidget::sendFile()
{
    Q_ASSERT(currentRoom() != nullptr);
    const auto& description = m_chatEdit->toPlainText();
    QFileInfo fileInfo(*m_fileToAttach);
    if (!fileInfo.isReadable() || !fileInfo.isFile())
        return tr("%1 is not readable or not a file")
            .arg(m_fileToAttach->fileName());

    currentRoom()->postFile(description.isEmpty() ? fileInfo.fileName()
                                                  : description,
                            contentFromFile(fileInfo));
    cancelAttaching();
    return {};
}

void ChatRoomWidget::sendSelection(int fromPosition, HtmlFilter::Options htmlFilterOptions)
{
    QTextCursor c(m_chatEdit->document());
    c.movePosition(QTextCursor::Right, QTextCursor::MoveAnchor, fromPosition);
    c.movePosition(QTextCursor::End, QTextCursor::KeepAnchor);
    currentRoom()->sendMessage(c.selection(), htmlFilterOptions);
}

void ChatRoomWidget::sendMessage()
{
    sendSelection(m_chatEdit->toPlainText().startsWith("//") ? 1 : 0,
                  m_uiSettings.get("auto_markdown", false) ? HtmlFilter::ConvertMarkdown
                                                           : HtmlFilter::Default);
}

static auto NothingToSendMsg()
{
    return ChatRoomWidget::tr("There's nothing to send");
}

QString ChatRoomWidget::sendCommand(QStringView command,
                                    const QString& argString)
{
    static const auto ReFlags = QRegularExpression::DotMatchesEverythingOption
                                | QRegularExpression::DontCaptureOption;

    // FIXME: copy-paste from lib/util.cpp
    static const auto ServerPartPattern =
        QStringLiteral("(\\[[^]]+\\]|[-[:alnum:].]+)" // Either IPv6 address or
                                                      // hostname/IPv4 address
                       "(:\\d{1,5})?" // Optional port
        );
    static const auto UserIdPattern =
        QString("@[-[:alnum:]._=/]+:" % ServerPartPattern);

    static const QRegularExpression
        RoomIdRE { "^([#!][^:[:space:]]+):" % ServerPartPattern % '$', ReFlags },
        UserIdRE { '^' % UserIdPattern % '$', ReFlags };
    Q_ASSERT(RoomIdRE.isValid() && UserIdRE.isValid());

    // Commands available without a current room
    if (command == u"join")
    {
        if (!argString.contains(RoomIdRE))
            return tr("/join argument doesn't look like a room ID or alias");
        mainWindow()->openResource(argString, "join");
        return {};
    }
    if (command == u"quit")
    {
        qApp->closeAllWindows();
        return {};
    }
    // --- Add more roomless commands here
    if (!currentRoom())
    {
        return tr("There's no such /command outside of room.");
    }

    // Commands available only in the room context
    using namespace Quotient;
    if (command == u"leave" || command == u"part")
    {
        if (!argString.isEmpty())
            return tr("Sending a farewell message is not supported yet."
                      " If you intended to leave another room, switch to it"
                      " and type /leave there.");

        currentRoom()->leaveRoom();
        return {};
    }
    if (command == u"forget")
    {
        if (argString.isEmpty())
            return tr("/forget must be followed by the room id/alias,"
                      " even for the current room");
        if (!argString.contains(RoomIdRE))
            return tr("%1 doesn't look like a room id or alias").arg(argString);

        // Forget the specified room using the current room's connection
        currentConnection()->forgetRoom(argString);
        return {};
    }
    if (command == u"invite")
    {
        if (argString.isEmpty())
            return tr("/invite <memberId>");
        if (!argString.contains(UserIdRE))
            return tr("%1 doesn't look like a user ID").arg(argString);

        currentRoom()->inviteToRoom(argString);
        return {};
    }
    if (command == u"kick" || command == u"ban")
    {
        const auto args = lazySplitRef(argString, ' ', 2);
        if (args.front().isEmpty())
            return tr("/%1 <userId> <reason>").arg(command.toString());
        if (!UserIdRE.match(args.front()).hasMatch())
            return tr("%1 doesn't look like a user id")
                    .arg(args.front());

        if (command == u"ban")
            currentRoom()->ban(args.front(), args.back());
        else {
            const auto& userId = args.front();
            if (!currentRoom()->isMember(userId))
                return tr("%1 is not a member of this room").arg(userId);

            currentRoom()->kickMember(userId, args.back());
        }
        return {};
    }
    if (command == u"unban")
    {
        if (argString.isEmpty())
            return tr("/unban <userId>");
        if (!argString.contains(UserIdRE))
            return tr("/unban argument doesn't look like a user ID");

        currentRoom()->unban(argString);
        return {};
    }
    if (command == u"ignore" || command == u"unignore")
    {
        if (argString.isEmpty())
            return tr("/ignore <userId>");
        if (!argString.contains(UserIdRE))
            return tr("/ignore argument doesn't look like a user ID");

        if (auto* user = currentConnection()->user(argString))
        {
            if (command == u"ignore")
                user->ignore();
            else
                user->unmarkIgnore();
            return {};
        }
        return tr("Couldn't find user %1 on the server").arg(argString);
    }
    using MsgType = RoomMessageEvent::MsgType;
    if (command == u"me")
    {
        if (argString.isEmpty())
            return tr("/me needs an argument");
        currentRoom()->postMessage(argString, MsgType::Emote);
        return {};
    }
    if (command == u"notice")
    {
        if (argString.isEmpty())
            return tr("/notice needs an argument");
        currentRoom()->postMessage(argString, MsgType::Notice);
        return {};
    }
    if (command == u"shrug") // Peeked at Discord
    {
        currentRoom()->postPlainText((argString.isEmpty() ? "" : argString + " ") +
                                     "¯\\_(ツ)_/¯");
        return {};
    }
    if (command == u"roomname")
    {
        currentRoom()->setName(argString);
        return {};
    }
    if (command == u"topic")
    {
        currentRoom()->setTopic(argString);
        return {};
    }
    if (command == u"nick" || command == u"mynick")
    {
        currentConnection()->user()->rename(argString);
        return {};
    }
    if (command == u"roomnick" || command == u"myroomnick")
    {
        currentConnection()->user()->rename(argString, currentRoom());
        return {};
    }
    if (command == u"pm" || command == u"msg")
    {
        const auto args = lazySplitRef(argString, ' ', 2);
        if (args.front().isEmpty()
            || (args.back().isEmpty() && command == u"msg"))
            return tr("/%1 <memberId> <message>").arg(command.toString());
        if (RoomIdRE.match(args.front()).hasMatch() && command == u"msg")
        {
            if (auto* room = currentRoom()->connection()->room(args.front()))
            {
                room->postPlainText(args.back());
                return {};
            }
            return tr("%1 doesn't seem to have joined room %2")
                   .arg(currentRoom()->localMember().id(), args.front());
        }
        if (UserIdRE.match(args.front()).hasMatch())
        {
            auto futureChat = currentConnection()->getDirectChat(args.front());
            if (!args.back().isEmpty())
                futureChat.then([msg=args.back()] (Room* dc) { dc->postPlainText(msg); });
            return {};
        }

        return tr("%1 doesn't look like a user id or room alias")
                .arg(args.front());
    }
    if (command == u"plain") {
        // argString eats away leading spaces, so can't be used here
        static const auto CmdLen = QStringLiteral("/plain ").size();
        const auto& plainMsg = m_chatEdit->toPlainText().mid(CmdLen);
        if (plainMsg.isEmpty())
            return NothingToSendMsg();
        currentRoom()->postPlainText(plainMsg);
        return {};
    }
    if (command == u"html")
    {
        // Assuming Matrix HTML, convert it to Qt and load to a fragment in
        // order to produce a plain text version (maybe introduce
        // filterMatrixHtmlToPlainText() one day instead...); then convert
        // back to Matrix HTML to produce the (clean) rich text version
        // of the message
        const auto& [cleanQtHtml, errorPos, errorString] =
            HtmlFilter::fromMatrixHtml(argString, { currentRoom() }, HtmlFilter::Validate);
        if (errorPos != -1)
            return tr("At character %1: %2",
                      "%1 is a position of the error; %2 is the error message")
                   .arg(errorPos).arg(errorString);

        currentRoom()->sendMessage(QTextDocumentFragment::fromHtml(cleanQtHtml));
        return {};
    }
    if (command == u"md") {
        // Send the part after /md and one whitespace character after it
        // (leading whitespaces have meaning in Markdown)
        sendSelection(4, HtmlFilter::ConvertMarkdown);
        return {};
    }
    if (command == u"query" || command == u"dc")
    {
        if (argString.isEmpty())
            return tr("/%1 <memberId>").arg(command.toString());
        if (!argString.contains(UserIdRE))
            return tr("%1 doesn't look like a user id").arg(argString);

        currentConnection()->requestDirectChat(argString);
        return {};
    }
    // --- Add more room commands here
    qCDebug(MSGINPUT) << "Unknown command:" << command;
    return tr("Unknown /command. If you intended to send a message, start with // instead of /");
}

void ChatRoomWidget::sendInput()
{
    QString error;
    if (m_fileToAttach)
        error = sendFile();
    else {
        const auto& text = m_chatEdit->toPlainText();
        if (text.isEmpty())
            error = NothingToSendMsg();
        else if (text.startsWith('/')
                 && !QStringView(text).mid(1).startsWith('/')) {
            static QRegularExpression cmdSplit(u"(\\w+)(?:\\s+(.*))?"_s,
                                               QRegularExpression::DotMatchesEverythingOption);
            const auto& blanksMatch = cmdSplit.match(text, 1);
            error = sendCommand(blanksMatch.capturedView(1),
                                blanksMatch.captured(2));
        } else if (!currentRoom())
            error = tr("You should select a room to send messages.");
        else
            sendMessage();
    }
    if (!error.isEmpty()) {
        showStatusMessage(error, 5000);
        return;
    }
    m_chatEdit->setPlaceholderText(DefaultPlaceholderText());
    m_chatEdit->saveInput();
}

ChatEdit::completions_t ChatRoomWidget::findCompletionMatches(const QString& pattern) const
{
    if (!currentRoom())
        return {};

    ChatEdit::completions_t matches;
    const auto& members = currentRoom()->joinedMembers();
    for (const auto& m: members) {
        using Quotient::Uri;
        if (m.displayName().startsWith(pattern, Qt::CaseInsensitive)
            || m.id().startsWith(pattern, Qt::CaseInsensitive))
            matches.emplace_back(m.displayName(), Uri(m.id()).toUrl(Uri::MatrixToUri));
    }
    std::ranges::sort(matches, [](const auto& p1, const auto& p2) {
        return p1.first.localeAwareCompare(p2.first) < 0;
    });
    return matches;
}

void ChatRoomWidget::quote(const QString& htmlText)
{
    const auto type = m_uiSettings.get<int>("quote_type");
    const auto defaultStyle = QStringLiteral("> \\1\n");
    const auto defaultRegex = QStringLiteral("(.+)(?:\n|$)");
    auto style = m_uiSettings.get<QString>("quote_style");
    auto regex = m_uiSettings.get<QString>("quote_regex");

    if (style.isEmpty())
        style = defaultStyle;
    if (regex.isEmpty())
        regex = defaultRegex;

    QTextDocument document;
    document.setHtml(htmlText);
    QString sendString;

    switch (type)
    {
        case 0:
            sendString = document.toPlainText()
                .replace(QRegularExpression(defaultRegex), defaultStyle);
            break;
        case 1:
            sendString = document.toPlainText()
                .replace(QRegularExpression(regex), style);
            break;
        case 2:
            sendString = QLocale().quoteString(document.toPlainText()) + "\n";
            break;
    }

    m_chatEdit->insertPlainText(sendString);
}

void ChatRoomWidget::resizeEvent(QResizeEvent*)
{
    m_chatEdit->setMaximumHeight(maximumChatEditHeight());
}

void ChatRoomWidget::keyPressEvent(QKeyEvent* event)
{
    // This only handles keypresses not handled by ChatEdit; in particular,
    // this means that PageUp/PageDown below are actually Ctrl-PageUp/PageDown
    switch (event->key()) {
    case Qt::Key_PageUp:
        emit m_timelineWidget->pageUpPressed();
        break;
    case Qt::Key_PageDown:
        emit m_timelineWidget->pageDownPressed();
        break;
    }
}

void ChatRoomWidget::dragEnterEvent(QDragEnterEvent* event)
{
    if (event->source() == m_chatEdit
        || !m_chatEdit->canInsertFromMimeData(event->mimeData())) {
        event->ignore();
        return;
    }
    checkDndEvent(event);
}

void ChatRoomWidget::dropEvent(QDropEvent* event)
{
    Q_ASSERT(event != nullptr); // Something very wrong with Qt if that fails
    auto* source = event->mimeData();
    if (!source) {
        qCWarning(MSGINPUT) << "Nothing to insert from the drop event";
        return;
    }

    event->setDropAction(Qt::CopyAction); // A default, but you never know
    qCDebug(MSGINPUT) << "MIME arrived:" << source->formats().join(u',');
    if (source->hasUrls())
        qCDebug(MSGINPUT) << "MIME URLs:" << source->urls();
    if (source->hasImage()) {
        attachImage(source->imageData().value<QImage>(), source->urls());
        event->accept();
    } else if (source->hasHtml()) {
        if (m_chatEdit->acceptMimeData(source))
            event->accept();
        return;
    } else if (source->hasUrls()) {
        bool hasAnyProcessed = false;
        for (const QUrl& url : source->urls())
            if (url.isLocalFile()) {
                attachFile(url.toLocalFile());
                hasAnyProcessed = true;
                // Only the first url is processed for now
                break;
            }
        if (hasAnyProcessed)
            event->accept();
    }
    if (m_chatEdit->acceptMimeData(source))
        event->accept();
}

QString ChatRoomWidget::matrixHtmlFromMime(const QMimeData* data) const
{
    QUO_CHECK(data->hasHtml());
    const auto [cleanHtml, errorPos, errorString] =
        HtmlFilter::fromLocalHtml(data->html(), { currentRoom() });
    if (errorPos != -1) {
        qCWarning(MSGINPUT) << "HTML validation failed at position" << errorPos << "with error"
                            << errorString;
        showStatusMessage(tr("Cannot insert HTML - it's either invalid or unsupported"), 5000);
    }
    return cleanHtml;
}

void ChatRoomWidget::checkDndEvent(QDropEvent* event) const
{
    // `event` may originally come to m_chatEdit or be a QDragEnterEvent instead - all that is fine
    if (const auto* data = event->mimeData(); data->hasHtml() && matrixHtmlFromMime(data).isEmpty())
        event->ignore();

    event->setDropAction(Qt::CopyAction);
    event->accept();
}

int ChatRoomWidget::maximumChatEditHeight() const
{
    return height() / 3;
}