#include "TimelineModel.h"

#include "Logging.h"
#include "Utils.h"

namespace {
template<class T>
QString
eventId(const T &event)
{
        return QString::fromStdString(event.event_id);
}
template<class T>
QString
roomId(const T &event)
{
        return QString::fromStdString(event.room_id);
}
template<class T>
QString
senderId(const T &event)
{
        return QString::fromStdString(event.sender);
}

template<class T>
QDateTime
eventTimestamp(const T &event)
{
        return QDateTime::fromMSecsSinceEpoch(event.origin_server_ts);
}
}

TimelineModel::TimelineModel(QString room_id, QObject *parent)
  : QAbstractListModel(parent)
  , room_id_(room_id)
{
        connect(
          this, &TimelineModel::oldMessagesRetrieved, this, &TimelineModel::addBackwardsEvents);
}

QHash<int, QByteArray>
TimelineModel::roleNames() const
{
        return {
          {Section, "section"},
          {Type, "type"},
          {Body, "body"},
          {FormattedBody, "formattedBody"},
          {UserId, "userId"},
          {UserName, "userName"},
          {Timestamp, "timestamp"},
        };
}
int
TimelineModel::rowCount(const QModelIndex &parent) const
{
        Q_UNUSED(parent);
        return (int)this->eventOrder.size();
}

QVariant
TimelineModel::data(const QModelIndex &index, int role) const
{
        if (index.row() < 0 && index.row() >= (int)eventOrder.size())
                return QVariant();

        QString id = eventOrder[index.row()];

        switch (role) {
        case Section: {
                QDateTime date = boost::apply_visitor(
                  [](const auto &e) -> QDateTime { return eventTimestamp(e); }, events.value(id));
                date.setTime(QTime());

                QString userId = boost::apply_visitor(
                  [](const auto &e) -> QString { return senderId(e); }, events.value(id));

                for (int r = index.row() - 1; r > 0; r--) {
                        QDateTime prevDate = boost::apply_visitor(
                          [](const auto &e) -> QDateTime { return eventTimestamp(e); },
                          events.value(eventOrder[r]));
                        prevDate.setTime(QTime());
                        if (prevDate != date)
                                return QString("%2 %1").arg(date.toMSecsSinceEpoch()).arg(userId);

                        QString prevUserId =
                          boost::apply_visitor([](const auto &e) -> QString { return senderId(e); },
                                               events.value(eventOrder[r]));
                        if (userId != prevUserId)
                                break;
                }

                return QString("%1").arg(userId);
        }
        case UserId:
                return QVariant(boost::apply_visitor(
                  [](const auto &e) -> QString { return senderId(e); }, events.value(id)));
        case UserName:
                return QVariant(displayName(boost::apply_visitor(
                  [](const auto &e) -> QString { return senderId(e); }, events.value(id))));

        case Timestamp:
                return QVariant(boost::apply_visitor(
                  [](const auto &e) -> QDateTime { return eventTimestamp(e); }, events.value(id)));
        default:
                return QVariant();
        }
}

void
TimelineModel::addEvents(const mtx::responses::Timeline &events)
{
        if (isInitialSync) {
                prev_batch_token_ = QString::fromStdString(events.prev_batch);
                isInitialSync     = false;
        }

        std::vector<QString> ids;
        for (const auto &e : events.events) {
                QString id =
                  boost::apply_visitor([](const auto &e) -> QString { return eventId(e); }, e);

                this->events.insert(id, e);
                ids.push_back(id);
        }

        beginInsertRows(QModelIndex(),
                        static_cast<int>(this->events.size()),
                        static_cast<int>(this->events.size() + ids.size() - 1));
        this->eventOrder.insert(this->eventOrder.end(), ids.begin(), ids.end());
        endInsertRows();
}

void
TimelineModel::fetchHistory()
{
        if (paginationInProgress) {
                nhlog::ui()->warn("Already loading older messages");
                return;
        }

        paginationInProgress = true;
        mtx::http::MessagesOpts opts;
        opts.room_id = room_id_.toStdString();
        opts.from    = prev_batch_token_.toStdString();

        nhlog::ui()->info("Paginationg room {}", opts.room_id);

        http::client()->messages(
          opts, [this, opts](const mtx::responses::Messages &res, mtx::http::RequestErr err) {
                  if (err) {
                          nhlog::net()->error("failed to call /messages ({}): {} - {}",
                                              opts.room_id,
                                              mtx::errors::to_string(err->matrix_error.errcode),
                                              err->matrix_error.error);
                          return;
                  }

                  emit oldMessagesRetrieved(std::move(res));
          });
}

void
TimelineModel::addBackwardsEvents(const mtx::responses::Messages &msgs)
{
        std::vector<QString> ids;
        for (const auto &e : msgs.chunk) {
                QString id =
                  boost::apply_visitor([](const auto &e) -> QString { return eventId(e); }, e);

                this->events.insert(id, e);
                ids.push_back(id);
        }

        beginInsertRows(QModelIndex(), 0, static_cast<int>(ids.size() - 1));
        this->eventOrder.insert(this->eventOrder.begin(), ids.rbegin(), ids.rend());
        endInsertRows();

        prev_batch_token_ = QString::fromStdString(msgs.end);

        paginationInProgress = false;
}

QColor
TimelineModel::userColor(QString id, QColor background)
{
        if (!userColors.contains(id))
                userColors.insert(
                  id, QColor(utils::generateContrastingHexColor(id, background.name())));
        return userColors.value(id);
}

QString
TimelineModel::displayName(QString id) const
{
        return Cache::displayName(room_id_, id);
}