// SPDX-FileCopyrightText: 2021 Nheko Contributors
// SPDX-FileCopyrightText: 2022 Nheko Contributors
//
// SPDX-License-Identifier: GPL-3.0-or-later

#include "RoomDirectoryModel.h"
#include "Cache.h"
#include "ChatPage.h"

#include <algorithm>

RoomDirectoryModel::RoomDirectoryModel(QObject *parent, const std::string &server)
  : QAbstractListModel(parent)
  , server_(server)
{
    connect(ChatPage::instance(), &ChatPage::newRoom, this, [this](const QString &roomid) {
        auto roomid_ = roomid.toStdString();

        int i = 0;
        for (const auto &room : publicRoomsData_) {
            if (room.room_id == roomid_) {
                emit dataChanged(index(i), index(i), {Roles::CanJoin});
                break;
            }
            i++;
        }
    });

    connect(this,
            &RoomDirectoryModel::fetchedRoomsBatch,
            this,
            &RoomDirectoryModel::displayRooms,
            Qt::QueuedConnection);
}

QHash<int, QByteArray>
RoomDirectoryModel::roleNames() const
{
    return {
      {Roles::Name, "name"},
      {Roles::Id, "roomid"},
      {Roles::AvatarUrl, "avatarUrl"},
      {Roles::Topic, "topic"},
      {Roles::MemberCount, "numMembers"},
      {Roles::Previewable, "canPreview"},
      {Roles::CanJoin, "canJoin"},
    };
}

void
RoomDirectoryModel::resetDisplayedData()
{
    beginResetModel();

    prevBatch_    = "";
    nextBatch_    = "";
    canFetchMore_ = true;

    publicRoomsData_.clear();

    endResetModel();
}

void
RoomDirectoryModel::setMatrixServer(const QString &s)
{
    server_ = s.toStdString();

    nhlog::ui()->debug("Received matrix server: {}", server_);

    resetDisplayedData();
}

void
RoomDirectoryModel::setSearchTerm(const QString &f)
{
    userSearchString_ = f.toStdString();

    nhlog::ui()->debug("Received user query: {}", userSearchString_);

    resetDisplayedData();
}

bool
RoomDirectoryModel::canJoinRoom(const QString &room) const
{
    return !room.isEmpty() && cache::getRoomInfo({room.toStdString()}).empty();
}

std::vector<std::string>
RoomDirectoryModel::getViasForRoom(const std::vector<std::string> &aliases)
{
    std::vector<std::string> vias;

    vias.reserve(aliases.size());

    std::transform(aliases.begin(), aliases.end(), std::back_inserter(vias), [](const auto &alias) {
        return alias.substr(alias.find(":") + 1);
    });

    // When joining a room hosted on a homeserver other than the one the
    // account has been registered on, the room's server has to be explicitly
    // specified in the "server_name=..." URL parameter of the Matrix Join Room
    // request. For more details consult the specs:
    // https://matrix.org/docs/spec/client_server/r0.6.1#post-matrix-client-r0-join-roomidoralias
    if (!server_.empty()) {
        vias.push_back(server_);
    }

    return vias;
}

void
RoomDirectoryModel::joinRoom(const int &index)
{
    if (index >= 0 && static_cast<size_t>(index) < publicRoomsData_.size()) {
        const auto &chunk = publicRoomsData_[index];
        nhlog::ui()->debug("'Joining room {}", chunk.room_id);
        ChatPage::instance()->joinRoomVia(chunk.room_id, getViasForRoom(chunk.aliases));
    }
}

QVariant
RoomDirectoryModel::data(const QModelIndex &index, int role) const
{
    if (hasIndex(index.row(), index.column(), index.parent())) {
        const auto &room_chunk = publicRoomsData_[index.row()];
        switch (role) {
        case Roles::Name:
            return QString::fromStdString(room_chunk.name);
        case Roles::Id:
            return QString::fromStdString(room_chunk.room_id);
        case Roles::AvatarUrl:
            return QString::fromStdString(room_chunk.avatar_url);
        case Roles::Topic:
            return QString::fromStdString(room_chunk.topic);
        case Roles::MemberCount:
            return QVariant::fromValue(room_chunk.num_joined_members);
        case Roles::Previewable:
            return QVariant::fromValue(room_chunk.world_readable);
        case Roles::CanJoin:
            return canJoinRoom(QString::fromStdString(room_chunk.room_id));
        }
    }
    return {};
}

void
RoomDirectoryModel::fetchMore(const QModelIndex &)
{
    if (!canFetchMore_)
        return;

    nhlog::net()->debug("Fetching more rooms from mtxclient...");

    mtx::requests::PublicRooms req;
    req.limit                      = limit_;
    req.since                      = prevBatch_;
    req.filter.generic_search_term = userSearchString_;
    // req.third_party_instance_id = third_party_instance_id;
    auto requested_server = server_;

    reachedEndOfPagination_ = false;
    emit reachedEndOfPaginationChanged();

    loadingMoreRooms_ = true;
    emit loadingMoreRoomsChanged();

    http::client()->post_public_rooms(
      req,
      [requested_server, this, req](const mtx::responses::PublicRooms &res,
                                    mtx::http::RequestErr err) {
          loadingMoreRooms_ = false;
          emit loadingMoreRoomsChanged();

          if (err) {
              nhlog::net()->error("Failed to retrieve rooms from mtxclient - {} - {} - {}",
                                  mtx::errors::to_string(err->matrix_error.errcode),
                                  err->matrix_error.error,
                                  err->parse_error);
          } else if (req.filter.generic_search_term == this->userSearchString_ &&
                     req.since == this->prevBatch_ && requested_server == this->server_) {
              nhlog::net()->debug("signalling chunk to GUI thread");
              emit fetchedRoomsBatch(res.chunk, res.next_batch);
          }
      },
      requested_server);
}

void
RoomDirectoryModel::displayRooms(std::vector<mtx::responses::PublicRoomsChunk> fetched_rooms,
                                 const std::string &next_batch)
{
    nhlog::net()->debug("Prev batch: {} | Next batch: {}", prevBatch_, next_batch);

    if (fetched_rooms.empty()) {
        nhlog::net()->error("mtxclient helper thread yielded empty chunk!");
        return;
    }

    beginInsertRows(QModelIndex(),
                    static_cast<int>(publicRoomsData_.size()),
                    static_cast<int>(publicRoomsData_.size() + fetched_rooms.size()) - 1);
    this->publicRoomsData_.insert(
      this->publicRoomsData_.end(), fetched_rooms.begin(), fetched_rooms.end());
    endInsertRows();

    if (next_batch.empty()) {
        canFetchMore_           = false;
        reachedEndOfPagination_ = true;
        emit reachedEndOfPaginationChanged();
    }

    prevBatch_ = next_batch;

    nhlog::ui()->debug("Finished loading rooms");
}