#include "messageeventmodel.h"

#include <QtCore/QDebug>
#include <QtCore/QSettings>
#include <QtQml>  // for qmlRegisterType()

#include "events/redactionevent.h"
#include "events/roomavatarevent.h"
#include "events/roommemberevent.h"
#include "events/simplestateevents.h"

#include "connection.h"
#include "settings.h"
#include "user.h"

MessageEventModel::MessageEventModel(QObject* parent)
    : QAbstractListModel(parent) {
  qmlRegisterType<QMatrixClient::FileTransferInfo>();
  qRegisterMetaType<QMatrixClient::FileTransferInfo>();
}

MessageEventModel::~MessageEventModel() {}

void MessageEventModel::setRoom(QMatrixClient::Room* room) {
  if (room == m_currentRoom) return;

  beginResetModel();
  if (m_currentRoom) {
    m_currentRoom->disconnect(this);
    qDebug() << "Disconnected from" << m_currentRoom->id();
  }

  m_currentRoom = room;
  if (room) {
    lastReadEventId = room->readMarkerEventId();
    using namespace QMatrixClient;
    connect(m_currentRoom, &Room::aboutToAddNewMessages, this,
            [=](RoomEventsRange events) {
              const auto pos = m_currentRoom->pendingEvents().size();
              beginInsertRows(QModelIndex(), int(pos),
                              int(pos + events.size() - 1));
            });
    connect(m_currentRoom, &Room::aboutToAddHistoricalMessages, this,
            [=](RoomEventsRange events) {
              if (rowCount() > 0) nextNewerRow = rowCount() - 1;  // See #312
              beginInsertRows(QModelIndex(), rowCount(),
                              rowCount() + int(events.size()) - 1);
            });
    connect(m_currentRoom, &Room::addedMessages, this, [=] {
      if (nextNewerRow > -1) {
        const auto idx = index(nextNewerRow);
        emit dataChanged(idx, idx);
        nextNewerRow = -1;
      }
      endInsertRows();
    });
    connect(m_currentRoom, &Room::pendingEventAboutToAdd, this,
            [this] { beginInsertRows({}, 0, 0); });
    connect(m_currentRoom, &Room::pendingEventAdded, this,
            &MessageEventModel::endInsertRows);
    connect(m_currentRoom, &Room::pendingEventAboutToMerge, this,
            [this](RoomEvent*, int i) {
              const auto timelineBaseIdx =
                  int(m_currentRoom->pendingEvents().size());
              if (i + 1 == timelineBaseIdx) return;  // No need to move anything
              mergingEcho = true;
              Q_ASSERT(beginMoveRows({}, i, i, {}, timelineBaseIdx));
            });
    connect(m_currentRoom, &Room::pendingEventMerged, this, [this] {
      if (mergingEcho) {
        endMoveRows();
        mergingEcho = false;
      }
      refreshEventRoles(int(m_currentRoom->pendingEvents().size()),
                        {SpecialMarksRole});
    });
    connect(m_currentRoom, &Room::pendingEventChanged, this,
            [this](int i) { refreshEventRoles(i, {SpecialMarksRole}); });
    connect(m_currentRoom, &Room::readMarkerMoved, this, [this] {
      refreshEventRoles(
          std::exchange(lastReadEventId, m_currentRoom->readMarkerEventId()),
          {ReadMarkerRole});
      refreshEventRoles(lastReadEventId, {ReadMarkerRole});
    });
    connect(
        m_currentRoom, &Room::replacedEvent, this,
        [this](const RoomEvent* newEvent) { refreshEvent(newEvent->id()); });
    connect(m_currentRoom, &Room::fileTransferProgress, this,
            &MessageEventModel::refreshEvent);
    connect(m_currentRoom, &Room::fileTransferCompleted, this,
            &MessageEventModel::refreshEvent);
    connect(m_currentRoom, &Room::fileTransferFailed, this,
            &MessageEventModel::refreshEvent);
    connect(m_currentRoom, &Room::fileTransferCancelled, this,
            &MessageEventModel::refreshEvent);
    qDebug() << "Connected to room" << room->id() << "as"
             << room->localUser()->id();
  } else
    lastReadEventId.clear();
  endResetModel();
}

void MessageEventModel::refreshEvent(const QString& eventId) {
  refreshEventRoles(eventId, {});
}

void MessageEventModel::refreshEventRoles(const int row,
                                          const QVector<int>& roles) {
  const auto idx = index(row);
  emit dataChanged(idx, idx, roles);
}

void MessageEventModel::refreshEventRoles(const QString& eventId,
                                          const QVector<int>& roles) {
  const auto it = m_currentRoom->findInTimeline(eventId);
  if (it != m_currentRoom->timelineEdge())
    refreshEventRoles(it - m_currentRoom->messageEvents().rbegin(), roles);
}

inline bool hasValidTimestamp(const QMatrixClient::TimelineItem& ti) {
  return ti->timestamp().isValid();
}

QDateTime MessageEventModel::makeMessageTimestamp(
    QMatrixClient::Room::rev_iter_t baseIt) const {
  const auto& timeline = m_currentRoom->messageEvents();
  auto ts = baseIt->event()->timestamp();
  if (ts.isValid()) return ts;

  // The event is most likely redacted or just invalid.
  // Look for the nearest date around and slap zero time to it.
  using QMatrixClient::TimelineItem;
  auto rit = std::find_if(baseIt, timeline.rend(), hasValidTimestamp);
  if (rit != timeline.rend())
    return {rit->event()->timestamp().date(), {0, 0}, Qt::LocalTime};
  auto it = std::find_if(baseIt.base(), timeline.end(), hasValidTimestamp);
  if (it != timeline.end())
    return {it->event()->timestamp().date(), {0, 0}, Qt::LocalTime};

  // What kind of room is that?..
  qCritical() << "No valid timestamps in the room timeline!";
  return {};
}

QString MessageEventModel::makeDateString(
    QMatrixClient::Room::rev_iter_t baseIt) const {
  auto date = makeMessageTimestamp(baseIt).toLocalTime().date();
  if (QMatrixClient::SettingsGroup("UI")
          .value("banner_human_friendly_date", true)
          .toBool()) {
    if (date == QDate::currentDate()) return tr("Today");
    if (date == QDate::currentDate().addDays(-1)) return tr("Yesterday");
    if (date == QDate::currentDate().addDays(-2))
      return tr("The day before yesterday");
    if (date > QDate::currentDate().addDays(-7)) return date.toString("dddd");
  }
  return date.toString(Qt::DefaultLocaleShortDate);
}

int MessageEventModel::rowCount(const QModelIndex& parent) const {
  if (!m_currentRoom || parent.isValid()) return 0;
  return m_currentRoom->timelineSize();
}

QVariant MessageEventModel::data(const QModelIndex& index, int role) const {
  const auto row = index.row();

  if (!m_currentRoom || row < 0 ||
      row >= int(m_currentRoom->pendingEvents().size()) +
                 m_currentRoom->timelineSize())
    return {};

  const auto timelineBaseIdx = int(m_currentRoom->pendingEvents().size());
  const auto timelineIt = m_currentRoom->messageEvents().crbegin() +
                          std::max(-1, row - timelineBaseIdx);
  const auto& evt = row < timelineBaseIdx
                        ? *m_currentRoom->pendingEvents()[size_t(row)]
                        : *timelineIt->event();

  using namespace QMatrixClient;
  if (role == Qt::DisplayRole) {
    if (evt.isRedacted()) {
      auto reason = evt.redactedBecause()->reason();
      if (reason.isEmpty()) return tr("Redacted");

      return tr("Redacted: %1").arg(evt.redactedBecause()->reason());
    }

    return visit(
        evt,
        [this](const RoomMessageEvent& e) {
          using namespace MessageEventContent;

          if (e.hasTextContent() && e.mimeType().name() != "text/plain")
            return static_cast<const TextContent*>(e.content())->body;
          if (e.hasFileContent()) {
            auto fileCaption = e.content()->fileInfo()->originalName;
            if (fileCaption.isEmpty())
              fileCaption = m_currentRoom->prettyPrint(e.plainBody());
            if (fileCaption.isEmpty()) return tr("a file");
          }
          return m_currentRoom->prettyPrint(e.plainBody());
        },
        [this](const RoomMemberEvent& e) {
          // FIXME: Rewind to the name that was at the time of this event
          QString subjectName = m_currentRoom->roomMembername(e.userId());
          // The below code assumes senderName output in AuthorRole
          switch (e.membership()) {
            case MembershipType::Invite:
              if (e.repeatsState())
                return tr("reinvited %1 to the room").arg(subjectName);
              FALLTHROUGH;
            case MembershipType::Join: {
              if (e.repeatsState()) return tr("joined the room (repeated)");
              if (!e.prevContent() ||
                  e.membership() != e.prevContent()->membership) {
                return e.membership() == MembershipType::Invite
                           ? tr("invited %1 to the room").arg(subjectName)
                           : tr("joined the room");
              }
              QString text{};
              if (e.displayName() != e.prevContent()->displayName) {
                if (e.displayName().isEmpty())
                  text = tr("cleared the display name");
                else
                  text =
                      tr("changed the display name to %1").arg(e.displayName());
              }
              if (e.avatarUrl() != e.prevContent()->avatarUrl) {
                if (!text.isEmpty()) text += " and ";
                if (e.avatarUrl().isEmpty())
                  text += tr("cleared the avatar");
                else
                  text += tr("updated the avatar");
              }
              return text;
            }
            case MembershipType::Leave:
              if (e.prevContent() &&
                  e.prevContent()->membership == MembershipType::Ban) {
                return (e.senderId() != e.userId())
                           ? tr("unbanned %1").arg(subjectName)
                           : tr("self-unbanned");
              }
              return (e.senderId() != e.userId())
                         ? tr("has put %1 out of the room").arg(subjectName)
                         : tr("left the room");
            case MembershipType::Ban:
              return (e.senderId() != e.userId())
                         ? tr("banned %1 from the room").arg(subjectName)
                         : tr("self-banned from the room");
            case MembershipType::Knock:
              return tr("knocked");
            default:;
          }
          return tr("made something unknown");
        },
        [](const RoomAliasesEvent& e) {
          return tr("set aliases to: %1").arg(e.aliases().join(", "));
        },
        [](const RoomCanonicalAliasEvent& e) {
          return (e.alias().isEmpty())
                     ? tr("cleared the room main alias")
                     : tr("set the room main alias to: %1").arg(e.alias());
        },
        [](const RoomNameEvent& e) {
          return (e.name().isEmpty())
                     ? tr("cleared the room name")
                     : tr("set the room name to: %1").arg(e.name());
        },
        [](const RoomTopicEvent& e) {
          return (e.topic().isEmpty())
                     ? tr("cleared the topic")
                     : tr("set the topic to: %1").arg(e.topic());
        },
        [](const RoomAvatarEvent&) { return tr("changed the room avatar"); },
        [](const EncryptionEvent&) {
          return tr("activated End-to-End Encryption");
        },
        tr("Unknown Event"));
  }

  if (role == Qt::ToolTipRole) {
    return evt.originalJson();
  }

  if (role == EventTypeRole) {
    if (auto e = eventCast<const RoomMessageEvent>(&evt)) {
      switch (e->msgtype()) {
        case MessageEventType::Emote:
          return "emote";
        case MessageEventType::Notice:
          return "notice";
        case MessageEventType::Image:
          return "image";
        case MessageEventType::File:
        case MessageEventType::Audio:
        case MessageEventType::Video:
          return "file";
        default:
          return "message";
      }
    }
    if (is<RedactionEvent>(evt)) return "redaction";
    if (evt.isStateEvent()) return "state";

    return "other";
  }

  if (role == EventResolvedTypeRole)
    return EventTypeRegistry::getMatrixType(evt.type());

  if (role == AuthorRole) {
    // FIXME: It shouldn't be User, it should be its state "as of event"
    return QVariant::fromValue(row < timelineBaseIdx
                                   ? m_currentRoom->localUser()
                                   : m_currentRoom->user(evt.senderId()));
  }

  if (role == ContentTypeRole) {
    if (auto e = eventCast<const RoomMessageEvent>(&evt)) {
      const auto& contentType = e->mimeType().name();
      return contentType == "text/plain" ? QStringLiteral("text/html")
                                         : contentType;
    }
    return QStringLiteral("text/plain");
  }

  if (role == ContentRole) {
    if (evt.isRedacted()) {
      auto reason = evt.redactedBecause()->reason();
      return (reason.isEmpty())
                 ? tr("Redacted")
                 : tr("Redacted: %1").arg(evt.redactedBecause()->reason());
    }

    if (auto e = eventCast<const RoomMessageEvent>(&evt)) {
      // Cannot use e.contentJson() here because some
      // EventContent classes inject values into the copy of the
      // content JSON stored in EventContent::Base
      return e->hasFileContent()
                 ? QVariant::fromValue(e->content()->originalJson)
                 : QVariant();
    };
  }

  // HighlightRole is missing. This will be fixed soon.

  if (role == ReadMarkerRole) return evt.id() == lastReadEventId;

  if (role == SpecialMarksRole) {
    if (row < timelineBaseIdx)
      return evt.id().isEmpty() ? "unsent" : "unsynced";

    if (evt.isStateEvent() &&
        static_cast<const StateEventBase&>(evt).repeatsState())
      return "noop";
    return evt.isRedacted() ? "redacted" : "";
  }

  if (role == EventIdRole) return evt.id();

  if (role == LongOperationRole) {
    if (auto e = eventCast<const RoomMessageEvent>(&evt))
      if (e->hasFileContent())
        return QVariant::fromValue(m_currentRoom->fileTransferInfo(e->id()));
  }

  if (row >= timelineBaseIdx - 1)  // The timeline and the topmost unsynced
  {
    if (role == TimeRole)
      return row < timelineBaseIdx ? QDateTime::currentDateTimeUtc()
                                   : makeMessageTimestamp(timelineIt);

    if (role == SectionRole)
      return row < timelineBaseIdx
                 ? tr("Today")
                 : makeDateString(
                       timelineIt);  // FIXME: move date rendering to QML

    // FIXME: shouldn't be here, because #312
    auto aboveEventIt = timelineIt + 1;
    if (aboveEventIt != m_currentRoom->timelineEdge()) {
      if (role == AboveSectionRole) return makeDateString(aboveEventIt);

      if (role == AboveAuthorRole)
        return QVariant::fromValue(
            m_currentRoom->user((*aboveEventIt)->senderId()));

      if (role == AboveTimeRole) return makeMessageTimestamp(aboveEventIt);
    }
  }

  return QVariant();
}

QHash<int, QByteArray> MessageEventModel::roleNames() const {
  QHash<int, QByteArray> roles = QAbstractItemModel::roleNames();
  roles[EventTypeRole] = "eventType";
  roles[EventIdRole] = "eventId";
  roles[TimeRole] = "time";
  roles[AboveTimeRole] = "aboveTime";
  roles[SectionRole] = "section";
  roles[AboveSectionRole] = "aboveSection";
  roles[AuthorRole] = "author";
  roles[AboveAuthorRole] = "aboveAuthor";
  roles[ContentRole] = "content";
  roles[ContentTypeRole] = "contentType";
  roles[HighlightRole] = "highlight";
  roles[ReadMarkerRole] = "readMarker";
  roles[SpecialMarksRole] = "marks";
  roles[LongOperationRole] = "progressInfo";
  roles[EventResolvedTypeRole] = "eventResolvedType";
  return roles;
}