#include <QDebug>

#include "../../utils.hpp"

#include "ContactsListProxyModel.hpp"

#define USERNAME_WEIGHT 50.f
#define SIP_ADDRESSES_WEIGHT 50.f

#define FACTOR_POS_0 1.0f
#define FACTOR_POS_1 0.9f
#define FACTOR_POS_2 0.8f
#define FACTOR_POS_3 0.7f
#define FACTOR_POS_OTHER 0.6f

using namespace std;

// =============================================================================

ContactsListModel *ContactsListProxyModel::m_list = nullptr;

// Notes:
//
// - First `^` is necessary to search two words with one separator
// between them like `Claire Manning`.
//
// - [^_.-;@ ] is used to search patterns which starts with
// a separator like ` word`.
//
// - [_.-;@ ] is the main pattern (a separator).
const QRegExp ContactsListProxyModel::m_search_separators("^[^_.-;@ ][_.-;@ ]");

// -----------------------------------------------------------------------------

ContactsListProxyModel::ContactsListProxyModel (QObject *parent) : QSortFilterProxyModel(parent) {
  if (m_list == nullptr)
    qFatal("Contacts list model is undefined.");

  setSourceModel(m_list);
  setFilterCaseSensitivity(Qt::CaseInsensitive);

  for (const ContactModel *contact : m_list->m_list)
    m_weights[contact] = 0;

  setDynamicSortFilter(false);
  sort(0);
}

void ContactsListProxyModel::initContactsListModel (ContactsListModel *list) {
  if (!m_list)
    m_list = list;
  else
    qWarning() << "Contacts list model is already defined.";
}

bool ContactsListProxyModel::filterAcceptsRow (
  int source_row,
  const QModelIndex &source_parent
) const {
  QModelIndex index = sourceModel()->index(source_row, 0, source_parent);
  const ContactModel *contact = qvariant_cast<ContactModel *>(index.data());

  m_weights[contact] = static_cast<unsigned int>(computeContactWeight(*contact));

  return m_weights[contact] > 0 && (
    !m_use_connected_filter ||
    contact->getPresenceLevel() != Presence::PresenceLevel::White
  );
}

bool ContactsListProxyModel::lessThan (const QModelIndex &left, const QModelIndex &right) const {
  const ContactModel *contact_a = qvariant_cast<ContactModel *>(sourceModel()->data(left));
  const ContactModel *contact_b = qvariant_cast<ContactModel *>(sourceModel()->data(right));

  unsigned int weight_a = m_weights[contact_a];
  unsigned int weight_b = m_weights[contact_b];

  // Sort by weight and name.
  return weight_a > weight_b || (
    weight_a == weight_b &&
    contact_a->m_linphone_friend->getName() <= contact_b->m_linphone_friend->getName()
  );
}

// -----------------------------------------------------------------------------

float ContactsListProxyModel::computeStringWeight (const QString &string, float percentage) const {
  int index = -1;
  int offset = -1;

  // Search pattern.
  while ((index = filterRegExp().indexIn(string, index + 1)) != -1) {
    // Search n chars between one separator and index.
    int tmp_offset = index - string.lastIndexOf(m_search_separators, index) - 1;

    if ((tmp_offset != -1 && tmp_offset < offset) || offset == -1)
      if ((offset = tmp_offset) == 0) break;
  }

  // No weight.
  if (offset == -1)
    return 0;

  // Weight & offset.
  switch (offset) {
    case 0: return percentage * FACTOR_POS_0;
    case 1: return percentage * FACTOR_POS_1;
    case 2: return percentage * FACTOR_POS_2;
    case 3: return percentage * FACTOR_POS_3;
    default: break;
  }

  return percentage * FACTOR_POS_OTHER;
}

float ContactsListProxyModel::computeContactWeight (const ContactModel &contact) const {
  float weight = computeStringWeight(contact.getVcardModel()->getUsername(), USERNAME_WEIGHT);

  // Get all contact's addresses.
  const list<shared_ptr<linphone::Address> > addresses = contact.m_linphone_friend->getAddresses();

  float size = static_cast<float>(addresses.size());
  for (auto it = addresses.cbegin(); it != addresses.cend(); ++it)
    weight += computeStringWeight(
        ::Utils::linphoneStringToQString((*it)->asString()),
        SIP_ADDRESSES_WEIGHT / size
      );

  return weight;
}

// -----------------------------------------------------------------------------

void ContactsListProxyModel::setConnectedFilter (bool use_connected_filter) {
  if (use_connected_filter != m_use_connected_filter) {
    m_use_connected_filter = use_connected_filter;
    invalidate();
  }
}