/* This file is part of Clementine.
   Copyright 2012, David Sansome <me@davidsansome.com>

   Clementine is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Clementine is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with Clementine.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "globalsearchmodel.h"

#include <QSortFilterProxyModel>

#include "core/mimedata.h"
#include "globalsearch.h"
#include "ui/iconloader.h"

GlobalSearchModel::GlobalSearchModel(GlobalSearch* engine, QObject* parent)
    : QStandardItemModel(parent),
      engine_(engine),
      proxy_(nullptr),
      use_pretty_covers_(true),
      artist_icon_(IconLoader::Load("x-clementine-artist", IconLoader::Base)),
      album_icon_(IconLoader::Load("x-clementine-album", IconLoader::Base)) {
  group_by_[0] = LibraryModel::GroupBy_AlbumArtist;
  group_by_[1] = LibraryModel::GroupBy_Album;
  group_by_[2] = LibraryModel::GroupBy_None;

  QIcon nocover = IconLoader::Load("nocover", IconLoader::Other);
  no_cover_icon_ = nocover.pixmap(nocover.availableSizes().last())
                       .scaled(LibraryModel::kPrettyCoverSize,
                               LibraryModel::kPrettyCoverSize,
                               Qt::KeepAspectRatio, Qt::SmoothTransformation);
}

void GlobalSearchModel::AddResults(const SearchProvider::ResultList& results) {
  int sort_index = 0;

  // Create a divider for this provider if we haven't seen it before.
  SearchProvider* provider = results.first().provider_;

  if (!provider_sort_indices_.contains(provider)) {
    // Use the user's preferred order if one was set
    int configured_index = provider_order_.indexOf(provider->id());
    if (configured_index != -1) {
      sort_index = configured_index;
    } else {
      sort_index = next_provider_sort_index_++;
    }

    QStandardItem* divider =
        new QStandardItem(provider->icon(), provider->name());
    divider->setData(true, LibraryModel::Role_IsDivider);
    divider->setData(sort_index, Role_ProviderIndex);
    divider->setFlags(Qt::ItemIsEnabled);
    appendRow(divider);

    provider_sort_indices_[provider] = sort_index;
  } else {
    sort_index = provider_sort_indices_[provider];
  }

  for (const SearchProvider::Result& result : results) {
    QStandardItem* parent = invisibleRootItem();

    // Find (or create) the container nodes for this result if we can.
    if (result.group_automatically_) {
      ContainerKey key;
      key.provider_index_ = sort_index;

      parent = BuildContainers(result.metadata_, parent, &key);
    }

    // Create the item
    QStandardItem* item = new QStandardItem;
    item->setText(result.metadata_.TitleWithCompilationArtist());
    item->setData(QVariant::fromValue(result), Role_Result);
    item->setData(sort_index, Role_ProviderIndex);

    parent->appendRow(item);
  }
}

QStandardItem* GlobalSearchModel::BuildContainers(const Song& s,
                                                  QStandardItem* parent,
                                                  ContainerKey* key,
                                                  int level) {
  if (level >= 3) {
    return parent;
  }

  bool has_artist_icon = false;
  bool has_album_icon = false;
  QString display_text;
  QString sort_text;
  int unique_tag = -1;
  int year = 0;

  switch (group_by_[level]) {
    case LibraryModel::GroupBy_Artist:
      if (s.is_compilation()) {
        display_text = tr("Various artists");
        sort_text = "aaaaaa";
      } else {
        display_text = LibraryModel::TextOrUnknown(s.artist());
        sort_text = LibraryModel::SortTextForArtist(s.artist());
      }
      has_artist_icon = true;
      break;

    case LibraryModel::GroupBy_YearAlbum:
      year = qMax(0, s.year());
      display_text = LibraryModel::PrettyYearAlbum(year, s.album());
      sort_text = LibraryModel::SortTextForNumber(year) + s.album();
      unique_tag = s.album_id();
      has_album_icon = true;
      break;

    case LibraryModel::GroupBy_OriginalYearAlbum:
      year = qMax(0, s.effective_originalyear());
      display_text = LibraryModel::PrettyYearAlbum(year, s.album());
      sort_text = LibraryModel::SortTextForNumber(year) + s.album();
      unique_tag = s.album_id();
      has_album_icon = true;
      break;

    case LibraryModel::GroupBy_Year:
      year = qMax(0, s.year());
      display_text = QString::number(year);
      sort_text = LibraryModel::SortTextForNumber(year) + " ";
      break;

    case LibraryModel::GroupBy_OriginalYear:
      year = qMax(0, s.effective_originalyear());
      display_text = QString::number(year);
      sort_text = LibraryModel::SortTextForNumber(year) + " ";
      break;

    case LibraryModel::GroupBy_Composer:
      display_text = s.composer();
      // fallthrough
    case LibraryModel::GroupBy_Performer:
      display_text = s.performer();
      // fallthrough
    case LibraryModel::GroupBy_Disc:
      display_text = s.disc();
      // fallthrough
    case LibraryModel::GroupBy_Grouping:
      display_text = s.grouping();
      // fallthrough
    case LibraryModel::GroupBy_Genre:
      if (display_text.isNull()) display_text = s.genre();
      // fallthrough
    case LibraryModel::GroupBy_Album:
      unique_tag = s.album_id();
      if (display_text.isNull()) {
        display_text = s.album();
      }
      // fallthrough
    case LibraryModel::GroupBy_AlbumArtist:
      if (display_text.isNull()) display_text = s.effective_albumartist();
      display_text = LibraryModel::TextOrUnknown(display_text);
      sort_text = LibraryModel::SortTextForArtist(display_text);
      has_album_icon = true;
      break;

    case LibraryModel::GroupBy_FileType:
      display_text = s.TextForFiletype();
      sort_text = display_text;
      break;

    case LibraryModel::GroupBy_Bitrate:
      display_text = QString(s.bitrate(), 1);
      sort_text = display_text;
      break;

    case LibraryModel::GroupBy_None:
      return parent;
  }

  // Find a container for this level
  key->group_[level] = display_text + QString::number(unique_tag);
  QStandardItem* container = containers_[*key];
  if (!container) {
    container = new QStandardItem(display_text);
    container->setData(key->provider_index_, Role_ProviderIndex);
    container->setData(sort_text, LibraryModel::Role_SortText);
    container->setData(group_by_[level], LibraryModel::Role_ContainerType);

    if (has_artist_icon) {
      container->setIcon(artist_icon_);
    } else if (has_album_icon) {
      if (use_pretty_covers_) {
        container->setData(no_cover_icon_, Qt::DecorationRole);
      } else {
        container->setIcon(album_icon_);
      }
    }

    parent->appendRow(container);
    containers_[*key] = container;
  }

  // Create the container for the next level.
  return BuildContainers(s, container, key, level + 1);
}

void GlobalSearchModel::Clear() {
  provider_sort_indices_.clear();
  containers_.clear();
  next_provider_sort_index_ = 1000;
  clear();
}

SearchProvider::ResultList GlobalSearchModel::GetChildResults(
    const QModelIndexList& indexes) const {
  QList<QStandardItem*> items;
  for (const QModelIndex& index : indexes) {
    items << itemFromIndex(index);
  }
  return GetChildResults(items);
}

SearchProvider::ResultList GlobalSearchModel::GetChildResults(
    const QList<QStandardItem*>& items) const {
  SearchProvider::ResultList results;
  QSet<const QStandardItem*> visited;

  for (QStandardItem* item : items) {
    GetChildResults(item, &results, &visited);
  }

  return results;
}

void GlobalSearchModel::GetChildResults(
    const QStandardItem* item, SearchProvider::ResultList* results,
    QSet<const QStandardItem*>* visited) const {
  if (visited->contains(item)) {
    return;
  }
  visited->insert(item);

  // Does this item have children?
  if (item->rowCount()) {
    const QModelIndex parent_proxy_index = proxy_->mapFromSource(item->index());

    // Yes - visit all the children, but do so through the proxy so we get them
    // in the right order.
    for (int i = 0; i < item->rowCount(); ++i) {
      const QModelIndex proxy_index =
          parent_proxy_index.model()->index(i, 0, parent_proxy_index);
      const QModelIndex index = proxy_->mapToSource(proxy_index);
      GetChildResults(itemFromIndex(index), results, visited);
    }
  } else {
    // No - maybe it's a song, add its result if valid
    QVariant result = item->data(Role_Result);
    if (result.isValid()) {
      results->append(result.value<SearchProvider::Result>());
    } else {
      // Maybe it's a provider then?
      bool is_provider;
      const int sort_index = item->data(Role_ProviderIndex).toInt(&is_provider);
      if (is_provider) {
        // Go through all the items (through the proxy to keep them ordered) and
        // add the ones belonging to this provider to our list
        for (int i = 0; i < proxy_->rowCount(invisibleRootItem()->index());
             ++i) {
          QModelIndex child_index =
              proxy_->index(i, 0, invisibleRootItem()->index());
          const QStandardItem* child_item =
              itemFromIndex(proxy_->mapToSource(child_index));
          if (child_item->data(Role_ProviderIndex).toInt() == sort_index) {
            GetChildResults(child_item, results, visited);
          }
        }
      }
    }
  }
}

QMimeData* GlobalSearchModel::mimeData(const QModelIndexList& indexes) const {
  return engine_->LoadTracks(GetChildResults(indexes));
}

namespace {
void GatherResults(const QStandardItem* parent,
                   QMap<SearchProvider*, SearchProvider::ResultList>* results) {
  QVariant result_variant = parent->data(GlobalSearchModel::Role_Result);
  if (result_variant.isValid()) {
    SearchProvider::Result result =
        result_variant.value<SearchProvider::Result>();
    (*results)[result.provider_].append(result);
  }

  for (int i = 0; i < parent->rowCount(); ++i) {
    GatherResults(parent->child(i), results);
  }
}
}  // namespace

void GlobalSearchModel::SetGroupBy(const LibraryModel::Grouping& grouping,
                                   bool regroup_now) {
  const LibraryModel::Grouping old_group_by = group_by_;
  group_by_ = grouping;

  if (regroup_now && group_by_ != old_group_by) {
    // Walk the tree gathering the results we have already
    QMap<SearchProvider*, SearchProvider::ResultList> results;
    GatherResults(invisibleRootItem(), &results);

    // Reset the model and re-add all the results using the new grouping.
    Clear();

    for (const SearchProvider::ResultList& result_list : results) {
      AddResults(result_list);
    }
  }
}