#include "filetreemodel.h"
#include "organizercore.h"
#include "shared/directoryentry.h"
#include "shared/fileentry.h"
#include "shared/filesorigin.h"
#include "shared/util.h"
#include <log.h>
#include <moassert.h>

using namespace MOBase;
using namespace MOShared;
namespace fs = std::filesystem;

// in mainwindow.cpp
QString UnmanagedModName();

#define trace(f)

// about queueRemoveItem(), queueSortItems() and the `forFetching` parameter
//
// update() can be called when refreshing the tree or expanding a node;
// there are certain operations that cannot be done during node expansion,
// namely removing or moving items
//
// 1) removing items
//    beginRemoveRows()/endRemoveRows() clears the internal list of visible
//    items in a QTreeView, which is repopulated during the next layout
//
//    doing this _during_ layout (which happens during node expansion) crashes
//    in Qt because it assumes the list of visible items doesn't change; that
//    is, fetchMore() cannot _remove_ items from the tree, it can only _add_
//    items
//
// 2) moving items
//    when a QSortFilterProxyModel is used between a tree and the FileTreeModel,
//    it maintains a mapping of indices between the source and proxy models;
//    calling layoutAboutToBeChanged()/layoutChanged() clears that mapping
//
//    the only time this is called in FileTreeModel is when sorting items,
//    which can happen during layout because since it calls fetchMore()
//
//    doing this _during_ layout (which happens during node expansion) crashes
//    in Qt because the QSortFilterProxyModel assumes the mapping doesn't
//    change; that is, fetchMore() cannot _move_ items in the tree, it can
//    only _add_ items
//
//
// therefore, these two operations are queued in a 1ms timer which is processed
// immediately after update()
//
// note that not all instances of removing items are currently getting queued
// (such as when removeDisappearingFiles()) because they cannot happen while
// fetching

// tracks a contiguous range in the model to avoid calling begin*Rows(), etc.
// for every single item that's added/removed
//
class FileTreeModel::Range
{
public:
  // note that file ranges can start from an index higher than 0 if there are
  // directories
  //
  Range(FileTreeModel* model, FileTreeItem& parentItem, int start = 0)
      : m_model(model), m_parentItem(parentItem), m_first(-1), m_current(start)
  {}

  // includes the current index in the range
  //
  void includeCurrent()
  {
    // just remember the start of the range, m_current will be used in add()
    // or remove() to figure out the actual range
    if (m_first == -1) {
      m_first = m_current;
    }
  }

  // moves to the next row
  //
  void next() { ++m_current; }

  // returns the current row
  //
  int current() const { return m_current; }

  // manually set this range
  //
  void set(int first, int last)
  {
    m_first   = first;
    m_current = last;
  }

  // adds the given items to this range
  //
  void add(FileTreeItem::Children toAdd)
  {
    if (m_first == -1) {
      // nothing to add
      MO_ASSERT(toAdd.empty());
      return;
    }

    const auto last        = m_current - 1;
    const auto parentIndex = m_model->indexFromItem(m_parentItem);

    // make sure the number of items is the same as the size of this range
    MO_ASSERT(static_cast<int>(toAdd.size()) == (last - m_first + 1));

    trace(log::debug("Range::add() {} to {}", m_first, last));

    m_model->beginInsertRows(parentIndex, m_first, last);

    m_parentItem.insert(std::make_move_iterator(toAdd.begin()),
                        std::make_move_iterator(toAdd.end()),
                        static_cast<std::size_t>(m_first));

    m_model->endInsertRows();

    // reset
    m_first = -1;
  }

  // removes the item in this range, returns an iterator to first item passed
  // this range once removed, which can be end()
  //
  FileTreeItem::Children::const_iterator remove()
  {
    if (m_first >= 0) {
      const auto last        = m_current - 1;
      const auto parentIndex = m_model->indexFromItem(m_parentItem);

      trace(log::debug("Range::remove() {} to {}", m_first, last));

      m_model->beginRemoveRows(parentIndex, m_first, last);

      m_parentItem.remove(static_cast<std::size_t>(m_first),
                          static_cast<std::size_t>(last - m_first + 1));

      m_model->endRemoveRows();

      m_model->removePendingIcons(parentIndex, m_first, last);

      // adjust current row to account for those that were just removed
      m_current -= (m_current - m_first);

      // reset
      m_first = -1;
    }

    if (m_current >= m_parentItem.children().size()) {
      return m_parentItem.children().end();
    }

    return m_parentItem.children().begin() + m_current + 1;
  }

  static void removeChildren(FileTreeModel* model, FileTreeItem& parentItem)
  {
    Range r(model, parentItem);
    r.set(0, static_cast<int>(parentItem.children().size()));
    r.remove();
    parentItem.clear();
  }

private:
  FileTreeModel* m_model;
  FileTreeItem& m_parentItem;
  int m_first;
  int m_current;
};

FileTreeItem* getItem(const QModelIndex& index)
{
  return static_cast<FileTreeItem*>(index.internalPointer());
}

void* makeInternalPointer(FileTreeItem* item)
{
  return item;
}

FileTreeModel::FileTreeModel(OrganizerCore& core, QObject* parent)
    : QAbstractItemModel(parent), m_core(core), m_enabled(true),
      m_root(FileTreeItem::createDirectory(this, nullptr, L"", L"")),
      m_flags(HiddenFiles), m_fullyLoaded(false), m_sortingEnabled(true)
{
  m_root->setExpanded(true);
  m_sortTimer.setSingleShot(true);

  connect(&m_removeTimer, &QTimer::timeout, [&] {
    removeItems();
  });
  connect(&m_sortTimer, &QTimer::timeout, [&] {
    sortItems();
  });
  connect(&m_iconPendingTimer, &QTimer::timeout, [&] {
    updatePendingIcons();
  });
}

void FileTreeModel::refresh()
{
  TimeThis tt("FileTreeModel::refresh()");

  m_fullyLoaded = false;
  update(*m_root, *m_core.directoryStructure(), L"", false);
  sortItem(*m_root, false);
}

void FileTreeModel::clear()
{
  m_fullyLoaded = false;

  beginResetModel();
  m_root->clear();
  endResetModel();
}

void FileTreeModel::recursiveFetchMore(const QModelIndex& m)
{
  if (canFetchMore(m)) {
    doFetchMore(m, false, false);
  }

  for (int i = 0; i < rowCount(m); ++i) {
    recursiveFetchMore(index(i, 0, m));
  }
}

void FileTreeModel::ensureFullyLoaded()
{
  if (!m_fullyLoaded) {
    TimeThis tt("FileTreeModel:: fully loading for search");
    recursiveFetchMore(QModelIndex());
    sortItem(*m_root, false);
    m_fullyLoaded = true;
  }
}

bool FileTreeModel::enabled() const
{
  return m_enabled;
}

void FileTreeModel::setEnabled(bool b)
{
  m_enabled = b;
}

void FileTreeModel::aboutToExpandAll()
{
  m_sortingEnabled = false;
}

void FileTreeModel::expandedAll()
{
  m_sortingEnabled = true;
  sortItem(*m_root, false);
}

const FileTreeModel::SortInfo& FileTreeModel::sortInfo() const
{
  return m_sort;
}

bool FileTreeModel::showArchives() const
{
  return (m_flags.testFlag(Archives) && m_core.settings().archiveParsing());
}

bool FileTreeModel::showHiddenFiles() const
{
  return m_flags.testAnyFlag(HiddenFiles);
}

QModelIndex FileTreeModel::index(int row, int col, const QModelIndex& parentIndex) const
{
  if (auto* parentItem = itemFromIndex(parentIndex)) {
    if (row < 0 || row >= parentItem->children().size()) {
      log::error("row {} out of range for {}", row, parentItem->debugName());
      return {};
    }

    return createIndex(row, col, makeInternalPointer(parentItem));
  }

  log::error("FileTreeModel::index(): parentIndex has no internal pointer");
  return {};
}

QModelIndex FileTreeModel::parent(const QModelIndex& index) const
{
  if (!index.isValid()) {
    return {};
  }

  auto* parentItem = getItem(index);
  if (!parentItem) {
    log::error("FileTreeModel::parent(): no internal pointer");
    return {};
  }

  return indexFromItem(*parentItem);
}

int FileTreeModel::rowCount(const QModelIndex& parent) const
{
  if (auto* item = itemFromIndex(parent)) {
    return static_cast<int>(item->children().size());
  }

  return 0;
}

int FileTreeModel::columnCount(const QModelIndex&) const
{
  return ColumnCount;
}

bool FileTreeModel::hasChildren(const QModelIndex& parent) const
{
  if (!m_enabled) {
    return false;
  }

  if (auto* item = itemFromIndex(parent)) {
    if (parent.column() <= 0) {
      return item->hasChildren();
    }
  }

  return false;
}

bool FileTreeModel::canFetchMore(const QModelIndex& parent) const
{
  if (!m_enabled) {
    return false;
  }

  if (auto* item = itemFromIndex(parent)) {
    return !item->isLoaded();
  }

  return false;
}

void FileTreeModel::fetchMore(const QModelIndex& parent)
{
  doFetchMore(parent, true, true);
}

void FileTreeModel::doFetchMore(const QModelIndex& parent, bool forFetch, bool doSort)
{
  FileTreeItem* item = itemFromIndex(parent);
  if (!item) {
    return;
  }

  const auto path = item->dataRelativeFilePath();

  auto* parentEntry =
      m_core.directoryStructure()->findSubDirectoryRecursive(path.toStdWString());

  if (!parentEntry) {
    log::error("FileTreeModel::fetchMore(): directory '{}' not found", path);
    return;
  }

  const auto parentPath = item->dataRelativeParentPath();
  update(*item, *parentEntry, parentPath.toStdWString(), forFetch);

  if (!forFetch && doSort) {
    sortItem(*item, false);
  }
}

QVariant FileTreeModel::data(const QModelIndex& index, int role) const
{
  switch (role) {
  case Qt::DisplayRole: {
    if (auto* item = itemFromIndex(index)) {
      return displayData(item, index.column());
    }

    break;
  }

  case Qt::FontRole: {
    if (auto* item = itemFromIndex(index)) {
      return item->font();
    }

    break;
  }

  case Qt::ToolTipRole: {
    if (auto* item = itemFromIndex(index)) {
      return makeTooltip(*item);
    }

    return {};
  }

  case Qt::ForegroundRole: {
    if (index.column() == 1) {
      if (auto* item = itemFromIndex(index)) {
        if (item->isConflicted()) {
          return QBrush(Qt::red);
        }
      }
    }

    break;
  }

  case Qt::DecorationRole: {
    if (index.column() == 0) {
      if (auto* item = itemFromIndex(index)) {
        return makeIcon(*item, index);
      }
    }

    break;
  }
  }

  return {};
}

QVariant FileTreeModel::headerData(int i, Qt::Orientation ori, int role) const
{
  static const std::array<QString, ColumnCount> names = {
      tr("Name"), tr("Mod"), tr("Type"), tr("Size"), tr("Date modified")};

  if (role == Qt::DisplayRole) {
    if (i >= 0 && i < static_cast<int>(names.size())) {
      return names[static_cast<std::size_t>(i)];
    }
  }

  return {};
}

Qt::ItemFlags FileTreeModel::flags(const QModelIndex& index) const
{
  auto f = QAbstractItemModel::flags(index);

  if (auto* item = itemFromIndex(index)) {
    if (!item->hasChildren()) {
      f |= Qt::ItemNeverHasChildren;
    }
  }

  return f;
}

void FileTreeModel::sortItem(FileTreeItem& item, bool force)
{
  emit layoutAboutToBeChanged({}, QAbstractItemModel::VerticalSortHint);

  const auto oldList = persistentIndexList();
  std::vector<std::pair<FileTreeItem*, int>> oldItems;

  const auto itemCount = oldList.size();
  oldItems.reserve(static_cast<std::size_t>(itemCount));

  for (int i = 0; i < itemCount; ++i) {
    const QModelIndex& index = oldList[i];
    oldItems.push_back({itemFromIndex(index), index.column()});
  }

  item.sort(m_sort.column, m_sort.order, force);

  QModelIndexList newList;
  newList.reserve(itemCount);

  for (int i = 0; i < itemCount; ++i) {
    const auto& pair = oldItems[static_cast<std::size_t>(i)];
    newList.append(indexFromItem(*pair.first, pair.second));
  }

  changePersistentIndexList(oldList, newList);

  emit layoutChanged({}, QAbstractItemModel::VerticalSortHint);
}

void FileTreeModel::sort(int column, Qt::SortOrder order)
{
  m_sort.column = column;
  m_sort.order  = order;

  sortItem(*m_root, true);
}

FileTreeItem* FileTreeModel::itemFromIndex(const QModelIndex& index) const
{
  if (!index.isValid()) {
    return m_root.get();
  }

  auto* parentItem = getItem(index);
  if (!parentItem) {
    log::error("FileTreeModel::itemFromIndex(): no internal pointer");
    return nullptr;
  }

  if (index.row() < 0 || index.row() >= parentItem->children().size()) {
    log::error("FileTreeModel::itemFromIndex(): row {} is out of range for {}",
               index.row(), parentItem->debugName());

    return nullptr;
  }

  return parentItem->children()[index.row()].get();
}

QModelIndex FileTreeModel::indexFromItem(FileTreeItem& item, int col) const
{
  auto* parent = item.parent();
  if (!parent) {
    return {};
  }

  const int index = parent->childIndex(item);
  if (index == -1) {
    log::error("FileTreeMode::indexFromItem(): item {} not found in parent",
               item.debugName());

    return {};
  }

  return createIndex(index, col, makeInternalPointer(parent));
}

void FileTreeModel::update(FileTreeItem& parentItem,
                           const MOShared::DirectoryEntry& parentEntry,
                           const std::wstring& parentPath, bool forFetching)
{
  trace(log::debug("updating {}", parentItem.debugName()));

  auto path = parentPath;
  if (!parentEntry.isTopLevel()) {
    if (!path.empty()) {
      path += L"\\";
    }

    path += parentEntry.getName();
  }

  parentItem.setLoaded(true);

  bool added = false;

  if (updateDirectories(parentItem, path, parentEntry, forFetching)) {
    added = true;
  }

  if (updateFiles(parentItem, path, parentEntry)) {
    added = true;
  }

  if (added) {
    parentItem.makeSortingStale();

    // see comment at the top of this file
    if (forFetching) {
      // don't pass a specific item, this will start a timer and re-sort the
      // whole tree, which is faster than potentially queuing every single
      // node if the whole tree is expanded
      queueSortItem(nullptr);
    }
  }
}

bool FileTreeModel::updateDirectories(FileTreeItem& parentItem,
                                      const std::wstring& parentPath,
                                      const MOShared::DirectoryEntry& parentEntry,
                                      bool forFetching)
{
  // removeDisappearingDirectories() will add directories that are in the
  // tree and still on the filesystem to this set; addNewDirectories() will
  // use this to figure out if a directory is new or not
  std::unordered_set<std::wstring_view> seen;

  removeDisappearingDirectories(parentItem, parentEntry, parentPath, seen, forFetching);
  return addNewDirectories(parentItem, parentEntry, parentPath, seen);
}

void FileTreeModel::removeDisappearingDirectories(
    FileTreeItem& parentItem, const MOShared::DirectoryEntry& parentEntry,
    const std::wstring& parentPath, std::unordered_set<std::wstring_view>& seen,
    bool forFetching)
{
  auto& children = parentItem.children();
  auto itor      = children.begin();

  // keeps track of the contiguous directories that need to be removed to
  // avoid calling beginRemoveRows(), etc. for each item
  Range range(this, parentItem);

  // for each item in this tree item
  while (itor != children.end()) {
    const auto& item = *itor;

    if (!item->isDirectory()) {
      // directories are always first, no point continuing once a file has
      // been seen
      break;
    }

    auto d = parentEntry.findSubDirectory(item->filenameWsLowerCase(), true);

    if (d) {
      trace(log::debug("dir {} still there", item->filename()));

      // directory is still there
      seen.emplace(d->getName());

      bool currentRemoved = false;

      if (item->areChildrenVisible()) {
        // the item is currently expanded, update it
        update(*item, *d, parentPath, forFetching);
      }

      if (shouldShowFolder(*d, item.get())) {
        // folder should be left in the list
        if (!item->areChildrenVisible() && item->isLoaded()) {
          if (!d->isEmpty()) {
            // the item is loaded (previously expanded but now collapsed) and
            // has children, mark it as unloaded so it updates when next
            // expanded
            item->setLoaded(false);

            if (!item->children().empty()) {
              // if the item had children, remove them from the tree

              // see comment at the top of this file
              if (forFetching) {
                queueRemoveItem(item.get());
              } else {
                Range::removeChildren(this, *item);
              }
            }
          }
        }
      } else {
        // item wouldn't have any children, prune it
        trace(log::debug("dir {} is empty and pruned", item->filename()));

        range.includeCurrent();
        currentRemoved = true;
        ++itor;
      }

      if (!currentRemoved) {
        // if there were directories before this row that need to be removed,
        // do it now
        itor = range.remove();
      }
    } else {
      // directory is gone from the parent entry
      trace(log::debug("dir {} is gone", item->filename()));

      range.includeCurrent();
      ++itor;
    }

    range.next();
  }

  // remove the last directory range, if any
  range.remove();
}

bool FileTreeModel::addNewDirectories(FileTreeItem& parentItem,
                                      const MOShared::DirectoryEntry& parentEntry,
                                      const std::wstring& parentPath,
                                      const std::unordered_set<std::wstring_view>& seen)
{
  // keeps track of the contiguous directories that need to be added to
  // avoid calling beginAddRows(), etc. for each item
  Range range(this, parentItem);
  std::vector<FileTreeItem::Ptr> toAdd;
  bool added = false;

  // for each directory on the filesystem
  for (auto&& d : parentEntry.getSubDirectories()) {
    if (seen.contains(d->getName())) {
      // already seen in the parent item

      // if there were directories before this row that need to be added,
      // do it now
      //
      // todo: if the directory was actually removed in
      // removeDisappearingDirectories(), the range doesn't need to be added
      // now and could be extended further
      range.add(std::move(toAdd));
      toAdd.clear();
    } else {
      if (!shouldShowFolder(*d, nullptr)) {
        // this is a new directory, but it doesn't contain anything interesting
        trace(log::debug("new dir {}, empty and pruned",
                         QString::fromStdWString(d->getName())));

        // act as if this directory doesn't exist at all
        continue;
      }

      // this is a new directory
      trace(log::debug("new dir {}", QString::fromStdWString(d->getName())));

      toAdd.push_back(createDirectoryItem(parentItem, parentPath, *d));
      added = true;

      range.includeCurrent();
    }

    range.next();
  }

  // add the last directory range, if any
  range.add(std::move(toAdd));

  return added;
}

bool FileTreeModel::updateFiles(FileTreeItem& parentItem,
                                const std::wstring& parentPath,
                                const MOShared::DirectoryEntry& parentEntry)
{
  // removeDisappearingFiles() will add files that are in the tree and still on
  // the filesystem to this set; addNewFiless() will use this to figure out if
  // a file is new or not
  std::unordered_set<FileIndex> seen;

  int firstFileRow = 0;

  removeDisappearingFiles(parentItem, parentEntry, firstFileRow, seen);
  return addNewFiles(parentItem, parentEntry, parentPath, firstFileRow, seen);
}

void FileTreeModel::removeDisappearingFiles(FileTreeItem& parentItem,
                                            const MOShared::DirectoryEntry& parentEntry,
                                            int& firstFileRow,
                                            std::unordered_set<FileIndex>& seen)
{
  auto& children = parentItem.children();
  auto itor      = children.begin();

  firstFileRow = -1;

  // keeps track of the contiguous directories that need to be removed to
  // avoid calling beginRemoveRows(), etc. for each item
  Range range(this, parentItem);

  // for each item in this tree item
  while (itor != children.end()) {
    const auto& item = *itor;

    if (!item->isDirectory()) {
      if (firstFileRow == -1) {
        firstFileRow = range.current();
      }

      auto f = parentEntry.findFile(item->key());

      if (f && shouldShowFile(*f)) {
        trace(log::debug("file {} still there", item->filename()));

        // file is still there
        seen.emplace(f->getIndex());

        if (f->getOrigin() != item->originID()) {
          // origin has changed
          updateFileItem(*item, *f);
        }

        // if there were files before this row that need to be removed,
        // do it now
        itor = range.remove();
      } else {
        // file is gone from the parent entry
        trace(log::debug("file {} is gone", item->filename()));

        range.includeCurrent();
        ++itor;
      }
    } else {
      ++itor;
    }

    range.next();
  }

  // remove the last file range, if any
  range.remove();

  if (firstFileRow == -1) {
    firstFileRow = static_cast<int>(children.size());
  }
}

bool FileTreeModel::addNewFiles(FileTreeItem& parentItem,
                                const MOShared::DirectoryEntry& parentEntry,
                                const std::wstring& parentPath, const int firstFileRow,
                                const std::unordered_set<FileIndex>& seen)
{
  // keeps track of the contiguous files that need to be added to
  // avoid calling beginAddRows(), etc. for each item
  std::vector<FileTreeItem::Ptr> toAdd;
  Range range(this, parentItem, firstFileRow);
  bool added = false;

  // for each directory on the filesystem
  parentEntry.forEachFileIndex([&](auto&& fileIndex) {
    if (seen.contains(fileIndex)) {
      // already seen in the parent item

      // if there were directories before this row that need to be added,
      // do it now
      range.add(std::move(toAdd));
      toAdd.clear();
    } else {
      const auto file = parentEntry.getFileByIndex(fileIndex);

      if (!file) {
        log::error("FileTreeModel::addNewFiles(): file index {} in path {} not found",
                   fileIndex, parentPath);

        return true;
      }

      if (shouldShowFile(*file)) {
        // this is a new file
        trace(log::debug("new file {}", QString::fromStdWString(file->getName())));

        toAdd.push_back(createFileItem(parentItem, parentPath, *file));
        added = true;

        range.includeCurrent();
      } else {
        // this is a new file, but it shouldn't be shown
        trace(log::debug("new file {}, not shown",
                         QString::fromStdWString(file->getName())));
        return true;
      }
    }

    range.next();

    return true;
  });

  // add the last file range, if any
  range.add(std::move(toAdd));

  return added;
}

void FileTreeModel::queueRemoveItem(FileTreeItem* item)
{
  trace(log::debug("queuing {} for removal", item->debugName()));

  m_removeItems.push_back(item);
  m_removeTimer.start(1);
}

void FileTreeModel::removeItems()
{
  // see comment at the top of this file
  trace(log::debug("remove item timer: removing {} items", m_removeItems.size()));

  auto copy = std::move(m_removeItems);
  m_removeItems.clear();
  m_removeTimer.stop();

  for (auto&& f : copy) {
    Range::removeChildren(this, *f);
  }
}

void FileTreeModel::queueSortItem(FileTreeItem* item)
{
  if (!m_sortingEnabled) {
    return;
  }

  if (item) {
    m_sortItems.push_back(item);
  }

  m_sortTimer.start(1);
}

void FileTreeModel::sortItems()
{
  // see comment at the top of this file

  if (m_sortItems.empty()) {
    sortItem(*m_root, false);
  } else {
    log::debug("sort item timer: sorting {} items", m_sortItems.size());

    auto items = std::move(m_sortItems);
    m_sortItems.clear();

    for (auto* item : items) {
      sortItem(*item, false);
    }
  }
}

FileTreeItem::Ptr FileTreeModel::createDirectoryItem(FileTreeItem& parentItem,
                                                     const std::wstring& parentPath,
                                                     const DirectoryEntry& d)
{
  auto item = FileTreeItem::createDirectory(this, &parentItem, parentPath, d.getName());

  if (d.isEmpty()) {
    // if this directory is empty, mark the item as loaded so the expand
    // arrow doesn't show
    item->setLoaded(true);
  }

  return item;
}

FileTreeItem::Ptr FileTreeModel::createFileItem(FileTreeItem& parentItem,
                                                const std::wstring& parentPath,
                                                const FileEntry& file)
{
  auto item = FileTreeItem::createFile(this, &parentItem, parentPath, file.getName());

  updateFileItem(*item, file);

  item->setLoaded(true);

  return item;
}

void FileTreeModel::updateFileItem(FileTreeItem& item, const MOShared::FileEntry& file)
{
  bool isArchive = false;
  int originID   = file.getOrigin(isArchive);

  FileTreeItem::Flags flags = FileTreeItem::NoFlags;

  if (isArchive) {
    flags |= FileTreeItem::FromArchive;
  }

  if (!file.getAlternatives().empty()) {
    flags |= FileTreeItem::Conflicted;
  }

  item.setOrigin(originID, file.getFullPath(), flags, makeModName(file, originID));

  if (file.getFileSize() != FileEntry::NoFileSize) {
    item.setFileSize(file.getFileSize());
  }

  if (file.getCompressedFileSize() != FileEntry::NoFileSize) {
    item.setCompressedFileSize(file.getCompressedFileSize());
  }
}

bool FileTreeModel::shouldShowFile(const FileEntry& file) const
{
  if (showConflictsOnly() &&
      ((file.getAlternatives().size() == 0) ||
       QString::fromStdWString(file.getName())
           .endsWith(ModInfo::s_HiddenExt, Qt::CaseInsensitive))) {
    // only conflicts should be shown, but this file is hidden or not conflicted
    return false;
  }

  if (!showArchives() && file.isFromArchive()) {
    // files from archives shouldn't be shown, but this file is from an archive
    return false;
  }

  if (!showHiddenFiles() && QString::fromStdWString(file.getName())
                                .endsWith(ModInfo::s_HiddenExt, Qt::CaseInsensitive)) {
    // hidden files shouldn't be shown, but this file is hidden
    return false;
  }

  return true;
}

bool FileTreeModel::shouldShowFolder(const DirectoryEntry& dir,
                                     const FileTreeItem* item) const
{
  if ((!showHiddenFiles() || showConflictsOnly()) &&
      QString::fromStdWString(dir.getName())
          .endsWith(ModInfo::s_HiddenExt, Qt::CaseInsensitive)) {
    return false;
  }

  bool shouldPrune = m_flags.testFlag(PruneDirectories);

  if (m_core.settings().archiveParsing()) {
    if (!m_flags.testFlag(Archives)) {
      // archive parsing is enabled but the tree shouldn't show archives; this
      // is a bit of a special case for folders because they have to be hidden
      // regardless of the PruneDirectories flag if they only exist in archives
      //
      // note that this test is inaccurate: if a loose folder exists but is
      // empty, and the same folder exists in an archive but is _not_ empty,
      // then it's considered to exist _only_ in an archive and will be pruned
      //
      // if directories are ever made first-class so they can retain their
      // origins, this test can be made more accurate
      shouldPrune = true;
    }
  }

  if (!shouldPrune) {
    // always show folders regardless of their content
    return true;
  }

  if (item) {
    if (item->isLoaded() && item->children().empty()) {
      // item is loaded and has no children; prune it
      return false;
    }
  }

  bool foundFile = false;

  // check all files in this directory, return early if a file should be shown
  dir.forEachFile([&](auto&& f) {
    if (shouldShowFile(f)) {
      foundFile = true;

      // stop
      return false;
    }

    // continue
    return true;
  });

  if (foundFile) {
    return true;
  }

  // recurse into subdirectories
  for (auto subdir : dir.getSubDirectories()) {
    if (shouldShowFolder(*subdir, nullptr)) {
      return true;
    }
  }

  return false;
}

QVariant FileTreeModel::displayData(const FileTreeItem* item, int column) const
{
  switch (column) {
  case FileName: {
    return item->filename();
  }

  case ModName: {
    return item->mod();
  }

  case FileType: {
    return item->fileType().value_or(QString());
  }

  case FileSize: {
    if (item->isDirectory()) {
      return {};
    } else {
      QString fs;

      if (auto n = item->fileSize()) {
        fs = localizedByteSize(*n);
      }

      if (auto n = item->compressedFileSize()) {
        return QString("%1 (%2)").arg(fs).arg(localizedByteSize(*n));
      } else {
        return fs;
      }
    }
  }

  case LastModified: {
    if (auto d = item->lastModified()) {
      if (d.has_value() && d.value().isValid()) {
        return QLocale::system().toString(d.value(), QLocale::ShortFormat);
      }
    }

    return {};
  }

  default: {
    return {};
  }
  }
}

std::wstring FileTreeModel::makeModName(const MOShared::FileEntry& file,
                                        int originID) const
{
  static const std::wstring Unmanaged = UnmanagedModName().toStdWString();

  const auto& origin = m_core.directoryStructure()->getOriginByID(originID);

  if (origin.getID() == 0) {
    return Unmanaged;
  }

  std::wstring name = origin.getName();

  const auto& archive = file.getArchive();
  if (!archive.name().empty()) {
    name += L" (" + archive.name() + L")";
  }

  return name;
}

QString FileTreeModel::makeTooltip(const FileTreeItem& item) const
{
  auto nowrap = [&](auto&& s) {
    return "<p style=\"white-space: pre; margin: 0; padding: 0;\">" + s + "</p>";
  };

  auto line = [&](auto&& caption, auto&& value) {
    if (value.isEmpty()) {
      return nowrap("<b>" + caption + ":</b>\n");
    } else {
      return nowrap("<b>" + caption + ":</b> " + value.toHtmlEscaped()) + "\n";
    }
  };

  if (item.isDirectory()) {
    return line(tr("Directory"), item.filename()) +
           line(tr("Virtual path"), item.virtualPath());
  }

  static const QString ListStart = "<ul style=\""
                                   "margin-left: 20px; "
                                   "margin-top: 0; "
                                   "margin-bottom: 0; "
                                   "padding: 0; "
                                   "-qt-list-indent: 0;"
                                   "\">";

  static const QString ListEnd = "</ul>";

  QString s = line(tr("Virtual path"), item.virtualPath()) +
              line(tr("Real path"), item.realPath()) + line(tr("From"), item.mod());

  const auto file = m_core.directoryStructure()->searchFile(
      item.dataRelativeFilePath().toStdWString(), nullptr);

  if (file) {
    const auto alternatives = file->getAlternatives();
    QStringList list;

    for (auto&& alt : alternatives) {
      const auto& origin = m_core.directoryStructure()->getOriginByID(alt.originID());
      list.push_back(QString::fromStdWString(origin.getName()));
    }

    if (list.size() == 1) {
      s += line(tr("Also in"), list[0]);
    } else if (list.size() >= 2) {
      s += line(tr("Also in"), QString()) + ListStart;

      for (auto&& alt : list) {
        s += "<li>" + alt + "</li>";
      }

      s += ListEnd;
    }
  }

  return s;
}

QVariant FileTreeModel::makeIcon(const FileTreeItem& item,
                                 const QModelIndex& index) const
{
  if (item.isDirectory()) {
    return m_iconFetcher.genericDirectoryIcon();
  }

  auto v = m_iconFetcher.icon(item.realPath());
  if (!v.isNull()) {
    return v;
  }

  m_iconPending.push_back(index);
  m_iconPendingTimer.start(std::chrono::milliseconds(1));

  return m_iconFetcher.genericFileIcon();
}

void FileTreeModel::updatePendingIcons()
{
  std::vector<QModelIndex> v(std::move(m_iconPending));
  m_iconPending.clear();

  for (auto&& index : v) {
    emit dataChanged(index, index, {Qt::DecorationRole});
  }

  if (m_iconPending.empty()) {
    m_iconPendingTimer.stop();
  }
}

void FileTreeModel::removePendingIcons(const QModelIndex& parent, int first, int last)
{
  auto itor = m_iconPending.begin();

  while (itor != m_iconPending.end()) {
    if (itor->parent() == parent) {
      if (itor->row() >= first && itor->row() <= last) {
        itor = m_iconPending.erase(itor);
        continue;
      }
    }

    ++itor;
  }
}