#include "FontCatalog.h"

#include <QFontDatabase>
#include <QVariantMap>

#include <array>
#include <cmath>

FontCatalog::FontCatalog(QObject* parent)
    : QObject(parent), m_standardSizes(QFontDatabase::standardSizes()) {
  const QStringList families = QFontDatabase::families();
  m_fixedFamilies.reserve(families.size());
  for (const QString& family : families) {
    if (!QFontDatabase::isPrivateFamily(family) &&
        QFontDatabase::isFixedPitch(family)) {
      m_fixedFamilies.append(family);
    }
  }
}

QStringList FontCatalog::fixedFamilies() const {
  return m_fixedFamilies;
}

QString FontCatalog::defaultFixedFamily() const {
  QString systemFamily =
      QFontDatabase::systemFont(QFontDatabase::FixedFont).family();
  if (m_fixedFamilies.contains(systemFamily)) {
    return systemFamily;
  }
  return m_fixedFamilies.isEmpty() ? QString() : m_fixedFamilies.first();
}

QList<int> FontCatalog::standardSizes() const {
  return m_standardSizes;
}

namespace {
struct WeightEntry {
  QFont::Weight weight;
  const char* name;
};
constexpr std::array<WeightEntry, 9> kFontWeights = {{
    {.weight=QFont::Thin, .name="Thin"},       {.weight=QFont::ExtraLight, .name="Extra Light"},
    {.weight=QFont::Light, .name="Light"},     {.weight=QFont::Normal, .name="Regular"},
    {.weight=QFont::Medium, .name="Medium"},   {.weight=QFont::DemiBold, .name="Semi Bold"},
    {.weight=QFont::Bold, .name="Bold"},       {.weight=QFont::ExtraBold, .name="Extra Bold"},
    {.weight=QFont::Black, .name="Black"},
}};
}  // namespace

QVariantList FontCatalog::fontWeights() {
  QVariantList entries;
  entries.reserve(std::size(kFontWeights));
  for (const WeightEntry& entry : kFontWeights) {
    QVariantMap item;
    item.insert(QStringLiteral("name"), QString::fromLatin1(entry.name));
    item.insert(QStringLiteral("weight"), static_cast<int>(entry.weight));
    entries.append(item);
  }
  return entries;
}

QString FontCatalog::fontWeightName(int weight) {
  // Snap to the nearest known entry so partial/legacy values still label.
  const WeightEntry* best = kFontWeights.data();
  for (const WeightEntry& entry : kFontWeights) {
    if (std::abs(weight - static_cast<int>(entry.weight)) <
        std::abs(weight - static_cast<int>(best->weight))) {
      best = &entry;
    }
  }
  return QString::fromLatin1(best->name);
}