public:

SdCardFontSystem() = default;

SdCardFontSystem(const SdCardFontSystem&) = delete;

SdCardFontSystem& operator=(const SdCardFontSystem&) = delete;

/// Discover SD card fonts and load user's saved selection. Call once during setup.

void begin(GfxRenderer& renderer);

/// Ensure the correct SD font family is loaded for the current settings.

/// Call before entering the reader or after settings change.

/// Also re-discovers if the registry has been marked dirty (e.g. by web upload).

void ensureLoaded(GfxRenderer& renderer);

/// Resolve an SD card font ID from family name + reader point size.

/// Returns 0 if not found. Used by CrossPointSettings::getReaderFontId().

int resolveFontId(const char* familyName, uint8_t pointSize) const;

/// Access the registry (e.g. for settings UI to enumerate available fonts).

const SdCardFontRegistry& registry() const { return registry_; }

/// Non-const access to the registry (for FontInstaller).

SdCardFontRegistry& registry() { return registry_; }

/// Mark the registry as needing re-discovery.

/// Thread-safe: can be called from the web server task.

void markRegistryDirty() { registryDirty_.store(true, std::memory_order_release); }

/// If the registry is dirty, re-scan the SD card now and clear the flag.

/// Used by the web UI so uploaded/deleted fonts appear in the list

/// without waiting for the reader activity to run ensureLoaded().

void refreshIfDirty() {

if (registryDirty_.exchange(false, std::memory_order_acquire)) {

registry_.discover();

}

}

private:

// Load the active SD family at the built-in UI point sizes and register each

// as a size-matched CJK fallback for the corresponding UI font, so CJK book

// titles/list rows render at the same size as the surrounding Latin UI text.

// No-op when no SD family is loaded. Safe to call repeatedly (sizes already

// loaded are reused).

void setupUiFallbacks(GfxRenderer& renderer);

SdCardFontRegistry registry_;

SdCardFontManager manager_;

std::atomic<bool> registryDirty_{false};