// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "CoreMinimal.h"
#include "Misc/CoreDelegates.h"

class IPackageLocalizationCache;

/** Singleton class that manages localized package data. */
class COREUOBJECT_API FPackageLocalizationManager
{
public:
    typedef TFunction<void(FPackageLocalizationManager&)> FLazyInitFunc;

    /**
     * Initialize the manager from the callback set by InitializeFromLazyCallback. It is expected that this callback calls one of the InitializeFromX functions.
     */
    void PerformLazyInitialization();

    /**
     * Initialize the manager lazily using the given callback. It is expected that this callback calls one of the InitializeFromX functions.
     *
     * @param InLazyInitFunc	The function to call to initialize the manager.
     */
    void InitializeFromLazyCallback(FLazyInitFunc InLazyInitFunc);

    /**
     * Initialize the manager using the given cache. This will perform an initial scan for localized packages.
     *
     * @param InCache	The cache the manager should use.
     */
    void InitializeFromCache(const TSharedRef<IPackageLocalizationCache>& InCache);

    /**
     * Initialize this manager using the default cache. This will perform an initial scan for localized packages.
     */
    void InitializeFromDefaultCache();

    /**
     * Try and find the localized package name for the given source package for the active culture.
     *
     * @param InSourcePackageName	The name of the source package to find.
     *
     * @return The localized package name, or NAME_None if there is no localized package.
     */
    FName FindLocalizedPackageName(const FName InSourcePackageName);

    /**
     * Try and find the localized package name for the given source package for the given culture.
     *
     * @param InSourcePackageName	The name of the source package to find.
     * @param InCultureName			The name of the culture to find the package for.
     *
     * @return The localized package name, or NAME_None if there is no localized package.
     */
    FName FindLocalizedPackageNameForCulture(const FName InSourcePackageName, const FString& InCultureName);

    /**
     * Update this cache, but only if it is dirty.
     */
    void ConditionalUpdateCache();

    /**
     * Singleton accessor.
     *
     * @return The singleton instance of the localization manager.
     */
    static FPackageLocalizationManager& Get();

private:
    /**
     * Try and find the localized package name for the given source package for the given culture, but without going through the cache.
     *
     * @param InSourcePackageName	The name of the source package to find.
     * @param InCultureName			The name of the culture to find the package for.
     *
     * @return The localized package name, or NAME_None if there is no localized package.
     */
    FName FindLocalizedPackageNameNoCache(const FName InSourcePackageName, const FString& InCultureName) const;

    /** Function to call to lazily initialize the manager. */
    FLazyInitFunc LazyInitFunc;

    /** Pointer to our currently active cache. Only valid after Initialize has been called. */
    TSharedPtr<IPackageLocalizationCache> ActiveCache;
};