#pragma once

#include "CoreMinimal.h"
#include "Subsystems/GameInstanceSubsystem.h"
#include "Engine/StreamableManager.h"
#include "PreloadSubsystem.generated.h"

DECLARE_DYNAMIC_MULTICAST_DELEGATE(FOnPreloadComplete);
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnPreloadProgress, float, Progress);

/**
 * Preloads assets before level transition to prevent streaming pop-in.
 *
 * Usage from Blueprint:
 *   1. Get this subsystem from GameInstance
 *   2. Bind OnPreloadComplete / OnPreloadProgress
 *   3. Call StartPreload with content paths to scan
 *   4. Poll GetProgress() for loading bar
 *   5. On complete, open your target level
 */
UCLASS()
class SIMULORE_TIRSOVA_API UPreloadSubsystem : public UGameInstanceSubsystem
{
	GENERATED_BODY()

public:
	/**
	 * Preload all assets found in the given content directory paths (recursive).
	 * Example paths: "/Game/ArchVis", "/Game/CollaborativeViewer"
	 */
	UFUNCTION(BlueprintCallable, Category = "Preload")
	void StartPreload(const TArray<FString>& ContentPaths);

	/**
	 * Preload specific assets by soft object path.
	 * Useful when you know exactly which heavy assets to load.
	 */
	UFUNCTION(BlueprintCallable, Category = "Preload")
	void PreloadAssets(const TArray<FSoftObjectPath>& Assets);

	/** Current loading progress 0.0 to 1.0. Poll this from your loading widget. */
	UFUNCTION(BlueprintCallable, BlueprintPure, Category = "Preload")
	float GetProgress() const;

	/** Number of assets being loaded. */
	UFUNCTION(BlueprintCallable, BlueprintPure, Category = "Preload")
	int32 GetTotalAssetCount() const;

	UFUNCTION(BlueprintCallable, BlueprintPure, Category = "Preload")
	bool IsPreloading() const;

	/** Fires when all assets finish loading. */
	UPROPERTY(BlueprintAssignable, Category = "Preload")
	FOnPreloadComplete OnPreloadComplete;

	/** Fires each frame with current progress. Bind to update your loading bar. */
	UPROPERTY(BlueprintAssignable, Category = "Preload")
	FOnPreloadProgress OnPreloadProgress;

private:
	void BeginAsyncLoad();
	void OnAssetsLoaded();
	bool TickProgress(float DeltaTime);

	TSharedPtr<FStreamableHandle> StreamableHandle;
	TArray<FSoftObjectPath> PendingAssets;
	FTSTicker::FDelegateHandle TickerHandle;
	int32 TotalAssets = 0;
	bool bIsPreloading = false;
};