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

/*=============================================================================
        EditorLevelUtils.h: Editor-specific level management routines
=============================================================================*/

#pragma once

#include "CoreMinimal.h"
#include "UObject/ObjectMacros.h"
#include "Templates/SubclassOf.h"
#include "EditorLevelUtils.generated.h"

class AActor;
class ULevel;
class ULevelStreaming;

DECLARE_LOG_CATEGORY_EXTERN(LogLevelTools, Warning, All);

UENUM(BlueprintType)
enum class ELevelVisibilityDirtyMode : uint8
{
    // Use when the user is causing the visibility change.  Will update transaction state and mark the package dirty.
    ModifyOnChange,
    // Use when code is causing the visibility change.
    DontModify
};

UCLASS(transient)
class UEditorLevelUtils: public UObject
{
    GENERATED_BODY()
public:
    /**
     * Creates a new streaming level in the current world
     *
     * @param	LevelStreamingClass					The streaming class type instead to use for the level.
     * @param	NewLevelPath						Optional path to the level package path format ("e.g /Game/MyLevel").  If empty, the user will be prompted during the save process.
     * @param	bMoveSelectedActorsIntoNewLevel		If true, move any selected actors into the new level.
     *
     * @return	Returns the newly created level, or NULL on failure
     */
    UFUNCTION(BlueprintCallable, Category = "Editor Scripting | Level Creation")
    static UNREALED_API ULevelStreaming* CreateNewStreamingLevel(TSubclassOf<ULevelStreaming> LevelStreamingClass, const FString& NewLevelPath = TEXT(""), bool bMoveSelectedActorsIntoNewLevel = false);

    /**
     * Makes the specified streaming level the current level for editing.
     * The current level is where actors are spawned to when calling SpawnActor
     *
     * @return	true	If a level was removed.
     */
    UFUNCTION(BlueprintCallable, Category = "Editor Scripting | Level Creation")
    static UNREALED_API void MakeLevelCurrent(ULevelStreaming* InStreamingLevel);

    /**
     * Moves the specified list of actors to the specified streaming level. The new actors will be selected
     *
     * @param	ActorsToMove			List of actors to move
     * @param	DestStreamingLevel		The destination streaming level of the current world to move the actors to
     * @param	bWarnAboutReferences	Whether or not to show a modal warning about referenced actors that may no longer function after being moved
     * @return							The number of actors that were successfully moved to the new level
     */
    UFUNCTION(BlueprintCallable, Category = "Editor Scripting | Level Creation")
    static UNREALED_API int32 MoveActorsToLevel(const TArray<AActor*>& ActorsToMove, ULevelStreaming* DestStreamingLevel, bool bWarnAboutReferences = true, bool bWarnAboutRenaming = true);

    /**
     * Moves the currently selected actors to the specified streaming level. The new actors will be selected
     *
     * @param	DestStreamingLevel		The destination streaming level of the current world to move the actors to
     * @param	bWarnAboutReferences	Whether or not to show a modal warning about referenced actors that may no longer function after being moved
     * @return							The number of actors that were successfully moved to the new level
     */
    UFUNCTION(BlueprintCallable, Category = "Editor Scripting | Level Creation")
    static UNREALED_API int32 MoveSelectedActorsToLevel(ULevelStreaming* DestLevel, bool bWarnAboutReferences = true);

    /**
     * Makes the specified level the current level for editing.
     * The current level is where actors are spawned to when calling SpawnActor
     * @param InLevel			The level to make current
     * @param bForceOperation	True if the operation should succeed even if the level is locked.  In certian circumstances (like removing the current level, we must be able to set a new current level even if the only one left is locked)
     *
     * @return	true	If a level was removed.
     */
    static UNREALED_API void MakeLevelCurrent(ULevel* InLevel, bool bEvenIfLocked = false);

    static UNREALED_API int32 MoveActorsToLevel(const TArray<AActor*>& ActorsToMove, ULevel* DestLevel, bool bWarnAboutReferences = true, bool bWarnAboutRenaming = true);

    static UNREALED_API int32 MoveSelectedActorsToLevel(ULevel* DestLevel, bool bWarnAboutReferences = true);

    /**
     * Creates a new streaming level and adds it to a world
     *
     * @param	InWorld								The world to add the streaming level to
     * @param	LevelStreamingClass					The streaming class type instead to use for the level.
     * @param	DefaultFilename						Optional file name for level.  If empty, the user will be prompted during the save process.
     * @param	bMoveSelectedActorsIntoNewLevel		If true, move any selected actors into the new level.
     * @param	InTemplateWorld						If valid, the new level will be a copy of the template world.
     *
     * @return	Returns the newly created level, or NULL on failure
     */
    static UNREALED_API ULevelStreaming* CreateNewStreamingLevelForWorld(UWorld& World, TSubclassOf<ULevelStreaming> LevelStreamingClass, const FString& DefaultFilename = TEXT(""), bool bMoveSelectedActorsIntoNewLevel = false, UWorld* InTemplateWorld = nullptr);

    /**
     * Adds the named level packages to the world.  Does nothing if all the levels already exist in the world.
     *
     * @param	InWorld				World in which to add the level
     * @param	LevelPackageName	The base filename of the level package to add.
     * @param	LevelStreamingClass	The streaming class type instead to use for the level.
     *
     * @return								The new level, or NULL if the level couldn't added.
     */
    static UNREALED_API ULevel* AddLevelsToWorld(UWorld* InWorld, TArray<FString> LevelPackageNames, TSubclassOf<ULevelStreaming> LevelStreamingClass);

    /**
     * Adds the named level package to the world.  Does nothing if the level already exists in the world.
     *
     * @param	InWorld				World in which to add the level.
     * @param	LevelPackageName	The package name ("e.g /Game/MyLevel") of the level package to add.
     * @param	LevelStreamingClass	The streaming class type to use for the level.
     *
     * @return								The new level, or NULL if the level couldn't added.
     */
    UFUNCTION(BlueprintCallable, Category = "Editor Scripting | Level Creation", meta = (DisplayName = "Add Level to World", ScriptName = "AddLevelToWorld"))
    static ULevelStreaming* K2_AddLevelToWorld(UWorld* World, const FString& LevelPackageName, TSubclassOf<ULevelStreaming> LevelStreamingClass)
    {
        return AddLevelToWorld(World, *LevelPackageName, LevelStreamingClass, FTransform::Identity);
    }

    /**
     * Adds the named level package to the world at the given position.  Does nothing if the level already exists in the world.
     *
     * @param	InWorld				World in which to add the level.
     * @param	LevelPackageName	The package name ("e.g /Game/MyLevel") of the level package to add.
     * @param	LevelStreamingClass	The streaming class type to use for the level.
     * @param	LevelTransform		The origin of the new level in the world.
     *
     * @return								The new level, or NULL if the level couldn't added.
     */
    UFUNCTION(BlueprintCallable, Category = "Editor Scripting | Level Creation", meta = (DisplayName = "Add Level to World with Transform", ScriptName = "AddLevelToWorldWithTransform"))
    static ULevelStreaming* K2_AddLevelToWorldWithTransform(UWorld* World, const FString& LevelPackageName, TSubclassOf<ULevelStreaming> LevelStreamingClass, const FTransform& LevelTransform)
    {
        return AddLevelToWorld(World, *LevelPackageName, LevelStreamingClass, LevelTransform);
    }

    /**
     * Adds the named level package to the world.  Does nothing if the level already exists in the world.
     *
     * @param	InWorld				World in which to add the level
     * @param	LevelPackageName	The base filename of the level package to add.
     * @param	LevelStreamingClass	The streaming class type instead to use for the level.
     *
     * @return								The new level, or NULL if the level couldn't added.
     */
    static UNREALED_API ULevelStreaming* AddLevelToWorld(UWorld* InWorld, const TCHAR* LevelPackageName, TSubclassOf<ULevelStreaming> LevelStreamingClass, const FTransform& LevelTransform = FTransform::Identity);

private:
    static UNREALED_API ULevelStreaming* AddLevelToWorld_Internal(UWorld* InWorld, const TCHAR* LevelPackageName, TSubclassOf<ULevelStreaming> LevelStreamingClass, const FTransform& LevelTransform = FTransform::Identity);

public:
    /** Sets the LevelStreamingClass for the specified Level
     * @param	InLevel				The level for which to change the streaming class
     * @param	LevelStreamingClass	The desired streaming class
     *
     * @return	The new streaming level object
     */
    static UNREALED_API ULevelStreaming* SetStreamingClassForLevel(ULevelStreaming* InLevel, TSubclassOf<ULevelStreaming> LevelStreamingClass);

    /**
     * Removes the specified level from the world.  Refreshes.
     *
     * @return	true	If a level was removed.
     */
    static UNREALED_API bool RemoveLevelFromWorld(ULevel* InLevel);

    /**
     * Removes the specified LevelStreaming from the world, and Refreshes.
     * Used to Clean up references of missing levels.
     *
     * @return	true	If a level was removed.
     */
    static UNREALED_API bool RemoveInvalidLevelFromWorld(ULevelStreaming* InLevelStreaming);

    /**
     * Sets the actors within a level's visibility via bHiddenEdLevel.
     * Warning: modifies ULevel::bIsVisible and bHiddenEdLevel without marking packages dirty or supporting undo.
     * Calling code must restore to the original state before the user can interact with the levels.
     */
    static UNREALED_API void SetLevelVisibilityTemporarily(ULevel* Level, bool bShouldBeVisible);

    /**
     * Sets a level's visibility in the editor. Less efficient than SetLevelsVisibility when changing the visibility of multiple levels simultaneously.
     *
     * @param	Level					The level to modify.
     * @param	bShouldBeVisible		The level's new visibility state.
     * @param	bForceLayersVisible		If true and the level is visible, force the level's layers to be visible.
     * @param	ModifyMode				ELevelVisibilityDirtyMode mode value.
     */
    UFUNCTION(BlueprintCallable, Category = "Editor Scripting | Level Utility")
    static UNREALED_API void SetLevelVisibility(ULevel* Level, const bool bShouldBeVisible, const bool bForceLayersVisible, const ELevelVisibilityDirtyMode ModifyMode = ELevelVisibilityDirtyMode::ModifyOnChange);

    /**
     * Sets a level's visibility in the editor. More efficient than SetLevelsVisibility when changing the visibility of multiple levels simultaneously.
     *
     * @param	Levels					The levels to modify.
     * @param	bShouldBeVisible		The level's new visibility state for each level.
     * @param	bForceLayersVisible		If true and the level is visible, force the level's layers to be visible.
     * @param	ModifyMode				ELevelVisibilityDirtyMode mode value.
     */
    UFUNCTION(BlueprintCallable, Category = "Editor Scripting | Level Utility")
    static UNREALED_API void SetLevelsVisibility(const TArray<ULevel*>& Levels, const TArray<bool>& bShouldBeVisible, const bool bForceLayersVisible, const ELevelVisibilityDirtyMode ModifyMode = ELevelVisibilityDirtyMode::ModifyOnChange);

    /**
     * Deselects all BSP surfaces in this level
     *
     * @param InLevel		The level to deselect the surfaces of.
     *
     */
    static UNREALED_API void DeselectAllSurfacesInLevel(ULevel* InLevel);

    /**
     * Executes an operation on the set of all referenced worlds.
     *
     * @param	InWorld				World containing streaming levels
     * @param	Operation			The operation to execute on the referenced worlds, return false to break iteration
     * @param	bIncludeInWorld		If true, include the InWorld in the output list.
     * @param	bOnlyEditorVisible	If true, only sub-levels that should be visible in-editor are included
     */
    static UNREALED_API void ForEachWorlds(UWorld* InWorld, TFunctionRef<bool(UWorld*)> Operation, bool bIncludeInWorld, bool bOnlyEditorVisible = false);

    /**
     * Assembles the set of all referenced worlds.
     *
     * @param	InWorld				World containing streaming levels
     * @param	Worlds				[out] The set of referenced worlds.
     * @param	bIncludeInWorld		If true, include the InWorld in the output list.
     * @param	bOnlyEditorVisible	If true, only sub-levels that should be visible in-editor are included
     */
    static UNREALED_API void GetWorlds(UWorld* InWorld, TArray<UWorld*>& OutWorlds, bool bIncludeInWorld, bool bOnlyEditorVisible = false);

    /**
     * Returns all levels for a world.
     *
     * @param	World				World containing levels
     * @return						Set of all levels
     */
    UFUNCTION(BlueprintCallable, Category = "Editor Scripting | Level Utility")
    static const TArray<ULevel*> GetLevels(UWorld* World);

    UE_DEPRECATED(4.17, "The CreateNewLevel method to create streaming levels has been deprecated. Use CreateNewStreamingLevelForWorld instead")
    static UNREALED_API ULevel* CreateNewLevel(UWorld* InWorld, bool bMoveSelectedActorsIntoNewLevel, TSubclassOf<ULevelStreaming> LevelStreamingClass, const FString& DefaultFilename = TEXT(""));

    /**
     * Moves the specified list of actors to the specified level
     *
     * @param	ActorsToMove		List of actors to move
     * @param	DestLevelStreaming	The level streaming object associated with the destination level
     * @param	OutNumMovedActors	The number of actors that were successfully moved to the new level
     */
    UE_DEPRECATED(4.17, "The MovesActorsToLevel method has been deprecated. Use MoveActorsToLevel instead")
    static void MovesActorsToLevel(TArray<AActor*>& ActorsToMove, ULevelStreaming* DestLevelStreaming, int32& OutNumMovedActors);

private:
    /**
     * Removes a level from the world.  Returns true if the level was removed successfully.
     *
     * @param	Level		The level to remove from the world.
     * @return				true if the level was removed successfully, false otherwise.
     */
    static bool PrivateRemoveLevelFromWorld(ULevel* Level);

    static bool PrivateRemoveInvalidLevelFromWorld(ULevelStreaming* InLevelStreaming);

    /**
     * Completely removes the level from the world, unloads its package and forces garbage collection.
     *
     * @note: This function doesn't remove the associated streaming level.
     *
     * @param	InLevel			A non-NULL, non-Persistent Level that will be destroyed.
     * @return					true if the level was removed.
     */
    static bool EditorDestroyLevel(ULevel* InLevel);

private:
};

// For backwards compatibility
typedef UEditorLevelUtils EditorLevelUtils;