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

/*=============================================================================
        AsyncLoading2.h: Unreal async loading #2 definitions.
=============================================================================*/

#pragma once

#include "CoreMinimal.h"
#include "UObject/ObjectResource.h"
#include "UObject/PackageId.h"
#include "Serialization/Archive.h"
#include "IO/IoContainerId.h"

class FArchive;
class IAsyncPackageLoader;
class FIoDispatcher;
class IEDLBootNotificationManager;

using FSourceToLocalizedPackageIdMap = TArray<TPair<FPackageId, FPackageId>>;
using FCulturePackageMap             = TMap<FString, FSourceToLocalizedPackageIdMap>;

class FMappedName
{
    static constexpr uint32 InvalidIndex = ~uint32(0);
    static constexpr uint32 IndexBits    = 30u;
    static constexpr uint32 IndexMask    = (1u << IndexBits) - 1u;
    static constexpr uint32 TypeMask     = ~IndexMask;
    static constexpr uint32 TypeShift    = IndexBits;

public:
    enum class EType
    {
        Package,
        Container,
        Global
    };

    inline FMappedName() = default;

    static inline FMappedName Create(const uint32 InIndex, const uint32 InNumber, EType InType)
    {
        check(InIndex <= MAX_int32);
        return FMappedName((uint32(InType) << TypeShift) | InIndex, InNumber);
    }

    static inline FMappedName FromMinimalName(const FMinimalName& MinimalName)
    {
        return *reinterpret_cast<const FMappedName*>(&MinimalName);
    }

    static inline bool IsResolvedToMinimalName(const FMinimalName& MinimalName)
    {
        // Not completely safe, relies on that no FName will have its Index and Number equal to Max_uint32
        const FMappedName MappedName = FromMinimalName(MinimalName);
        return MappedName.IsValid();
    }

    static inline FName SafeMinimalNameToName(const FMinimalName& MinimalName)
    {
        return IsResolvedToMinimalName(MinimalName) ? MinimalNameToName(MinimalName) : NAME_None;
    }

    inline FMinimalName ToUnresolvedMinimalName() const
    {
        return *reinterpret_cast<const FMinimalName*>(this);
    }

    inline bool IsValid() const
    {
        return Index != InvalidIndex && Number != InvalidIndex;
    }

    inline EType GetType() const
    {
        return static_cast<EType>(uint32((Index & TypeMask) >> TypeShift));
    }

    inline bool IsGlobal() const
    {
        return ((Index & TypeMask) >> TypeShift) != 0;
    }

    inline uint32 GetIndex() const
    {
        return Index & IndexMask;
    }

    inline uint32 GetNumber() const
    {
        return Number;
    }

    inline bool operator!=(FMappedName Other) const
    {
        return Index != Other.Index || Number != Other.Number;
    }

    COREUOBJECT_API friend FArchive& operator<<(FArchive& Ar, FMappedName& MappedName);

private:
    inline FMappedName(const uint32 InIndex, const uint32 InNumber)
        : Index(InIndex), Number(InNumber) {}

    uint32 Index  = InvalidIndex;
    uint32 Number = InvalidIndex;
};

struct FContainerHeader
{
    FIoContainerId ContainerId;
    uint32 PackageCount = 0;
    TArray<uint8> Names;
    TArray<uint8> NameHashes;
    TArray<FPackageId> PackageIds;
    TArray<uint8> StoreEntries;  // FPackageStoreEntry[PackageCount]
    FCulturePackageMap CulturePackageMap;
    TArray<TPair<FPackageId, FPackageId>> PackageRedirects;

    COREUOBJECT_API friend FArchive& operator<<(FArchive& Ar, FContainerHeader& ContainerHeader);
};

class FPackageObjectIndex
{
    static constexpr uint64 IndexBits = 62ull;
    static constexpr uint64 IndexMask = (1ull << IndexBits) - 1ull;
    static constexpr uint64 TypeMask  = ~IndexMask;
    static constexpr uint64 TypeShift = IndexBits;
    static constexpr uint64 Invalid   = ~0ull;

    uint64 TypeAndId                  = Invalid;

    enum EType
    {
        Export,
        ScriptImport,
        PackageImport,
        Null,
        TypeCount = Null,
    };
    static_assert((TypeCount - 1) <= (TypeMask >> TypeShift), "FPackageObjectIndex: Too many types for TypeMask");

    inline explicit FPackageObjectIndex(EType InType, uint64 InId): TypeAndId((uint64(InType) << TypeShift) | InId) {}

    COREUOBJECT_API static uint64 GenerateImportHashFromObjectPath(const FStringView& ObjectPath);

public:
    FPackageObjectIndex() = default;

    inline static FPackageObjectIndex FromExportIndex(const int32 Index)
    {
        return FPackageObjectIndex(Export, Index);
    }

    inline static FPackageObjectIndex FromScriptPath(const FStringView& ScriptObjectPath)
    {
        return FPackageObjectIndex(ScriptImport, GenerateImportHashFromObjectPath(ScriptObjectPath));
    }

    inline static FPackageObjectIndex FromPackagePath(const FStringView& PackageObjectPath)
    {
        return FPackageObjectIndex(PackageImport, GenerateImportHashFromObjectPath(PackageObjectPath));
    }

    inline bool IsNull() const
    {
        return TypeAndId == Invalid;
    }

    inline bool IsExport() const
    {
        return (TypeAndId >> TypeShift) == Export;
    }

    inline bool IsImport() const
    {
        return IsScriptImport() || IsPackageImport();
    }

    inline bool IsScriptImport() const
    {
        return (TypeAndId >> TypeShift) == ScriptImport;
    }

    inline bool IsPackageImport() const
    {
        return (TypeAndId >> TypeShift) == PackageImport;
    }

    inline uint32 ToExport() const
    {
        check(IsExport());
        return uint32(TypeAndId);
    }

    inline uint64 Value() const
    {
        return TypeAndId & IndexMask;
    }

    inline bool operator==(FPackageObjectIndex Other) const
    {
        return TypeAndId == Other.TypeAndId;
    }

    inline bool operator!=(FPackageObjectIndex Other) const
    {
        return TypeAndId != Other.TypeAndId;
    }

    COREUOBJECT_API friend FArchive& operator<<(FArchive& Ar, FPackageObjectIndex& Value)
    {
        Ar << Value.TypeAndId;
        return Ar;
    }

    inline friend uint32 GetTypeHash(const FPackageObjectIndex& Value)
    {
        return uint32(Value.TypeAndId);
    }
};

/**
 * Export filter flags.
 */
enum class EExportFilterFlags : uint8
{
    None,
    NotForClient,
    NotForServer
};

/**
 * Package summary.
 */
struct FPackageSummary
{
    FMappedName Name;
    FMappedName SourceName;
    uint32 PackageFlags;
    uint32 CookedHeaderSize;
    int32 NameMapNamesOffset;
    int32 NameMapNamesSize;
    int32 NameMapHashesOffset;
    int32 NameMapHashesSize;
    int32 ImportMapOffset;
    int32 ExportMapOffset;
    int32 ExportBundlesOffset;
    int32 GraphDataOffset;
    int32 GraphDataSize;
    int32 Pad = 0;
};

/**
 * Export bundle entry.
 */
struct FExportBundleEntry
{
    enum EExportCommandType
    {
        ExportCommandType_Create,
        ExportCommandType_Serialize,
        ExportCommandType_Count
    };
    uint32 LocalExportIndex;
    uint32 CommandType;

    COREUOBJECT_API friend FArchive& operator<<(FArchive& Ar, FExportBundleEntry& ExportBundleEntry);
};

template <typename T>
class TPackageStoreEntryCArrayView
{
    const uint32 ArrayNum             = 0;
    const uint32 OffsetToDataFromThis = 0;

public:
    inline uint32 Num() const { return ArrayNum; }

    inline const T* Data() const { return (T*)((char*)this + OffsetToDataFromThis); }
    inline T* Data() { return (T*)((char*)this + OffsetToDataFromThis); }

    inline const T* begin() const { return Data(); }
    inline T* begin() { return Data(); }

    inline const T* end() const { return Data() + ArrayNum; }
    inline T* end() { return Data() + ArrayNum; }

    inline const T& operator[](uint32 Index) const { return Data()[Index]; }
    inline T& operator[](uint32 Index) { return Data()[Index]; }
};

struct FPackageStoreEntry
{
    uint64 ExportBundlesSize;
    int32 ExportCount;
    int32 ExportBundleCount;
    uint32 LoadOrder;
    uint32 Pad;
    TPackageStoreEntryCArrayView<FPackageId> ImportedPackages;
};

/**
 * Export bundle header
 */
struct FExportBundleHeader
{
    uint32 FirstEntryIndex;
    uint32 EntryCount;

    COREUOBJECT_API friend FArchive& operator<<(FArchive& Ar, FExportBundleHeader& ExportBundleHeader);
};

struct FScriptObjectEntry
{
    FMinimalName ObjectName;
    FPackageObjectIndex GlobalIndex;
    FPackageObjectIndex OuterIndex;
    FPackageObjectIndex CDOClassIndex;

    COREUOBJECT_API friend FArchive& operator<<(FArchive& Ar, FScriptObjectEntry& ScriptObjectEntry);
};

/**
 * Export map entry.
 */
struct FExportMapEntry
{
    uint64 CookedSerialOffset = 0;
    uint64 CookedSerialSize   = 0;
    FMappedName ObjectName;
    FPackageObjectIndex OuterIndex;
    FPackageObjectIndex ClassIndex;
    FPackageObjectIndex SuperIndex;
    FPackageObjectIndex TemplateIndex;
    FPackageObjectIndex GlobalImportIndex;
    EObjectFlags ObjectFlags       = EObjectFlags::RF_NoFlags;
    EExportFilterFlags FilterFlags = EExportFilterFlags::None;
    uint8 Pad[3]                   = {};

    COREUOBJECT_API friend FArchive& operator<<(FArchive& Ar, FExportMapEntry& ExportMapEntry);
};

COREUOBJECT_API void FindAllRuntimeScriptPackages(TArray<UPackage*>& OutPackages);

#ifndef WITH_ASYNCLOADING2
#define WITH_ASYNCLOADING2 (WITH_IOSTORE_IN_EDITOR || !WITH_EDITORONLY_DATA)
#endif

#if WITH_ASYNCLOADING2

/**
 * Creates a new instance of the AsyncPackageLoader #2.
 *
 * @param InIoDispatcher				The I/O dispatcher.
 *
 * @return The async package loader.
 */
IAsyncPackageLoader* MakeAsyncPackageLoader2(FIoDispatcher& InIoDispatcher);

#endif