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

#include "Serialization/BulkDataManifest.h"

#include "CoreGlobals.h"
#include "HAL/FileManager.h"
#include "Misc/Guid.h"
#include "Misc/Paths.h"
#include "Serialization/CustomVersion.h"

struct FBulkDataManifestVersion
{
    FBulkDataManifestVersion() = delete;

    enum Type
    {
        // Before any version changes were made
        BeforeCustomVersionWasAdded = 0,

        // -----<new versions can be added above this line>-------------------------------------------------
        VersionPlusOne,
        LatestVersion = VersionPlusOne - 1
    };

    // The GUID for this custom version number
    const static FGuid GUID;
};

const FGuid FBulkDataManifestVersion::GUID(0x54683250, 0x809948AF, 0x8BC89896, 0xFBADF9B7);
FCustomVersionRegistration GRegisterBulkDataManifestVersion(FBulkDataManifestVersion::GUID, FBulkDataManifestVersion::LatestVersion, TEXT("BulkDataManifestVersion"));

void FPackageStoreBulkDataManifest::FPackageDesc::AddData(EBulkdataType InType, uint64 InChunkId, uint64 InOffset, uint64 InSize, const FString& DebugFilename)
{
    // The ChunkId is supposed to be unique for each type
    auto func = [=](const FBulkDataDesc& Entry)
    {
        return Entry.ChunkId == InChunkId && Entry.Type == InType;
    };
    if (Data.FindByPredicate(func) != nullptr)
    {
        FString Message;
        for (int i = 0; i < Data.Num(); ++i)
        {
            const FBulkDataDesc& Entry = Data[i];
            Message.Appendf(TEXT("[%3d] ID: %20llu Offset: %8llu Size: %8llu Type: %d\n"),
                            i, Entry.ChunkId, Entry.Offset, Entry.Size, Entry.Type);
        }

        Message.Appendf(TEXT("[New] ID: %20llu Offset: %8llu Size: %8llu Type: %d\n"),
                        InChunkId, InOffset, InSize, InType);

        UE_LOG(LogSerialization, Warning, TEXT("Duplicate BulkData description found in Package '%s', this will cause issues trying to run IoStore!\n%s"), *DebugFilename, *Message);
    }
    else
    {
        FBulkDataDesc& Entry = Data.Emplace_GetRef();

        Entry.ChunkId        = InChunkId;
        Entry.Offset         = InOffset;
        Entry.Size           = InSize;
        Entry.Type           = InType;
    }
}

void FPackageStoreBulkDataManifest::FPackageDesc::AddZeroByteData(EBulkdataType InType)
{
    // Make sure we only add one empty read per Bulkdata type!
    auto func = [=](const FBulkDataDesc& Entry)
    {
        return Entry.Type == InType && Entry.Size == 0;
    };
    if (Data.FindByPredicate(func) == nullptr)
    {
        FBulkDataDesc& Entry = Data.Emplace_GetRef();

        Entry.ChunkId        = TNumericLimits<uint64>::Max();
        Entry.Offset         = 0;
        Entry.Size           = 0;
        Entry.Type           = InType;
    }
}

FPackageStoreBulkDataManifest::FPackageStoreBulkDataManifest(const FString& ProjectPath)
{
    Filename = ProjectPath / TEXT("Metadata/BulkDataInfo.ubulkmanifest");
}

FArchive& operator<<(FArchive& Ar, FPackageStoreBulkDataManifest::FPackageDesc::FBulkDataDesc& Entry)
{
    Ar << Entry.ChunkId;
    Ar << Entry.Offset;
    Ar << Entry.Size;
    Ar << Entry.Type;

    return Ar;
}

FArchive& operator<<(FArchive& Ar, FPackageStoreBulkDataManifest::FPackageDesc& Entry)
{
    Ar << Entry.Data;

    return Ar;
}

bool FPackageStoreBulkDataManifest::Load()
{
    Data.Empty();

    TUniquePtr<FArchive> BinArchive(IFileManager::Get().CreateFileReader(*Filename));
    if (BinArchive != nullptr)
    {
        // Load and apply the custom versions before we load any data
        FCustomVersionContainer CustomVersions;
        CustomVersions.Serialize(*BinArchive);
        BinArchive->SetCustomVersions(CustomVersions);

        *BinArchive << Data;
        return true;
    }
    else
    {
        return false;
    }
}

void FPackageStoreBulkDataManifest::Save()
{
    TUniquePtr<FArchive> BinArchive(IFileManager::Get().CreateFileWriter(*Filename));
    BinArchive->UsingCustomVersion(FBulkDataManifestVersion::GUID);

    // Take the versions from the archive and serialize them out
    // NOTE: Serializing out now means we cannot add additional versions while serializing
    // it is assumed that we are only using FBulkDataManifestVersion::GUID
    FCustomVersionContainer CustomVersions = BinArchive->GetCustomVersions();
    CustomVersions.Serialize(*BinArchive);

    *BinArchive << Data;
}

const FPackageStoreBulkDataManifest::FPackageDesc* FPackageStoreBulkDataManifest::Find(const FString& PackageFilename) const
{
    const FString NormalizedFilename = FixFilename(PackageFilename);
    return Data.Find(NormalizedFilename);
}

void FPackageStoreBulkDataManifest::AddFileAccess(const FString& PackageFilename, EBulkdataType InType, uint64 InChunkId, uint64 InOffset, uint64 InSize)
{
    const FString NormalizedFilename = FixFilename(PackageFilename);

    FPackageDesc& Entry              = GetOrCreateFileAccess(NormalizedFilename);

    if (InSize > 0)
    {
        Entry.AddData(InType, InChunkId, InOffset, InSize, NormalizedFilename);
    }
    else
    {
        Entry.AddZeroByteData(InType);
    }
}

FPackageStoreBulkDataManifest::FPackageDesc& FPackageStoreBulkDataManifest::GetOrCreateFileAccess(const FString& PackageFilename)
{
    if (FPackageDesc* Entry = Data.Find(PackageFilename))
    {
        return *Entry;
    }
    else
    {
        return Data.Add(PackageFilename);
    }
}

FString FPackageStoreBulkDataManifest::FixFilename(const FString& InFilename) const
{
    FString OutFilename = InFilename;
    FPaths::NormalizeFilename(OutFilename);
    FPaths::MakePathRelativeTo(OutFilename, *RootPath);

    return OutFilename;
}