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

#pragma once

#include "Containers/Array.h"
#include "Containers/RingBuffer.h"
#include "Containers/Set.h"
#include "CookRequests.h"
#include "CookTypes.h"
#include "HAL/CriticalSection.h"
#include "INetworkFileSystemModule.h"
#include "Misc/ScopeLock.h"
#include "Templates/UnrealTemplate.h"
#include "UObject/NameTypes.h"
#include "UObject/UObjectArray.h"

class ITargetPlatform;
class UPackage;

namespace UE
{
namespace Cook
{

struct FPackageDatas;
struct FRecompileRequest;

/** Helper to pass a recompile request to game thread */
struct FRecompileRequest
{
    struct FShaderRecompileData RecompileData;
    volatile bool bComplete = false;
};

template <typename Type>
struct FThreadSafeQueue
{
private:
    mutable FCriticalSection SynchronizationObject;  // made this mutable so this class can have const functions and still be thread safe
    TRingBuffer<Type> Items;

public:
    void Enqueue(const Type& Item)
    {
        FScopeLock ScopeLock(&SynchronizationObject);
        Items.Add(Item);
    }

    void EnqueueUnique(const Type& Item)
    {
        FScopeLock ScopeLock(&SynchronizationObject);
        for (const Type& Existing: Items)
        {
            if (Existing == Item)
            {
                return;
            }
        }
        Items.PushBack(Item);
    }

    bool Dequeue(Type* Result)
    {
        FScopeLock ScopeLock(&SynchronizationObject);
        if (Items.Num())
        {
            *Result = Items.PopFrontValue();
            return true;
        }
        return false;
    }

    void DequeueAll(TArray<Type>& Results)
    {
        FScopeLock ScopeLock(&SynchronizationObject);
        Results.Reserve(Results.Num() + Items.Num());
        while (!Items.IsEmpty())
        {
            Results.Add(Items.PopFrontValue());
        }
    }

    bool HasItems() const
    {
        FScopeLock ScopeLock(&SynchronizationObject);
        return Items.Num() > 0;
    }

    void Remove(const Type& Item)
    {
        FScopeLock ScopeLock(&SynchronizationObject);
        Items.Remove(Item);
    }

    void CopyItems(const TArray<Type>& InItems) const
    {
        FScopeLock ScopeLock(&SynchronizationObject);
        Items.Empty(InItems.Num());
        for (const Type& Item: InItems)
        {
            Items.PushBack(Item);
        }
    }

    int Num() const
    {
        FScopeLock ScopeLock(&SynchronizationObject);
        return Items.Num();
    }

    void Empty()
    {
        FScopeLock ScopeLock(&SynchronizationObject);
        Items.Empty();
    }
};

/** Simple thread safe proxy for TSet<FName> */
template <typename T>
class FThreadSafeSet
{
    TSet<T> InnerSet;
    FCriticalSection SetCritical;

public:
    void Add(T InValue)
    {
        FScopeLock SetLock(&SetCritical);
        InnerSet.Add(InValue);
    }
    bool AddUnique(T InValue)
    {
        FScopeLock SetLock(&SetCritical);
        if (!InnerSet.Contains(InValue))
        {
            InnerSet.Add(InValue);
            return true;
        }
        return false;
    }
    bool Contains(T InValue)
    {
        FScopeLock SetLock(&SetCritical);
        return InnerSet.Contains(InValue);
    }
    void Remove(T InValue)
    {
        FScopeLock SetLock(&SetCritical);
        InnerSet.Remove(InValue);
    }
    void Empty()
    {
        FScopeLock SetLock(&SetCritical);
        InnerSet.Empty();
    }

    void GetValues(TSet<T>& OutSet)
    {
        FScopeLock SetLock(&SetCritical);
        OutSet.Append(InnerSet);
    }
};

struct FThreadSafeUnsolicitedPackagesList
{
    void AddCookedPackage(const FFilePlatformRequest& PlatformRequest);
    void GetPackagesForPlatformAndRemove(const ITargetPlatform* Platform, TArray<FName>& PackageNames);
    void Empty();

private:
    FCriticalSection SyncObject;
    TArray<FFilePlatformRequest> CookedPackages;
};

struct FPackageTracker: public FUObjectArray::FUObjectCreateListener
    , public FUObjectArray::FUObjectDeleteListener
{
public:
    FPackageTracker(FPackageDatas& InPackageDatas);
    ~FPackageTracker();

    /* Returns all packages that have been loaded since the last time GetNewPackages was called */
    TArray<UPackage*> GetNewPackages();

    virtual void NotifyUObjectCreated(const class UObjectBase* Object, int32 Index) override;
    virtual void NotifyUObjectDeleted(const class UObjectBase* Object, int32 Index) override;
    virtual void OnUObjectArrayShutdown() override;

    /** Swap all ITargetPlatform* stored on this instance according to the mapping in @param Remap. */
    void RemapTargetPlatforms(const TMap<ITargetPlatform*, ITargetPlatform*>& Remap);

    // This is the set of packages which have already had PostLoadFixup called
    TSet<UPackage*> PostLoadFixupPackages;

    // This is a complete list of currently loaded UPackages
    TFastPointerSet<UPackage*> LoadedPackages;

    // This list contains the UPackages loaded since last call to GetNewPackages
    TArray<UPackage*> NewPackages;

    /** The package currently being loaded at CookOnTheFlyServer's direct request. Used to determine which load dependencies were not preloaded. */
    FPackageData* LoadingPackageData = nullptr;

    FPackageDatas& PackageDatas;

    FThreadSafeUnsolicitedPackagesList UnsolicitedCookedPackages;
    FThreadSafeQueue<FRecompileRequest*> RecompileRequests;

    FThreadSafeSet<FName> NeverCookPackageList;
    FThreadSafeSet<FName> UncookedEditorOnlyPackages;  // set of packages that have been rejected due to being referenced by editor-only properties
    TFastPointerMap<const ITargetPlatform*, TSet<FName>> PlatformSpecificNeverCookPackages;
};
}  // namespace Cook
}  // namespace UE