/*     Copyright 2019 Diligent Graphics LLC
 *  
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF ANY PROPRIETARY RIGHTS.
 *
 *  In no event and under no legal theory, whether in tort (including negligence), 
 *  contract, or otherwise, unless required by applicable law (such as deliberate 
 *  and grossly negligent acts) or agreed to in writing, shall any Contributor be
 *  liable for any damages, including any direct, indirect, special, incidental, 
 *  or consequential damages of any character arising as a result of this License or 
 *  out of the use or inability to use the software (including but not limited to damages 
 *  for loss of goodwill, work stoppage, computer failure or malfunction, or any and 
 *  all other commercial damages or losses), even if such Contributor has been advised 
 *  of the possibility of such damages.
 */

#pragma once

/// \file
/// Declaration of the Diligent::ResourceMappingImpl class

#include "ResourceMapping.h"
#include "ObjectBase.h"
#include <unordered_map>
#include "HashUtils.h"
#include "STDAllocator.h"

namespace Diligent
{
struct ResMappingHashKey
{
    ResMappingHashKey(const Char* Str, bool bMakeCopy, Uint32 ArrInd) :
        StrKey{Str, bMakeCopy},
        ArrayIndex{ArrInd}
    {
    }

    ResMappingHashKey(ResMappingHashKey&& rhs) :
        StrKey{std::move(rhs.StrKey)},
        ArrayIndex{rhs.ArrayIndex}
    {}

    bool operator==(const ResMappingHashKey& RHS) const
    {
        return StrKey == RHS.StrKey && ArrayIndex == RHS.ArrayIndex;
    }

    size_t GetHash() const
    {
        if (Hash == 0)
        {
            Hash = ComputeHash(StrKey.GetHash(), ArrayIndex);
        }

        return Hash;
    }

    // clang-format off
    ResMappingHashKey             ( const ResMappingHashKey& ) = delete;
    ResMappingHashKey& operator = ( const ResMappingHashKey& ) = delete;
    ResMappingHashKey& operator = ( ResMappingHashKey&& )      = delete;
    // clang-format on

    HashMapStringKey StrKey;
    Uint32           ArrayIndex;
    mutable size_t   Hash = 0;
};
} // namespace Diligent

namespace std
{
template <>
struct hash<Diligent::ResMappingHashKey>
{
    size_t operator()(const Diligent::ResMappingHashKey& Key) const
    {
        return Key.GetHash();
    }
};
} // namespace std

namespace Diligent
{
class FixedBlockMemoryAllocator;

/// Implementation of the resource mapping
class ResourceMappingImpl : public ObjectBase<IResourceMapping>
{
public:
    typedef ObjectBase<IResourceMapping> TObjectBase;

    /// \param pRefCounters - reference counters object that controls the lifetime of this resource mapping
    /// \param RawMemAllocator - raw memory allocator that is used by the m_HashTable member
    ResourceMappingImpl(IReferenceCounters* pRefCounters, IMemoryAllocator& RawMemAllocator) :
        TObjectBase(pRefCounters),
        m_HashTable(STD_ALLOCATOR_RAW_MEM(HashTableElem, RawMemAllocator, "Allocator for unordered_map< ResMappingHashKey, RefCntAutoPtr<IDeviceObject> >"))
    {}

    ~ResourceMappingImpl();

    virtual void QueryInterface(const INTERFACE_ID& IID, IObject** ppInterface) override final;

    /// Implementation of IResourceMapping::AddResource()
    virtual void AddResource(const Char* Name, IDeviceObject* pObject, bool bIsUnique) override final;

    /// Implementation of IResourceMapping::AddResourceArray()
    virtual void AddResourceArray(const Char* Name, Uint32 StartIndex, IDeviceObject* const* ppObjects, Uint32 NumElements, bool bIsUnique) override final;

    /// Implementation of IResourceMapping::RemoveResourceByName()
    virtual void RemoveResourceByName(const Char* Name, Uint32 ArrayIndex) override final;

    /// Implementation of IResourceMapping::GetResource()
    virtual void GetResource(const Char* Name, IDeviceObject** ppResource, Uint32 ArrayIndex) override final;

    /// Returns number of resources in the resource mapping.
    virtual size_t GetSize() override final;

private:
    ThreadingTools::LockHelper Lock();

    ThreadingTools::LockFlag                                                                                                                                               m_LockFlag;
    typedef std::pair<const ResMappingHashKey, RefCntAutoPtr<IDeviceObject>>                                                                                               HashTableElem;
    std::unordered_map<ResMappingHashKey, RefCntAutoPtr<IDeviceObject>, std::hash<ResMappingHashKey>, std::equal_to<ResMappingHashKey>, STDAllocatorRawMem<HashTableElem>> m_HashTable;
};
} // namespace Diligent
