// This file is part of the FidelityFX SDK.
//
// Copyright (c) 2023 Advanced Micro Devices, Inc. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// 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. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#pragma once

#include "ffx_assert.h"
#include "ffx_types.h"
#include "ffx_error.h"

namespace Fsr31
{
#if defined(__cplusplus)
#define FFX_CPU
extern "C"
{
#endif // #if defined(__cplusplus)

    /// @defgroup Backends Backends
    /// Core interface declarations and natively supported backends
    ///
    /// @ingroup ffxSDK

    /// @defgroup FfxInterface FfxInterface
    /// FidelityFX SDK function signatures and core defines requiring
    /// overrides for backend implementation.
    ///
    /// @ingroup Backends
    FFX_FORWARD_DECLARE(FfxInterface);

    /// FidelityFX SDK major version.
    ///
    /// @ingroup FfxInterface
#define FFX_SDK_VERSION_MAJOR (1)

/// FidelityFX SDK minor version.
///
/// @ingroup FfxInterface
#define FFX_SDK_VERSION_MINOR (0)

/// FidelityFX SDK patch version.
///
/// @ingroup FfxInterface
#define FFX_SDK_VERSION_PATCH (1)

/// Macro to pack a FidelityFX SDK version id together.
///
/// @ingroup FfxInterface
#define FFX_SDK_MAKE_VERSION(major, minor, patch) ((major << 22) | (minor << 12) | patch)

    /// Stand in type for FfxPass
    ///
    /// These will be defined for each effect individually (i.e. FfxFsr2Pass).
    /// They are used to fetch the proper blob index to build effect shaders
    ///
    /// @ingroup FfxInterface
    typedef uint32_t FfxPass;

    /// Get the SDK version of the backend context.
    ///
    /// Newer effects may require support that legacy versions of the SDK will not be
    /// able to provide. A version query is thus required to ensure an effect component
    /// will always be paired with a backend which will support all needed functionality.
    ///
    /// @param [in]  backendInterface                    A pointer to the backend interface.
    ///
    /// @returns
    /// The SDK version a backend was built with.
    ///
    /// @ingroup FfxInterface
    typedef FfxUInt32 (*FfxGetSDKVersionFunc)(FfxInterface* backendInterface);

    /// Create and initialize the backend context.
    ///
    /// The callback function sets up the backend context for rendering.
    /// It will create or reference the device and create required internal data structures.
    ///
    /// @param [in]  backendInterface                    A pointer to the backend interface.
    /// @param [out] effectContextId                     The context space to be used for the effect in question.
    ///
    /// @retval
    /// FFX_OK                                          The operation completed successfully.
    /// @retval
    /// Anything else                                   The operation failed.
    ///
    /// @ingroup FfxInterface
    typedef FfxErrorCode (*FfxCreateBackendContextFunc)(FfxInterface* backendInterface, FfxUInt32* effectContextId);

    /// Get a list of capabilities of the device.
    ///
    /// When creating an <c><i>FfxEffectContext</i></c> it is desirable for the FFX
    /// core implementation to be aware of certain characteristics of the platform
    /// that is being targetted. This is because some optimizations which FFX SDK
    /// attempts to perform are more effective on certain classes of hardware than
    /// others, or are not supported by older hardware. In order to avoid cases
    /// where optimizations actually have the effect of decreasing performance, or
    /// reduce the breadth of support provided by FFX SDK, the FFX interface queries the
    /// capabilities of the device to make such decisions.
    ///
    /// For target platforms with fixed hardware support you need not implement
    /// this callback function by querying the device, but instead may hardcore
    /// what features are available on the platform.
    ///
    /// @param [in] backendInterface                    A pointer to the backend interface.
    /// @param [out] outDeviceCapabilities              The device capabilities structure to fill out.
    ///
    /// @retval
    /// FFX_OK                                          The operation completed successfully.
    /// @retval
    /// Anything else                                   The operation failed.
    ///
    /// @ingroup FfxInterface
    typedef FfxErrorCode (*FfxGetDeviceCapabilitiesFunc)(FfxInterface* backendInterface,
                                                         FfxDeviceCapabilities* outDeviceCapabilities);

    /// Destroy the backend context and dereference the device.
    ///
    /// This function is called when the <c><i>FfxEffectContext</i></c> is destroyed.
    ///
    /// @param [in] backendInterface                    A pointer to the backend interface.
    /// @param [in] effectContextId                     The context space to be used for the effect in question.
    ///
    /// @retval
    /// FFX_OK                                          The operation completed successfully.
    /// @retval
    /// Anything else                                   The operation failed.
    ///
    /// @ingroup FfxInterface
    typedef FfxErrorCode (*FfxDestroyBackendContextFunc)(FfxInterface* backendInterface, FfxUInt32 effectContextId);

    /// Create a resource.
    ///
    /// This callback is intended for the backend to create internal resources.
    ///
    /// Please note: It is also possible that the creation of resources might
    /// itself cause additional resources to be created by simply calling the
    /// <c><i>FfxCreateResourceFunc</i></c> function pointer again. This is
    /// useful when handling the initial creation of resources which must be
    /// initialized. The flow in such a case would be an initial call to create the
    /// CPU-side resource, another to create the GPU-side resource, and then a call
    /// to schedule a copy render job to move the data between the two. Typically
    /// this type of function call flow is only seen during the creation of an
    /// <c><i>FfxEffectContext</i></c>.
    ///
    /// @param [in] backendInterface                    A pointer to the backend interface.
    /// @param [in] createResourceDescription           A pointer to a <c><i>FfxCreateResourceDescription</i></c>.
    /// @param [in] effectContextId                     The context space to be used for the effect in question.
    /// @param [out] outResource                        A pointer to a <c><i>FfxResource</i></c> object.
    ///
    /// @retval
    /// FFX_OK                                          The operation completed successfully.
    /// @retval
    /// Anything else                                   The operation failed.
    ///
    /// @ingroup FfxInterface
    typedef FfxErrorCode (*FfxCreateResourceFunc)(FfxInterface* backendInterface,
                                                  const FfxCreateResourceDescription* createResourceDescription,
                                                  FfxUInt32 effectContextId, FfxResourceInternal* outResource);

    /// Register a resource in the backend for the current frame.
    ///
    /// Since the FfxInterface and the backends are not aware how many different
    /// resources will get passed in over time, it's not safe
    /// to register all resources simultaneously in the backend.
    /// Also passed resources may not be valid after the dispatch call.
    /// As a result it's safest to register them as FfxResourceInternal
    /// and clear them at the end of the dispatch call.
    ///
    /// @param [in] backendInterface                    A pointer to the backend interface.
    /// @param [in] inResource                          A pointer to a <c><i>FfxResource</i></c>.
    /// @param [in] effectContextId                     The context space to be used for the effect in question.
    /// @param [out] outResource                        A pointer to a <c><i>FfxResourceInternal</i></c> object.
    ///
    /// @retval
    /// FFX_OK                                          The operation completed successfully.
    /// @retval
    /// Anything else                                   The operation failed.
    ///
    /// @ingroup FfxInterface
    typedef FfxErrorCode (*FfxRegisterResourceFunc)(FfxInterface* backendInterface, const FfxResource* inResource,
                                                    FfxUInt32 effectContextId, FfxResourceInternal* outResource);

    /// Get an FfxResource from an FfxResourceInternal resource.
    ///
    /// At times it is necessary to create an FfxResource representation
    /// of an internally created resource in order to register it with a
    /// child effect context. This function sets up the FfxResource needed
    /// to register.
    ///
    /// @param [in] backendInterface                    A pointer to the backend interface.
    /// @param [in] resource                            The <c><i>FfxResourceInternal</i></c> for which to setup an
    /// FfxResource.
    ///
    /// @returns
    /// An FfxResource built from the internal resource
    ///
    /// @ingroup FfxInterface
    typedef FfxResource (*FfxGetResourceFunc)(FfxInterface* backendInterface, FfxResourceInternal resource);

    /// Unregister all temporary FfxResourceInternal from the backend.
    ///
    /// Unregister FfxResourceInternal referencing resources passed to
    /// a function as a parameter.
    ///
    /// @param [in] backendInterface                    A pointer to the backend interface.
    /// @param [in] commandList                         A pointer to a <c><i>FfxCommandList</i></c> structure.
    /// @param [in] effectContextId                     The context space to be used for the effect in question.
    ///
    /// @retval
    /// FFX_OK                                          The operation completed successfully.
    /// @retval
    /// Anything else                                   The operation failed.
    ///
    /// @ingroup FfxInterface
    typedef FfxErrorCode (*FfxUnregisterResourcesFunc)(FfxInterface* backendInterface, FfxCommandList commandList,
                                                       FfxUInt32 effectContextId);

    /// Retrieve a <c><i>FfxResourceDescription</i></c> matching a
    /// <c><i>FfxResource</i></c> structure.
    ///
    /// @param [in] backendInterface                    A pointer to the backend interface.
    /// @param [in] resource                            A pointer to a <c><i>FfxResource</i></c> object.
    ///
    /// @returns
    /// A description of the resource.
    ///
    /// @ingroup FfxInterface
    typedef FfxResourceDescription (*FfxGetResourceDescriptionFunc)(FfxInterface* backendInterface,
                                                                    FfxResourceInternal resource);

    /// Destroy a resource
    ///
    /// This callback is intended for the backend to release an internal resource.
    ///
    /// @param [in] backendInterface                    A pointer to the backend interface.
    /// @param [in] resource                            A pointer to a <c><i>FfxResource</i></c> object.
    /// @param [in] effectContextId                     The context space to be used for the effect in question.
    ///
    /// @retval
    /// FFX_OK                                          The operation completed successfully.
    /// @retval
    /// Anything else                                   The operation failed.
    ///
    /// @ingroup FfxInterface
    typedef FfxErrorCode (*FfxDestroyResourceFunc)(FfxInterface* backendInterface, FfxResourceInternal resource,
                                                   FfxUInt32 effectContextId);

    /// Create a render pipeline.
    ///
    /// A rendering pipeline contains the shader as well as resource bindpoints
    /// and samplers.
    ///
    /// @param [in] backendInterface                    A pointer to the backend interface.
    /// @param [in] pass                                The identifier for the pass.
    /// @param [in] pipelineDescription                 A pointer to a <c><i>FfxPipelineDescription</i></c> describing
    /// the pipeline to be created.
    /// @param [in] effectContextId                     The context space to be used for the effect in question.
    /// @param [out] outPipeline                        A pointer to a <c><i>FfxPipelineState</i></c> structure which
    /// should be populated.
    ///
    /// @retval
    /// FFX_OK                                          The operation completed successfully.
    /// @retval
    /// Anything else                                   The operation failed.
    ///
    /// @ingroup FfxInterface
    typedef FfxErrorCode (*FfxCreatePipelineFunc)(FfxInterface* backendInterface, FfxEffect effect, FfxPass pass,
                                                  uint32_t permutationOptions,
                                                  const FfxPipelineDescription* pipelineDescription,
                                                  FfxUInt32 effectContextId, FfxPipelineState* outPipeline);

    typedef FfxErrorCode (*FfxGetPermutationBlobByIndexFunc)(FfxEffect effectId, FfxPass passId, FfxBindStage bindStage,
                                                             uint32_t permutationOptions, FfxShaderBlob* outBlob);

    /// Destroy a render pipeline.
    ///
    /// @param [in] backendInterface                    A pointer to the backend interface.
    /// @param [in] effectContextId                     The context space to be used for the effect in question.
    /// @param [out] pipeline                           A pointer to a <c><i>FfxPipelineState</i></c> structure which
    /// should be released.
    /// @param [in] effectContextId                     The context space to be used for the effect in question.
    ///
    /// @retval
    /// FFX_OK                                          The operation completed successfully.
    /// @retval
    /// Anything else                                   The operation failed.
    ///
    /// @ingroup FfxInterface
    typedef FfxErrorCode (*FfxDestroyPipelineFunc)(FfxInterface* backendInterface, FfxPipelineState* pipeline,
                                                   FfxUInt32 effectContextId);

    /// Schedule a render job to be executed on the next call of
    /// <c><i>FfxExecuteGpuJobsFunc</i></c>.
    ///
    /// Render jobs can perform one of three different tasks: clear, copy or
    /// compute dispatches.
    ///
    /// @param [in] backendInterface                    A pointer to the backend interface.
    /// @param [in] job                                 A pointer to a <c><i>FfxGpuJobDescription</i></c> structure.
    ///
    /// @retval
    /// FFX_OK                                          The operation completed successfully.
    /// @retval
    /// Anything else                                   The operation failed.
    ///
    /// @ingroup FfxInterface
    typedef FfxErrorCode (*FfxScheduleGpuJobFunc)(FfxInterface* backendInterface, const FfxGpuJobDescription* job);

    /// Execute scheduled render jobs on the <c><i>comandList</i></c> provided.
    ///
    /// The recording of the graphics API commands should take place in this
    /// callback function, the render jobs which were previously enqueued (via
    /// callbacks made to <c><i>FfxScheduleGpuJobFunc</i></c>) should be
    /// processed in the order they were received. Advanced users might choose to
    /// reorder the rendering jobs, but should do so with care to respect the
    /// resource dependencies.
    ///
    /// Depending on the precise contents of <c><i>FfxDispatchDescription</i></c> a
    /// different number of render jobs might have previously been enqueued (for
    /// example if sharpening is toggled on and off).
    ///
    /// @param [in] backendInterface                    A pointer to the backend interface.
    /// @param [in] commandList                         A pointer to a <c><i>FfxCommandList</i></c> structure.
    ///
    /// @retval
    /// FFX_OK                                          The operation completed successfully.
    /// @retval
    /// Anything else                                   The operation failed.
    ///
    /// @ingroup FfxInterface
    typedef FfxErrorCode (*FfxExecuteGpuJobsFunc)(FfxInterface* backendInterface, FfxCommandList commandList);

    typedef FfxErrorCode (*FfxPresentCallbackFunc)(const FfxPresentCallbackDescription* params);
    typedef FfxErrorCode (*FfxFrameGenerationDispatchFunc)(const FfxFrameGenerationDispatchDescription* params);

    typedef struct FfxFrameGenerationConfig
    {
        FfxSwapchain swapChain;
        FfxPresentCallbackFunc presentCallback;
        FfxFrameGenerationDispatchFunc frameGenerationCallback;
        bool frameGenerationEnabled;
        bool allowAsyncWorkloads;
        FfxResource HUDLessColor;
        FfxUInt32 flags;
        bool onlyPresentInterpolated;
    } FfxFrameGenerationConfig;

    typedef FfxErrorCode (*ffxSwapChainConfigureFrameGenerationFunc)(FfxFrameGenerationConfig const* config);

    /// A structure encapsulating the interface between the core implementation of
    /// the FfxInterface and any graphics API that it should ultimately call.
    ///
    /// This set of functions serves as an abstraction layer between FfxInterfae and the
    /// API used to implement it. While the FidelityFX SDK ships with backends for DirectX12 and
    /// Vulkan, it is possible to implement your own backend for other platforms
    /// which sit on top of your engine's own abstraction layer. For details on the
    /// expectations of what each function should do you should refer the
    /// description of the following function pointer types:
    ///
    ///     <c><i>FfxCreateDeviceFunc</i></c>
    ///     <c><i>FfxGetDeviceCapabilitiesFunc</i></c>
    ///     <c><i>FfxDestroyDeviceFunc</i></c>
    ///     <c><i>FfxCreateResourceFunc</i></c>
    ///     <c><i>FfxRegisterResourceFunc</i></c>
    ///     <c><i>FfxGetResourceFunc</i></c>
    ///     <c><i>FfxUnregisterResourcesFunc</i></c>
    ///     <c><i>FfxGetResourceDescriptionFunc</i></c>
    ///     <c><i>FfxDestroyResourceFunc</i></c>
    ///     <c><i>FfxCreatePipelineFunc</i></c>
    ///     <c><i>FfxDestroyPipelineFunc</i></c>
    ///     <c><i>FfxScheduleGpuJobFunc</i></c>
    ///     <c><i>FfxExecuteGpuJobsFunc</i></c>
    ///
    /// Depending on the graphics API that is abstracted by the backend, it may be
    /// required that the backend is to some extent stateful. To ensure that
    /// applications retain full control to manage the memory used by the FidelityFX SDK, the
    /// <c><i>scratchBuffer</i></c> and <c><i>scratchBufferSize</i></c> fields are
    /// provided. A backend should provide a means of specifying how much scratch
    /// memory is required for its internal implementation (e.g: via a function
    /// or constant value). The application is then responsible for allocating that
    /// memory and providing it when setting up the SDK backend. Backends provided
    /// with the FidelityFX SDK do not perform dynamic memory allocations, and instead
    /// sub-allocate all memory from the scratch buffers provided.
    ///
    /// The <c><i>scratchBuffer</i></c> and <c><i>scratchBufferSize</i></c> fields
    /// should be populated according to the requirements of each backend. For
    /// example, if using the DirectX 12 backend you should call the
    /// <c><i>ffxGetScratchMemorySizeDX12</i></c> function. It is not required
    /// that custom backend implementations use a scratch buffer.
    ///
    /// Any functional addition to this interface mandates a version
    /// bump to ensure full functionality across effects and backends.
    ///
    /// @ingroup FfxInterface
    typedef struct FfxInterface
    {

        FfxGetSDKVersionFunc fpGetSDKVersion; ///< A callback function to query the SDK version.
        FfxCreateBackendContextFunc
            fpCreateBackendContext; ///< A callback function to create and initialize the backend context.
        FfxGetDeviceCapabilitiesFunc fpGetDeviceCapabilities; ///< A callback function to query device capabilities.
        FfxDestroyBackendContextFunc fpDestroyBackendContext; ///< A callback function to destroy the backend context.
                                                              ///< This also dereferences the device.
        FfxCreateResourceFunc fpCreateResource;               ///< A callback function to create a resource.
        FfxRegisterResourceFunc fpRegisterResource;           ///< A callback function to register an external resource.
        FfxGetResourceFunc
            fpGetResource; ///< A callback function to convert an internal resource to external resource type
        FfxUnregisterResourcesFunc fpUnregisterResources; ///< A callback function to unregister external resource.
        FfxGetResourceDescriptionFunc
            fpGetResourceDescription;             ///< A callback function to retrieve a resource description.
        FfxDestroyResourceFunc fpDestroyResource; ///< A callback function to destroy a resource.
        FfxCreatePipelineFunc fpCreatePipeline;   ///< A callback function to create a render or compute pipeline.
        FfxGetPermutationBlobByIndexFunc fpGetPermutationBlobByIndex;
        FfxDestroyPipelineFunc fpDestroyPipeline; ///< A callback function to destroy a render or compute pipeline.
        FfxScheduleGpuJobFunc fpScheduleGpuJob;   ///< A callback function to schedule a render job.
        FfxExecuteGpuJobsFunc fpExecuteGpuJobs;   ///< A callback function to execute all queued render jobs.
        ffxSwapChainConfigureFrameGenerationFunc
            fpSwapChainConfigureFrameGeneration; ///< A callback function to configure swap chain present callback.

        void* scratchBuffer;      ///< A preallocated buffer for memory utilized internally by the backend.
        size_t scratchBufferSize; ///< Size of the buffer pointed to by <c><i>scratchBuffer</i></c>.
        FfxDevice device;         ///< A backend specific device

    } FfxInterface;

#if defined(__cplusplus)
}
#endif // #if defined(__cplusplus)

} // namespace Fsr31