#pragma once

/* <editor-fold desc="MIT License">

Copyright(c) 2022 Robert Osfield

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.

</editor-fold> */

#include <vsg/app/CompileTraversal.h>
#include <vsg/threading/OperationQueue.h>

namespace vsg
{

    // forward declare
    class RecordAndSubmitTask;
    class Viewer;

    /// CompileResult struct encapsulates the results of compile traversal.
    /// Used to help guide further operations done with the compiled subgraph.
    struct VSG_DECLSPEC CompileResult
    {
        int result = VK_INCOMPLETE;
        std::string message;
        Slots maxSlots;
        bool containsPagedLOD = false;
        ResourceRequirements::Views views;
        DynamicData dynamicData;

        explicit operator bool() const noexcept { return result == VK_SUCCESS; }

        void reset();
        void add(const CompileResult& cr);
        bool requiresViewerUpdate(const Viewer* viewer = nullptr) const;
    };

    /// ResourceScavenger provides a mechanism for releasing and reusing unused resources when allocation of required GPU memory fails.
    class VSG_DECLSPEC ResourceScavenger : public Inherit<Object, ResourceScavenger>
    {
    public:
        explicit ResourceScavenger(ref_ptr<DatabasePager> in_databasePager);

        virtual bool scavenge(ResourceRequirements& resourceRequirements);

        uint64_t sleepDuration = 16 * 5; /// milliseconds sleep to make after adjusting load targets to allow other threads to free up space, default to 5 frames at 60fps
        observer_ptr<DatabasePager> databasePager;
    };

    /// CompileManager is a helper class that compiles subgraphs for the windows/framebuffers associated with the CompileManager.
    class VSG_DECLSPEC CompileManager : public Inherit<Object, CompileManager>
    {
    public:
        CompileManager(Viewer& viewer, ref_ptr<ResourceHints> hints);

        /// add a compile Context for device
        void add(ref_ptr<Device> device, const ResourceRequirements& resourceRequirements = {});

        /// add a compile Context for Window and associated viewport.
        void add(Window& window, ref_ptr<ViewportState> viewport = {}, const ResourceRequirements& resourceRequirements = {});

        /// add a compile Context for View
        void add(Window& window, ref_ptr<View> view, const ResourceRequirements& resourceRequirements = {});

        /// add a compile Context for Framebuffer and associated View
        void add(Framebuffer& framebuffer, ref_ptr<View> view, const ResourceRequirements& resourceRequirements = {});

        /// add a compile Context for all the Views assigned to a Viewer
        void add(const Viewer& viewer, const ResourceRequirements& resourceRequirements = {});

        /// assign Instrumentation to all CompileTraversal and their associated Context
        void assignInstrumentation(ref_ptr<Instrumentation> in_instrumentation);

        using ContextSelectionFunction = std::function<bool(vsg::Context&)>;

        /// compile object
        CompileResult compile(ref_ptr<Object> object, ContextSelectionFunction contextSelection = {});

        /// compile all the command graphs in a task
        CompileResult compileTask(ref_ptr<RecordAndSubmitTask> task, const ResourceRequirements& resourceRequirements = {});

        /// mechanism for releasing and reusing used resources
        ref_ptr<ResourceScavenger> resourceScavenger;

        std::atomic_uint successfulCompileCount{0};
        std::atomic_uint failedCompileCount{0};

    protected:
        ~CompileManager() override;

        using CompileTraversals = ThreadSafeQueue<ref_ptr<CompileTraversal>>;
        size_t numCompileTraversals = 0;
        ref_ptr<CompileTraversals> compileTraversals;

        CompileTraversals::container_type takeCompileTraversals(size_t count);
    };
    VSG_type_name(vsg::CompileManager);

} // namespace vsg
