/*
* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
* its licensors.
*
* For complete copyright and license terms please see the LICENSE at the root of this
* distribution (the "License"). All use of this software is governed by the License,
* or, if provided, by the license below or the license accompanying this file. Do not
* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
*
*/

#include <Atom/RPI.Public/Shader/Metrics/ShaderMetricsSystem.h>
#include <Atom/RPI.Public/Shader/Metrics/ShaderMetrics.h>
#include <Atom/RPI.Reflect/Shader/ShaderAsset.h>


#include <AzCore/Interface/Interface.h>
#include <AzCore/IO/SystemFile.h>
#include <AzCore/Utils//Utils.h>

#include <AtomCore/Serialization/Json/JsonUtils.h>

#include <AzFramework/IO/LocalFileIO.h>

namespace AZ
{
    namespace RPI
    {
        AZStd::string GetMetricsFilePath()
        {
            char shaderMetricPath[AZ_MAX_PATH_LEN];
            AZ::Utils::GetExecutableDirectory(shaderMetricPath, AZ_MAX_PATH_LEN);
            return AZStd::string(shaderMetricPath) + AZ_CORRECT_FILESYSTEM_SEPARATOR_STRING + "ShaderMetrics.json";
        }

        ShaderMetricsSystemInterface* ShaderMetricsSystemInterface::Get()
        {
            return Interface<ShaderMetricsSystemInterface>::Get();
        }

        void ShaderMetricsSystem::Reflect(ReflectContext* context)
        {
            ShaderVariantRequest::Reflect(context);
            ShaderVariantMetrics::Reflect(context);
        }

        void ShaderMetricsSystem::Init()
        {
            // Register the system to the interface.
            Interface<ShaderMetricsSystemInterface>::Register(this);

            ReadLog();
        }

        void ShaderMetricsSystem::Shutdown()
        {
            WriteLog();

            // Unregister the system to the interface.
            Interface<ShaderMetricsSystemInterface>::Unregister(this);
        }

        void ShaderMetricsSystem::Reset()
        {
            m_metrics.m_requests.clear();
        }

        void ShaderMetricsSystem::ReadLog()
        {
            const AZStd::string metricsFilePath = GetMetricsFilePath();

            if (AZ::IO::LocalFileIO::GetInstance()->Exists(metricsFilePath.c_str()))
            {
                auto loadResult = AZ::JsonSerializationUtils::LoadObjectFromFile<ShaderVariantMetrics>(m_metrics, metricsFilePath.c_str());

                if (!loadResult.IsSuccess())
                {
                    AZ_Error("ShaderMetrics", false, "Unable to read %s file", metricsFilePath.c_str());
                    return;
                }
            }
        }

        void ShaderMetricsSystem::WriteLog()
        {
            const AZStd::string metricsFilePath = GetMetricsFilePath();

            auto saveResult = AZ::JsonSerializationUtils::SaveObjectToFile<ShaderVariantMetrics>(&m_metrics, metricsFilePath.c_str());

            if (!saveResult.IsSuccess())
            {
                AZ_Error("ShaderMetrics", false, "Unable to write %s file", metricsFilePath.c_str());
                return;
            }
        }

        bool ShaderMetricsSystem::IsEnabled() const
        {
            return m_isEnabled;
        }

        void ShaderMetricsSystem::SetEnabled(bool value)
        {
            m_isEnabled = value;
        }

        const ShaderVariantMetrics& ShaderMetricsSystem::GetMetrics() const
        {
            return m_metrics;
        }

        void ShaderMetricsSystem::RequestShaderVariant(const ShaderAsset* shader, const ShaderVariantId& shaderVariantId, const ShaderVariantSearchResult& result)
        {
            if (!m_isEnabled)
            {
                return;
            }

            AZ_PROFILE_FUNCTION(Debug::ProfileCategory::AzRender);

            AZStd::lock_guard<AZStd::mutex> lock(m_metricsMutex);

            // Log a new request
            ShaderVariantRequest newRequest;
            newRequest.m_shaderId = shader->GetId();
            newRequest.m_shaderName = shader->GetName();
            newRequest.m_shaderVariantId = shaderVariantId;
            newRequest.m_shaderVariantStableId = result.GetStableId();
            newRequest.m_dynamicOptionCount = result.GetDynamicOptionCount();
            newRequest.m_requestCount = 1;

            // Check if the specific shader variant was already requested to increase its request count
            for (auto request = m_metrics.m_requests.begin(); request != m_metrics.m_requests.end(); ++request)
            {
                if (request->m_shaderId == newRequest.m_shaderId &&
                    request->m_shaderVariantId == newRequest.m_shaderVariantId)
                {
                    request->m_requestCount++;
                    return;
                }
            }

            // Otherwise, add a new request
            m_metrics.m_requests.push_back(newRequest);
        }

    }; // namespace RPI
}; // namespace AZ