#include <windows.h>
#include <sal.h>
#include "nvapi.h"
#include "NvApiDriverSettings.h"

// Force NVidia Optimus to use NVidia GPU on drivers 302 and later.
// http://developer.download.nvidia.com/devzone/devcenter/gamegraphics/files/OptimusRenderingPolicies.pdf
extern "C" {
    _declspec(dllexport) DWORD NvOptimusEnablement = 0x00000001;
}

namespace Lair
{

    // When NvOptimusEnablement fails, we both link NVApi (also supposed to enable it) 
    // and specifically enable it in the driver settings.
    class nVidia
    {
    public:
        nVidia( void )
        {
            NvAPI_Status status;
            // (0) Initialize NVAPI. This must be done first of all
            status = NvAPI_Initialize();
            if (status != NVAPI_OK) 
            {
                return;
            }
            // (1) Create the session handle to access driver settings
            NvDRSSessionHandle hSession = 0;
            status = NvAPI_DRS_CreateSession(&hSession);
            if (status != NVAPI_OK) 
            {
                return;
            }
            // (2) load all the system settings into the session
            status = NvAPI_DRS_LoadSettings(hSession);
            if (status != NVAPI_OK) 
            {
                return;
            }
            // (3) Obtain the Base profile. Any setting needs to be inside
            // a profile, putting a setting on the Base Profile enforces it
            // for all the processes on the system
            NvDRSProfileHandle hProfile = 0;
            status = NvAPI_DRS_GetBaseProfile(hSession, &hProfile);
            if (status != NVAPI_OK) 
            {
                return;
            }
            NVDRS_SETTING drsSetting1 = {0};
            drsSetting1.version = NVDRS_SETTING_VER;
            drsSetting1.settingId = SHIM_MCCOMPAT_ID;
            drsSetting1.settingType = NVDRS_DWORD_TYPE;
            NVDRS_SETTING drsSetting2 = {0};
            drsSetting2.version = NVDRS_SETTING_VER;
            drsSetting2.settingId = SHIM_RENDERING_MODE_ID;
            drsSetting2.settingType = NVDRS_DWORD_TYPE;
            NVDRS_SETTING drsSetting3 = {0};
            drsSetting3.version = NVDRS_SETTING_VER;
            drsSetting3.settingId = SHIM_RENDERING_OPTIONS_ID;
            drsSetting3.settingType = NVDRS_DWORD_TYPE;
            drsSetting1.u32CurrentValue = SHIM_MCCOMPAT_ENABLE;
            drsSetting2.u32CurrentValue = SHIM_RENDERING_MODE_ENABLE;
            drsSetting3.u32CurrentValue = SHIM_RENDERING_OPTIONS_DEFAULT_RENDERING_MODE;
            status = NvAPI_DRS_SetSetting(hSession, hProfile, &drsSetting1);
            if (status != NVAPI_OK) 
            {
                return;
            }
            status = NvAPI_DRS_SetSetting(hSession, hProfile, &drsSetting2);
            if (status != NVAPI_OK) 
            {
                return;
            }
            status = NvAPI_DRS_SetSetting(hSession, hProfile, &drsSetting3);
            if (status != NVAPI_OK) 
            {
                return;
            }
            // (5) Now we apply (or save) our changes to the system
            status = NvAPI_DRS_SaveSettings(hSession);
            if (status != NVAPI_OK) 
            {
                return;
            }
            // (6) We clean up. This is analogous to doing a free()
            NvAPI_DRS_DestroySession(hSession);
            hSession = 0;
            NvAPI_Unload();
        }
        ~nVidia()
        {
        }
    };

    // Global, so this gets instantiated with no other outside code.
    nVidia gNvApi;

}