/*
 Copyright (C) 2010 erik

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software Foundation,
 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "CompilerTechniqueProvider.h"
#include "Shader.h"
#include "OnePixelMaterialGenerator.h"

#include "components/ogre/ShaderManager.h"

#include "services/EmberServices.h"
#include "services/config/ConfigService.h"

#include <OgreRoot.h>
#include <OgreGpuProgramManager.h>
#include <OgreTextureManager.h>


namespace Ember::OgreView::Terrain::Techniques {
CompilerTechniqueProvider::CompilerTechniqueProvider(ShaderManager& shaderManager, Ogre::SceneManager& sceneManager) :
		mShaderManager(shaderManager),
		mSceneManager(sceneManager),
		mOnePixelMaterialGenerator(std::make_unique<OnePixelMaterialGenerator>()) {
	//Our shaders use the one pixel normal texture whenever there's no existing normal map, so we need to create it.
	const std::string onePixelMaterialName("dynamic/onepixel");
	if (Ogre::TextureManager::getSingleton().resourceExists(onePixelMaterialName, Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME)) {
		logger->warn("Texture '{}' already existed when CompilerTechniqueProvider was created; this should not be the case.", onePixelMaterialName);
	} else {
		Ogre::TextureManager::getSingleton().createManual(onePixelMaterialName,
														  Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME,
														  Ogre::TEX_TYPE_2D,
														  1,
														  1,
														  1,
														  Ogre::PF_R8G8B8,
														  Ogre::TU_DEFAULT,
														  mOnePixelMaterialGenerator.get());
	}
}

CompilerTechniqueProvider::~CompilerTechniqueProvider() {
	Ogre::TextureManager::getSingleton().remove("dynamic/onepixel", Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME);
}

std::unique_ptr<TerrainPageSurfaceCompilerTechnique> CompilerTechniqueProvider::createTechnique(
		const TerrainPageGeometryPtr& geometry,
		const SurfaceLayerStore& terrainPageSurfaces) const {
	std::string preferredTech;
	if (ConfigService::getSingleton().itemExists("terrain", "preferredtechnique")) {
		preferredTech = static_cast<std::string>(ConfigService::getSingleton().getValue("terrain", "preferredtechnique"));
	}

	ShaderManager::GraphicsLevel graphicsLevel = mShaderManager.getGraphicsLevel();

	bool useNormalMapping = (preferredTech == "ShaderNormalMapped");
	if ((useNormalMapping || preferredTech == "Shader") && graphicsLevel >= ShaderManager::LEVEL_HIGH) {
		//Use shader tech with shadows
		return std::make_unique<Techniques::Shader>(true, geometry, terrainPageSurfaces, mSceneManager, useNormalMapping);
	}
	//Use shader tech without shadows
	return std::make_unique<Techniques::Shader>(false, geometry, terrainPageSurfaces, mSceneManager, false);
}

}



