/* Copyright (C) 2023 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. 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.
 *
 * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Sky settings and texture management
 */

#ifndef INCLUDED_SKYMANAGER
#define INCLUDED_SKYMANAGER

#include "graphics/Texture.h"
#include "renderer/backend/IDeviceCommandContext.h"
#include "renderer/backend/IShaderProgram.h"
#include "renderer/backend/ITexture.h"
#include "renderer/VertexArray.h"

#include <memory>
#include <vector>

/**
 * Class SkyManager: Maintain sky settings and textures, and render the sky.
 */
class SkyManager
{
public:
	SkyManager();

	/**
	 * Render the sky.
	 */
	void RenderSky(
		Renderer::Backend::IDeviceCommandContext* deviceCommandContext);

	/**
	 * Return the currently selected sky set name.
	 */
	inline const CStrW& GetSkySet() const
	{
		return m_SkySet;
	}

	Renderer::Backend::ITexture* GetSkyCube();

	/**
	 * Set the sky set name.
	 */
	void SetSkySet(const CStrW& name);

	/**
	 * Return a sorted list of available sky sets, in a form suitable
	 * for passing to SetSkySet.
	 */
	std::vector<CStrW> GetSkySets() const;

	bool IsSkyVisible() const
	{
		return m_SkyVisible;
	}

	void SetSkyVisible(bool value)
	{
		m_SkyVisible = value;
	}

	/**
	 * Load all sky textures from files and upload to GPU.
	 */
	void LoadAndUploadSkyTexturesIfNeeded(
		Renderer::Backend::IDeviceCommandContext* deviceCommandContext);

private:
	void CreateSkyCube();

	bool m_SkyVisible = true;

	/// Name of current skyset (a directory within art/textures/skies)
	CStrW m_SkySet;

	// Indices into m_SkyTexture
	enum
	{
		FRONT,
		BACK,
		RIGHT,
		LEFT,
		TOP,
		NUMBER_OF_TEXTURES
	};

	// Sky textures
	CTexturePtr m_SkyTexture[NUMBER_OF_TEXTURES];
	CTexturePtr m_SkyTextureCube;

	VertexArray m_VertexArray;
	VertexArray::Attribute m_AttributePosition;
	VertexArray::Attribute m_AttributeUV;

	Renderer::Backend::IVertexInputLayout* m_VertexInputLayout = nullptr;
};


#endif // INCLUDED_SKYMANAGER