/***************************************************************************
 *   Copyright (C) 2005-2019 by the FIFE team                              *
 *   http://www.fifengine.net                                              *
 *   This file is part of FIFE.                                            *
 *                                                                         *
 *   FIFE is free software; you can redistribute it and/or                 *
 *   modify it under the terms of the GNU Lesser General Public            *
 *   License as published by the Free Software Foundation; either          *
 *   version 2.1 of the License, or (at your option) any later version.    *
 *                                                                         *
 *   This library 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     *
 *   Lesser General Public License for more details.                       *
 *                                                                         *
 *   You should have received a copy of the GNU Lesser General Public      *
 *   License along with this library; if not, write to the                 *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA          *
 ***************************************************************************/

#ifndef FIFE_VIDEO_RENDERBACKEND_H
#define FIFE_VIDEO_RENDERBACKEND_H

// Standard C++ library includes
#include <string>
#include <vector>

// Platform specific includes
#include "util/base/fife_stdint.h"

// 3rd party library includes
#include <SDL.h>
#include <SDL_video.h>

// FIFE includes
// These includes are split up in two parts, separated by one empty line
// First block: files included from the FIFE root src directory
// Second block: files included from the same folder
#include "util/base/singleton.h"
#include "util/structures/point.h"
#include "util/structures/rect.h"
#include "video/devicecaps.h"

#include "image.h"
#include "color.h"

#ifdef HAVE_OPENGL
#include "video/opengl/fife_opengl.h"
#endif

namespace FIFE {

	class Image;

#ifdef HAVE_OPENGL
	enum GLConstants {
		KEEP = GL_KEEP,
		ZERO = GL_ZERO,
		REPLACE = GL_REPLACE,
		INCR = GL_INCR,
		DECR = GL_DECR,
		INVERT = GL_INVERT,
		NEVER = GL_NEVER,
		LESS = GL_LESS,
		LEQUAL = GL_LEQUAL,
		GREATER = GL_GREATER,
		GEQUAL = GL_GEQUAL,
		EQUAL = GL_EQUAL,
		NOTEQUAL = GL_NOTEQUAL,
		ALWAYS = GL_ALWAYS
	};
#else
	enum GLConstants {
		KEEP = 0,
		ZERO,
		REPLACE,
		INCR,
		DECR,
		INVERT,
		NEVER,
		LESS,
		LEQUAL,
		GREATER,
		GEQUAL,
		EQUAL,
		NOTEQUAL,
		ALWAYS
	};
#endif
	
	enum OverlayType {
		OVERLAY_TYPE_NONE = 0,
		OVERLAY_TYPE_COLOR = 1,
		OVERLAY_TYPE_COLOR_AND_TEXTURE = 2,
		OVERLAY_TYPE_TEXTURES_AND_FACTOR = 3
	};

	enum TextureFiltering {
		TEXTURE_FILTER_NONE = 0,
		TEXTURE_FILTER_BILINEAR = 1,
		TEXTURE_FILTER_TRILINEAR = 2,
		TEXTURE_FILTER_ANISOTROPIC = 3
	};

	enum RenderDataType {
		RENDER_DATA_WITHOUT_Z = 0,
		RENDER_DATA_TEXTURE_Z = 1,
		RENDER_DATA_TEXCOLOR_Z = 2,
		RENDER_DATA_MULTITEXTURE_Z = 3
	};

	class GuiVertex {
	public:
		DoublePoint position;
		Color color;
		DoublePoint texCoords;
	};

	 /** Abstract interface for all the renderbackends. */
	class RenderBackend: public DynamicSingleton<RenderBackend> {
	public:
		/** Constructor.
		 * @param colorkey The colorkey to use.
		 */
		RenderBackend(const SDL_Color& colorkey);

		/** Destructor.
		 */
		virtual ~RenderBackend();

		/** The name of the renderbackend.
		 * @return The name of this renderbackend.
		 */
		virtual const std::string& getName() const = 0;

		/** Called when a new frame starts.
		 */
		virtual void startFrame();

		/** Called when a frame is finished and ready to be displayed.
		 */
		virtual void endFrame();

		/** Initializes the backend.
		 */
		virtual void init(const std::string& driver) = 0;

		/** Forces a clear of the backbuffer
		 */
		virtual void clearBackBuffer() = 0;

		/** Initializes the light.
		 */
		virtual void setLightingModel(uint32_t lighting) = 0;

		/** Gets the current light model.
		 */
		virtual uint32_t getLightingModel() const = 0;

		/** Set colors for lighting
		 */
		virtual void setLighting(float red, float green, float blue) = 0;

		/** Reset lighting with default values.
		 */
		virtual void resetLighting() = 0;

		/** Reset stencil buffer with given value.
		 */
		virtual void resetStencilBuffer(uint8_t buffer) = 0;

		/** Change the Blendingmodel.
		 */
		virtual void changeBlending(int32_t scr, int32_t dst) = 0;

		/** Performs cleanup actions.
		 */
		void deinit();

		/** Creates the mainscreen (the display window).
		 * @param mode The ScreenMode to use.  @see FIFE::ScreenMode.
		 * @param title The window title to use.
		 * @param icon The window icon to use.
		 */
		virtual void createMainScreen(const ScreenMode& mode, const std::string& title, const std::string& icon) = 0;

		/** Sets the mainscreen display mode.
		 * @param mode The ScreenMode to change the display to.  @see FIFE::ScreenMode.
		 */
		virtual void setScreenMode(const ScreenMode& mode) = 0;

		virtual Image* createImage(IResourceLoader* loader = 0) = 0;
		virtual Image* createImage(const std::string& name, IResourceLoader* loader = 0) = 0;

		/** Creates an Image suitable for this renderbackend.
		 * @param data Pointer to the imagedata (needs to be in RGBA, 8 bits per channel).
		 * @param width Width of the image.
		 * @param height Height of the image.
		 * @return The new Image.
		 */
		virtual Image* createImage(const uint8_t* data, uint32_t width, uint32_t height) = 0;
		virtual Image* createImage(const std::string& name, const uint8_t* data, uint32_t width, uint32_t height) = 0;

		/** Helper function to create images from SDL_Surfaces.
		 * Takes ownership over the surface.
		 * @param surface The surface to convert.
		 * @return The new Image.
		 */
		virtual Image* createImage(SDL_Surface* surface) = 0;
		virtual Image* createImage(const std::string& name, SDL_Surface* surface) = 0;

		/** Render the Vertex Arrays, only for primitives (points, lines,...)
		 */
		virtual void renderVertexArrays() = 0;

		/** Add the Image data to the array
		 */
		virtual void addImageToArray(uint32_t id, const Rect& rec, float const* st, uint8_t alpha, uint8_t const* rgba) = 0;

		/** Dirty helper function to change the render infos
		 */
		virtual void changeRenderInfos(RenderDataType type, uint16_t elements, int32_t src, int32_t dst, bool light, bool stentest, uint8_t stenref, GLConstants stenop, GLConstants stenfunc, OverlayType otype = OVERLAY_TYPE_NONE) = 0;

		/** Creates a Screenshot and saves it to a file.
		 */
		virtual void captureScreen(const std::string& filename) = 0;

		/** Creates a Screenshot with the given size(w,h) and saves it to a file.
		 */
		virtual void captureScreen(const std::string& filename, uint32_t width, uint32_t height) = 0;

		SDL_Window* getWindow() {return m_window; }

		/** Get current screen mode
		 * @return The current screen mode
		 */
		const ScreenMode& getCurrentScreenMode() const;

		uint32_t getWidth() const;
		uint32_t getHeight() const;
		uint32_t getScreenWidth() const { return getWidth(); }
		uint32_t getScreenHeight() const { return getHeight(); }
		const Rect& getArea() const;

		/** Pushes clip area to clip stack
		 *  Clip areas define which area is drawn on screen. Usable e.g. with viewports
		 *  note that previous items in stack do not affect the latest area pushed
		 */
		void pushClipArea(const Rect& cliparea, bool clear=true);

		/** Pops clip area from clip stack
		 *  @see pushClipArea
		 */
		void popClipArea();

		/** Gets the current clip area
		 *  @see pushClipArea
		 */
		const Rect& getClipArea() const;

		/** Writes pixel to given position. Returns true, if pixel was written (not out of bounds)
		 */
		virtual bool putPixel(int32_t x, int32_t y, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws line between given points with given RGBA
		 */
		virtual void drawLine(const Point& p1, const Point& p2, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws line between given points with given RGBA and width.
		 */
		virtual void drawThickLine(const Point& p1, const Point& p2, uint8_t width, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws lines between given points with given RGBA and width.
		 */
		virtual void drawPolyLine(const std::vector<Point>& points, uint8_t width, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws bezier curve between given points with given RGBA and width.
		 */
		virtual void drawBezier(const std::vector<Point>& points, int32_t steps, uint8_t width, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws triangle between given points with given RGBA
		 */
		virtual void drawTriangle(const Point& p1, const Point& p2, const Point& p3, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws an axis parallel rectangle.
		 */
		virtual void drawRectangle(const Point& p, uint16_t w, uint16_t h, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws a filled axis parallel rectangle.
		 */
		virtual void fillRectangle(const Point& p, uint16_t w, uint16_t h, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255)  = 0;

		/** Draws quad between given points with given RGBA
		 */
		virtual void drawQuad(const Point& p1, const Point& p2, const Point& p3, const Point& p4,  uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws a quad that represents a vertex with given RGBA
		 */
		virtual void drawVertex(const Point& p, const uint8_t size, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws a circle.
		 */
		virtual void drawCircle(const Point& p, uint32_t radius, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws a filled circle.
		 */
		virtual void drawFillCircle(const Point& p, uint32_t radius, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws a circle segment.
		 * Note: The start angle must be less than the end angle. 0 angle is right side.
		 */
		virtual void drawCircleSegment(const Point& p, uint32_t radius, int32_t sangle, int32_t eangle, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws a filled circle segment. 0 angle is right side.
		 * Note: The start angle must be less than the end angle.
		 */
		virtual void drawFillCircleSegment(const Point& p, uint32_t radius, int32_t sangle, int32_t eangle, uint8_t r, uint8_t g, uint8_t b, uint8_t a = 255) = 0;

		/** Draws a light primitive that based on a triangle fan
		 */
		virtual void drawLightPrimitive(const Point& p, uint8_t intensity, float radius, int32_t subdivisions, float xstretch, float ystretch, uint8_t red, uint8_t green, uint8_t blue) = 0;

		/** Enables scissor test on the render backend.
		 */
		virtual void enableScissorTest() = 0;
		
		/** Disables scissor test on the render backend.
		 */
		virtual void disableScissorTest() = 0;

		/** Enable or disable the alpha 'optimizing' code
		 *
		 * @param enabled Optimize whether the image shall be analysed for 'fake' alpha images.
		 * Only implemented by and useful for the SDL backend at the moment.
		 */
		void setAlphaOptimizerEnabled(bool enabled){ m_isalphaoptimized = enabled; }

		/** @see setAlphaOptimizerEnabled
		 */
		bool isAlphaOptimizerEnabled() const { return m_isalphaoptimized; }

		/** Enables or disable compressing images by video driver.
		 * @remarks This is relevant for in OpenGL renderbackend
		 */
		void setImageCompressingEnabled(bool enabled) { m_compressimages = enabled; }

		/** @see setImageCompressingEnabled
		 */
		bool isImageCompressingEnabled() const { return m_compressimages; }

		/** Enables or disable the usage of the framebuffer, if available
		 */
		void setFramebufferEnabled(bool enabled) { m_useframebuffer = enabled; }

		/** @see setFramebufferEnabled
		 */
		bool isFramebufferEnabled() const { return m_useframebuffer; }

		/** Enables or disable the usage of npot, if available
		 */
		void setNPOTEnabled(bool enabled) { m_usenpot = enabled; }

		/** @see setNPOTEnabled
		 */
		bool isNPOTEnabled() const { return m_usenpot; }

		/** Sets the texture filtering method.
		 * Supports none, bilinear, trilinear and anisotropic filtering.
		 * Note! Works only for OpenGL backends.
		 * @see TextureFiltering
		 */
		void setTextureFiltering(TextureFiltering filter);

		/** @see setTextureFiltering
		 */
		TextureFiltering getTextureFiltering() const;

		/** Enables or disables the usage of mipmapping.
		 * Note! Works only for OpenGL backends.
		 */
		void setMipmappingEnabled(bool enabled);

		/** @see setMipmappingEnabled
		 */
		bool isMipmappingEnabled() const;
		
		/** Gets max antisotropy for antisotropic filtering.
		 */
		int32_t getMaxAnisotropy() const;

		/** Enables or disables monochrome rendering.
		 * Note! Works only for OpenGL backends.
		 */
		void setMonochromeEnabled(bool enabled);

		/** @see setMonochromeEnabled
		 */
		bool isMonochromeEnabled() const;

		/** Enables or disables depth buffer rendering.
		 * Note! Works only for OpenGL backend.
		 */
		void setDepthBufferEnabled(bool enabled);

		/** @see setMonochromeEnabled
		 */
		bool isDepthBufferEnabled() const;

		/** Sets the value for alpha test.
		 * Discards a fragment if its value is not greater. Only used if depth buffer is enabled. 
		 * Note! Works only for OpenGL backend.
		 */
		void setAlphaTestValue(float alpha);

		/** @see setAlphaValue
		 */
		float getAlphaTestValue() const;

		/** Sets whether to use the colorkey feature
		*/
		void setColorKeyEnabled(bool colorkeyenable);

		/** Gets whether the colorkey feature is in use
		*/
		bool isColorKeyEnabled() const;

		/** Sets the global colorkey to use for images
		 */
		void setColorKey(const SDL_Color& colorkey);

		/** Gets the global colorkey setting
		 */
		const SDL_Color& getColorKey() const;

		/** Set the background color
		 */
		void setBackgroundColor(uint8_t r, uint8_t g, uint8_t b);

		/** Reset the background color to black
		 */
		void resetBackgroundColor();

		/** Gets the current screen rgba format
		*/
		const SDL_PixelFormat& getPixelFormat() const;

		/** Sets whether to use VSync
		 */
		void setVSyncEnabled(bool vsync);

		/** Gets whether VSync is in use
		 */
		bool isVSyncEnabled() const;

		/** Sets whether to use the frame limiter
		 */
		void setFrameLimitEnabled(bool limited);

		/** Gets whether the frame limiter is in use
		 */
		bool isFrameLimitEnabled() const;

		/** Sets the frame limit
		 */
		void setFrameLimit(uint16_t framelimit);

		/** Gets the frame limit
		 */
		uint16_t getFrameLimit() const;

		/** Returns screen render surface
		 */
		 SDL_Surface* getScreenSurface();

		/** Returns currently attached render surface
		 */
		SDL_Surface* getRenderTargetSurface();

		/** Attaches given image as a new render surface
		 */
		virtual void attachRenderTarget(ImagePtr& img, bool discard) = 0;

		/** Detaches current render surface
		 */
		virtual void detachRenderTarget() = 0;
		
		/** Renders geometry required by gui.
		 */
		virtual void renderGuiGeometry(const std::vector<GuiVertex>& vertices, const std::vector<int>& indices, const DoublePoint& translation, ImagePtr texture) = 0;
		
		/** Helper that returns an interpolated Point
		 */
		Point getBezierPoint(const std::vector<Point>& points, int32_t elements, float t);

		/** Helper that adds the control points for bezier curves.
		 */
		void addControlPoints(const std::vector<Point>& points, std::vector<Point>& newPoints);

	protected:
		
		/** Sets given clip area into image
		 *  @see pushClipArea
		 */
		virtual void setClipArea(const Rect& cliparea, bool clear) = 0;

		SDL_Window* m_window;
		SDL_Surface* m_screen;
		SDL_Surface* m_target;
		bool m_compressimages;
		bool m_useframebuffer;
		bool m_usenpot;
		bool m_isalphaoptimized;
		bool m_iscolorkeyenabled;
		SDL_Color m_colorkey;
		ScreenMode m_screenMode;
		SDL_PixelFormat m_rgba_format;

		bool m_isbackgroundcolor;
		SDL_Color m_backgroundcolor;

		// mipmapping
		bool m_isMipmapping;
		// texture filter
		TextureFiltering m_textureFilter;
		// max anisotropy
		int32_t m_maxAnisotropy;
		// monochrome rendering
		bool m_monochrome;
		// depth buffer rendering
		bool m_isDepthBuffer;
		// alpha test value
		float m_alphaValue;
		// vsync value
		bool m_vSync;

		/** Clears any possible clip areas
		 *  @see pushClipArea
		 */
		void clearClipArea();

		class ClipInfo {
		public:
			Rect r;
			bool clearing;
		};
		std::stack<ClipInfo> m_clipstack;

		ClipInfo m_guiClip;
	private:
		bool m_isframelimit;
		uint32_t m_frame_start;
		uint16_t m_framelimit;
		
	};
}

#endif