/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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.
 *
 */

#ifndef SCI_GRAPHICS_PALETTE32_H
#define SCI_GRAPHICS_PALETTE32_H

#include "sci/graphics/palette.h"

enum PalCyclerDirection {
	PalCycleBackward = 0,
	PalCycleForward = 1
};

struct PalCycler {
	/**
	 * The color index of the palette cycler. This value is effectively used as the ID for the
	 * cycler.
	 */
	uint8 fromColor;

	/**
	 * The number of palette slots which are cycled by the palette cycler.
	 */
	uint16 numColorsToCycle;

	/**
	 * The position of the cursor in its cycle.
	 */
	uint8 currentCycle;

	/**
	 * The direction of the cycler.
	 */
	PalCyclerDirection direction;

	/**
	 * The cycle tick at the last time the cycler’s currentCycle was updated.
	 * 795 days of game time ought to be enough for everyone? :)
	 */
	uint32 lastUpdateTick;

	/**
	 * The amount of time in ticks each cycle should take to complete. In other words,
	 * the higher the delay, the slower the cycle animation. If delay is 0, the cycler
	 * does not automatically cycle and needs to be pumped manually with DoCycle.
	 */
	int16 delay;

	/**
	 * The number of times this cycler has been paused.
	 */
	uint16 numTimesPaused;
};

namespace Sci {
	class GfxPalette32 : public GfxPalette {
	public:
		GfxPalette32(ResourceManager *resMan, GfxScreen *screen);
		~GfxPalette32();

	protected:
		/**
		 * The palette revision version. Increments once per game
		 * loop that changes the source palette. TODO: Possibly
		 * other areas also change _version, double-check once it
		 * is all implemented.
		 */
		uint32 _version;

		/**
		 * Whether or not the palette manager version was updated
		 * during this loop.
		 */
		bool _versionUpdated;

		/**
		 * The unmodified source palette loaded by kPalette. Additional
		 * palette entries may be mixed into the source palette by
		 * CelObj objects, which contain their own palettes.
		 */
		Palette _sourcePalette;

		/**
		 * The palette to be used when the hardware is next updated.
		 * On update, _nextPalette is transferred to _sysPalette.
		 */
		Palette _nextPalette;

		// SQ6 defines 10 cyclers
		PalCycler *_cyclers[10];

		/**
		 * The cycle map is used to detect overlapping cyclers.
		 * According to SCI engine code, when two cyclers overlap,
		 * a fatal error has occurred and the engine will display
		 * an error and then exit.
		 */
		bool _cycleMap[256];
		inline void clearCycleMap(uint16 fromColor, uint16 numColorsToClear);
		inline void setCycleMap(uint16 fromColor, uint16 numColorsToClear);
		inline PalCycler *getCycler(uint16 fromColor);

		/**
		 * The fade table records the expected intensity level of each pixel
		 * in the palette that will be displayed on the next frame.
		 */
		byte _fadeTable[256];

		/**
		 * An optional lookup table used to remap RGB565 colors to a palette
		 * index. Used by Phantasmagoria 2 in 8-bit color environments.
		 */
		byte *_clutTable;

		/**
		 * An optional palette used to describe the source colors used
		 * in a palette vary operation. If this palette is not specified,
		 * sourcePalette is used instead.
		 */
		Palette *_varyStartPalette;

		/**
		 * An optional palette used to describe the target colors used
		 * in a palette vary operation.
		 */
		Palette *_varyTargetPalette;

		/**
		 * The minimum palette index that has been varied from the
		 * source palette. 0–255
		 */
		uint8 _varyFromColor;

		/**
		 * The maximum palette index that is has been varied from the
		 * source palette. 0-255
		 */
		uint8 _varyToColor;

		/**
		 * The tick at the last time the palette vary was updated.
		 */
		uint32 _varyLastTick;

		/**
		 * TODO: Document
		 * The velocity of change in percent?
		 */
		int _varyTime;

		/**
		 * TODO: Better documentation
		 * The direction of change, -1, 0, or 1.
		 */
		int16 _varyDirection;

		/**
		 * The amount, in percent, that the vary color is currently
		 * blended into the source color.
		 */
		int16 _varyPercent;

		/**
		 * The target amount that a vary color will be blended into
		 * the source color.
		 */
		int16 _varyTargetPercent;

		/**
		 * The number of time palette varying has been paused.
		 */
		uint16 _varyNumTimesPaused;

		/**
		 * Submits a palette to display. Entries marked as “used” in the
		 * submitted palette are merged into the existing entries of
		 * _sourcePalette.
		 */
		void submit(Palette &palette);

	public:
		virtual void saveLoadWithSerializer(Common::Serializer &s) override;

		bool kernelSetFromResource(GuiResourceId resourceId, bool force) override;
		int16 kernelFindColor(uint16 r, uint16 g, uint16 b) override;
		void set(Palette *newPalette, bool force, bool forceRealMerge = false) override;
		int16 matchColor(const byte matchRed, const byte matchGreen, const byte matchBlue, const int defaultDifference, int &lastCalculatedDifference, const bool *const matchTable);

		void updateForFrame();
		void updateHardware();
		void applyAll();

		bool loadClut(uint16 clutId);
		byte matchClutColor(uint16 color);
		void unloadClut();

		void kernelPalVarySet(const GuiResourceId paletteId, const int16 percent, const int time, const int16 fromColor, const int16 toColor);
		void kernelPalVaryMergeTarget(const GuiResourceId paletteId);
		void kernelPalVarySetTarget(const GuiResourceId paletteId);
		void kernelPalVarySetStart(const GuiResourceId paletteId);
		void kernelPalVaryMergeStart(const GuiResourceId paletteId);
		virtual void kernelPalVaryPause(bool pause) override;

		void setVary(const Palette *const targetPalette, const int16 percent, const int time, const int16 fromColor, const int16 toColor);
		void setVaryPercent(const int16 percent, const int time, const int16 fromColor, const int16 fromColorAlternate);
		int16 getVaryPercent() const;
		void varyOff();
		void mergeTarget(const Palette *const palette);
		void varyPause();
		void varyOn();
		void setVaryTime(const int time);
		void setTarget(const Palette *const palette);
		void setStart(const Palette *const palette);
		void mergeStart(const Palette *const palette);
	private:
		bool createPaletteFromResourceInternal(const GuiResourceId paletteId, Palette *const out) const;
		Palette getPaletteFromResourceInternal(const GuiResourceId paletteId) const;
		void setVaryTimeInternal(const int16 percent, const int time);
	public:
		void applyVary();

		void setCycle(const uint8 fromColor, const uint8 toColor, const int16 direction, const int16 delay);
		void doCycle(const uint8 fromColor, const int16 speed);
		void cycleOn(const uint8 fromColor);
		void cyclePause(const uint8 fromColor);
		void cycleAllOn();
		void cycleAllPause();
		void cycleOff(const uint8 fromColor);
		void cycleAllOff();
		void applyAllCycles();
		void applyCycles();

		void setFade(const uint8 percent, const uint8 fromColor, const uint16 toColor);
		void fadeOff();
		void applyFade();
	};
}

#endif