/* 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef CINE_PAL_H
#define CINE_PAL_H

#include "graphics/pixelformat.h"

namespace Cine {

/**
 * Endian types. Used at least by Palette class's load and save functions.
 * TODO: Move somewhere more general as this is definitely not Cine-engine specific
 *
 * NOTE: It seems LITTLE_ENDIAN and/or BIG_ENDIAN were defined already on some platforms so
 * therefore renamed the enumerations to something not clashing by giving them "CINE_"-prefixes.
 */
enum EndianType {
	CINE_NATIVE_ENDIAN,
	CINE_LITTLE_ENDIAN,
	CINE_BIG_ENDIAN
};

struct PalEntry {
	char name[10];
	byte pal1[16];
	byte pal2[16];
};

void loadPal(const char *fileName);

void loadRelatedPalette(const char *fileName);

/**
 * A class for handling Cine-engine's palettes.
 * TODO: Test a bit more
 */
class Palette {
public:
	struct Color {
		uint8 r, g, b;
	};

	/**
	 * Create an initially black palette with the given color format and number of colors.
	 * @param format Color format
	 * @param numColors Number of colors
	 * @note For the default constructed object (i.e. no parameters given) this will hold: empty() && !isValid()
	 */
	Palette(const Graphics::PixelFormat format = Graphics::PixelFormat(), const uint numColors = 0);
	Palette(const Palette& other);
	Palette& operator=(const Palette& other);

	/**
	 * Clear the palette (Set color count to zero, release memory, overwrite color format with default value).
	 * @note This is very different from using fillWithBlack-function which fills the palette with black.
	 */
	Palette &clear();

	/**
	 * Load palette from buffer with given color format, endianness and number of colors.
	 * @param buf Input buffer
	 * @param size Input buffer size in bytes
	 * @param format Input color format
	 * @param numColors Number of colors to load
	 * @param endian The endianness of the colors in the input buffer
	 */
	Palette &load(const byte *buf, const uint size, const Graphics::PixelFormat format, const uint numColors, const EndianType endian);

	/**
	 * Save the whole palette to buffer in original color format using defined endianness.
	 * @param buf Output buffer
	 * @param size Output buffer size in bytes
	 * @param endian The endian type to use
	 */
	byte *save(byte *buf, const uint size, const EndianType endian) const;

	/**
	 * Save the whole palette to buffer in given color format using defined endianness.
	 * @param buf Output buffer
	 * @param size Output buffer size in bytes
	 * @param format Output color format
	 * @param endian The endian type to use
	 */
	byte *save(byte *buf, const uint size, const Graphics::PixelFormat format, const EndianType endian) const;

	/**
	 * Save (partial) palette to buffer in given color format using defined endianness.
	 * @param buf Output buffer
	 * @param size Output buffer size in bytes
	 * @param format Output color format
	 * @param numColors Number of colors to save
	 * @param endian The endian type to use
	 * @param firstIndex Starting color index (from which onwards to save the colors)
	 */
	byte *save(byte *buf, const uint size, const Graphics::PixelFormat format, const uint numColors, const EndianType endian, const byte firstIndex = 0) const;

	/**
	 * Rotate the palette in color range [firstIndex, lastIndex] to the right by one.
	 */
	Palette &rotateRight(byte firstIndex, byte lastIndex);
	Palette &rotateLeft(byte firstIndex, byte lastIndex);
	Palette &saturatedAddColor(Palette &output, byte firstIndex, byte lastIndex, signed r, signed g, signed b) const;

	/**
	 * Saturated add an RGB color in given color format to current palette's subset and save the modified colors in the given output palette.
	 * @param output The output palette (Only this palette is modified)
	 * @param firstIndex First color index of the palette's subset (Inclusive range)
	 * @param lastIndex Last color index of the palette's subset (Inclusive range)
	 * @param rSource The red color component in the source color format
	 * @param gSource The green color component in the source color format
	 * @param bSource The blue color component in the source color format
	 * @param sourceFormat The source color format (i.e. the color format of the given RGB color)
	 * @note This function basically converts the given color to the palette's internal color format
	 * and adds that using the normal saturatedAddColor-function.
	 */
	Palette &saturatedAddColor(Palette &output, byte firstIndex, byte lastIndex, signed rSource, signed gSource, signed bSource, const Graphics::PixelFormat &sourceFormat) const;

	/**
	 * Saturated add a normalized gray value to current palette's subset and save the modified colors in the given output palette.
	 * @param output The output palette (Only this palette is modified)
	 * @param firstIndex First color index of the palette's subset (Inclusive range)
	 * @param lastIndex Last color index of the palette's subset (Inclusive range)
	 * @param grayDividend Dividend of the normalized gray value
	 * @param grayDenominator Denominator of the normalized gray value
	 * @note The normalized gray value (i.e. in range [-1, +1]) is given as a fractional number
	 * (i.e. the normalized gray value is calculated by dividing grayDividend by grayDenominator).
	 */
	Palette &saturatedAddNormalizedGray(Palette &output, byte firstIndex, byte lastIndex, signed grayDividend, signed grayDenominator) const;

	bool empty() const;
	uint colorCount() const;
	Palette &fillWithBlack();

	/** Is the palette valid? (Mostly just checks the color format for correctness) */
	bool isValid() const;

	/** The original color format in which this palette was loaded. */
	const Graphics::PixelFormat &colorFormat() const;

	/** Sets current palette to global OSystem's palette using g_system->getPaletteManager()->setPalette. */
	void setGlobalOSystemPalette() const;

	/** Get the color at the given palette index. */
	Color getColor(byte index) const;

	/** Get the red color component of the color at the given palette index. */
	uint8 getR(byte index) const;

	/** Get the green color component of the color at the given palette index. */
	uint8 getG(byte index) const;

	/** Get the blue color component of the color at the given palette index. */
	uint8 getB(byte index) const;

	bool ensureContrast(byte &minBrightnessColorIndex);
	bool isEqual(byte index1, byte index2);

private:
	int findMinBrightnessColorIndex(uint minColorIndex = 1);
	byte brightness(byte colorIndex);
	void setColorFormat(const Graphics::PixelFormat format);
	void saturatedAddColor(Color &result, const Color &baseColor, signed r, signed g, signed b) const;

private:
	Graphics::PixelFormat _format; ///< The used source color format
	Common::Array<Color> _colors;  ///< The actual palette data
};

} // End of namespace Cine

#endif
