/* 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_CELOBJ32_H
#define SCI_GRAPHICS_CELOBJ32_H

#include "common/rational.h"
#include "common/rect.h"
#include "sci/resource.h"
#include "sci/engine/vm_types.h"

namespace Sci {
typedef Common::Rational Ratio;

enum CelType {
	kCelTypeView  = 0,
	kCelTypePic   = 1,
	kCelTypeMem   = 2,
	kCelTypeColor = 3
};

enum CelCompressionType {
	kCelCompressionNone    = 0,
	kCelCompressionRLE     = 138,
	kCelCompressionInvalid = 1000
};

/**
 * A CelInfo32 object describes the basic properties of a
 * cel object.
 */
struct CelInfo32 {
	/**
	 * The type of the cel object.
	 */
	CelType type;

	/**
	 * For cel objects that draw from resources, the ID of
	 * the resource to load.
	 */
	GuiResourceId resourceId;

	/**
	 * For CelObjView, the loop number to draw from the
	 * view resource.
	 */
	int16 loopNo;

	/**
	 * For CelObjView and CelObjPic, the cel number to draw
	 * from the view or pic resource.
	 */
	int16 celNo;

	/**
	 * For CelObjMem, a segment register pointing to a heap
	 * resource containing headered bitmap data.
	 */
	reg_t bitmap;

	/**
	 * For CelObjColor, the fill color.
	 */
	uint8 color;

	// NOTE: In at least SCI2.1/SQ6, color is left
	// uninitialised.
	CelInfo32() :
		type(kCelTypeMem),
		resourceId(0),
		loopNo(0),
		celNo(0),
		bitmap(NULL_REG) {}

	// NOTE: This is the equivalence criteria used by
	// CelObj::searchCache in at least SCI2.1/SQ6. Notably,
	// it does not check the color field.
	inline bool operator==(const CelInfo32 &other) {
		return (
			type == other.type &&
			resourceId == other.resourceId &&
			loopNo == other.loopNo &&
			celNo == other.celNo &&
			bitmap == other.bitmap
		);
	}

	inline bool operator!=(const CelInfo32 &other) {
		return !(*this == other);
	}
};

class CelObj;
struct CelCacheEntry {
	/**
	 * A monotonically increasing cache ID used to identify
	 * the least recently used item in the cache for
	 * replacement.
	 */
	int id;
	CelObj *celObj;
	CelCacheEntry() : id(0), celObj(nullptr) {}
};

typedef Common::Array<CelCacheEntry> CelCache;

#pragma mark -
#pragma mark CelScaler

struct CelScalerTable {
	/**
	 * A lookup table of indexes that should be used to find
	 * the correct column to read from the source bitmap
	 * when drawing a scaled version of the source bitmap.
	 */
	int valuesX[1024];

	/**
	 * The ratio used to generate the x-values.
	 */
	Ratio scaleX;

	/**
	 * A lookup table of indexes that should be used to find
	 * the correct row to read from a source bitmap when
	 * drawing a scaled version of the source bitmap.
	 */
	int valuesY[1024];

	/**
	 * The ratio used to generate the y-values.
	 */
	Ratio scaleY;
};

class CelScaler {
	/**
	 * Cached scale tables.
	 */
	CelScalerTable _scaleTables[2];

	/**
	 * The index of the most recently used scale table.
	 */
	int _activeIndex;

	/**
	 * Activates a scale table for the given X and Y ratios.
	 * If there is no table that matches the given ratios,
	 * the least most recently used table will be replaced
	 * and activated.
	 */
	void activateScaleTables(const Ratio &scaleX, const Ratio &scaleY);

	/**
	 * Builds a pixel lookup table in `table` for the given
	 * ratio. The table will be filled up to the specified
	 * size, which should be large enough to draw across the
	 * entire target buffer.
	 */
	void buildLookupTable(int *table, const Ratio &ratio, const int size);

public:
	CelScaler() :
	_scaleTables(),
	_activeIndex(0) {
		CelScalerTable &table = _scaleTables[0];
		table.scaleX = Ratio();
		table.scaleY = Ratio();
		for (int i = 0; i < ARRAYSIZE(table.valuesX); ++i) {
			table.valuesX[i] = i;
			table.valuesY[i] = i;
		}
		for (int i = 1; i < ARRAYSIZE(_scaleTables); ++i) {
			_scaleTables[i] = _scaleTables[0];
		}
	}

	/**
	 * Retrieves scaler tables for the given X and Y ratios.
	 */
	const CelScalerTable *getScalerTable(const Ratio &scaleX, const Ratio &scaleY);
};

#pragma mark -
#pragma mark CelObj

class ScreenItem;
/**
 * A cel object is the lowest-level rendering primitive in
 * the SCI engine and draws itself directly to a target
 * pixel buffer.
 */
class CelObj {
protected:
	/**
	 * When true, this cel will be horizontally mirrored
	 * when it is drawn. This is an internal flag that is
	 * set by draw methods based on the combination of the
	 * cel's `_mirrorX` property and the owner screen item's
	 * `_mirrorX` property.
	 */
	bool _drawMirrored;

public:
	static CelScaler *_scaler;

	/**
	 * The basic identifying information for this cel. This
	 * information effectively acts as a composite key for
	 * a cel object, and any cel object can be recreated
	 * from this data alone.
	 */
	CelInfo32 _info;

	/**
	 * The offset to the cel header for this cel within the
	 * raw resource data.
	 */
	uint32 _celHeaderOffset;

	/**
	 * The offset to the embedded palette for this cel
	 * within the raw resource data.
	 */
	uint32 _hunkPaletteOffset;

	/**
	 * The natural dimensions of the cel.
	 */
	uint16 _width, _height;

	/**
	 * TODO: Documentation
	 */
	Common::Point _displace;

	/**
	 * The dimensions of the original coordinate system for
	 * the cel. Used to scale cels from their native size
	 * to the correct size on screen.
	 *
	 * @note This is set to scriptWidth/Height for
	 * CelObjColor. For other cel objects, the value comes
	 * from the raw resource data. For text bitmaps, this is
	 * the width/height of the coordinate system used to
	 * generate the text, which also defaults to
	 * scriptWidth/Height but seems to typically be changed
	 * to more closely match the native screen resolution.
	 */
	uint16 _scaledWidth, _scaledHeight;

	/**
	 * The skip (transparent) color for the cel. When
	 * compositing, any pixels matching this color will not
	 * be copied to the buffer.
	 */
	uint8 _transparentColor;

	/**
	 * Whether or not this cel has any transparent regions.
	 * This is used for optimised drawing of non-transparent
	 * cels.
	 */
	bool _transparent; // TODO: probably "skip"?

	/**
	 * The compression type for the pixel data for this cel.
	 */
	CelCompressionType _compressionType;

	/**
	 * Whether or not this cel should be palette-remapped?
	 */
	bool _remap;

	/**
	 * If true, the cel contains pre-mirrored picture data.
	 * This value comes directly from the resource data and
	 * is XORed with the `_mirrorX` property of the owner
	 * screen item when rendering.
	 */
	bool _mirrorX;

	/**
	 * Initialises static CelObj members.
	 */
	static void init();

	/**
	 * Frees static CelObj members.
	 */
	static void deinit();

	virtual ~CelObj() {};

	/**
	 * Draws the cel to the target buffer using the priority
	 * and positioning information from the given screen
	 * item. The mirroring of the cel will be unchanged from
	 * any previous call to draw.
	 */
	void draw(Buffer &target, const ScreenItem &screenItem, const Common::Rect &targetRect) const;

	/**
	 * Draws the cel to the target buffer using the priority
	 * and positioning information from the given screen
	 * item and the given mirror flag.
	 *
	 * @note In SCI engine, this function was a virtual
	 * function, but CelObjView, CelObjPic, and CelObjMem
	 * all used the same function and the compiler
	 * deduplicated the copies; we deduplicate the source by
	 * putting the implementation on CelObj instead of
	 * copying it to 3/4 of the subclasses.
	 */
	virtual void draw(Buffer &target, const ScreenItem &screenItem, const Common::Rect &targetRect, const bool mirrorX);

	/**
	 * Draws the cel to the target buffer using the
	 * positioning and mirroring information from the
	 * provided arguments.
	 *
	 * @note In SCI engine, this function was a virtual
	 * function, but CelObjView, CelObjPic, and CelObjMem
	 * all used the same function and the compiler
	 * deduplicated the copies; we deduplicate the source by
	 * putting the implementation on CelObj instead of
	 * copying it to 3/4 of the subclasses.
	 */
	virtual void draw(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition, const bool mirrorX);

	/**
	 * Draws the cel to the target buffer using the given
	 * position and scaling parameters. The mirroring of the
	 * cel will be unchanged from any previous call to draw.
	 */
	void drawTo(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition, const Ratio &scaleX, const Ratio &scaleY) const;

	/**
	 * Creates a copy of this cel on the free store and
	 * returns a pointer to the new object. The new cel will
	 * point to a shared copy of bitmap/resource data.
	 */
	virtual CelObj *duplicate() const = 0;

	/**
	 * Retrieves a pointer to the raw resource data for this
	 * cel. This method cannot be used with a CelObjColor.
	 */
	virtual byte *getResPointer() const = 0;

	/**
	 * Reads the pixel at the given coordinates. This method
	 * is valid only for CelObjView and CelObjPic.
	 */
	virtual uint8 readPixel(uint16 x, uint16 y, bool mirrorX) const;

	/**
	 * Submits the palette from this cel to the palette
	 * manager for integration into the master screen
	 * palette.
	 */
	void submitPalette() const;

#pragma mark -
#pragma mark CelObj - Drawing
private:
	template<typename MAPPER, typename SCALER>
	void render(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;

	template<typename MAPPER, typename SCALER>
	void render(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition, const Ratio &scaleX, const Ratio &scaleY) const;

	void drawHzFlip(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void drawNoFlip(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void drawUncompNoFlip(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void drawUncompHzFlip(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void scaleDraw(Buffer &target, const Ratio &scaleX, const Ratio &scaleY, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void scaleDrawUncomp(Buffer &target, const Ratio &scaleX, const Ratio &scaleY, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;

	void drawHzFlipMap(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void drawNoFlipMap(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void drawUncompNoFlipMap(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void drawUncompHzFlipMap(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void scaleDrawMap(Buffer &target, const Ratio &scaleX, const Ratio &scaleY, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void scaleDrawUncompMap(Buffer &target, const Ratio &scaleX, const Ratio &scaleY, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	// NOTE: The original includes versions of the above functions with priority parameters, which were not actually used in SCI32

	void drawHzFlipNoMD(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void drawNoFlipNoMD(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void drawUncompNoFlipNoMD(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void drawUncompNoFlipNoMDNoSkip(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void drawUncompHzFlipNoMD(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void drawUncompHzFlipNoMDNoSkip(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void scaleDrawNoMD(Buffer &target, const Ratio &scaleX, const Ratio &scaleY, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	void scaleDrawUncompNoMD(Buffer &target, const Ratio &scaleX, const Ratio &scaleY, const Common::Rect &targetRect, const Common::Point &scaledPosition) const;
	// NOTE: The original includes versions of the above functions with priority parameters, which were not actually used in SCI32

#pragma mark -
#pragma mark CelObj - Caching
protected:
	/**
	 * A monotonically increasing cache ID used to identify
	 * the least recently used item in the cache for
	 * replacement.
	 */
	static int _nextCacheId;

	/**
	 * A cache of cel objects used to avoid reinitialisation
	 * overhead for cels with the same CelInfo32.
	 */
	// NOTE: At least SQ6 uses a fixed cache size of 100.
	static CelCache *_cache;

	/**
	 * Searches the cel cache for a CelObj matching the
	 * provided CelInfo32. If not found, -1 is returned.
	 * nextInsertIndex will receive the index of the oldest
	 * item in the cache, which can be used to replace
	 * the oldest item with a newer item.
	 */
	int searchCache(const CelInfo32 &celInfo, int *nextInsertIndex) const;

	/**
	 * Puts a copy of this CelObj into the cache at the
	 * given cache index.
	 */
	void putCopyInCache(int index) const;
};

#pragma mark -
#pragma mark CelObjView

/**
 * A CelObjView is the drawing primitive for a View type
 * resource. Each CelObjView corresponds to a single cel
 * within a single loop of a view.
 */
class CelObjView : public CelObj {
private:
	/**
	 * Analyses resources without baked-in remap flags
	 * to determine whether or not they should be remapped.
	 */
	bool analyzeUncompressedForRemap() const;

	/**
	 * Analyses compressed resources without baked-in remap
	 * flags to determine whether or not they should be
	 * remapped.
	 */
	bool analyzeForRemap() const;

public:
	CelObjView(const GuiResourceId viewId, const int16 loopNo, const int16 celNo);
	virtual ~CelObjView() override {};

	using CelObj::draw;

	/**
	 * Draws the cel to the target buffer using the
	 * positioning, mirroring, and scaling information from
	 * the provided arguments.
	 */
	void draw(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition, bool mirrorX, const Ratio &scaleX, const Ratio &scaleY);

	virtual CelObjView *duplicate() const override;
	virtual byte *getResPointer() const override;
};

#pragma mark -
#pragma mark CelObjPic

/**
 * A CelObjPic is the drawing primitive for a Picture type
 * resource. Each CelObjPic corresponds to a single cel
 * within a picture.
 */
class CelObjPic : public CelObj {
private:
	/**
	 * Analyses uncompressed resources without baked-in skip
	 * flags to determine whether or not they can use fast
	 * blitting.
	 */
	bool analyzeUncompressedForSkip() const;

public:
	/**
	 * The number of cels in the original picture resource.
	 */
	uint8 _celCount;

	/**
	 * The position of this cel relative to the top-left
	 * corner of the picture.
	 */
	Common::Point _relativePosition;

	/**
	 * The z-buffer priority for this cel. Higher prorities
	 * are drawn on top of lower priorities.
	 */
	int16 _priority;

	CelObjPic(const GuiResourceId pictureId, const int16 celNo);
	virtual ~CelObjPic() override {};

	using CelObj::draw;
	virtual void draw(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition, const bool mirrorX) override;

	virtual CelObjPic *duplicate() const override;
	virtual byte *getResPointer() const override;
};

#pragma mark -
#pragma mark CelObjMem

/**
 * A CelObjMem is the drawing primitive for arbitrary
 * bitmaps generated in memory. Generated bitmaps in SCI32
 * include text & vector drawings and per-pixel screen
 * transitions like dissolves.
 */
class CelObjMem : public CelObj {
public:
	CelObjMem(const reg_t bitmap);
	virtual ~CelObjMem() override {};

	virtual CelObjMem *duplicate() const override;
	virtual byte *getResPointer() const override;
};

#pragma mark -
#pragma mark CelObjColor

/**
 * A CelObjColor is the drawing primitive for fast,
 * low-memory, flat color fills.
 */
class CelObjColor : public CelObj {
public:
	CelObjColor(const uint8 color, const int16 width, const int16 height);
	virtual ~CelObjColor() override {};

	using CelObj::draw;
	/**
	 * Block fills the target buffer with the cel color.
	 */
	void draw(Buffer &target, const Common::Rect &targetRect) const;
	virtual void draw(Buffer &target, const ScreenItem &screenItem, const Common::Rect &targetRect, const bool mirrorX) override;
	virtual void draw(Buffer &target, const Common::Rect &targetRect, const Common::Point &scaledPosition, const bool mirrorX) override;

	virtual CelObjColor *duplicate() const override;
	virtual byte *getResPointer() const override;
};
} // End of namespace Sci

#endif