/* 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.
 *
 */

#include "common/endian.h"
#include "common/system.h"
#include "graphics/palette.h"
#include "mortevielle/graphics.h"
#include "mortevielle/mortevielle.h"
#include "mortevielle/mouse.h"
#include "mortevielle/var_mor.h"

namespace Mortevielle {

/*-------------------------------------------------------------------------*
 * Palette Manager 
 * 
 *-------------------------------------------------------------------------*/

/**
 * Set palette entries from the 64 colour available EGA palette
 */
void PaletteManager::setPalette(const int *palette, uint idx, uint size) {
	assert((idx + size) <= 16);

	// Build up the EGA palette
	byte egaPalette[64 * 3];

	byte *p = &egaPalette[0];
	for (int i = 0; i < 64; i++) {
		*p++ = (i >> 2 & 1) * 0xaa + (i >> 5 & 1) * 0x55;
		*p++ = (i >> 1 & 1) * 0xaa + (i >> 4 & 1) * 0x55;
		*p++ = (i      & 1) * 0xaa + (i >> 3 & 1) * 0x55;
    }

	// Loop through setting palette colours based on the passed indexes
	for (; size > 0; --size, ++idx) {
		int palIndex = palette[idx];
		assert(palIndex < 64);

		const byte *pRgb = (const byte *)&egaPalette[palIndex * 3];
		g_system->getPaletteManager()->setPalette(pRgb, idx, 1);
	}
}

/**
 * Set the default EGA palette
 */
void PaletteManager::setDefaultPalette() {
	int defaultPalette[16] = { 0, 1, 2, 3, 4, 5, 20, 7, 56, 57, 58, 59, 60, 61, 62, 63 };
	setPalette(defaultPalette, 0, 16);
}

/*-------------------------------------------------------------------------*
 * Image decoding
 * 
 * The code in this section is responsible for decoding image resources.
 * Images are broken down into rectangular sections, which can use one
 * of 18 different encoding methods.
 *-------------------------------------------------------------------------*/

#define INCR_TAIX { if (_xSize & 1) ++_xSize; }
#define DEFAULT_WIDTH (SCREEN_WIDTH / 2)
#define BUFFER_SIZE 65536

void GfxSurface::decode(const byte *pSrc) {
	_width = _height = 0;
	_var1 = *pSrc++;
	int entryCount = *pSrc++;
	pSrc += 2;

	if (!_var1)
		pSrc += 30;

	// First run through the data to calculate starting offsets
	const byte *p = pSrc;
	_offset.x = _offset.y = 999;

	assert(entryCount > 0);
	for (int idx = 0; idx < entryCount; ++idx) {
		_xp = READ_BE_UINT16(p + 4);
		if (_xp < _offset.x)
			_offset.x = _xp;

		_yp = READ_BE_UINT16(p + 6);
		if (_yp < _offset.y)
			_offset.y = _yp;

		// Move to next entry
		int size = READ_BE_UINT16(p) + READ_BE_UINT16(p + 2);
		if ((size % 2) == 1)
			++size;

		p += size + 14;
	}

	// Temporary output buffer
	byte outputBuffer[65536];
	Common::fill(&outputBuffer[0], &outputBuffer[65536], 0);

	byte *pDest = &outputBuffer[0];
	const byte *pSrcStart = pSrc;
	const byte *pLookup = NULL;

	byte lookupTable[BUFFER_SIZE];
	byte srcBuffer[BUFFER_SIZE];

	// Main processing loop
	for (int entryIndex = 0; entryIndex < entryCount; ++entryIndex) {
		int lookupBytes = READ_BE_UINT16(pSrc);
		int srcSize = READ_BE_UINT16(pSrc + 2);
		_xp = READ_BE_UINT16(pSrc + 4) - _offset.x;
		_yp = READ_BE_UINT16(pSrc + 6) - _offset.y;
		pSrc += 8;

		int decomCode = READ_BE_UINT16(pSrc);
		_xSize = READ_BE_UINT16(pSrc + 2) + 1;
		_ySize = READ_BE_UINT16(pSrc + 4) + 1;
		majTtxTty();
		
		pSrc += 6;
		pDest = &outputBuffer[0];

		_var18 = 0;
		_nibbleFlag = false;

		int decomIndex = 0;
		if (decomCode >> 8) {
			// Build up reference table
			int tableOffset = 0;

			if (decomCode & 1) {
				// Handle decompression of the pattern lookup table
				do {
					_var12 = desanalyse(pSrc);
					_var14 = desanalyse(pSrc);

					const byte *pSrcSaved = pSrc;
					bool savedNibbleFlag = _nibbleFlag;
					int savedVar18 = _var18;
					
					do {
						pSrc = pSrcSaved;
						_nibbleFlag = savedNibbleFlag;
						_var18 = savedVar18;

						for (int idx = 0; idx < _var14; ++idx, ++tableOffset) {
							assert(tableOffset < BUFFER_SIZE);
							lookupTable[tableOffset] = suiv(pSrc);
						}
					} while (--_var12 > 0);
				} while (_var18 < (lookupBytes - 1));

			} else {
				assert(lookupBytes < BUFFER_SIZE);
				for (int idx = 0; idx < (lookupBytes * 2); ++idx)
					lookupTable[idx] = suiv(pSrc);
			}

			if (_nibbleFlag) {
				++pSrc;
				_nibbleFlag = false;
			}
			if ((lookupBytes + srcSize) & 1)
				++pSrc;

			tableOffset = 0;
			_var18 = 0;

			if (decomCode & 2) {
				// Handle decompression of the temporary source buffer
				do {
					_var12 = desanalyse(pSrc);
					_var14 = desanalyse(pSrc);
					_var18 += _var14;

					if (_nibbleFlag) {
						++pSrc;
						++_var18;
						_nibbleFlag = false;
					}

					const byte *pStart = pSrc;
					do {
						pSrc = pStart;
						for (int idx = 0; idx < _var14; ++idx) {
							assert(tableOffset < BUFFER_SIZE);
							srcBuffer[tableOffset++] = *pSrc++;
						}
					} while (--_var12 > 0);
				} while (_var18 < (srcSize - 1));
			} else {
				assert(srcSize < BUFFER_SIZE);
				for (int idx = 0; idx < srcSize; ++idx)
					srcBuffer[idx] = *pSrc++;
			}

			if (_nibbleFlag)
				++pSrc;

			// Switch over to using the decompressed source and lookup buffers
			pSrcStart = pSrc;
			pDest = &outputBuffer[_yp * DEFAULT_WIDTH + _xp];
			pSrc = &srcBuffer[0];
			pLookup = &lookupTable[0] - 1;

			_lookupValue = _var18 = 0;
			_nibbleFlag = false;
			decomIndex = decomCode >> 8;
		}

		// Main decompression switch
		switch (decomIndex) {
		case 0:
			// Draw rect at pos
			pDest = &outputBuffer[_yp * DEFAULT_WIDTH + _xp];
			pSrcStart = pSrc;
			INCR_TAIX;
			
			for (int yCtr = 0; yCtr < _ySize; ++yCtr, pDest += DEFAULT_WIDTH) {
				byte *pDestLine = pDest;
				for (int xCtr = 0; xCtr < _xSize; ++xCtr) {
					*pDestLine++ = suiv(pSrc);
				}
			}

			pSrc = pSrcStart + lookupBytes + ((lookupBytes & 1) ? 1 : 0);
			break;

		case 1:
			// Draw rect using horizontal lines alternating left to right, then right to left
			INCR_TAIX;
			for (int yCtr = 0; yCtr < _ySize; ++yCtr) {
				if ((yCtr % 2) == 0) {
					for (int xCtr = 0; xCtr < _xSize; ++xCtr) {
						*pDest++ = csuiv(pSrc, pLookup);
					}
				} else {
					for (int xCtr = 0; xCtr < _xSize; ++xCtr) {
						*--pDest = csuiv(pSrc, pLookup);
					}
				}
				pDest += DEFAULT_WIDTH;
			}
			break;

		case 2:
			// Draw rect alternating top to bottom, bottom to top
			INCR_TAIX;
			for (int xCtr = 0; xCtr < _xSize; ++xCtr) {
				if ((xCtr % 2) == 0) {
					for (int yCtr = 0; yCtr < _ySize; ++yCtr, pDest += DEFAULT_WIDTH) {
						*pDest = csuiv(pSrc, pLookup);
					}
				} else {
					for (int yCtr = 0; yCtr < _ySize; ++yCtr) {
						pDest -= DEFAULT_WIDTH;
						*pDest = csuiv(pSrc, pLookup);
					}
				}
				++pDest;
			}
			break;

		case 3:
			// Draw horizontal area?
			_thickness = 2;
			horizontal(pSrc, pDest, pLookup);
			break;

		case 4:
			// Draw vertical area?
			_thickness = 2;
			vertical(pSrc, pDest, pLookup);
			break;

		case 5:
			_thickness = 3;
			horizontal(pSrc, pDest, pLookup);
			break;

		case 6:
			_thickness = 4;
			vertical(pSrc, pDest, pLookup);
			break;

		case 7:
			// Draw rect using horizontal lines left to right
			INCR_TAIX;
			for (int yCtr = 0; yCtr < _ySize; ++yCtr, pDest += DEFAULT_WIDTH) {
				byte *pDestLine = pDest;
				for (int xCtr = 0; xCtr < _xSize; ++xCtr)
					*pDestLine++ = csuiv(pSrc, pLookup);
			}
			break;

		case 8:
			// Draw box
			for (int xCtr = 0; xCtr < _xSize; ++xCtr, ++pDest) {
				byte *pDestLine = pDest;
				for (int yCtr = 0; yCtr < _ySize; ++yCtr, pDestLine += DEFAULT_WIDTH)
					*pDestLine = csuiv(pSrc, pLookup);
			}
			break;

		case 9:
			_thickness = 4;
			horizontal(pSrc, pDest, pLookup);
			break;

		case 10:
			_thickness = 6;
			horizontal(pSrc, pDest, pLookup);
			break;

		case 11:
			decom11(pSrc, pDest, pLookup);
			break;

		case 12:
			INCR_TAIX;
			_thickness = _xInc = 1;
			_yInc = DEFAULT_WIDTH;
			_var20 = _ySize;
			_var24 = _xSize;
			diag(pSrc, pDest, pLookup);
			break;

		case 13:
			INCR_TAIX;
			_thickness = _xSize;
			_yInc = 1;
			_var20 = _xSize;
			_xInc = DEFAULT_WIDTH;
			_var24 = _ySize;
			diag(pSrc, pDest, pLookup);
			break;

		case 14:
			_thickness = _yInc = 1;
			_var20 = _xSize;
			_xInc = DEFAULT_WIDTH;
			_var24 = _ySize;
			diag(pSrc, pDest, pLookup);
			break;

		case 15:
			INCR_TAIX;
			_thickness = 2;
			_yInc = DEFAULT_WIDTH;
			_var20 = _ySize;
			_xInc = 1;
			_var24 = _xSize;
			diag(pSrc, pDest, pLookup);
			break;

		case 16:
			_thickness = 3;
			_yInc = 1;
			_var20 = _xSize;
			_xInc = DEFAULT_WIDTH;
			_var24 = _ySize;
			diag(pSrc, pDest, pLookup);
			break;

		case 17:
			INCR_TAIX;
			_thickness = 3;
			_yInc = DEFAULT_WIDTH;
			_var20 = _ySize;
			_xInc = 1;
			_var24 = _xSize;
			diag(pSrc, pDest, pLookup);
			break;

		case 18:
			INCR_TAIX;
			_thickness = 5;
			_yInc = DEFAULT_WIDTH;
			_var20 = _ySize;
			_xInc = 1;
			_var24 = _xSize;
			diag(pSrc, pDest, pLookup);
			break;
		}

		pSrc = pSrcStart;
		debugC(1, kMortevielleGraphics, "Decoding image block %d position %d,%d size %d,%d method %d",
			entryIndex + 1, _xp, _yp, _width, _height, decomIndex);
	}

	// At this point, the outputBuffer has the data for the image. Initialise the surface
	// with the calculated size, and copy the lines to the surface
	create(_width, _height, Graphics::PixelFormat::createFormatCLUT8());

	for (int yCtr = 0; yCtr < _height; ++yCtr) {
		const byte *copySrc = &outputBuffer[yCtr * DEFAULT_WIDTH];
		byte *copyDest = (byte *)getBasePtr(0, yCtr);

		Common::copy(copySrc, copySrc + _width, copyDest);
	}
}

void GfxSurface::majTtxTty() {
	if (!_yp)
		_width += _xSize;

	if (!_xp)
		_height += _ySize;
}

byte GfxSurface::suiv(const byte *&pSrc) {
	int v = *pSrc;
	if (_nibbleFlag) {
		++pSrc;
		++_var18;
		_nibbleFlag = false;
		return v & 0xf;
	} else {
		_nibbleFlag = !_nibbleFlag;
		return v >> 4;
	}
}

byte GfxSurface::csuiv(const byte *&pSrc, const byte *&pLookup) {
	assert(pLookup);

	while (!_lookupValue) {
		int v;
		do {
			v = suiv(pSrc) & 0xff;
			_lookupValue += v;
		} while (v == 0xf);
		++pLookup;
	}

	--_lookupValue;
	return *pLookup;
}

int GfxSurface::desanalyse(const byte *&pSrc) {
	int total = 0;
	int v = suiv(pSrc);
	if (v == 15) {
		int v2;
		do {
			v2 = suiv(pSrc);
			total += v2;
		} while (v2 == 15);

		total *= 15;
		v = suiv(pSrc);
	}

	total += v;
	return total;
}

void GfxSurface::horizontal(const byte *&pSrc, byte *&pDest, const byte *&pLookup) {
	INCR_TAIX;
	byte *pDestEnd = pDest + (_ySize - 1) * DEFAULT_WIDTH + _xSize;

	for (;;) {
		// If position is past end point, then skip this line
		if (((_thickness - 1) * DEFAULT_WIDTH) + pDest >= pDestEnd) {
			if (--_thickness == 0) break;
			continue;
		}
		
		bool continueFlag = false;
		do {
			for (int xIndex = 0; xIndex < _xSize; ++xIndex) {
				if ((xIndex % 2) == 0) {
					if (xIndex != 0)
						++pDest;

					// Write out vertical slice top to bottom
					for (int yIndex = 0; yIndex < _thickness; ++yIndex, pDest += DEFAULT_WIDTH)
						*pDest = csuiv(pSrc, pLookup);

					++pDest;
				} else {
					// Write out vertical slice bottom to top
					for (int yIndex = 0; yIndex < _thickness; ++yIndex, pDest -= DEFAULT_WIDTH)
						*pDest = csuiv(pSrc, pLookup);
				}
			}

			if ((_xSize % 2) == 0) {
				int blockSize = _thickness * DEFAULT_WIDTH;
				pDest += blockSize;
				blockSize -= DEFAULT_WIDTH;

				if (pDestEnd < (pDest + blockSize)) {
					do {
						if (--_thickness == 0)
							return;
					} while ((pDest + (_thickness - 1) * DEFAULT_WIDTH) >= pDestEnd);
				}
			} else {
				while ((pDest + (_thickness - 1) * DEFAULT_WIDTH) >= pDestEnd) {
					if (--_thickness == 0)
						return;
				}
			}

			for (int xIndex = 0; xIndex < _xSize; ++xIndex, --pDest) {
				if ((xIndex % 2) == 0) {
					// Write out vertical slice top to bottom
					for (int yIndex = 0; yIndex < _thickness; ++yIndex, pDest += DEFAULT_WIDTH)
						*pDest = csuiv(pSrc, pLookup);
				} else {
					// Write out vertical slice top to bottom
					for (int yIndex = 0; yIndex < _thickness; ++yIndex, pDest -= DEFAULT_WIDTH)
						*pDest = csuiv(pSrc, pLookup);
				}
			}

			if ((_xSize % 2) == 1) {
				++pDest;

				if ((pDest + (_thickness - 1) * DEFAULT_WIDTH) < pDestEnd) {
					continueFlag = true;
					break;
				}
			} else {
				pDest += _thickness * DEFAULT_WIDTH + 1;
				continueFlag = true;
				break;
			}

			++pDest;
		} while (((_thickness - 1) * DEFAULT_WIDTH + pDest) < pDestEnd);

		if (continueFlag)
			continue;

		// Move to next line
		if (--_thickness == 0)
			break;
	}
}

void GfxSurface::vertical(const byte *&pSrc, byte *&pDest, const byte *&pLookup) {
//	byte *pDestEnd = pDest + (_ySize - 1) * DEFAULT_WIDTH + _xSize;
	int var28 = 0;

	for (;;) {
		// Reduce thickness as necessary
		while ((var28 + _thickness) > _xSize) {
			if (--_thickness == 0)
				return;
		}

		// Loop
		for (int yCtr = 0; yCtr < _ySize; ++yCtr) {
			if ((yCtr % 2) == 0) {
				if (yCtr > 0)
					pDest += DEFAULT_WIDTH;

				var28 += _thickness;
				for (int xCtr = 0; xCtr < _thickness; ++xCtr)
					*pDest++ = csuiv(pSrc, pLookup);
			} else {
				pDest += DEFAULT_WIDTH;
				var28 -= _thickness;
				for (int xCtr = 0; xCtr < _thickness; ++xCtr)
					*--pDest = csuiv(pSrc, pLookup);
			}
		}
		if ((_ySize % 2) == 0) {
			pDest += _thickness;
			var28 += _thickness;
		}
		
		while (_xSize < (var28 + _thickness)) {
			if (--_thickness == 0)
				return;
		}

		// Loop
		for (int yCtr = 0; yCtr < _ySize; ++yCtr) {
			if ((yCtr % 2) == 0) {
				if (yCtr > 0)
					pDest -= DEFAULT_WIDTH;

				var28 += _thickness;

				for (int xCtr = 0; xCtr < _thickness; ++xCtr)
					*pDest++ = csuiv(pSrc, pLookup);
			} else {
				pDest -= DEFAULT_WIDTH;
				var28 -= _thickness;

				for (int xCtr = 0; xCtr < _thickness; ++xCtr)
					*--pDest = csuiv(pSrc, pLookup);
			}
		}				
		if ((_ySize % 2) == 0) {
			pDest += _thickness;
			var28 += _thickness;
		}
	}
}

void GfxSurface::decom11(const byte *&pSrc, byte *&pDest, const byte *&pLookup) {
	int var26 = 0, var28 = 0;
	_yInc = DEFAULT_WIDTH;
	_xInc = -1;
	--_xSize;
	--_ySize;

	int areaNum = 0;
	while (areaNum != -1) {
		switch (areaNum) {
		case 0:
			*pDest = csuiv(pSrc, pLookup);
			areaNum = 1;
			break;

		case 1:
			increments(pDest);

			if (!var28) {
				NIH();
				NIV();

				if (var26 == _ySize) {
					increments(pDest);
					++var28;
				} else {
					++var26;
				}

				*++pDest = csuiv(pSrc, pLookup);
				areaNum = 2;
			} else if (var26 != _ySize) {
				++var26;
				--var28;
				areaNum = 0;
			} else {
				NIH();
				NIV();
				increments(pDest);
				++var28;

				*++pDest = csuiv(pSrc, pLookup);

				if (var28 == _xSize) {
					areaNum = -1;
				} else {
					areaNum = 2;
				}
			}
			break;

		case 2:
			increments(pDest);

			if (!var26) {
				NIH();
				NIV();

				if (var28 == _xSize) {
					increments(pDest);
					++var26;
				} else {
					++var28;
				}

				pDest += DEFAULT_WIDTH;
				areaNum = 0;
			} else if (var28 != _xSize) {
				++var28;
				--var26;

				*pDest = csuiv(pSrc, pLookup);
				areaNum = 2;
			} else {
				pDest += DEFAULT_WIDTH;
				++var26;
				NIH();
				NIV();
				increments(pDest);

				*pDest = csuiv(pSrc, pLookup);

				if (var26 == _ySize)
					areaNum = -1;
				else
					areaNum = 1;
			}
			break;
		}
	}
}

void GfxSurface::diag(const byte *&pSrc, byte *&pDest, const byte *&pLookup) {
	int var26 = 0, var28 = 0;
	--_var24;

	while (!TFP(var26)) {
		for (;;) {
			NIH();
			for (int idx = 0; idx <= _thickness; ++idx) {
				*pDest = csuiv(pSrc, pLookup);
				NIH();
				increments(pDest);
			}

			NIV();
			pDest += _yInc;

			for (int idx = 0; idx <= _thickness; ++idx) {
				*pDest = csuiv(pSrc, pLookup);
				NIH();
				increments(pDest);
			}
			
			NIH();
			NIV();
			increments(pDest);

			++var28;
			if (_var24 < (var28 + 1)) {
				TF1(pDest, var26);
				break;
			}

			pDest += _xInc;
			++var28;
			if (_var24 < (var28 + 1)) {
				TF2(pSrc, pDest, pLookup, var26);
				break;
			}
		}

		if (TFP(var26))
			break;

		for (;;) {
			for (int idx = 0; idx <= _thickness; ++idx) {
				*pDest = csuiv(pSrc, pLookup);
				NIH();
				increments(pDest);
			}

			NIV();
			pDest += _yInc;

			for (int idx = 0; idx <= _thickness; ++idx) {
				*pDest = csuiv(pSrc, pLookup);
				NIH();
				increments(pDest);
			}
			
			NIH();
			NIV();
			increments(pDest);

			if (--var28 == 0) {
				TF1(pDest, var26);
				NIH();
				break;
			} else {
				pDest += _xInc;
				
				if (--var28 == 0) {
					TF2(pSrc, pDest, pLookup, var26);
					NIH();
					break;
				}
			} 

			NIH();
		}
	}
}


void GfxSurface::increments(byte *&pDest) {
	pDest += _xInc + _yInc;
}

void GfxSurface::NIH() {
	_xInc = -_xInc;
}

void GfxSurface::NIV() {
	_yInc = -_yInc;
}

bool GfxSurface::TFP(int v) {
	int diff = _var20 - v;
	if (!diff)
		// Time to finish loop in outer method
		return true;

	if (diff < (_thickness + 1))
		_thickness = diff - 1;

	return false;
}

void GfxSurface::TF1(byte *&pDest, int &v) {
	v += _thickness + 1;
	pDest += (_thickness + 1) * _yInc;
}

void GfxSurface::TF2(const byte *&pSrc, byte *&pDest, const byte *&pLookup, int &v) {
	v += _thickness + 1;

	for (int idx = 0; idx <= _thickness; ++idx) {
		*pDest = csuiv(pSrc, pLookup);
		pDest += _yInc;
	}
}

/*-------------------------------------------------------------------------*/

GfxSurface::~GfxSurface() {
	free();
}

/*-------------------------------------------------------------------------*
 * Screen surface
 *-------------------------------------------------------------------------*/

/**
 * Called to populate the font data from the passed file
 */
void ScreenSurface::readFontData(Common::File &f, int dataSize) {
	assert(dataSize == (FONT_NUM_CHARS * FONT_HEIGHT));
	f.read(_fontData, FONT_NUM_CHARS * FONT_HEIGHT);
}

/**
 * Returns a graphics surface representing a subset of the screen. The affected area
 * is also marked as dirty
 */
Graphics::Surface ScreenSurface::lockArea(const Common::Rect &bounds) {
	_dirtyRects.push_back(bounds);

	Graphics::Surface s;
	s.format = format;
	s.pixels = getBasePtr(bounds.left, bounds.top);
	s.pitch = pitch;
	s.w = bounds.width();
	s.h = bounds.height();

	return s;
}

/**
 * Updates the affected areas of the surface to the underlying physical screen
 */
void ScreenSurface::updateScreen() {
	// Iterate through copying dirty areas to the screen
	for (Common::List<Common::Rect>::iterator i = _dirtyRects.begin(); i != _dirtyRects.end(); ++i) {
		Common::Rect r = *i;
		g_system->copyRectToScreen((const byte *)getBasePtr(r.left, r.top), pitch, 
			r.left, r.top, r.width(), r.height());
	}
	_dirtyRects.clear();

	// Update the screen
	g_system->updateScreen();
}

/**
 * Draws a decoded picture on the screen
 * @remarks		- Because the ScummVM surface is using a double height 640x400 surface to 
 *		simulate the original 640x400 surface, all Y values have to be doubled.
 *		- Image resources are stored at 320x200, so when drawn onto the screen every
 *		other column is interpolated.
 *		- Because the original game supported 320 width resolutions, the X coordinate
 *		also needs to be doubled for EGA mode
 */
void ScreenSurface::drawPicture(GfxSurface &surface, int x, int y) {
	// Adjust the draw position by the draw offset
	x += surface._offset.x;
	y += surface._offset.y;

	// Lock the affected area of the surface to write to
	Graphics::Surface destSurface = lockArea(Common::Rect(x * 2, y * 2, 
		(x + surface.w) * 2, (y + surface.h) * 2));

	// Loop through writing 
	for (int yp = 0; yp < surface.h; ++yp) {
		if (((y + yp) < 0) || ((y + yp) >= 200))
			continue;

		const byte *pSrc = (const byte *)surface.getBasePtr(0, yp);
		byte *pDest = (byte *)destSurface.getBasePtr(0, yp * 2);

		for (int xp = 0; xp < surface.w; ++xp, ++pSrc) {
			// Draw pixel from source image
			*pDest = *pSrc;
			*(pDest + SCREEN_WIDTH) = *pSrc;
			++pDest;

			// TODO: I'm not sure what algorithm the original uses to calculate
			// which pixel to use on the alternate columns, so for now I'm doing
			// a simple output of null values. This should be revisited once we've
			// got the palette loading so we can compare palettes. In fact, the 
			// original had the alternate columns very noticablely striped. With
			// the larger 256 colour palette, it may be worthwhile to offer a 
			// better blended graphics mode as an option.
			*pDest = 0;
			*(pDest + SCREEN_WIDTH) = 0;
			++pDest;
		}
	}
	g_vm->_screenSurface.updateScreen();
}

/**
 * Draws a character at the specified co-ordinates
 * @remarks		Because the ScummVM surface is using a double height 640x400 surface to 
 *		simulate the original 640x400 surface, all Y values have to be doubled
 */
void ScreenSurface::writeCharacter(const Common::Point &pt, unsigned char ch, int palIndex) {
	Graphics::Surface destSurface = lockArea(Common::Rect(pt.x, pt.y * 2, 
		pt.x + FONT_WIDTH, (pt.y + FONT_HEIGHT) * 2));

	// Get the start of the character to use
	assert((ch >= ' ') && (ch <= (unsigned char)(32 + FONT_NUM_CHARS)));
	const byte *charData = &_fontData[((int)ch - 32) * FONT_HEIGHT];

	// Loop through decoding each character's data
	for (int yp = 0; yp < FONT_HEIGHT; ++yp) {
		byte *lineP = (byte *)destSurface.getBasePtr(0, yp * 2);
		byte byteVal = *charData++;

		for (int xp = 0; xp < FONT_WIDTH; ++xp, ++lineP, byteVal <<= 1) {
			if (byteVal & 0x80) {
				*lineP = palIndex;
				*(lineP + SCREEN_WIDTH) = palIndex;
			}
		}
	}
}

/**
 * Draws a box at the specified position and size
 * @remarks		Because the ScummVM surface is using a double height 640x400 surface to 
 *		simulate the original 640x400 surface, all Y values have to be doubled
 */
void ScreenSurface::drawBox(int x, int y, int dx, int dy, int col) {
	if (res == 1) {
		x = (uint)x >> 1;
		dx = (uint)dx >> 1;
	}

	Graphics::Surface destSurface = lockArea(Common::Rect(x, y * 2, x + dx, (y + dy) * 2));

	destSurface.hLine(0, 0, dx, col);
	destSurface.hLine(0, 1, dx, col);
	destSurface.hLine(0, destSurface.h - 1, dx, col);
	destSurface.hLine(0, destSurface.h - 2, dx, col);
	destSurface.vLine(0, 2, destSurface.h - 3, col);
	destSurface.vLine(1, 2, destSurface.h - 3, col);
	destSurface.vLine(dx - 1, 2, destSurface.h - 3, col);
	destSurface.vLine(dx - 2, 2, destSurface.h - 3, col);
}


/**
 * Sets a single pixel at the specified co-ordinates
 * @remarks		Because the ScummVM surface is using a double height 640x400 surface to 
 *		simulate the original 640x400 surface, all Y values have to be doubled
 */
void ScreenSurface::setPixel(const Common::Point &pt, int palIndex) {
	Graphics::Surface destSurface = lockArea(Common::Rect(pt.x, pt.y * 2, pt.x + 1, (pt.y + 1) * 2));

	byte *destP = (byte *)destSurface.pixels;
	*destP = palIndex;
	*(destP + SCREEN_WIDTH) = palIndex;
}

} // End of namespace Mortevielle