/* 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.
 *
 * $URL$
 * $Id$
 *
 */

/*
 * This code is based on original Hugo Trilogy source code
 *
 * Copyright (c) 1989-1995 David P. Gray
 *
 */

// Display.c - DIB related code for HUGOWIN

#include "common/system.h"

#include "hugo/hugo.h"
#include "hugo/display.h"
#include "hugo/util.h"

namespace Hugo {

#define DMAX            16              // Size of add/restore rect lists
#define BMAX                (DMAX * 2)  // Size of dirty rect blit list

#define INX(X, B) (X >= B->x && X <= B->x + B->dx)
#define INY(Y, B) (Y >= B->y && Y <= B->y + B->dy)
#define OVERLAP(A, B) ((INX(A->x, B) || INX(A->x + A->dx, B) || INX(B->x, A) || INX(B->x + B->dx, A)) && (INY(A->y, B) || INY(A->y + A->dy, B) || INY(B->y, A) || INY(B->y + B->dy, A)))

Screen::Screen(HugoEngine *vm) : _vm(vm), _palette(0) {
	for (int j = 0; j < NUM_FONTS; j++) {
		_arrayFont[j] = 0;
		fontLoadedFl[j] = false;
	}
}

Screen::~Screen() {
}

void Screen::createPal() {
	debugC(1, kDebugDisplay, "createPal");

	g_system->setPalette(_palette, 0, NUM_COLORS);
}

/**
* Create logical palette
*/
void Screen::initDisplay() {
	debugC(1, kDebugDisplay, "initDisplay");
	createPal();
}

/**
* Move an image from source to destination
*/
void Screen::moveImage(image_pt srcImage, uint16 x1, uint16 y1, uint16 dx, uint16 dy, uint16 width1, image_pt dstImage, uint16 x2, uint16 y2, uint16 width2) {
	debugC(3, kDebugDisplay, "moveImage(srcImage, %d, %d, %d, %d, %d, dstImage, %d, %d, %d)", x1, y1, dx, dy, width1, x2, y2, width2);

	int16 wrap_src = width1 - dx;                   // Wrap to next src row
	int16 wrap_dst = width2 - dx;                   // Wrap to next dst row

	srcImage += y1 * width1 + x1;                   // Offset into src image
	dstImage += y2 * width2 + x2;                   // offset into dst image

	while (dy--) {                                  // For each row
		for (int16 x = dx; x--;)                    // For each column
			*dstImage++ = *srcImage++;
		srcImage += wrap_src;                       // Wrap to next line
		dstImage += wrap_dst;
	}
}

void Screen::displayBackground() {
	debugC(1, kDebugDisplay, "displayBackground");

	g_system->copyRectToScreen(_frontBuffer, 320, 0, 0, 320, 200);
}

/**
* Blit the supplied rectangle from _frontBuffer to the screen
*/
void Screen::displayRect(int16 x, int16 y, int16 dx, int16 dy) {
	debugC(3, kDebugDisplay, "displayRect(%d, %d, %d, %d)", x, y, dx, dy);

	g_system->copyRectToScreen(&_frontBuffer[x + y * 320], 320, x, y, dx, dy);
}

/**
* Change a color by remapping supplied palette index with new index
*/
void Screen::remapPal(uint16 oldIndex, uint16 newIndex) {
	debugC(1, kDebugDisplay, "Remap_pal(%d, %d)", oldIndex, newIndex);

	byte pal[4];

	pal[0] = _palette[newIndex * 4 + 0];
	pal[1] = _palette[newIndex * 4 + 1];
	pal[2] = _palette[newIndex * 4 + 2];
	pal[3] = _palette[newIndex * 4 + 3];

	g_system->setPalette(pal, oldIndex, 1);
}

void Screen::savePal(Common::WriteStream *f) {
	debugC(1, kDebugDisplay, "savePal");

	for (int i = 0; i < _paletteSize; i++)
		f->writeByte(_palette[i]);
}

void Screen::restorePal(Common::SeekableReadStream *f) {
	debugC(1, kDebugDisplay, "restorePal");

	for (int i = 0; i < _paletteSize; i++)
		_palette[i] = f->readByte();
}


/**
* Set the new background color
*/
void Screen::setBackgroundColor(long color) {
	debugC(1, kDebugDisplay, "setBackgroundColor(%ld)", color);

	// How???  Translate existing pixels in dib before objects rendered?
}

/**
* Return the overlay state (Foreground/Background) of the currently
* processed object by looking down the current column for an overlay
* base bit set (in which case the object is foreground).
*/
overlayState_t Screen::findOvl(seq_t *seq_p, image_pt dst_p, uint16 y) {
	debugC(4, kDebugDisplay, "findOvl");

	for (; y < seq_p->lines; y++) {              // Each line in object
		image_pt ovb_p = _vm->getBaseBoundaryOverlay() + ((uint16)(dst_p - _frontBuffer) >> 3);  // Ptr into overlay bits
		if (*ovb_p & (0x80 >> ((uint16)(dst_p - _frontBuffer) & 7))) // Overlay bit is set
			return FG;                              // Found a bit - must be foreground
		dst_p += XPIX;
	}

	return BG;                                      // No bits set, must be background
}

/**
* Merge an object frame into _frontBuffer at sx, sy and update rectangle list.
* If fore TRUE, force object above any overlay
*/
void Screen::displayFrame(int sx, int sy, seq_t *seq, bool foreFl) {
	debugC(3, kDebugDisplay, "displayFrame(%d, %d, seq, %d)", sx, sy, (foreFl) ? 1 : 0);

	image_pt image = seq->imagePtr;                 // Ptr to object image data
	image_pt subFrontBuffer = &_frontBuffer[sy * XPIX + sx]; // Ptr to offset in _frontBuffer
	image_pt overlay = &_vm->getFirstOverlay()[(sy * XPIX + sx) >> 3]; // Ptr to overlay data
	int16 frontBufferwrap = XPIX - seq->x2 - 1;     // Wraps dest_p after each line
	int16 imageWrap = seq->bytesPerLine8 - seq->x2 - 1;

	overlayState_t overlayState = UNDEF;            // Overlay state of object
	for (uint16 y = 0; y < seq->lines; y++) {       // Each line in object
		for (uint16 x = 0; x <= seq->x2; x++) {
			if (*image) {                           // Non-transparent
				overlay = _vm->getFirstOverlay() + ((uint16)(subFrontBuffer - _frontBuffer) >> 3);       // Ptr into overlay bits
				if (*overlay & (0x80 >> ((uint16)(subFrontBuffer - _frontBuffer) & 7))) {   // Overlay bit is set
					if (overlayState == UNDEF)      // Overlay defined yet?
						overlayState = findOvl(seq, subFrontBuffer, y);// No, find it.
					if (foreFl || overlayState == FG)   // Object foreground
						*subFrontBuffer = *image;   // Copy pixel
				} else {                            // No overlay
					*subFrontBuffer = *image;       // Copy pixel
				}
			}
			image++;
			subFrontBuffer++;
		}
		image += imageWrap;
		subFrontBuffer += frontBufferwrap;
	}

	// Add this rectangle to the display list
	displayList(D_ADD, sx, sy, seq->x2 + 1, seq->lines);
}

/**
* Merge rectangles A,B leaving result in B
*/
void Screen::merge(rect_t *rectA, rect_t *rectB) {
	debugC(6, kDebugDisplay, "merge");

	int16 xa = rectA->x + rectA->dx;                // Find x2,y2 for each rectangle
	int16 xb = rectB->x + rectB->dx;
	int16 ya = rectA->y + rectA->dy;
	int16 yb = rectB->y + rectB->dy;

	rectB->x = MIN(rectA->x, rectB->x);             // Minimum x,y
	rectB->y = MIN(rectA->y, rectB->y);
	rectB->dx = MAX(xa, xb) - rectB->x;             // Maximum dx,dy
	rectB->dy = MAX(ya, yb) - rectB->y;
}

/**
* Coalesce the rectangles in the restore/add list into one unified
* blist.  len is the sizes of alist or rlist.  blen is current length
* of blist.  bmax is the max size of the blist.  Note that blist can
* have holes, in which case dx = 0.  Returns used length of blist.
*/
int16 Screen::mergeLists(rect_t *list, rect_t *blist, int16 len, int16 blen, int16 bmax) {
	debugC(4, kDebugDisplay, "mergeLists");

	int16   coalesce[BMAX];                         // List of overlapping rects
	// Process the list
	for (int16 a = 0; a < len; a++, list++) {
		// Compile list of overlapping rectangles in blit list
		int16 c = 0;
		rect_t *bp = blist;
		for (int16 b = 0; b < blen; b++, bp++) {
			if (bp->dx)                             // blist entry used
				if (OVERLAP(list, bp))
					coalesce[c++] = b;
		}

		// Any overlapping blit rects?
		if (c == 0) {                               // None, add a new entry
			blist[blen++] = *list;
		} else {                                    // At least one overlapping
			// Merge add-list entry with first blist entry
			bp = &blist[coalesce[0]];
			merge(list, bp);

			// Merge any more blist entries
			while (--c) {
				rect_t *cp = &blist[coalesce[c]];
				merge(cp, bp);
				cp->dx = 0;                         // Delete entry
			}
		}
	}
	return blen;
}

/**
* Process the display list
* Trailing args are int16 x,y,dx,dy for the D_ADD operation
*/
void Screen::displayList(dupdate_t update, ...) {
	debugC(6, kDebugDisplay, "displayList");

	static int16  addIndex, restoreIndex;           // Index into add/restore lists
	static rect_t restoreList[DMAX];                // The restore list
	static rect_t addList[DMAX];                    // The add list
	static rect_t blistList[BMAX];                  // The blit list
	int16         blitLength = 0;                   // Length of blit list
	va_list       marker;                           // Args used for D_ADD operation
	rect_t       *p;                                // Ptr to dlist entry

	switch (update) {
	case D_INIT:                                    // Init lists, restore whole screen
		addIndex = restoreIndex = 0;
		memcpy(_frontBuffer, _backBuffer, sizeof(_frontBuffer));
		break;
	case D_ADD:                                     // Add a rectangle to list
		if (addIndex >= DMAX) {
			warning("Display list exceeded");
			return;
		}
		va_start(marker, update);                   // Initialize variable arguments
		p = &addList[addIndex];
		p->x  = va_arg(marker, int);                // x
		p->y  = va_arg(marker, int);                // y
		p->dx = va_arg(marker, int);                // dx
		p->dy = va_arg(marker, int);                // dy
		va_end(marker);                             // Reset variable arguments
		addIndex++;
		break;
	case D_DISPLAY:                                 // Display whole list
		// Don't blit if newscreen just loaded because _frontBuffer will
		// get blitted via InvalidateRect() at end of this cycle
		// and blitting here causes objects to appear too soon.
		if (_vm->getGameStatus().newScreenFl) {
			_vm->getGameStatus().newScreenFl = false;
			break;
		}

		// Coalesce restore-list, add-list into combined blit-list
		blitLength = mergeLists(restoreList, blistList, restoreIndex, blitLength, BMAX);
		blitLength = mergeLists(addList, blistList, addIndex,  blitLength, BMAX);

		// Blit the combined blit-list
		for (restoreIndex = 0, p = blistList; restoreIndex < blitLength; restoreIndex++, p++) {
			if (p->dx)                              // Marks a used entry
				displayRect(p->x, p->y, p->dx, p->dy);
		}
		break;
	case D_RESTORE:                                 // Restore each rectangle
		for (restoreIndex = 0, p = addList; restoreIndex < addIndex; restoreIndex++, p++) {
			// Restoring from _backBuffer to _frontBuffer
			restoreList[restoreIndex] = *p;         // Copy add-list to restore-list
			moveImage(_backBuffer, p->x, p->y, p->dx, p->dy, XPIX, _frontBuffer, p->x, p->y, XPIX);
		}
		addIndex = 0;                               // Reset add-list
		break;
	}
}

/**
* Write supplied character (font data) at sx,sy in supplied color
* Font data as follows:
* *(fontdata+1) = Font Height (pixels)
* *(fontdata+1) = Font Width (pixels)
* *(fontdata+x) = Font Bitmap (monochrome)
*/
void Screen::writeChr(int sx, int sy, byte color, char *local_fontdata) {
	debugC(2, kDebugDisplay, "writeChr(%d, %d, %d, %d)", sx, sy, color, local_fontdata[0]);

	byte height = local_fontdata[0];
	byte width = 8; //local_fontdata[1];

	// This can probably be optimized quite a bit...
	for (int y = 0; y < height; ++y) {
		for (int x = 0; x < width; ++x) {
			int pixel = y * width + x;
			int bitpos = pixel % 8;
			int offset = pixel / 8;
			byte bitTest = (1 << bitpos);
			if ((local_fontdata[2 + offset] & bitTest) == bitTest)
				_frontBuffer[(sy + y) * 320 + sx + x] = color;
		}
	}
}

/**
* Returns height of characters in current font
*/
int16 Screen::fontHeight() {
	debugC(2, kDebugDisplay, "fontHeight");

	static int16 height[NUM_FONTS] = {5, 7, 8};
	return height[_fnt - FIRST_FONT];
}

/**
* Returns length of supplied string in pixels
*/
int16 Screen::stringLength(const char *s) {
	debugC(2, kDebugDisplay, "stringLength(%s)", s);

	byte **fontArr = _font[_fnt];
	int16 sum = 0;
	for (; *s; s++)
		sum += *(fontArr[(uint)*s] + 1) + 1;

	return sum;
}

/**
* Return x which would center supplied string
*/
int16 Screen::center(const char *s) {
	debugC(1, kDebugDisplay, "center(%s)", s);

	return (int16)((XPIX - stringLength(s)) >> 1);
}

/**
* Write string at sx,sy in supplied color in current font
* If sx == CENTER, center it
*/
void Screen::writeStr(int16 sx, int16 sy, const char *s, byte color) {
	debugC(2, kDebugDisplay, "writeStr(%d, %d, %s, %d)", sx, sy, s, color);

	if (sx == CENTER)
		sx = center(s);

	byte **font = _font[_fnt];
	for (; *s; s++) {
		writeChr(sx, sy, color, (char *)font[(uint)*s]);
		sx += *(font[(uint)*s] + 1) + 1;
	}
}

/**
* Shadowed version of writestr
*/
void Screen::shadowStr(int16 sx, int16 sy, const char *s, byte color) {
	debugC(1, kDebugDisplay, "shadowStr(%d, %d, %s, %d)", sx, sy, s, color);

	if (sx == CENTER)
		sx = center(s);

	writeStr(sx + 1, sy + 1, s, _TBLACK);
	writeStr(sx, sy, s, color);
}

/** Introduce user to the game
* DOS versions Only
*/
void Screen::userHelp() {
	Utils::Box(BOX_ANY , "%s",
	           "F1  - Press F1 again\n"
	           "      for instructions\n"
	           "F2  - Sound on/off\n"
	           "F3  - Recall last line\n"
	           "F4  - Save game\n"
	           "F5  - Restore game\n"
	           "F6  - Inventory\n"
	           "F8  - Turbo button\n"
	           "F9  - Boss button\n\n"
	           "ESC - Return to game");
}

void Screen::drawStatusText() {
	debugC(4, kDebugDisplay, "drawStatusText");

	loadFont(U_FONT8);
	uint16 sdx = stringLength(_vm->_statusLine);
	uint16 sdy = fontHeight() + 1;                 // + 1 for shadow
	uint16 posX = 0;
	uint16 posY = YPIX - sdy;

	// Display the string and add rect to display list
	writeStr(posX, posY, _vm->_statusLine, _TLIGHTYELLOW);
	displayList(D_ADD, posX, posY, sdx, sdy);

	sdx = stringLength(_vm->_scoreLine);
	posY = 0;
	writeStr(posX, posY, _vm->_scoreLine, _TCYAN);
	displayList(D_ADD, posX, posY, sdx, sdy);
}

void Screen::drawShape(int x, int y, int color1, int color2) {
	for (int i = 0; i < shapeSize; i++) {
		for (int j = 0; j < i; j++) {
			_backBuffer[320 * (y + i) + (x + shapeSize + j - i)] = color1;
			_frontBuffer[320 * (y + i) + (x + shapeSize + j - i)] = color1;
			_backBuffer[320 * (y + i) + (x + shapeSize + j)] = color2;
			_frontBuffer[320 * (y + i) + (x + shapeSize + j)] = color2;
			_backBuffer[320 * (y + (2 * shapeSize - 1) - i) + (x + shapeSize + j - i)] = color1;
			_frontBuffer[320 * (y + (2 * shapeSize - 1) - i) + (x + shapeSize + j - i)] = color1;
			_backBuffer[320 * (y + (2 * shapeSize - 1) - i) + (x + shapeSize + j)] = color2;
			_frontBuffer[320 * (y + (2 * shapeSize - 1) - i) + (x + shapeSize + j)] = color2;
		}
	}
}

void Screen::drawRectangle(bool filledFl, uint16 x1, uint16 y1, uint16 x2, uint16 y2, int color) {
	assert(x1 <= x2);
	assert(y1 <= y2);

	if (filledFl) {
		for (int i = y1; i < y2; i++) {
			for (int j = x1; j < x2; j++) {
				_backBuffer[320 * i + j] = color;
				_frontBuffer[320 * i + j] = color;
			}
		}
	} else {
		warning("STUB: drawRectangle()");
	}
}

/**
* Initialize screen components and display results
*/
void Screen::initNewScreenDisplay() {
	displayList(D_INIT);
	setBackgroundColor(_TBLACK);
	displayBackground();

	// Stop premature object display in Display_list(D_DISPLAY)
	_vm->getGameStatus().newScreenFl = true;
}

/**
* Load palette from Hugo.dat
*/
void Screen::loadPalette(Common::File &in) {
	// Read palette
	_paletteSize = in.readUint16BE();
	_palette = (byte *)malloc(sizeof(byte) * _paletteSize);
	for (int i = 0; i < _paletteSize; i++)
		_palette[i] = in.readByte();
}

/**
* Free palette
*/
void Screen::freePalette() {
	free(_palette);
}

/**
* Free fonts
*/
void Screen::freeFonts() {
	for (int i = 0; i < NUM_FONTS; i++) {
		if (_arrayFont[i])
			free(_arrayFont[i]);
	}
}
} // End of namespace Hugo