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

#include "common/util.h"
#include "common/stack.h"
#include "graphics/primitives.h"

#include "sci/sci.h"
#include "sci/engine/state.h"
#include "sci/tools.h"
#include "sci/gui/gui.h"
#include "sci/gui/gui_screen.h"
#include "sci/gui/gui_palette.h"
#include "sci/gui/gui_transitions.h"

namespace Sci {

SciGuiTransitions::SciGuiTransitions(SciGui *gui, SciGuiScreen *screen, SciGuiPalette *palette, bool isVGA)
	: _gui(gui), _screen(screen), _palette(palette), _isVGA(isVGA) {
	init();
}

SciGuiTransitions::~SciGuiTransitions() {
	delete[] _oldScreen;
}

void SciGuiTransitions::init() {
	_oldScreen = new byte[_screen->_displayHeight * _screen->_displayWidth];
}

void SciGuiTransitions::setup(int16 number) {
	_number = number;
}

void SciGuiTransitions::doit(Common::Rect picRect) {
	_picRect = picRect;

	if (_isVGA) {
		// === VGA transitions
		switch (_number) {
		case SCI_TRANSITIONS_VGA_PIXELATION:
			setNewPalette(); pixelation();
			break;

		case SCI_TRANSITIONS_VGA_BLOCKS:
			setNewPalette(); blocks();
			break;

		case SCI_TRANSITIONS_VGA_FADEPALETTE:
			fadeOut(); setNewScreen(); fadeIn();
			break;

		case SCI_TRANSITIONS_VGA_SCROLLUP:
			scroll(SCI_TRANSITIONS_SCROLL_UP);
			break;

		default:
			warning("SciGuiTransitions: VGA-%d not implemented", _number);
			setNewPalette(); setNewScreen();
		}
	} else {
		// === EGA transitions
		switch (_number) {
		case SCI_TRANSITIONS_EGA_PIXELATION:
			pixelation();
			break;

		case SCI_TRANSITIONS_EGA_BLOCKS:
			blocks();
			break;

		case SCI_TRANSITIONS_EGA_FADEPALETTE:
			fadeOut(); setNewScreen(); fadeIn();
			break;

		default:
			warning("SciGuiTransitions: EGA-%d not implemented", _number);
			setNewScreen();
		}
	}
	_screen->_picNotValid = 0;
}

void SciGuiTransitions::setNewPalette() {
	_palette->setOnScreen();
}

void SciGuiTransitions::setNewScreen() {
	_screen->copyRectToScreen(_picRect);
	g_system->updateScreen();
}

// Note: dont do too many steps in here, otherwise cpu will crap out because of the load
void SciGuiTransitions::fadeOut() {
	byte oldPalette[4 * 256], workPalette[4 * 256];
	int16 stepNr, colorNr;

	g_system->grabPalette(oldPalette, 0, 256);

	for (stepNr = 100; stepNr >= 0; stepNr -= 10) {
		for (colorNr = 0; colorNr < 256; colorNr++){
			workPalette[colorNr * 4 + 0] = oldPalette[colorNr * 4] * stepNr / 100;
			workPalette[colorNr * 4 + 1] = oldPalette[colorNr * 4 + 1] * stepNr / 100;
			workPalette[colorNr * 4 + 2] = oldPalette[colorNr * 4 + 2] * stepNr / 100;
		}
		g_system->setPalette(workPalette, 0, 256);
		_gui->wait(2);
	}
}

// Note: dont do too many steps in here, otherwise cpu will crap out because of the load
void SciGuiTransitions::fadeIn() {
	byte workPalette[4 * 256];
	GuiPalette *newPalette = &_palette->_sysPalette;
	int16 stepNr, colorNr;

	for (stepNr = 0; stepNr <= 100; stepNr += 10) {
		for (colorNr = 0; colorNr < 256; colorNr++){
			workPalette[colorNr * 4 + 0] = newPalette->colors[colorNr].r * stepNr / 100;
			workPalette[colorNr * 4 + 1] = newPalette->colors[colorNr].g * stepNr / 100;
			workPalette[colorNr * 4 + 2] = newPalette->colors[colorNr].b * stepNr / 100;
			workPalette[colorNr * 4 + 3] = 100;
		}
		g_system->setPalette(workPalette, 0, 256);
		_gui->wait(2);
	}
}

// pixelates the new picture over the old one - works against the whole screen
void SciGuiTransitions::pixelation () {
	uint16 mask = 0x40, stepNr = 0;
	Common::Rect pixelRect;

	do {
		mask = (mask & 1) ? (mask >> 1) ^ 0xB400 : mask >> 1;
		if (mask >= 320 * 200)
			continue;
		pixelRect.left = mask % 320; pixelRect.right = pixelRect.left + 1;
		pixelRect.top = mask / 320;	pixelRect.bottom = pixelRect.top + 1;
		_screen->copyRectToScreen(pixelRect);
		if ((stepNr & 0x3FF) == 0) {
			g_system->updateScreen();
			g_system->delayMillis(5);
		}
		stepNr++;
	} while (mask != 0x40);
}

// like pixelation but uses 8x8 blocks - works against the whole screen
void SciGuiTransitions::blocks() {
	uint16 mask = 0x40, stepNr = 0;
	Common::Rect blockRect;

	do {
		mask = (mask & 1) ? (mask >> 1) ^ 0x240 : mask >> 1;
		if (mask >= 40 * 25)
			continue;
		blockRect.left = (mask % 40) << 3; blockRect.right = blockRect.left + 8;
		blockRect.top = (mask / 40) << 3; blockRect.bottom = blockRect.top + 8;
		_screen->copyRectToScreen(blockRect);
		if ((stepNr & 7) == 0) {
			g_system->updateScreen();
			g_system->delayMillis(4);
		}
		stepNr++;
	} while (mask != 0x40);
}

// scroll old screen (up/down/left/right) and insert new screen that way - works on _picRect area
void SciGuiTransitions::scroll(int16 direction) {
	int16 screenWidth, screenHeight;
	int16 oldWidth, oldHeight;
	int16 newWidth, newHeight;
	byte *oldScreenPtr;
	int16 x, y;
	Common::Rect newScreenRect = _picRect;

	_screen->copyFromScreen(_oldScreen);
	screenWidth = _screen->_displayWidth; screenHeight = _screen->_displayHeight;

	x = _picRect.left; y = _picRect.top;
	oldWidth = _picRect.width(); oldHeight = _picRect.height();
	newWidth = 0; newHeight = 0;

	oldScreenPtr = _oldScreen + _picRect.left + _picRect.top * screenWidth;

	switch (direction) {
	case SCI_TRANSITIONS_SCROLL_UP:
		newScreenRect.bottom = newScreenRect.top;
		y += oldHeight;
		while (oldHeight > 0) {
			oldScreenPtr += screenWidth; oldHeight--;
			if (oldHeight)
				g_system->copyRectToScreen(oldScreenPtr, _screen->_displayWidth, _picRect.left, _picRect.top, oldWidth, oldHeight);
			newScreenRect.bottom++;	y--;
			_screen->copyRectToScreen(newScreenRect, x, y);
			g_system->updateScreen();
			g_system->delayMillis(3);
		}
		break;
	}
}

} // End of namespace Sci