/* 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 "sherlock/screen.h"
#include "sherlock/sherlock.h"
#include "common/system.h"
#include "graphics/palette.h"

namespace Sherlock {

Screen::Screen(SherlockEngine *vm) : Surface(SHERLOCK_SCREEN_WIDTH, SHERLOCK_SCREEN_HEIGHT), _vm(vm),
		_backBuffer1(SHERLOCK_SCREEN_WIDTH, SHERLOCK_SCREEN_HEIGHT),
		_backBuffer2(SHERLOCK_SCREEN_WIDTH, SHERLOCK_SCREEN_HEIGHT) {
	setFont(1);
}

void Screen::setFont(int fontNumber) {
	_fontNumber = fontNumber;
	Common::String fname = Common::String::format("FONT%d.VGS", fontNumber);
	Common::SeekableReadStream *stream = _vm->_res->load(fname);

	debug("TODO: Loading font %s, size - %d", fname.c_str(), stream->size());

	delete stream;
}

void Screen::update() {
	// Merge the dirty rects
	mergeDirtyRects();

	// Loop through copying dirty areas to the physical screen
	Common::List<Common::Rect>::iterator i;
	for (i = _dirtyRects.begin(); i != _dirtyRects.end(); ++i) {
		const Common::Rect &r = *i;
		const byte *srcP = (const byte *)getBasePtr(r.left, r.top);
		g_system->copyRectToScreen(srcP, this->pitch, r.left, r.top,
			r.width(), r.height());
	}

	// Signal the physical screen to update
	g_system->updateScreen();
	_dirtyRects.clear();
}

void Screen::getPalette(byte palette[PALETTE_SIZE]) {
	g_system->getPaletteManager()->grabPalette(palette, 0, PALETTE_COUNT);
}

void Screen::setPalette(const byte palette[PALETTE_SIZE]) {
	g_system->getPaletteManager()->setPalette(palette, 0, PALETTE_COUNT);
}

int Screen::equalizePalette(const byte palette[PALETTE_SIZE]) {
	int total = 0;
	byte tempPalette[PALETTE_SIZE];
	getPalette(tempPalette);

	// For any palette component that doesn't already match the given destination
	// palette, change by 1 towards the reference palette component
	for (int idx = 0; idx < PALETTE_SIZE; ++idx) {
		if (tempPalette[idx] > palette[idx])
		{
			--tempPalette[idx];
			++total;
		} else if (tempPalette[idx] < palette[idx]) {
			++tempPalette[idx];
			++total;
		}
	}

	if (total > 0)
		// Palette changed, so reload it
		setPalette(tempPalette);

	return total;
}

void Screen::fadeToBlack() {
	const int FADE_AMOUNT = 2;
	bool repeatFlag;
	byte *srcP;
	int count;
	byte tempPalette[PALETTE_SIZE];

	getPalette(tempPalette);
	do {
		repeatFlag = false;
		for (srcP = &tempPalette[0], count = 0; count < PALETTE_SIZE; ++count, ++srcP) {
			int v = *srcP;
			if (v) {
				repeatFlag = true;
				*srcP = MAX(*srcP - FADE_AMOUNT, 0);
			}
		}

		setPalette(tempPalette);
		_vm->_events->pollEventsAndWait();
	} while (repeatFlag && !_vm->shouldQuit());
}

/**
 * Adds a rectangle to the list of modified areas of the screen during the
 * current frame
 */
void Screen::addDirtyRect(const Common::Rect &r) {
	_dirtyRects.push_back(r);
	assert(r.isValidRect() && r.width() > 0 && r.height() > 0);
}

/**
 * Merges together overlapping dirty areas of the screen
 */
void Screen::mergeDirtyRects() {
	Common::List<Common::Rect>::iterator rOuter, rInner;

	// Ensure dirty rect list has at least two entries
	rOuter = _dirtyRects.begin();
	for (int i = 0; i < 2; ++i, ++rOuter) {
		if (rOuter == _dirtyRects.end())
			return;
	}

	// Process the dirty rect list to find any rects to merge
	for (rOuter = _dirtyRects.begin(); rOuter != _dirtyRects.end(); ++rOuter) {
		rInner = rOuter;
		while (++rInner != _dirtyRects.end()) {

			if ((*rOuter).intersects(*rInner)) {
				// these two rectangles overlap or
				// are next to each other - merge them

				unionRectangle(*rOuter, *rOuter, *rInner);

				// remove the inner rect from the list
				_dirtyRects.erase(rInner);

				// move back to beginning of list
				rInner = rOuter;
			}
		}
	}
}

/**
 * Returns the union of two dirty area rectangles
 */
bool Screen::unionRectangle(Common::Rect &destRect, const Common::Rect &src1, const Common::Rect &src2) {
	destRect = src1;
	destRect.extend(src2);

	return !destRect.isEmpty();
}

} // End of namespace Sherlock