/* 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */

#include "engines/nancy/graphics.h"
#include "engines/nancy/sound.h"
#include "engines/nancy/nancy.h"

#include "engines/nancy/misc/lightning.h"

#include "engines/nancy/state/scene.h"

#include "common/stream.h"
#include "common/random.h"

namespace Nancy {
namespace Misc {

void editPalette(byte *colors, uint percent) {
	float alpha = (float) percent / 100;

	for (int i = 0; i < 256 * 3; ++i) {
		uint16 origColor = colors[i];
		colors[i] = MIN<uint16>(alpha * origColor + origColor, 255);
	}
}

void Lightning::beginLightning(int16 distance, uint16 pulseTime, int16 rgbPercent) {
	int16 midpoint;
	float delta;

	// Calculate the min & max power of the lightning
	midpoint = (rgbPercent - (distance * 5));
	delta = 0.4 * midpoint;

	_minRGBPercent = MAX<uint16>(0, midpoint - delta);
	_maxRGBPercent = MIN<uint16>(rgbPercent, midpoint + delta);

	// Calculate the min & max delay between lightning strikes
	midpoint = 13000 - (pulseTime * 500);
	delta = 1.5 * midpoint;

	_minInterPulseDelay = MAX<int16>(500, midpoint - delta);
	_maxInterPulseDelay = MIN<int16>(13000, midpoint + delta);

	// Calculate the min & max length of the lightning strikes
	// _minPulseLength is always 5 due to an oversight in the original code
	_maxPulseLength = pulseTime * 10;

	// Calculate the min & max delay between end of lightning and start of thunder sound
	midpoint = distance * 400;
	delta = midpoint * 0.4;

	_minSoundStartDelay = MAX<int16>(250, midpoint - delta);
	_maxSoundStartDelay = midpoint + delta; // No minimum value, probably a bug

	_state = kBegin;
}

void Lightning::endLightning() {
	_state = kNotRunning;

	_viewportObjs.clear();
	_viewportObjOriginalPalettes.clear();
}

void Lightning::run() {
	switch (_state) {
	case kNotRunning: {
		// Check if the endgame has started
		if (NancySceneState.getEventFlag(82, g_nancy->_true)) {
			uint16 sceneID = NancySceneState.getSceneInfo().sceneID;

			// Check if we're inside an appropriate scene
			if ((sceneID < 152) ||
				(sceneID > 177 && sceneID < 230) ||
				(sceneID > 230 && sceneID < 233) ||
				(sceneID > 235 && sceneID < 318) ||
				(sceneID > 326 && sceneID < 334) ||
				(sceneID > 341 && sceneID < 1726) ||
				(sceneID > 1731)) {

				beginLightning(2, 22, 65);
			}
		}

		break;
	}
	case kBegin:
		g_nancy->_graphics->grabViewportObjects(_viewportObjs);

		for (RenderObject *obj : _viewportObjs) {
			if (!obj) {
				continue;
			}

			_viewportObjOriginalPalettes.push_back(new byte[256 * 3]);
			obj->grabPalette(_viewportObjOriginalPalettes.back());
		}

		_state = kStartPulse;
		// fall through
	case kStartPulse:
		_nextStateTime = g_nancy->getTotalPlayTime() + g_nancy->_randomSource->getRandomNumberRngSigned(_minPulseLength, _maxPulseLength);
		handleThunder();
		handlePulse(true);
		_state = kPulse;
		break;
	case kPulse:
		if (g_nancy->getTotalPlayTime() > _nextStateTime) {

			_nextStateTime = g_nancy->getTotalPlayTime() + g_nancy->_randomSource->getRandomNumberRngSigned(_minInterPulseDelay, _maxInterPulseDelay);

			_state = kThunder;

			if (!g_nancy->_sound->isSoundPlaying("TH1")) {
				_nextSoundToPlay = 0;
				_nextSoundTime0 = g_nancy->getTotalPlayTime() + g_nancy->_randomSource->getRandomNumberRngSigned(_minSoundStartDelay, _maxSoundStartDelay);
			} else if (!g_nancy->_sound->isSoundPlaying("TH2")) {
				_nextSoundToPlay = 1;
				_nextSoundTime1 = g_nancy->getTotalPlayTime() + g_nancy->_randomSource->getRandomNumberRngSigned(_minSoundStartDelay, _maxSoundStartDelay);
			} else {
				_nextSoundToPlay = -1;
			}

			handlePulse(false);
		}

		handleThunder();
		break;
	case kThunder:
		if (g_nancy->getTotalPlayTime() > _nextStateTime) {
			_state = kStartPulse;
		}

		handleThunder();
		break;
	}
}

void Lightning::handlePulse(bool on) {
	for (uint i = 0; i < _viewportObjs.size(); ++i) {
		RenderObject *obj = _viewportObjs[i];

		if (!obj) {
			continue;
		}

		if (on) {
			byte newPalette[256 * 3];
			obj->grabPalette(newPalette);
			editPalette(newPalette, g_nancy->_randomSource->getRandomNumberRngSigned(_minRGBPercent, _maxRGBPercent));
			obj->setPalette(newPalette);
		} else {
			obj->setPalette(_viewportObjOriginalPalettes[i]);
		}

	}
}

void Lightning::handleThunder() {
	if (_nextSoundToPlay == 0) {
		if (g_nancy->getTotalPlayTime() > _nextSoundTime0) {
			g_nancy->_sound->playSound("TH1");
			_nextSoundToPlay = -1;
		}
	} else if (_nextSoundToPlay == 1) {
		if (g_nancy->getTotalPlayTime() > _nextSoundTime1) {
			g_nancy->_sound->playSound("TH2");
			_nextSoundToPlay = -1;
		}
	}
}

} // End of namespace Misc
} // End of namespace Nancy