/* 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 "common/system.h"
#include "common/debug.h"
#include "common/error.h"
#include "common/file.h"
#include "common/stream.h"
#include "common/memstream.h"

#include "adl/adl_v5.h"
#include "adl/display_a2.h"
#include "adl/graphics.h"
#include "adl/disk.h"

namespace Adl {

class HiRes6Engine : public AdlEngine_v5 {
public:
	HiRes6Engine(OSystem *syst, const AdlGameDescription *gd) :
			AdlEngine_v5(syst, gd),
			_currVerb(0),
			_currNoun(0) {
	}

private:
	// AdlEngine
	void gameLoop() override;
	void setupOpcodeTables() override;
	void runIntro() override;
	void init() override;
	void initGameState() override;
	void showRoom() override;
	int goDirection(ScriptEnv &e, Direction dir) override;
	Common::String formatVerbError(const Common::String &verb) const override;
	Common::String formatNounError(const Common::String &verb, const Common::String &noun) const override;
	void loadState(Common::ReadStream &stream) override;
	void saveState(Common::WriteStream &stream) override;

	// AdlEngine_v2
	void printString(const Common::String &str) override;

	// Engine
	bool canSaveGameStateCurrently() override;

	int o_fluteSound(ScriptEnv &e);

	static const uint kRegions = 3;
	static const uint kItems = 15;

	byte _currVerb, _currNoun;
};

void HiRes6Engine::gameLoop() {
	AdlEngine_v5::gameLoop();

	// Variable 25 starts at 5 and counts down every 160 moves.
	// When it reaches 0, the game ends. This variable determines
	// what you see when you "LOOK SUNS".
	// Variable 39 is used to advance the suns based on game events,
	// so even a fast player will see the suns getting closer together
	// as he progresses.
	if (getVar(39) != 0) {
		if (getVar(39) < getVar(25))
			setVar(25, getVar(39));
		setVar(39, 0);
	}

	if (getVar(25) != 0) {
		if (getVar(25) > 5)
			error("Variable 25 has unexpected value %d", getVar(25));
		if ((6 - getVar(25)) * 160 == _state.moves)
			setVar(25, getVar(25) - 1);
	}
}

void HiRes6Engine::setupOpcodeTables() {
	AdlEngine_v5::setupOpcodeTables();

	_actOpcodes[0x1e] = opcode(&HiRes6Engine::o_fluteSound);
}

int HiRes6Engine::goDirection(ScriptEnv &e, Direction dir) {
	OP_DEBUG_0((Common::String("\tGO_") + dirStr(dir) + "()").c_str());

	byte room = getCurRoom().connections[dir];

	if (room == 0) {
		// Don't penalize invalid directions at escapable Garthim encounter
		if (getVar(33) == 2)
			setVar(34, getVar(34) + 1);

		printMessage(_messageIds.cantGoThere);
		return -1;
	}

	switchRoom(room);

	// Escapes an escapable Garthim encounter by going to a different room
	if (getVar(33) == 2) {
		printMessage(102);
		setVar(33, 0);
	}

	return -1;
}

int HiRes6Engine::o_fluteSound(ScriptEnv &e) {
	OP_DEBUG_0("\tFLUTE_SOUND()");

	Tones tones;

	tones.push_back(Tone(1072.0, 587.6));
	tones.push_back(Tone(1461.0, 495.8));
	tones.push_back(Tone(0.0, 1298.7));

	playTones(tones, false);

	_linesPrinted = 0;

	return 0;
}

bool HiRes6Engine::canSaveGameStateCurrently() {
	if (!_canSaveNow)
		return false;

	// Back up variables that may be changed by this test
	const byte var2 = getVar(2);
	const byte var24 = getVar(24);
	const bool abortScript = _abortScript;

	const bool retval = AdlEngine_v5::canSaveGameStateCurrently();

	setVar(2, var2);
	setVar(24, var24);
	_abortScript = abortScript;

	return retval;
}


#define SECTORS_PER_TRACK 16
#define BYTES_PER_SECTOR 256

static Common::MemoryReadStream *loadSectors(DiskImage *disk, byte track, byte sector = SECTORS_PER_TRACK - 1, byte count = SECTORS_PER_TRACK) {
	const int bufSize = count * BYTES_PER_SECTOR;
	byte *const buf = (byte *)malloc(bufSize);
	byte *p = buf;

	while (count-- > 0) {
		StreamPtr stream(disk->createReadStream(track, sector, 0, 0));
		stream->read(p, BYTES_PER_SECTOR);

		if (stream->err() || stream->eos())
			error("Error loading from disk image");

		p += BYTES_PER_SECTOR;
		if (sector > 0)
			--sector;
		else {
			++track;

			// Skip VTOC track
			if (track == 17)
				++track;

			sector = SECTORS_PER_TRACK - 1;
		}
	}

	return new Common::MemoryReadStream(buf, bufSize, DisposeAfterUse::YES);
}

void HiRes6Engine::runIntro() {
	Display_A2 *display = static_cast<Display_A2 *>(_display);

	insertDisk(0);

	StreamPtr stream(loadSectors(_disk, 11, 1, 96));

	display->setMode(Display::kModeGraphics);
	display->loadFrameBuffer(*stream);
	display->renderGraphics();
	delay(256 * 8609 / 1000);

	display->loadFrameBuffer(*stream);
	display->renderGraphics();
	delay(256 * 8609 / 1000);

	display->loadFrameBuffer(*stream);

	// Load copyright string from boot file
	Files_AppleDOS *files(new Files_AppleDOS());

	if (!files->open(getDiskImageName(0)))
		error("Failed to open disk volume 0");

	stream.reset(files->createReadStream("\010\010\010\010\010\010"));
	Common::String copyright(readStringAt(*stream, 0x103, _display->asciiToNative('\r')));

	delete files;

	display->renderGraphics();
	display->home();
	display->setMode(Display::kModeMixed);
	display->moveCursorTo(Common::Point(0, 21));
	display->printString(copyright);
	delay(256 * 8609 / 1000);
}

void HiRes6Engine::init() {
	_graphics = new GraphicsMan_v3<Display_A2>(*static_cast<Display_A2 *>(_display));

	insertDisk(0);

	StreamPtr stream(_disk->createReadStream(0x3, 0xf, 0x05));
	loadRegionLocations(*stream, kRegions);

	stream.reset(_disk->createReadStream(0x5, 0xa, 0x07));
	loadRegionInitDataOffsets(*stream, kRegions);

	stream.reset(loadSectors(_disk, 0x7));

	_strings.verbError = readStringAt(*stream, 0x666);
	_strings.nounError = readStringAt(*stream, 0x6bd);
	_strings.enterCommand = readStringAt(*stream, 0x6e9);

	_strings.lineFeeds = readStringAt(*stream, 0x408);

	_strings_v2.saveInsert = readStringAt(*stream, 0xad8);
	_strings_v2.saveReplace = readStringAt(*stream, 0xb95);
	_strings_v2.restoreInsert = readStringAt(*stream, 0xc07);
	_strings.playAgain = readStringAt(*stream, 0xcdf, 0xff);

	_messageIds.cantGoThere = 249;
	_messageIds.dontUnderstand = 247;
	_messageIds.itemDoesntMove = 253;
	_messageIds.itemNotHere = 254;
	_messageIds.thanksForPlaying = 252;

	stream.reset(loadSectors(_disk, 0x6, 0xb, 2));
	stream->seek(0x16);
	loadItemDescriptions(*stream, kItems);

	stream.reset(_disk->createReadStream(0x8, 0x9, 0x16));
	loadDroppedItemOffsets(*stream, 16);

	stream.reset(_disk->createReadStream(0xb, 0xd, 0x08));
	loadItemPicIndex(*stream, kItems);
}

void HiRes6Engine::initGameState() {
	_state.vars.resize(40);

	insertDisk(0);

	StreamPtr stream(_disk->createReadStream(0x3, 0xe, 0x03));
	loadItems(*stream);

	// A combined total of 91 rooms
	static const byte rooms[kRegions] = { 35, 29, 27 };

	initRegions(rooms, kRegions);

	loadRegion(1);

	_currVerb = _currNoun = 0;
}

void HiRes6Engine::showRoom() {
	_state.curPicture = getCurRoom().curPicture;

	bool redrawPic = false;

	if (getVar(26) == 0xfe)
		setVar(26, 0);
	else if (getVar(26) != 0xff)
		setVar(26, _state.room);

	if (_state.room != _roomOnScreen) {
		loadRoom(_state.room);

		if (getVar(26) < 0x80 && getCurRoom().isFirstTime)
			setVar(26, 0);

		_graphics->clearScreen();

		if (!_state.isDark)
			redrawPic = true;
	} else {
		if (getCurRoom().curPicture != _picOnScreen || _itemRemoved)
			redrawPic = true;
	}

	if (redrawPic) {
		_roomOnScreen = _state.room;
		_picOnScreen = getCurRoom().curPicture;

		drawPic(getCurRoom().curPicture);
		_itemRemoved = false;
		_itemsOnScreen = 0;

		Common::List<Item>::iterator item;
		for (item = _state.items.begin(); item != _state.items.end(); ++item)
			item->isOnScreen = false;
	}

	if (!_state.isDark)
		drawItems();

	_display->renderGraphics();
	setVar(2, 0xff);
	printString(_roomData.description);
}

Common::String HiRes6Engine::formatVerbError(const Common::String &verb) const {
	Common::String err = _strings.verbError;

	for (uint i = 0; i < verb.size(); ++i)
		err.setChar(verb[i], i + 24);

	const char spaceChar = _display->asciiToNative(' ');

	err.setChar(spaceChar, 32);

	uint i = 24;
	while (err[i] != spaceChar)
		++i;

	err.setChar(_display->asciiToNative('.'), i);

	return err;
}

Common::String HiRes6Engine::formatNounError(const Common::String &verb, const Common::String &noun) const {
	Common::String err = _strings.nounError;

	for (uint i = 0; i < noun.size(); ++i)
		err.setChar(noun[i], i + 24);

	const char spaceChar = _display->asciiToNative(' ');

	for (uint  i = 35; i > 31; --i)
		err.setChar(spaceChar, i);

	uint i = 24;
	while (err[i] != spaceChar)
		++i;

	err.setChar(_display->asciiToNative('I'), i + 1);
	err.setChar(_display->asciiToNative('S'), i + 2);
	err.setChar(_display->asciiToNative('.'), i + 3);

	return err;
}

void HiRes6Engine::loadState(Common::ReadStream &stream) {
	AdlEngine_v5::loadState(stream);
	_state.moves = (getVar(39) << 8) | getVar(24);
	setVar(39, 0);
}

void HiRes6Engine::saveState(Common::WriteStream &stream) {
	// Move counter is stuffed into variables, in order to save it
	setVar(24, _state.moves & 0xff);
	setVar(39, _state.moves >> 8);
	AdlEngine_v5::saveState(stream);
	setVar(39, 0);
}

void HiRes6Engine::printString(const Common::String &str) {
	Common::String s;
	uint found = 0;

	// Variable 27 is 1 when Kira is present, 0 otherwise. It's used for choosing
	// between singular and plural variants of a string.
	// This does not emulate the corner cases of the original, hence this check
	if (getVar(27) > 1)
		error("Invalid value %i encountered for variable 27", getVar(27));

	for (uint i = 0; i < str.size(); ++i) {
		if (str[i] == '%') {
			++found;
			if (found == 3)
				found = 0;
		} else {
			if (found == 0 || found - 1 == getVar(27))
				s += str[i];
		}
	}

	// Variables 2 and 26 are used for controlling the printing of room descriptions
	if (getVar(2) == 0xff) {
		if (getVar(26) == 0) {
			// This checks for special room description string " "
			if (str.size() == 1 && _display->asciiToNative(str[0]) == _display->asciiToNative(' ')) {
				setVar(2, 160);
			} else {
				AdlEngine_v5::printString(s);
				setVar(2, 1);
			}
		} else if (getVar(26) == 0xff) {
			// Storing the room number in a variable allows for range comparisons
			setVar(26, _state.room);
			setVar(2, 1);
		} else {
			setVar(2, 80);
		}

		doAllCommands(_globalCommands, _currVerb, _currNoun);
	} else {
		AdlEngine_v5::printString(s);
	}
}

Engine *HiRes6Engine_create(OSystem *syst, const AdlGameDescription *gd) {
	return new HiRes6Engine(syst, gd);
}

} // End of namespace Adl
