/* 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 "parallaction/parallaction.h"


namespace Parallaction {

char			_tokens[20][MAX_TOKEN_LEN];

Script::Script(Common::ReadStream *input, bool disposeSource) : _input(input), _disposeSource(disposeSource), _line(0) {}

Script::~Script() {
	if (_disposeSource)
		delete _input;
}

char *Script::readLine(char *buf, size_t bufSize) {

	uint16 _si;
	char v2 = 0;
	for ( _si = 0; _si<bufSize; _si++) {

		v2 = _input->readSByte();

		if (v2 == 0xA || v2 == 0xD || _input->eos()) break;
		if (!_input->eos() && _si < bufSize) buf[_si] = v2;
	}

	_line++;

	if (_si == 0 && _input->eos())
		return 0;

	buf[_si] = 0xA;
	buf[_si+1] = '\0';

	return buf;

}



void Script::clearTokens() {

	for (uint16 i = 0; i < 20; i++)
		_tokens[i][0] = '\0';

	return;

}

void Script::skip(const char* endToken) {

	while (scumm_stricmp(_tokens[0], endToken)) {
		readLineToken(true);
	}

}

//
//	Scans 's' until one of the stop-chars in 'brk' is found, building a token.
//	If the routine encounters quotes, it will extract the contained text and
//  make a proper token. When scanning inside quotes, 'brk' is ignored and
//  only newlines are considered stop-chars.
//
//	The routine returns the unparsed portion of the input string 's'.
//
char *parseNextToken(char *s, char *tok, uint16 count, const char *brk, bool ignoreQuotes) {

	enum STATES { NORMAL, QUOTED };

	STATES state = NORMAL;

	while (count > 0) {

		switch (state) {
		case NORMAL:
			if (*s == '\0') {
				*tok = '\0';
				return s;
			}

			if (strchr(brk, *s)) {
				*tok = '\0';
				return ++s;
			}

			if (*s == '"') {
				if (ignoreQuotes) {
					*tok++ = *s++;
					count--;
				} else {
					state = QUOTED;
					s++;
				}
			} else {
				*tok++ = *s++;
				count--;
			}
			break;

		case QUOTED:
			if (*s == '\0') {
				*tok = '\0';
				return s;
			}
			if (*s == '"' || *s == '\n' || *s == '\t') {
				*tok = '\0';
				return ++s;
			}

			*tok++ = *s++;
			count--;
			break;
		}

	}

	*tok = '\0';
	// TODO: if execution flows here, make *REALLY* sure everything has been parsed
	// out of the input string. This is what is supposed to happen, but never ever
	// allocated time to properly check.

	return tok;

}

uint16 Script::fillTokens(char* line) {

	uint16 i = 0;
	while (strlen(line) > 0 && i < 20) {
		line = parseNextToken(line, _tokens[i], MAX_TOKEN_LEN, " \t\n");
		line = Common::ltrim(line);
		i++;
	}

	return i;
}

bool isCommentLine(char *text) {
	return text[0] == '#';
}

bool isStartOfCommentBlock(char *text) {
	return (text[0] == '[');
}

bool isEndOfCommentBlock(char *text) {
	return (text[0] == ']');
}

uint16 Script::readLineToken(bool errorOnEOF) {

	clearTokens();

	bool inBlockComment = false, inLineComment;

	char buf[200];
	char *line = NULL;
	do {
		inLineComment = false;

		line = readLine(buf, 200);

		if (line == NULL) {
			if (errorOnEOF)
				error("unexpected end of file while parsing");
			else
				return 0;
		}
		line = Common::ltrim(line);

		if (isCommentLine(line)) {
			inLineComment = true;
		} else
		if (isStartOfCommentBlock(line)) {
			inBlockComment = true;
		} else
		if (isEndOfCommentBlock(line)) {
			inBlockComment = false;
		}

	} while (inLineComment || inBlockComment || strlen(line) == 0);

	return fillTokens(line);
}


void Parser::reset() {
	_currentOpcodes = 0;
	_currentStatements = 0;

	_statements.clear();
	_opcodes.clear();
}

void Parser::pushTables(OpcodeSet *opcodes, Table *statements) {
	_opcodes.push(_currentOpcodes);
	_statements.push(_currentStatements);

	_currentOpcodes = opcodes;
	_currentStatements = statements;
}

void Parser::popTables() {
	assert(_opcodes.size() > 0);

	_currentOpcodes = _opcodes.pop();
	_currentStatements = _statements.pop();
}

void Parser::parseStatement() {
	assert(_currentOpcodes != 0);

	_lookup = _currentStatements->lookup(_tokens[0]);

	debugC(9, kDebugParser, "parseStatement: %s (lookup = %i)", _tokens[0], _lookup);

	(*(*_currentOpcodes)[_lookup])();
}


} // namespace Parallaction