/* ========================================================================
 * PlantUML : a free UML diagram generator
 * ========================================================================
 *
 * (C) Copyright 2009-2020, Arnaud Roques
 *
 * Project Info:  http://plantuml.com
 *
 * If you like this project or if you find it useful, you can support us at:
 *
 * http://plantuml.com/patreon (only 1$ per month!)
 * http://plantuml.com/paypal
 *
 * This file is part of PlantUML.
 *
 * PlantUML 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.
 *
 * PlantUML 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 library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 *
 * Original Author:  Arnaud Roques
 *
 */
package net.sourceforge.plantuml.tim.expression;

import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Deque;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import net.sourceforge.plantuml.tim.Eater;
import net.sourceforge.plantuml.tim.EaterException;
import net.sourceforge.plantuml.tim.TContext;
import net.sourceforge.plantuml.tim.TMemory;

public class TokenStack {

	final private List<Token> tokens;

	public TokenStack() {
		this(new ArrayList<Token>());
	}

	private TokenStack(List<Token> list) {
		this.tokens = list;
	}

	public TokenStack subTokenStack(int i) {
		return new TokenStack(Collections.unmodifiableList(tokens.subList(i, tokens.size())));
	}

	@Override
	public String toString() {
		return tokens.toString();
	}

	public void add(Token token) {
		this.tokens.add(token);
	}

	public TokenStack withoutSpace() {
		final TokenStack result = new TokenStack();
		for (Token token : tokens) {
			if (token.getTokenType() != TokenType.SPACES) {
				result.add(token);
			}
		}
		return result;
	}

	static public TokenStack eatUntilCloseParenthesisOrComma(Eater eater) throws EaterException {
		final TokenStack result = new TokenStack();
		int level = 0;
		while (true) {
			eater.skipSpaces();
			final char ch = eater.peekChar();
			if (ch == 0) {
				throw new EaterException("until001");
			}
			if (level == 0 && (ch == ',' || ch == ')')) {
				return result;
			}
			final Token token = TokenType.eatOneToken(eater, false);
			final TokenType type = token.getTokenType();
			if (type == TokenType.OPEN_PAREN_MATH) {
				level++;
			} else if (type == TokenType.CLOSE_PAREN_MATH) {
				level--;
			}
			result.add(token);
		}
	}

	static public void eatUntilCloseParenthesisOrComma(TokenIterator it) throws EaterException {
		int level = 0;
		while (true) {
			final Token ch = it.peekToken();
			if (ch == null) {
				throw new EaterException("until002");
			}
			final TokenType typech = ch.getTokenType();
			if (level == 0 && (typech == TokenType.COMMA || typech == TokenType.CLOSE_PAREN_MATH)
					|| typech == TokenType.CLOSE_PAREN_FUNC) {
				return;
			}
			final Token token = it.nextToken();
			final TokenType type = token.getTokenType();
			if (type == TokenType.OPEN_PAREN_MATH || type == TokenType.OPEN_PAREN_FUNC) {
				level++;
			} else if (type == TokenType.CLOSE_PAREN_MATH || type == TokenType.CLOSE_PAREN_FUNC) {
				level--;
			}
		}
	}

	private int countFunctionArg(TokenIterator it) throws EaterException {
		// return 42;
		final TokenType type1 = it.peekToken().getTokenType();
		if (type1 == TokenType.CLOSE_PAREN_MATH || type1 == TokenType.CLOSE_PAREN_FUNC) {
			return 0;
		}
		int result = 1;
		while (it.hasMoreTokens()) {
			eatUntilCloseParenthesisOrComma(it);
			final Token token = it.nextToken();
			final TokenType type = token.getTokenType();
			if (type == TokenType.CLOSE_PAREN_MATH || type == TokenType.CLOSE_PAREN_FUNC) {
				return result;
			} else if (type == TokenType.COMMA) {
				result++;
			} else {
				throw new EaterException("count13");
			}
		}
		throw new EaterException("count12");
	}

	public void guessFunctions() throws EaterException {
		final Deque<Integer> open = new ArrayDeque<Integer>();
		final Map<Integer, Integer> parens = new HashMap<Integer, Integer>();
		for (int i = 0; i < tokens.size(); i++) {
			final Token token = tokens.get(i);
			if (token.getTokenType().equals(TokenType.OPEN_PAREN_MATH)) {
				open.addFirst(i);
			} else if (token.getTokenType().equals(TokenType.CLOSE_PAREN_MATH)) {
				parens.put(open.pollFirst(), i);
			}
		}
		// System.err.println("before=" + toString());
		// System.err.println("guessFunctions2" + parens);
		for (Map.Entry<Integer, Integer> ids : parens.entrySet()) {
			final int iopen = ids.getKey();
			final int iclose = ids.getValue();
			assert tokens.get(iopen).getTokenType() == TokenType.OPEN_PAREN_MATH;
			assert tokens.get(iclose).getTokenType() == TokenType.CLOSE_PAREN_MATH;
			if (iopen > 0 && tokens.get(iopen - 1).getTokenType() == TokenType.PLAIN_TEXT) {
				tokens.set(iopen - 1, new Token(tokens.get(iopen - 1).getSurface(), TokenType.FUNCTION_NAME));
				final int nbArg = countFunctionArg(subTokenStack(iopen + 1).tokenIterator());
				tokens.set(iopen, new Token("" + nbArg, TokenType.OPEN_PAREN_FUNC));
				tokens.set(iclose, new Token(")", TokenType.CLOSE_PAREN_FUNC));
			}
		}
		// System.err.println("after=" + toString());
	}

	class InternalIterator implements TokenIterator {

		private int pos = 0;

		public Token peekToken() {
			return tokens.get(pos);
		}

		public Token nextToken() {
			if (hasMoreTokens() == false) {
				return null;
			}
			return tokens.get(pos++);
		}

		public boolean hasMoreTokens() {
			return pos < tokens.size();
		}

	}

	public TokenIterator tokenIterator() {
		return new InternalIterator();
	}

	public TValue getResult(TContext context, TMemory memory) throws EaterException {
		final Knowledge knowledge = context.asKnowledge(memory);
		final TokenStack tmp = withoutSpace();
		tmp.guessFunctions();
		final TokenIterator it = tmp.tokenIterator();
		final ShuntingYard shuntingYard = new ShuntingYard(it, knowledge);
		final ReversePolishInterpretor rpn = new ReversePolishInterpretor(shuntingYard.getQueue(), knowledge, memory,
				context);
		return rpn.getResult();

	}

}
