/*

 * Copyright (C) 2007-2010 Júlio Vilmar Gesser.

 * Copyright (C) 2011, 2013-2021 The JavaParser Team.

 *

 * This file is part of JavaParser.

 *

 * JavaParser can be used either under the terms of

 * a) the GNU Lesser General Public License as published by

 *     the Free Software Foundation, either version 3 of the License, or

 *     (at your option) any later version.

 * b) the terms of the Apache License

 *

 * You should have received a copy of both licenses in LICENCE.LGPL and

 * LICENCE.APACHE. Please refer to those files for details.

 *

 * JavaParser 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 Lesser General Public License for more details.

 */

package com.github.javaparser;

import static com.github.javaparser.utils.Utils.assertNotNull;

import java.util.Iterator;

import java.util.Optional;

/**

 * The range of tokens covered by this node.

 */

public class TokenRange implements Iterable<JavaToken> {

    public static final TokenRange INVALID = new TokenRange(JavaToken.INVALID, JavaToken.INVALID);

    private final JavaToken begin;

    private final JavaToken end;

    public TokenRange(JavaToken begin, JavaToken end) {

        this.begin = assertNotNull(begin);

        this.end = assertNotNull(end);

    }

    public JavaToken getBegin() {

        return begin;

    }

    public JavaToken getEnd() {

        return end;

    }

    public Optional<Range> toRange() {

        if (begin.hasRange() && end.hasRange()) {

            return Optional.of(new Range(begin.getRange().get().begin, end.getRange().get().end));

        }

        return Optional.empty();

    }

    public TokenRange withBegin(JavaToken begin) {

        return new TokenRange(assertNotNull(begin), end);

    }

    public TokenRange withEnd(JavaToken end) {

        return new TokenRange(begin, assertNotNull(end));

    }

    @Override

    public String toString() {

        StringBuilder result = new StringBuilder();

        for(JavaToken t: this) {

            result.append(t.getText());

        }

        return result.toString();

    }

    @Override

    public Iterator<JavaToken> iterator() {

        return new Iterator<JavaToken>() {

            private boolean hasNext = true;

            private JavaToken current = begin;

            @Override

            public boolean hasNext() {

                return hasNext;

            }

            @Override

            public JavaToken next() {

                JavaToken retval = current;

                if(current == null){

                    throw new IllegalStateException("Attempting to move past end of range.");

                }

                if (current == end) {

                    hasNext = false;

                }

                current = current.getNextToken().orElse(null);

                if(current == null && hasNext){

                    throw new IllegalStateException("End token is not linked to begin token.");

                }

                return retval;

            }

        };

    }

}