/*
 * Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package com.sun.el.parser;

/**
 * This exception is thrown when parse errors are encountered. You can explicitly create objects of this exception type
 * by calling the method generateParseException in the generated parser.
 *
 * You can modify this class to customize your error reporting mechanisms so long as you retain the public fields.
 */
public class ParseException extends Exception {

    /**
     * This constructor is used by the method "generateParseException" in the generated parser. Calling this constructor
     * generates a new object of this type with the fields "currentToken", "expectedTokenSequences", and "tokenImage" set.
     * The boolean flag "specialConstructor" is also set to true to indicate that this constructor was used to create this
     * object. This constructor calls its super class with the empty string to force the "toString" method of parent class
     * "Throwable" to print the error message in the form: ParseException: <result of getMessage>
     */
    public ParseException(Token currentTokenVal, int[][] expectedTokenSequencesVal, String[] tokenImageVal) {
        super("");
        specialConstructor = true;
        currentToken = currentTokenVal;
        expectedTokenSequences = expectedTokenSequencesVal;
        tokenImage = tokenImageVal;
    }

    /**
     * The following constructors are for use by you for whatever purpose you can think of. Constructing the exception in
     * this manner makes the exception behave in the normal way - i.e., as documented in the class "Throwable". The fields
     * "errorToken", "expectedTokenSequences", and "tokenImage" do not contain relevant information. The JavaCC generated
     * code does not use these constructors.
     */

    public ParseException() {
        super();
        specialConstructor = false;
    }

    public ParseException(String message) {
        super(message);
        specialConstructor = false;
    }

    /**
     * This variable determines which constructor was used to create this object and thereby affects the semantics of the
     * "getMessage" method (see below).
     */
    protected boolean specialConstructor;

    /**
     * This is the last token that has been consumed successfully. If this object has been created due to a parse error, the
     * token followng this token will (therefore) be the first error token.
     */
    public Token currentToken;

    /**
     * Each entry in this array is an array of integers. Each array of integers represents a sequence of tokens (by their
     * ordinal values) that is expected at this point of the parse.
     */
    public int[][] expectedTokenSequences;

    /**
     * This is a reference to the "tokenImage" array of the generated parser within which the parse error occurred. This
     * array is defined in the generated ...Constants interface.
     */
    public String[] tokenImage;

    /**
     * This method has the standard behavior when this object has been created using the standard constructors. Otherwise,
     * it uses "currentToken" and "expectedTokenSequences" to generate a parse error message and returns it. If this object
     * has been created due to a parse error, and you do not catch it (it gets thrown from the parser), then this method is
     * called during the printing of the final stack trace, and hence the correct error message gets displayed.
     */
    @Override
    public String getMessage() {
        if (!specialConstructor) {
            return super.getMessage();
        }
        String expected = "";
        int maxSize = 0;
        for (int i = 0; i < expectedTokenSequences.length; i++) {
            if (maxSize < expectedTokenSequences[i].length) {
                maxSize = expectedTokenSequences[i].length;
            }
            for (int j = 0; j < expectedTokenSequences[i].length; j++) {
                expected += tokenImage[expectedTokenSequences[i][j]] + " ";
            }
            if (expectedTokenSequences[i][expectedTokenSequences[i].length - 1] != 0) {
                expected += "...";
            }
            expected += eol + "    ";
        }
        String retval = "Encountered \"";
        Token tok = currentToken.next;
        for (int i = 0; i < maxSize; i++) {
            if (i != 0) {
                retval += " ";
            }
            if (tok.kind == 0) {
                retval += tokenImage[0];
                break;
            }
            retval += add_escapes(tok.image);
            tok = tok.next;
        }
        retval += "\" at line " + currentToken.next.beginLine + ", column " + currentToken.next.beginColumn;
        retval += "." + eol;
        if (expectedTokenSequences.length == 1) {
            retval += "Was expecting:" + eol + "    ";
        } else {
            retval += "Was expecting one of:" + eol + "    ";
        }
        retval += expected;
        return retval;
    }

    /**
     * The end of line string for this machine.
     */
    protected String eol = System.getProperty("line.separator", "\n");

    /**
     * Used to convert raw characters to their escaped version when these raw version cannot be used as part of an ASCII
     * string literal.
     */
    protected String add_escapes(String str) {
        StringBuffer retval = new StringBuffer();
        char ch;
        for (int i = 0; i < str.length(); i++) {
            switch (str.charAt(i)) {
            case 0:
                continue;
            case '\b':
                retval.append("\\b");
                continue;
            case '\t':
                retval.append("\\t");
                continue;
            case '\n':
                retval.append("\\n");
                continue;
            case '\f':
                retval.append("\\f");
                continue;
            case '\r':
                retval.append("\\r");
                continue;
            case '\"':
                retval.append("\\\"");
                continue;
            case '\'':
                retval.append("\\\'");
                continue;
            case '\\':
                retval.append("\\\\");
                continue;
            default:
                if ((ch = str.charAt(i)) < 0x20 || ch > 0x7e) {
                    String s = "0000" + Integer.toString(ch, 16);
                    retval.append("\\u" + s.substring(s.length() - 4, s.length()));
                } else {
                    retval.append(ch);
                }
                continue;
            }
        }
        return retval.toString();
    }

}
