/*

 * Copyright (c) 2013 Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.nashorn.api.scripting;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

/**

 * Formatter is a class to get the type conversion between javascript types and

 * java types for the format (sprintf) method working.

 *

 * <p>In javascript the type for numbers can be different from the format type

 * specifier. For format type '%d', '%o', '%x', '%X' double need to be

 * converted to integer. For format type 'e', 'E', 'f', 'g', 'G', 'a', 'A'

 * integer needs to be converted to double.

 *

 * <p>Format type "%c" and javascript string needs special handling.

 *

 * <p>The javascript date objects can be handled if they are type double (the

 * related javascript code will convert with Date.getTime() to double). So

 * double date types are converted to long.

 *

 * <p>Pattern and the logic for parameter position: java.util.Formatter

 *

 */

    private Formatter() {

    }

    /**

     * Method which converts javascript types to java types for the

     * String.format method (jrunscript function sprintf).

     *

     * @param format a format string

     * @param args arguments referenced by the format specifiers in format

     * @return a formatted string

     */

        int positionalParameter = 1;

        while (m.find()) {

            int index = index(m.group(1));

            boolean previous = isPreviousArgument(m.group(2));

            char conversion = m.group(6).charAt(0);

            // skip over some formats

            if (index < 0 || previous

                    || conversion == 'n' || conversion == '%') {

                continue;

            }

            // index 0 here means take a positional parameter

            if (index == 0) {

                index = positionalParameter++;

            }

            // out of index, String.format will handle

            if (index > args.length) {

                continue;

            }

            // current argument

            Object arg = args[index - 1];

            // for date we convert double to long

            if (m.group(5) != null) {

                // convert double to long

                if (arg instanceof Double) {

                    args[index - 1] = ((Double) arg).longValue();

                }

            } else {

                // we have to convert some types

                switch (conversion) {

                    case 'd':

                    case 'o':

                    case 'x':

                    case 'X':

                        if (arg instanceof Double) {

                            // convert double to long

                            args[index - 1] = ((Double) arg).longValue();

                        } else if (arg instanceof String

                                && ((String) arg).length() > 0) {

                            // convert string (first character) to int

                            args[index - 1] = (int) ((String) arg).charAt(0);

                        }

                        break;

                    case 'e':

                    case 'E':

                    case 'f':

                    case 'g':

                    case 'G':

                    case 'a':

                    case 'A':

                        if (arg instanceof Integer) {

                            // convert integer to double

                            args[index - 1] = ((Integer) arg).doubleValue();

                        }

                        break;

                    case 'c':

                        if (arg instanceof Double) {

                            // convert double to integer

                            args[index - 1] = ((Double) arg).intValue();

                        } else if (arg instanceof String

                                && ((String) arg).length() > 0) {

                            // get the first character from string

                            args[index - 1] = (int) ((String) arg).charAt(0);

                        }

                        break;

                    default:

                        break;

                }

            }

        }

        return String.format(format, args);

    }

    /**

     * Method to parse the integer of the argument index.

     *

     * @return -1 if parsing failed, 0 if string is null, > 0 integer

     */

    private static int index(final String s) {

        int index = -1;

        if (s != null) {

            try {

                index = Integer.parseInt(s.substring(0, s.length() - 1));

            } catch (final NumberFormatException e) {

                //ignored

            }

        } else {

            index = 0;

        }

        return index;

    }

    /**

     * Method to check if a string contains '<'. This is used to find out if

     * previous parameter is used.

     *

     * @return true if '<' is in the string, else false

     */

    private static boolean isPreviousArgument(final String s) {

        return (s != null && s.indexOf('<') >= 0) ? true : false;

    }

    // %[argument_index$][flags][width][.precision][t]conversion

    private static final String formatSpecifier =

            "%(\\d+\\$)?([-#+ 0,(\\<]*)?(\\d+)?(\\.\\d+)?([tT])?([a-zA-Z%])";

    // compiled format string

    private static final Pattern FS_PATTERN;

    static {

        FS_PATTERN = Pattern.compile(formatSpecifier);

    }

}