/*

 * Copyright (c) 1995, 2016, 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.internal.jshell.tool;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import java.util.Map.Entry;

import static java.util.stream.Collectors.toList;

/**

 * Parse command arguments, derived from StreamTokenizer by

 * @author  James Gosling

 */

class ArgTokenizer {

    private final String str;

    private final String prefix;

    private final int length;

    private int next = 0;

    private char buf[] = new char[20];

    private int mark;

    private final byte ctype[] = new byte[256];

    private static final byte CT_ALPHA = 0;

    private static final byte CT_WHITESPACE = 1;

    private static final byte CT_QUOTE = 8;

    private String sval;

    private boolean isQuoted = false;

    private final Map<String, Boolean> options = new HashMap<>();

    private final List<String> badOptions = new ArrayList<>();

    ArgTokenizer(String prefix, String arg) {

        this.str = arg;

        this.prefix = prefix + " ";

        this.length = arg.length();

        quoteChar('"');

        quoteChar('\'');

        whitespaceChars(0x09, 0x0D);

        whitespaceChars(0x1C, 0x20);

        whitespaceChars(0x85, 0x85);

        whitespaceChars(0xA0, 0xA0);

    }

    /**

     * Return the next non-option argument. Encountered options are stored.

     *

     * @return the token string, or null if there are no more tokens

     */

    String next() {

        while (true) {

            nextToken();

            if (sval != null && !isQuoted() && sval.startsWith("-")) {

                // allow POSIX getopt() option format,

                // to be consistent with command-line

                String opt = sval.startsWith("--")

                        ? sval.substring(1)

                        : sval;

                foundOption(opt);

            } else {

                break;

            }

        }

        return sval;

    }

    private void foundOption(String opt) {

        if (options.containsKey(opt)) {

            options.put(opt, true);

            return;

        }

        List<Map.Entry<String,Boolean>> matches =

                options.entrySet()

                       .stream()

                       .filter(e -> e.getKey().startsWith(opt))

                       .collect(toList());

        if (matches.size() == 1) {

            matches.get(0).setValue(true);

        } else {

            badOptions.add(opt);

        }

    }

    /**

     * Set the allowed options. Must be called before any options would be read

     * and before calling any of the option functionality below.

     */

    void allowedOptions(String... opts) {

        for (String opt : opts) {

            options.putIfAbsent(opt, false);

        }

    }

    /**

     * Has the specified option been encountered.

     *

     * @param opt the option to check

     * @return true if the option has been encountered

     */

    boolean hasOption(String opt) {

        Boolean has = options.get(opt);

        if (has == null) {

            throw new InternalError("hasOption called before allowedOptions or on bad option");

        }

        return has;

    }

    /**

     * Return the number of encountered options

     *

     * @return the option count

     */

    int optionCount() {

        return (int) options.entrySet().stream()

                .filter(Entry::getValue)

                .count();

    }

    /**

     * Return the bad options encountered. Bad options are those that were not

     * listed in the call to allowedOptions().

     *

     * @return as space-separated list the bad options encountered, or the empty

     * string if none.

     */

    String badOptions() {

        return String.join(" ", badOptions);

    }

    /**

     * Consume the remainder of the input. This is useful to sure all options

     * have been encountered and to check to unexpected additional non-option

     * input.

     *

     * @return the string-separated concatenation of all remaining non-option

     * arguments.

     */

    String remainder() {

        List<String> rem = new ArrayList<>();

        while (next() != null) {

            rem.add(sval);

        }

        return String.join(" ", rem);

    }

    String val() {

        return sval;

    }

    boolean isQuoted() {

        return isQuoted;

    }

    String whole() {

        return prefix + str;

    }

    void mark() {

        mark = next;

    }

    void rewind() {

        next = mark;

    }

    /**

     * Reads a single character.

     *

     * @return The character read, or -1 if the end of the stream has been

     * reached

     */

    private int read() {

        if (next >= length) {

            return -1;

        }

        return str.charAt(next++);

    }

    /**

     * Specifies that all characters <i>c</i> in the range

     * <code>low&nbsp;&lt;=&nbsp;<i>c</i>&nbsp;&lt;=&nbsp;high</code>

     * are white space characters. White space characters serve only to

     * separate tokens in the input stream.

     *

     * <p>Any other attribute settings for the characters in the specified

     * range are cleared.

     *

     * @param   low   the low end of the range.

     * @param   hi    the high end of the range.

     */

    private void whitespaceChars(int low, int hi) {

        if (low < 0)

            low = 0;

        if (hi >= ctype.length)

            hi = ctype.length - 1;

        while (low <= hi)

            ctype[low++] = CT_WHITESPACE;

    }

    /**

     * Specifies that matching pairs of this character delimit string

     * constants in this tokenizer.

     * <p>

     * If a string quote character is encountered, then a string is

     * recognized, consisting of all characters after (but not including)

     * the string quote character, up to (but not including) the next

     * occurrence of that same string quote character, or a line

     * terminator, or end of file. The usual escape sequences such as

     * {@code "\u005Cn"} and {@code "\u005Ct"} are recognized and

     * converted to single characters as the string is parsed.

     *

     * <p>Any other attribute settings for the specified character are cleared.

     *

     * @param   ch   the character.

     */

    private void quoteChar(int ch) {

        if (ch >= 0 && ch < ctype.length)

            ctype[ch] = CT_QUOTE;

    }

    private int unicode2ctype(int c) {

        switch (c) {

            case 0x1680:

            case 0x180E:

            case 0x200A:

            case 0x202F:

            case 0x205F:

            case 0x3000:

                return CT_WHITESPACE;

            default:

                return CT_ALPHA;

        }

    }

    /**

     * Parses the next token of this tokenizer.

     */

    public void nextToken() {

        byte ct[] = ctype;

        int c;

        int lctype;

        sval = null;

        isQuoted = false;

        do {

            c = read();

            if (c < 0) {

                return;

            }

            lctype = (c < 256) ? ct[c] : unicode2ctype(c);

        } while (lctype == CT_WHITESPACE);

        if (lctype == CT_ALPHA) {

            int i = 0;

            do {

                if (i >= buf.length) {

                    buf = Arrays.copyOf(buf, buf.length * 2);

                }

                buf[i++] = (char) c;

                c = read();

                lctype = c < 0 ? CT_WHITESPACE : (c < 256)? ct[c] : unicode2ctype(c);

            } while (lctype == CT_ALPHA);

            if (c >= 0) --next; // push last back

            sval = String.copyValueOf(buf, 0, i);

            return;

        }

        if (lctype == CT_QUOTE) {

            int quote = c;

            int i = 0;

            /* Invariants (because \Octal needs a lookahead):

             *   (i)  c contains char value

             *   (ii) d contains the lookahead

             */

            int d = read();

            while (d >= 0 && d != quote) {

                if (d == '\\') {

                    c = read();

                    int first = c;   /* To allow \377, but not \477 */

                    if (c >= '0' && c <= '7') {

                        c = c - '0';

                        int c2 = read();

                        if ('0' <= c2 && c2 <= '7') {

                            c = (c << 3) + (c2 - '0');

                            c2 = read();

                            if ('0' <= c2 && c2 <= '7' && first <= '3') {

                                c = (c << 3) + (c2 - '0');

                                d = read();

                            } else

                                d = c2;

                        } else

                          d = c2;

                    } else {

                        switch (c) {

                        case 'a':

                            c = 0x7;

                            break;

                        case 'b':

                            c = '\b';

                            break;

                        case 'f':

                            c = 0xC;

                            break;

                        case 'n':

                            c = '\n';

                            break;

                        case 'r':

                            c = '\r';

                            break;

                        case 't':

                            c = '\t';

                            break;

                        case 'v':

                            c = 0xB;

                            break;

                        }

                        d = read();

                    }

                } else {

                    c = d;

                    d = read();

                }

                if (i >= buf.length) {

                    buf = Arrays.copyOf(buf, buf.length * 2);

                }

                buf[i++] = (char)c;

            }

            if (d == quote) {

                isQuoted = true;

            }

            sval = String.copyValueOf(buf, 0, i);

        }

    }

}