# DateFormatParser.java

    /*
    ** Module   : DateFormatParser.java
    ** Abstract : Base class for Progress date format parsers/formatters.
    **
    ** Copyright (c) 2021, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ---------------------------------Description---------------------------------
    ** 001 VVT 20210413 Created initial version.
    **     VVT 20210417 Moved here from the test/ directory.
    **     VVT 20210426 The visitYear/Month/Day callbacks eliminated in favor of
    **                  visitDateComponent.
    **     VVT 20210624 Javadoc fixed
    */
    /*
    ** This program is free software: you can redistribute it and/or modify
    ** it under the terms of the GNU Affero General Public License as
    ** published by the Free Software Foundation, either version 3 of the
    ** License, or (at your option) any later version.
    **
    ** This program 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 Affero General Public License for more details.
    **
    ** You may find a copy of the GNU Affero GPL version 3 at the following
    ** location: https://www.gnu.org/licenses/agpl-3.0.en.html
    **
    ** Additional terms under GNU Affero GPL version 3 section 7:
    **
    **   Under Section 7 of the GNU Affero GPL version 3, the following additional
    **   terms apply to the works covered under the License.  These additional terms
    **   are non-permissive additional terms allowed under Section 7 of the GNU
    **   Affero GPL version 3 and may not be removed by you.
    **
    **   0. Attribution Requirement.
    **
    **     You must preserve all legal notices or author attributions in the covered
    **     work or Appropriate Legal Notices displayed by works containing the covered
    **     work.  You may not remove from the covered work any author or developer
    **     credit already included within the covered work.
    **
    **   1. No License To Use Trademarks.
    **
    **     This license does not grant any license or rights to use the trademarks
    **     Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
    **     of Golden Code Development Corporation. You are not authorized to use the
    **     name Golden Code, FWD, or the names of any author or contributor, for
    **     publicity purposes without written authorization.
    **
    **   2. No Misrepresentation of Affiliation.
    **
    **     You may not represent yourself as Golden Code Development Corporation or FWD.
    **
    **     You may not represent yourself for publicity purposes as associated with
    **     Golden Code Development Corporation, FWD, or any author or contributor to
    **     the covered work, without written authorization.
    **
    **   3. No Misrepresentation of Source or Origin.
    **
    **     You may not represent the covered work as solely your work.  All modified
    **     versions of the covered work must be marked in a reasonable way to make it
    **     clear that the modified work is not originating from Golden Code Development
    **     Corporation or FWD.  All modified versions must contain the notices of
    **     attribution required in this license.
    */
    package com.goldencode.p2j.util;

    /**
     * Base class for Progress date format parsers/formatters.
     *
     * The {@link #parse(String)} method is responsible for checking the
     * Progress date format validity.
     *
     * Also this class provides a set of callback methods,
     * each callback is called when the corresponding format component is parsed.
     *
     * By default, all callbacks do nothing, they are expected to be re-defined in subclasses.
     */
    public class DateFormatParser
    {
       /**
        * The first date component separator was parsed: one of '.', '-' or '/'.
        * <p>
        * Subclasses are expected to overload this method,
        * default implementation does nothing.
        * <p>
        * Note: if date format has no separators, this callback is never called.
        *
        * @param sep
        *        the first separator character
        */
       protected void visitSep1(final char sep)
       {
          // no-op
       }

       /**
        * The second date component separator was parsed: one of '.', '-' or '/'.
        * <p>
        * Subclasses are expected to overload this method,
        * default implementation does nothing.
        * <p>
        * Note: if date format has no separators, this callback is never called.
        *
        * @param sep
        *        the second separator character
        */
       protected void visitSep2(final char sep)
       {
          // no-op
       }

       /**
        * Dispatch the date component to a matching callback.
        *
        * @param componentIndex
        *        the number of the component in the format spec
        * @param startIdx
        *        the component start index, zero based
        * @param endIdx
        *        the component end index, zero based, exclusive
        */
       protected void visitDateComponent(final int componentIndex, final int startIdx, final int endIdx)
       {
          // no-op
       }

       /**
        * Parse date format, call callbacks while parsing.
        *
        * @param format
        *        the format to parse
        *
        * @throws ErrorConditionException
        *         in case the date format is invalid
        */
       public void parse(final String format)
       throws ErrorConditionException
       {
          final int len = format.length();

          // handle special cases first
          switch (format)
          {
             case "999999":
             case "99999999":
                visitDateComponent(0, 0, 2);
                visitDateComponent(1, 2, 4);
                visitDateComponent(2, 4, len);
                return;

             default:
          }

          int idx = 0;

          for (; idx < len && format.charAt(idx) == '9'; idx++)
             ;

          if (idx == len)
          {
             genDateFormatIncomleteError(format);
             return;
          }

          // Start if component 2 if exist
          final int comp2idx;
          char c = format.charAt(idx);
          switch (c)
          {
             case '.':
             case '-':
             case '/':
                visitDateComponent(0, 0, idx);
                visitSep1(c);
                idx++;
                comp2idx = idx;
                break;
             default:
                ErrorManager.genInvalidCharError(idx, format);
                return;
          }

          if (idx == len)
          {
             genDateFormatIncomleteError(format);
             return;
          }

          int sectionStart = idx;
          for (; idx < len && format.charAt(idx) == '9'; idx++)
             ;
          if (idx == len)
          {
             genDateFormatIncomleteError(format);
             return;
          }

          if (idx == sectionStart)
          {
             ErrorManager.genInvalidCharError(idx, format);
             return;
          }

          final int comp3idx;
          c = format.charAt(idx);
          switch (c)
          {
             case '.':
             case '-':
             case '/':
                visitDateComponent(1, comp2idx, idx);
                visitSep2(c);
                idx++;
                comp3idx = idx;
                break;
             default:
                ErrorManager.genInvalidCharError(idx, format);
                return;
          }

          sectionStart = idx;
          for (; idx < len && format.charAt(idx) == '9'; idx++)
             ;

          // We must check these two error conditions in this very order to match the OE error handling.
          if (idx < len)
          {
             ErrorManager.genInvalidCharError(idx, format);
             return;
          }

          if (idx == sectionStart)
          {
             genDateFormatIncomleteError(format);
             return;
          }

          visitDateComponent(2, comp3idx, len);
       }

       /**
        * Record or throw the error number 154.
        *
        * @param fmt
        *        the problematic format string
        */
       private static final void genDateFormatIncomleteError(final String fmt)
       {
          ErrorManager.recordOrThrowError(154, "Date format " + fmt + " is incomplete");
       }
    }