# ServiceArgumentsParser.java

    /*
    ** Module   : ServiceArgumentsParser.java
    ** Abstract : Base class to interpret input arguments for a web service (REST or SOAP).
    **
    ** Copyright (c) 2020-2022, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ---------------------------------------Description----------------------------------------
    ** 001 CA  20200514 First version.
    **     CA  20200528 Added APIs for REST extent arguments (not implemented yet).
    ** 002 CA  20211112 Refactored to allow transfer of the DATASET or TABLE via XML, for SOAP.
    **     CA  20220329 Added support for REST services written directly in Java.
    */

    /*
    ** 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.
    **
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    **
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    **
    **     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.rest;

    import java.io.*;

    import javax.servlet.http.*;

    import com.goldencode.p2j.main.*;
    import com.goldencode.p2j.persist.*;
    import com.goldencode.p2j.util.*;

    /**
     * Base class for parsing the input arguments for a web service call (REST or SOAP).
     */
    public abstract class ServiceArgumentsParser
    {
       /**
        * Parse an extent argument.
        *
        * @param    body
        *           The HTTP body.
        * @param    request
        *           The request payload.
        * @param    idx
        *           The argument's index.
        * @param    source
        *           The arguments's source.
        * @param    type
        *           The arguments's type.
        * @param    extent
        *           The arguments's length.
        *
        * @return   An array with the argument's values.
        */
       protected abstract Object[] parseExtentArgument(String             body,
                                                       HttpServletRequest request,
                                                       int                idx,
                                                       String             source,
                                                       String             type,
                                                       int                extent)
       throws RequestArgumentError;

       /**
        * Assign the given argument to the specified value.
        *
        * @param    idx
        *           The argument's index.
        * @param    bdt
        *           The argument's {@link BaseDataType} instance (may be <code>null</code>).
        * @param    sval
        *           The string representation of this argument.
        */
       protected abstract void assignArgument(int idx, BaseDataType bdt, String sval)
       throws RequestArgumentError;

       /**
        * Parse the argument, by interpreting the request.
        *
        * @param    body
        *           The request body.
        * @param    source
        *           The parameter's encoded source.
        * @param    request
        *           The request payload.
        *
        * @return   The resolved argument.
        */
       protected abstract String parseArgumentInt(String body, String source, HttpServletRequest request)
       throws IOException;

       /**
        * Load the specified table.
        *
        * @param    content
        *           The table definition.
        *
        * @return   A {@link TableWrapper} instance to be passed as argument to the remote call.
        */
       protected abstract TableWrapper loadTable(String content)
       throws IOException,
              RequestArgumentError;

       /**
        * Load the specified dataset.
        *
        * @param    content
        *           The dataset definition.
        *
        * @return   A {@link DatasetWrapper} instance to be passed as argument to the remote call.
        */
       protected abstract DatasetWrapper loadDataSet(String content)
       throws IOException,
              RequestArgumentError;

       /**
        * Create a new {@link DatasetWrapper}.  This implementation by default returns <code>null</code>.
        *
        * @param    name
        *           The dataset name.
        * @param    input
        *           The INPUT mode.
        * @param    output
        *           The OUTPUT mode.
        * @param    asHandle
        *           Flag indicating if this is a DATASET-HANDLE parameter.
        *
        * @return   <code>null</code> by default.
        */
       protected DatasetWrapper createDataset(String name, boolean input, boolean output, boolean asHandle)
       {
          return null;
       }

       /**
        * Create a new {@link TableWrapper}.  This implementation by default returns <code>null</code>.
        *
        * @param    name
        *           The table name.
        * @param    input
        *           The INPUT mode.
        * @param    output
        *           The OUTPUT mode.
        * @param    asHandle
        *           Flag indicating if this is a DATASET-HANDLE parameter.
        *
        * @return   <code>null</code> by default.
        */
       protected TableWrapper createTable(String name, boolean input, boolean output, boolean asHandle)
       {
          return null;
       }

       /**
        * Parse the arguments, by interpreting the request.
        * <p>
        * For OUTPUT, they will be set to default value.  For INPUT, they will be resolved from
        * the request.
        *
        * @param    service
        *           The service definition.
        * @param    request
        *           The request payload.
        *
        * @return   The resolved arguments.
        */
       public final Object[] parseArguments(RestService service, HttpServletRequest request)
       throws IOException,
              RequestArgumentError
       {
          LegacyServiceParameter[] serviceParameters = service.ls.parameters();
          LegacyServiceParameter[] original = service.getDefinitionParameters();
          ArgumentsParser parser = service.getParser(this);

          return parseArguments(parser, serviceParameters, original, request);
       }

       /**
        * Parse the arguments, by interpreting the request.
        * <p>
        * For OUTPUT, they will be set to default value.  For INPUT, they will be resolved from
        * the request.
        *
        * @param    serviceParameters
        *           The legacy service definition parameters.
        * @param    original
        *           The definition parameters.
        * @param    request
        *           The request payload.
        *
        * @return   The resolved arguments.
        */
       public final Object[] parseArguments(LegacyServiceParameter[] serviceParameters,
                                            LegacyServiceParameter[] original,
                                            HttpServletRequest       request)
       throws IOException,
              RequestArgumentError
       {
          return parseArguments(new LegacyArgumentsParser(this), serviceParameters, original, request);
       }

       /**
        * Parse the arguments, by interpreting the request.
        * <p>
        * For OUTPUT, they will be set to default value.  For INPUT, they will be resolved from
        * the request.
        *
        * @param    parser
        *           The parser to be used for parsing the arguments
        * @param    serviceParameters
        *           The legacy service definition parameters.
        * @param    original
        *           The definition parameters.
        * @param    request
        *           The request payload.
        *
        * @return   The resolved arguments.
        */
       public final Object[] parseArguments(ArgumentsParser          parser,
                                            LegacyServiceParameter[] serviceParameters,
                                            LegacyServiceParameter[] original,
                                            HttpServletRequest       request)
       throws IOException,
              RequestArgumentError
       {
          byte[] bbody = LegacyServiceHandler.readBody(request);
          String body = new String(bbody);

          Object[] args = new Object[original.length];
          for (int i = 0; i < args.length; i++)
          {
             LegacyServiceParameter lsp = original[i];

             args[i] = parser.initArgument(lsp, serviceParameters, i);
          }

          for (int i = 0; i < serviceParameters.length; i++)
          {
             LegacyServiceParameter lsp = serviceParameters[i];
             if (lsp.returnValue())
             {
                continue;
             }

             if (lsp.input())
             {
                int idx = lsp.ordinal() - 1;
                Object arg = parser.parseArgument(lsp, original, args[idx], i, body, request);
                args[idx] = arg;
             }
          }

          return args;
       }

       /**
        * Raises an error so that the request stops with a 5xx internal server error.
        *
        * @param    bdt
        *           The BDT for which the value could not be parsed.
        * @param    val
        *           The attempted value to assign.
        */
       protected void notAValue(BaseDataType bdt, String val)
       throws RequestArgumentError
       {
          String msg = "The value was not a " + bdt.getTypeName();
          switch (bdt.getClass().getSimpleName())
          {
             case "decimal":
                msg = "Unable to convert from java.lang.String to java.math.BigDecimal - The value was not a DECIMAL";
                break;
             case "integer":
                msg = "Unable to convert from java.lang.String to java.lang.Integer - The value was not an INTEGER";
                break;
             case "int64":
                msg = "Unable to convert from java.lang.String to java.lang.Long - The value was not a LONG";
                break;
             case "date":
             case "datetime":
             case "datetimetz":
                msg = "Unable to convert from java.lang.String to java.util.GregorianCalendar - The value was not a DATE, DATETIME or DATETIME-TZ";
                break;
             case "rowid":
                // TODO: what is the correct message?
                msg = "The value was not a Rowid";
                break;
             case "memptr":
                // TODO: what is the correct message?
                msg = "The value was not a Memptr";
                break;
          }

          throw new RequestArgumentError(msg);
       }

       /**
        * Generate an unknown instance for the given type.
        *
        * @param    type
        *           The parameter's type.
        *
        * @return   The unknown instance.
        */
       BaseDataType unknownInstance(String type)
       {
          return BaseDataType.generateUnknown(BaseDataType.fromTypeName(type));
       }
    }