/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package dev.metaschema.core.metapath.function.library;
   
   import org.apache.commons.lang3.StringUtils;
   
  import java.util.List;
  
  import dev.metaschema.core.metapath.DynamicContext;
  import dev.metaschema.core.metapath.MetapathConstants;
  import dev.metaschema.core.metapath.function.FunctionUtils;
  import dev.metaschema.core.metapath.function.IArgument;
  import dev.metaschema.core.metapath.function.IFunction;
  import dev.metaschema.core.metapath.item.IItem;
  import dev.metaschema.core.metapath.item.ISequence;
  import dev.metaschema.core.metapath.item.atomic.IStringItem;
  import dev.metaschema.core.util.ObjectUtils;
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  // CPD-OFF
  /**
   * Implements the XPath 3.1 <a href=
   * "https://www.w3.org/TR/xpath-functions-31/#func-substring-after">fn:substring-after</a>
   * function.
   */
  public final class FnSubstringAfter {
    private static final String NAME = "substring-after";
    @NonNull
    static final IFunction SIGNATURE_TWO_ARG = IFunction.builder()
        .name(NAME)
        .namespace(MetapathConstants.NS_METAPATH_FUNCTIONS)
        .deterministic()
        .contextIndependent()
        .focusIndependent()
        .argument(IArgument.builder()
            .name("arg1")
            .type(IStringItem.type())
            .zeroOrOne()
            .build())
        .argument(IArgument.builder()
            .name("arg2")
            .type(IStringItem.type())
            .zeroOrOne()
            .build())
        .returnType(IStringItem.type())
        .returnOne()
        .functionHandler(FnSubstringAfter::executeTwoArg)
        .build();
    // CPD-ON
  
    private FnSubstringAfter() {
      // disable construction
    }
  
    @SuppressWarnings("unused")
    @NonNull
    private static ISequence<IStringItem> executeTwoArg(
        @NonNull IFunction function,
        @NonNull List<ISequence<?>> arguments,
        @NonNull DynamicContext dynamicContext,
        IItem focus) {
  
      // From the XPath 3.1 specification:
      // If the value of $arg1 or $arg2 is the empty sequence, or contains only
      // ignorable collation units, it is interpreted as the zero-length string.
      IStringItem arg1 = arguments.get(0).isEmpty()
          ? IStringItem.valueOf("")
          : FunctionUtils.asType(ObjectUtils.notNull(arguments.get(0).getFirstItem(true)));
      IStringItem arg2 = arguments.get(1).isEmpty()
          ? IStringItem.valueOf("")
          : FunctionUtils.asType(ObjectUtils.notNull(arguments.get(1).getFirstItem(true)));
  
      return ISequence.of(IStringItem.valueOf(fnSubstringAfter(arg1.asString(), arg2.asString())));
    }
  
    /**
     * An implementation of XPath 3.1 <a href=
     * "https://www.w3.org/TR/xpath-functions-31/#func-substring-after">fn:substring-after</a>.
     *
     * @param arg1
     *          the source string to get a substring from
     * @param arg2
     *          the substring to match and find the substring to return after the
     *          match
     * @return the substring
     */
    @NonNull
    public static String fnSubstringAfter(
        @NonNull String arg1,
        @NonNull String arg2) {
      return ObjectUtils.notNull(StringUtils.substringAfter(arg1, arg2));
    }
  }