/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package dev.metaschema.core.metapath.function.library;
   
   import java.util.List;
   
  import dev.metaschema.core.metapath.DynamicContext;
  import dev.metaschema.core.metapath.MetapathConstants;
  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.IDateTimeItem;
  import dev.metaschema.core.metapath.item.atomic.IDateTimeWithTimeZoneItem;
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  /**
   * Implements the XPath 3.1 <a href=
   * "https://www.w3.org/TR/xpath-functions-31/#func-current-dateTime">fn:current-dateTime</a>
   * function.
   */
  public final class FnCurrentDateTime {
    private static final String NAME = "current-dateTime";
    @NonNull
    static final IFunction SIGNATURE = IFunction.builder()
        .name(NAME)
        .namespace(MetapathConstants.NS_METAPATH_FUNCTIONS)
        .deterministic()
        .contextDependent()
        .focusIndependent()
        .returnType(IDateTimeItem.type())
        .returnOne()
        .functionHandler(FnCurrentDateTime::execute)
        .build();
  
    private FnCurrentDateTime() {
      // disable construction
    }
  
    @SuppressWarnings("unused")
    @NonNull
    private static ISequence<IDateTimeItem> execute(@NonNull IFunction function,
        @NonNull List<ISequence<?>> arguments,
        @NonNull DynamicContext dynamicContext,
        IItem focus) {
      return ISequence.of(fnCurrentDateTime(dynamicContext));
    }
  
    /**
     * Implements <a href=
     * "https://www.w3.org/TR/xpath-functions-31/#func-current-dateTime">fn:current-dateTime</a>.
     *
     * @param dynamicContext
     *          the dynamic evaluation context
     * @return the current date
     */
    @NonNull
    public static IDateTimeItem fnCurrentDateTime(@NonNull DynamicContext dynamicContext) {
      // FIXME: support implicit timezone
      return IDateTimeWithTimeZoneItem.valueOf(dynamicContext.getCurrentDateTime());
    }
  }