/*
    * SPDX-FileCopyrightText: none
    * SPDX-License-Identifier: CC0-1.0
    */
   
   package dev.metaschema.core.metapath.item.atomic.impl;
   
   import java.util.regex.Pattern;
   
  import dev.metaschema.core.metapath.item.atomic.AbstractAnyAtomicItem;
  import dev.metaschema.core.metapath.item.atomic.IStringItem;
  import dev.metaschema.core.metapath.item.function.IMapKey;
  import dev.metaschema.core.metapath.item.function.impl.AbstractStringMapKey;
  import edu.umd.cs.findbugs.annotations.NonNull;
  
  /**
   * A common base class for all items derived from {@link IStringItem}.
   */
  public abstract class AbstractStringItem
      extends AbstractAnyAtomicItem<String>
      implements IStringItem {
    private static final String WHITESPACE_SEGMENT = "[ \t\r\n]";
    /**
     * Pattern to match one or more whitespace characters at the end of a string.
     */
    private static final Pattern TRIM_END = Pattern.compile(WHITESPACE_SEGMENT + "++$");
    /**
     * Pattern to match one or more whitespace characters at the start of a string.
     */
    private static final Pattern TRIM_START = Pattern.compile("^" + WHITESPACE_SEGMENT + "+");
    /**
     * Pattern to match two or more consecutive whitespace characters.
     */
    private static final Pattern TRIM_MIDDLE = Pattern.compile(WHITESPACE_SEGMENT + "{2,}");
  
    /**
     * Construct a new string item with the provided {@code value}.
     *
     * @param value
     *          the value to wrap
     */
    protected AbstractStringItem(@NonNull String value) {
      super(value);
    }
  
    @Override
    public String asString() {
      return getValue();
    }
  
    @Override
    public IMapKey asMapKey() {
      return new MapKey();
    }
  
    @Override
    public IStringItem normalizeSpace() {
      String value = asString();
      value = TRIM_START.matcher(value).replaceFirst("");
      value = TRIM_MIDDLE.matcher(value).replaceAll(" ");
      value = TRIM_END.matcher(value).replaceFirst("");
      assert value != null;
  
      return IStringItem.valueOf(value);
    }
  
    @Override
    protected String getValueSignature() {
      return "'" + getValue() + "'";
    }
  
    @Override
    public int hashCode() {
      return asString().hashCode();
    }
  
    @Override
    public boolean equals(Object obj) {
      return this == obj
          || obj instanceof IStringItem && compareTo((IStringItem) obj) == 0;
    }
  
    private final class MapKey
        extends AbstractStringMapKey {
  
      @Override
      public IStringItem getKey() {
        return AbstractStringItem.this;
      }
  
      @Override
      public String asString() {
        return getKey().asString();
      }
    }
  
  }