/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.juneau.http.entity;

import static org.apache.juneau.commons.utils.AssertionUtils.*;
import static org.apache.juneau.commons.utils.IoUtils.*;
import static org.apache.juneau.commons.utils.Utils.*;

import java.io.*;
import java.nio.charset.*;
import java.util.function.*;

import org.apache.juneau.commons.io.*;
import org.apache.juneau.http.header.*;

/**
 * A self contained, repeatable entity that obtains its content from a {@link String}.
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JuneauRestCommonBasics">juneau-rest-common Basics</a>
 * </ul>
 */
@SuppressWarnings("resource")
public class StringEntity extends BasicHttpEntity {
   private static final String EMPTY = "";
   private byte[] byteCache;

   /**
    * Constructor.
    */
   public StringEntity() {}

   /**
    * Constructor.
    *
    * @param contentType The entity content type.
    * @param content The entity contents.
    */
   public StringEntity(ContentType contentType, String content) {
      super(contentType, content);
   }

   /**
    * Copy constructor.
    *
    * @param copyFrom The bean being copied.
    */
   protected StringEntity(StringEntity copyFrom) {
      super(copyFrom);
   }

   @Override /* Overridden from AbstractHttpEntity */
   public byte[] asBytes() throws IOException {
      if (isCached() && byteCache == null)
         byteCache = content().getBytes(getCharset());
      if (nn(byteCache))
         return byteCache;
      return content().getBytes(getCharset());
   }

   @Override /* Overridden from AbstractHttpEntity */
   public String asString() throws IOException {
      return content();
   }

   @Override
   public StringEntity copy() {
      return new StringEntity(this);
   }

   @Override /* Overridden from HttpEntity */
   public InputStream getContent() throws IOException {
      if (isCached())
         return new ByteArrayInputStream(asBytes());
      return new ReaderInputStream(new StringReader(content()), getCharset());
   }

   @Override /* Overridden from HttpEntity */
   public long getContentLength() {
      if (isCached())
         return asSafeBytes().length;
      long l = super.getContentLength();
      if (l != -1 || isSupplied())
         return l;
      String s = content();
      if (getCharset() == UTF8)
         for (var i = 0; i < s.length(); i++)
            if (s.charAt(i) > 127)
               return -1;
      return s.length();
   }

   @Override /* Overridden from HttpEntity */
   public boolean isRepeatable() { return true; }

   @Override /* Overridden from HttpEntity */
   public boolean isStreaming() { return false; }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setCached() throws IOException {
      super.setCached();
      return this;
   }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setCharset(Charset value) {
      super.setCharset(value);
      return this;
   }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setChunked() {
      super.setChunked();
      return this;
   }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setChunked(boolean value) {
      super.setChunked(value);
      return this;
   }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setContent(Object value) {
      super.setContent(value);
      return this;
   }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setContent(Supplier<?> value) {
      super.setContent(value);
      return this;
   }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setContentEncoding(ContentEncoding value) {
      super.setContentEncoding(value);
      return this;
   }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setContentEncoding(String value) {
      super.setContentEncoding(value);
      return this;
   }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setContentLength(long value) {
      super.setContentLength(value);
      return this;
   }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setContentType(ContentType value) {
      super.setContentType(value);
      return this;
   }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setContentType(String value) {
      super.setContentType(value);
      return this;
   }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setMaxLength(int value) {
      super.setMaxLength(value);
      return this;
   }

   @Override /* Overridden from BasicHttpEntity */
   public StringEntity setUnmodifiable() {
      super.setUnmodifiable();
      return this;
   }

   @Override /* Overridden from HttpEntity */
   public void writeTo(OutputStream out) throws IOException {
      assertArgNotNull("out", out);
      if (isCached()) {
         out.write(asBytes());
      } else {
         var osw = new OutputStreamWriter(out, getCharset());
         osw.write(content());
         osw.flush();
      }
   }

   private String content() {
      return contentOrElse(EMPTY);
   }
}