/*
 * 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.rest.mock;

import static org.apache.juneau.commons.utils.CollectionUtils.*;
import static org.apache.juneau.commons.utils.Shorts.*;

import java.io.*;
import java.time.*;
import java.time.format.*;
import java.util.*;

import org.apache.juneau.rest.server.util.*;

import jakarta.servlet.*;
import jakarta.servlet.http.*;

/**
 * An implementation of {@link HttpServletResponse} for mocking purposes.
 *
 * <h2 class='section'>See Also:</h2><ul>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JuneauRestMock">juneau-rest-mock</a>
 * </ul>
*/
@SuppressWarnings({
   "java:S1192", // The "UTF-8" default-encoding literal reads clearer inline than behind a constant
   "java:S115", // Constants use UPPER_snakeCase convention (e.g., HEADER_ContentType)
   "java:S4144", // Identical methods intentional for different test scenarios
   "resource" // Streams returned to servlet container; lifecycle managed by the container
})
public class MockServletResponse implements HttpServletResponse {

   private static final String HEADER_ContentType = "Content-Type";

   /**
    * Creates a new servlet response.
    *
    * @return A new response.
    */
   public static MockServletResponse create() {
      return new MockServletResponse();
   }

   private String characterEncoding = "UTF-8";
   private final ByteArrayOutputStream baos = new ByteArrayOutputStream();
   private int bufferSize;
   private Locale locale;
   private int sc = 200;
   private String msg;

   private final Map<String,String[]> headerMap = map();

   @Override /* Overridden from HttpServletResponse */
   public void addCookie(Cookie cookie) {
      // No-op: Mock implementation - full functionality not required
   }

   @Override /* Overridden from HttpServletResponse */
   public void addDateHeader(String name, long date) {
      Instant instant = Instant.ofEpochMilli(date);
      DateTimeFormatter formatter = DateTimeFormatter.RFC_1123_DATE_TIME
         .withZone(ZoneId.of("GMT"));
      headerMap.put(name, a(formatter.format(instant)));
   }

   @Override /* Overridden from HttpServletResponse */
   public void addHeader(String name, String value) {
      headerMap.put(name, a(value));
   }

   @Override /* Overridden from HttpServletResponse */
   public void addIntHeader(String name, int value) {
      headerMap.put(name, a(String.valueOf(value)));
   }

   @Override /* Overridden from HttpServletResponse */
   public boolean containsHeader(String name) {
      return nn(getHeader(name));
   }

   @Override /* Overridden from HttpServletResponse */
   public String encodeRedirectURL(String url) {
      return null;
   }

   @Override /* Overridden from HttpServletResponse */
   public String encodeURL(String url) {
      return null;
   }

   @Override /* Overridden from HttpServletResponse */
   public void flushBuffer() throws IOException {
      // No-op: Mock implementation - full functionality not required
   }

   @Override /* Overridden from HttpServletResponse */
   public int getBufferSize() { return bufferSize; }

   @Override /* Overridden from HttpServletResponse */
   public String getCharacterEncoding() { return characterEncoding; }

   @Override /* Overridden from HttpServletResponse */
   public String getContentType() { return getHeader(HEADER_ContentType); }

   @Override /* Overridden from HttpServletResponse */
   public String getHeader(String name) {
      String[] s = headerMap.get(name);
      return s == null || s.length == 0 ? null : s[0];
   }

   @Override /* Overridden from HttpServletResponse */
   public Collection<String> getHeaderNames() { return headerMap.keySet(); }

   @Override /* Overridden from HttpServletResponse */
   public Collection<String> getHeaders(String name) {
      String[] s = headerMap.get(name);
      return s == null ? Collections.emptyList() : u(l(s));
   }

   @Override /* Overridden from HttpServletResponse */
   public Locale getLocale() { return locale; }

   /**
    * Returns the response message.
    *
    * @return The response message.
    */
   public String getMessage() { return msg; }

   @Override /* Overridden from HttpServletResponse */
   public ServletOutputStream getOutputStream() throws IOException { return new FinishableServletOutputStream(baos); }

   @Override /* Overridden from HttpServletResponse */
   public int getStatus() { return sc; }

   @Override /* Overridden from HttpServletResponse */
   public PrintWriter getWriter() throws IOException { return new PrintWriter(new OutputStreamWriter(getOutputStream(), characterEncoding == null ? "UTF-8" : characterEncoding)); }

   /**
    * Fluent setter for {@link #setHeader(String,String)}.
    *
    * @param name The header name.
    * @param value The new header value.
    * @return This object.
    */
   public MockServletResponse header(String name, String value) {
      setHeader(name, value);
      return this;
   }

   @Override /* Overridden from HttpServletResponse */
   public boolean isCommitted() { return false; }

   @Override /* Overridden from HttpServletResponse */
   public void reset() {
      // No-op: Mock implementation - full functionality not required
   }

   @Override /* Overridden from HttpServletResponse */
   public void resetBuffer() {
      // Mock implementation - no-op for testing purposes
   }

   @Override /* Overridden from HttpServletResponse */
   public void sendError(int sc) throws IOException {
      this.sc = sc;
   }

   @Override /* Overridden from HttpServletResponse */
   public void sendError(int sc, String msg) throws IOException {
      this.sc = sc;
      this.msg = msg;
   }

   @Override /* Overridden from HttpServletResponse */
   public void sendRedirect(String location) throws IOException {
      this.sc = 302;
      headerMap.put("Location", a(location));
   }

   @Override /* Overridden from HttpServletResponse */
   public void sendRedirect(String location, int sc, boolean clearBuffer) throws IOException {
      this.sc = sc;
      headerMap.put("Location", a(location));
   }

   @Override /* Overridden from HttpServletResponse */
   public void setBufferSize(int size) { this.bufferSize = size; }

   @Override /* Overridden from HttpServletResponse */
   public void setCharacterEncoding(String charset) {
      this.characterEncoding = charset;
      updateContentTypeHeader();
   }

   @Override /* Overridden from HttpServletResponse */
   public void setContentLength(int len) {
      header("Content-Length", String.valueOf(len));
   }

   @Override /* Overridden from HttpServletResponse */
   public void setContentLengthLong(long len) {
      header("Content-Length", String.valueOf(len));
   }

   @Override /* Overridden from HttpServletResponse */
   public void setContentType(String type) {
      setHeader(HEADER_ContentType, type);
      updateContentTypeHeader();
   }

   @Override /* Overridden from HttpServletResponse */
   public void setDateHeader(String name, long date) {
      Instant instant = Instant.ofEpochMilli(date);
      DateTimeFormatter formatter = DateTimeFormatter.RFC_1123_DATE_TIME
         .withZone(ZoneId.of("GMT"));
      headerMap.put(name, a(formatter.format(instant)));
   }

   @Override /* Overridden from HttpServletResponse */
   public void setHeader(String name, String value) {
      headerMap.put(name, a(value));
   }

   @Override /* Overridden from HttpServletResponse */
   public void setIntHeader(String name, int value) {
      headerMap.put(name, a(String.valueOf(value)));
   }

   @Override /* Overridden from HttpServletResponse */
   public void setLocale(Locale loc) { this.locale = loc; }

   @Override /* Overridden from HttpServletResponse */
   public void setStatus(int sc) { this.sc = sc; }

   /**
    * Fluent setter for {@link #setStatus(int)}.
    *
    * @param value The new property value.
    * @return This object.
    */
   public MockServletResponse status(int value) {
      setStatus(value);
      return this;
   }

   private void updateContentTypeHeader() {
      var contentType = getContentType();
      String charset = characterEncoding;
      if (contentType != null && charset != null) {
         if (contentType.indexOf("charset=") != -1)
            contentType = contentType.replaceAll("\\;\\s*charset=.*", "");
         if (neqic("UTF-8", charset))
            contentType = contentType + ";charset=" + charset;
         header(HEADER_ContentType, contentType);
      }
   }

   /**
    * Returns the raw bytes written to the response body.
    *
    * @return The response body bytes. Never <jk>null</jk>.
    * @throws IOException If the stream cannot be flushed.
    */
   public byte[] getContent() throws IOException {
      baos.flush();
      return baos.toByteArray();
   }

   /**
    * Returns the raw header map backing this response.
    *
    * @return The header map, keyed by header name to all values set for that name. Never <jk>null</jk>.
    */
   public Map<String,String[]> getHeaders() { return headerMap; }
}