// Copyright (C) 2015 The Android Open Source Project
//
// Licensed 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 com.google.gerrit.util.http.testutil;

import static com.google.common.base.Preconditions.checkArgument;
import static java.nio.charset.StandardCharsets.UTF_8;
import static java.util.Objects.requireNonNull;
import static java.util.stream.Collectors.toList;

import com.google.common.base.Splitter;
import com.google.common.base.Strings;
import com.google.common.collect.Iterables;
import com.google.common.collect.LinkedListMultimap;
import com.google.common.collect.ListMultimap;
import com.google.common.collect.Maps;
import com.google.gerrit.common.Nullable;
import java.io.BufferedReader;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.security.Principal;
import java.time.Instant;
import java.time.format.DateTimeFormatter;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.function.Supplier;
import javax.servlet.AsyncContext;
import javax.servlet.DispatcherType;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpUpgradeHandler;
import javax.servlet.http.Part;

/** Simple fake implementation of {@link HttpServletRequest}. */
public class FakeHttpServletRequest implements HttpServletRequest {
  public static final String SERVLET_PATH = "/b";
  public static final DateTimeFormatter rfcDateformatter =
      DateTimeFormatter.ofPattern("EEE, dd MMM yyyy HH:mm:ss ZZZ");

  private final Map<String, Object> attributes;
  private final ListMultimap<String, String> headers;

  private ListMultimap<String, String> parameters;
  private String queryString;
  private String hostName;
  private int port;
  private String contextPath;
  private String servletPath;
  private String path;
  private String method;
  private final Supplier<HttpSession> sessionSupplier;
  private HttpSession session;

  public FakeHttpServletRequest() {
    this("gerrit.example.com", 80, "", SERVLET_PATH);
  }

  public FakeHttpServletRequest(String hostName, int port, String contextPath, String servletPath) {
    this(hostName, port, contextPath, servletPath, null, null);
  }

  public FakeHttpServletRequest(
      String hostName,
      int port,
      String contextPath,
      String servletPath,
      @Nullable Supplier<HttpSession> sessionSupplier,
      @Nullable HttpSession currentSession) {
    this.hostName = requireNonNull(hostName, "hostName");
    checkArgument(port > 0);
    this.port = port;
    this.contextPath = requireNonNull(contextPath, "contextPath");
    this.servletPath = requireNonNull(servletPath, "servletPath");
    attributes = Maps.newConcurrentMap();
    parameters = LinkedListMultimap.create();
    headers = LinkedListMultimap.create();
    method = "GET";
    this.sessionSupplier = sessionSupplier;
    this.session = currentSession;
  }

  @Override
  public Object getAttribute(String name) {
    return attributes.get(name);
  }

  @Override
  public Enumeration<String> getAttributeNames() {
    return Collections.enumeration(attributes.keySet());
  }

  @Override
  public String getCharacterEncoding() {
    return UTF_8.name();
  }

  @Override
  public int getContentLength() {
    return -1;
  }

  @Nullable
  @Override
  public String getContentType() {
    List<String> contentType = headers.get("Content-Type");
    if (contentType != null && !contentType.isEmpty()) {
      return contentType.get(0);
    }

    return null;
  }

  @Override
  public ServletInputStream getInputStream() {
    throw new UnsupportedOperationException();
  }

  @Override
  public String getLocalAddr() {
    return "1.2.3.4";
  }

  @Override
  public String getLocalName() {
    return hostName;
  }

  @Override
  public int getLocalPort() {
    return port;
  }

  @Override
  public Locale getLocale() {
    return Locale.US;
  }

  @Override
  public Enumeration<Locale> getLocales() {
    return Collections.enumeration(Collections.singleton(Locale.US));
  }

  @Override
  public String getParameter(String name) {
    return Iterables.getFirst(parameters.get(name), null);
  }

  @Override
  public Map<String, String[]> getParameterMap() {
    return Collections.unmodifiableMap(
        Maps.transformValues(parameters.asMap(), vs -> vs.toArray(new String[0])));
  }

  @Override
  public Enumeration<String> getParameterNames() {
    return Collections.enumeration(parameters.keySet());
  }

  @Override
  public String[] getParameterValues(String name) {
    return parameters.get(name).toArray(new String[0]);
  }

  public void setQueryString(String qs) {
    this.queryString = qs;
    ListMultimap<String, String> params = LinkedListMultimap.create();
    for (String entry : Splitter.on('&').split(qs)) {
      List<String> kv = Splitter.on('=').limit(2).splitToList(entry);
      try {
        params.put(
            URLDecoder.decode(kv.get(0), UTF_8.name()),
            kv.size() == 2 ? URLDecoder.decode(kv.get(1), UTF_8.name()) : "");
      } catch (UnsupportedEncodingException e) {
        throw new IllegalArgumentException(e);
      }
    }
    parameters = params;
  }

  @Override
  public String getProtocol() {
    return "HTTP/1.1";
  }

  @Override
  public BufferedReader getReader() {
    throw new UnsupportedOperationException();
  }

  @Override
  @Deprecated
  public String getRealPath(String path) {
    throw new UnsupportedOperationException();
  }

  @Override
  public String getRemoteAddr() {
    return "5.6.7.8";
  }

  @Override
  public String getRemoteHost() {
    return "remotehost";
  }

  @Override
  public int getRemotePort() {
    return 1234;
  }

  @Override
  public RequestDispatcher getRequestDispatcher(String path) {
    throw new UnsupportedOperationException();
  }

  @Override
  public String getScheme() {
    return port == 443 ? "https" : "http";
  }

  @Override
  public String getServerName() {
    return hostName;
  }

  @Override
  public int getServerPort() {
    return port;
  }

  @Override
  public boolean isSecure() {
    return port == 443;
  }

  @Override
  public void removeAttribute(String name) {
    attributes.remove(name);
  }

  @Override
  public void setAttribute(String name, Object value) {
    attributes.put(name, value);
  }

  @Override
  public void setCharacterEncoding(String env) throws UnsupportedOperationException {
    throw new UnsupportedOperationException();
  }

  @Override
  public String getAuthType() {
    return null;
  }

  @Override
  public String getContextPath() {
    return contextPath;
  }

  @Override
  public Cookie[] getCookies() {
    return Splitter.on(";").splitToList(Strings.nullToEmpty(getHeader("Cookie"))).stream()
        .filter(s -> !s.isEmpty())
        .map(
            (String cookieValue) -> {
              List<String> kv = Splitter.on("=").splitToList(cookieValue);
              return new Cookie(kv.get(0), kv.get(1));
            })
        .collect(toList())
        .toArray(new Cookie[0]);
  }

  @Override
  public long getDateHeader(String name) {
    String v = getHeader(name);
    return v == null ? 0 : rfcDateformatter.parse(v, Instant::from).getEpochSecond();
  }

  @Override
  public String getHeader(String name) {
    return Iterables.getFirst(headers.get(name), null);
  }

  @Override
  public Enumeration<String> getHeaderNames() {
    return Collections.enumeration(headers.keySet());
  }

  @Override
  public Enumeration<String> getHeaders(String name) {
    return Collections.enumeration(headers.get(name));
  }

  @Override
  public int getIntHeader(String name) {
    return Integer.parseInt(getHeader(name));
  }

  @Override
  public String getMethod() {
    return method;
  }

  public void setMethod(String method) {
    this.method = method;
  }

  @Override
  public String getPathInfo() {
    return path;
  }

  public FakeHttpServletRequest setPathInfo(String path) {
    this.path = path;
    return this;
  }

  @Override
  public String getPathTranslated() {
    return path;
  }

  @Override
  public String getQueryString() {
    return queryString;
  }

  @Override
  public String getRemoteUser() {
    return null;
  }

  @Override
  public String getRequestURI() {
    return contextPath + servletPath + path;
  }

  @Override
  public StringBuffer getRequestURL() {
    return null;
  }

  @Override
  public String getRequestedSessionId() {
    return null;
  }

  @Override
  public String getServletPath() {
    return servletPath;
  }

  @Override
  public HttpSession getSession() {
    return getSession(true);
  }

  @Override
  @Nullable
  public HttpSession getSession(boolean create) {
    if (session != null || !create) {
      return session;
    }

    if (sessionSupplier == null) {
      throw new UnsupportedOperationException();
    }

    session = sessionSupplier.get();
    return session;
  }

  @Override
  public Principal getUserPrincipal() {
    throw new UnsupportedOperationException();
  }

  @Override
  public boolean isRequestedSessionIdFromCookie() {
    throw new UnsupportedOperationException();
  }

  @Override
  public boolean isRequestedSessionIdFromURL() {
    throw new UnsupportedOperationException();
  }

  @Override
  @Deprecated
  public boolean isRequestedSessionIdFromUrl() {
    throw new UnsupportedOperationException();
  }

  @Override
  public boolean isRequestedSessionIdValid() {
    throw new UnsupportedOperationException();
  }

  @Override
  public boolean isUserInRole(String role) {
    throw new UnsupportedOperationException();
  }

  @Override
  public AsyncContext getAsyncContext() {
    throw new UnsupportedOperationException();
  }

  @Override
  public DispatcherType getDispatcherType() {
    throw new UnsupportedOperationException();
  }

  @Override
  public ServletContext getServletContext() {
    throw new UnsupportedOperationException();
  }

  @Override
  public boolean isAsyncStarted() {
    return false;
  }

  @Override
  public boolean isAsyncSupported() {
    return false;
  }

  @Override
  public AsyncContext startAsync() {
    throw new UnsupportedOperationException();
  }

  @Override
  public AsyncContext startAsync(ServletRequest req, ServletResponse res) {
    throw new UnsupportedOperationException();
  }

  @Override
  public boolean authenticate(HttpServletResponse res) {
    throw new UnsupportedOperationException();
  }

  @Override
  public Part getPart(String name) {
    throw new UnsupportedOperationException();
  }

  @Override
  public Collection<Part> getParts() {
    throw new UnsupportedOperationException();
  }

  @Override
  public void login(String username, String password) {
    throw new UnsupportedOperationException();
  }

  @Override
  public void logout() {
    throw new UnsupportedOperationException();
  }

  @Override
  public long getContentLengthLong() {
    return getContentLength();
  }

  @Override
  public String changeSessionId() {
    throw new UnsupportedOperationException();
  }

  @Override
  public <T extends HttpUpgradeHandler> T upgrade(Class<T> httpUpgradeHandlerClass) {
    throw new UnsupportedOperationException();
  }

  public FakeHttpServletRequest addHeader(String name, String value) {
    headers.put(name, value);
    return this;
  }
}