// Copyright (C) 2016 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.acceptance.rest.change;

import static com.google.common.net.HttpHeaders.ACCESS_CONTROL_ALLOW_CREDENTIALS;
import static com.google.common.net.HttpHeaders.ACCESS_CONTROL_ALLOW_HEADERS;
import static com.google.common.net.HttpHeaders.ACCESS_CONTROL_ALLOW_METHODS;
import static com.google.common.net.HttpHeaders.ACCESS_CONTROL_ALLOW_ORIGIN;
import static com.google.common.net.HttpHeaders.ACCESS_CONTROL_MAX_AGE;
import static com.google.common.net.HttpHeaders.ACCESS_CONTROL_REQUEST_HEADERS;
import static com.google.common.net.HttpHeaders.ACCESS_CONTROL_REQUEST_METHOD;
import static com.google.common.net.HttpHeaders.AUTHORIZATION;
import static com.google.common.net.HttpHeaders.CONTENT_TYPE;
import static com.google.common.net.HttpHeaders.ORIGIN;
import static com.google.common.net.HttpHeaders.VARY;
import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;

import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.truth.StringSubject;
import com.google.gerrit.acceptance.AbstractDaemonTest;
import com.google.gerrit.acceptance.PushOneCommit.Result;
import com.google.gerrit.acceptance.RestResponse;
import com.google.gerrit.acceptance.RestSession;
import com.google.gerrit.common.Nullable;
import com.google.gerrit.extensions.common.ChangeInfo;
import com.google.gerrit.extensions.restapi.RestApiException;
import com.google.gerrit.server.UrlEncoded;
import com.google.gerrit.testing.ConfigSuite;
import java.nio.charset.StandardCharsets;
import java.util.Locale;
import java.util.stream.Stream;
import org.apache.http.Header;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.fluent.Executor;
import org.apache.http.client.fluent.Request;
import org.apache.http.cookie.Cookie;
import org.apache.http.impl.client.BasicCookieStore;
import org.apache.http.message.BasicHeader;
import org.eclipse.jgit.lib.Config;
import org.junit.Test;

public class CorsIT extends AbstractDaemonTest {
  @ConfigSuite.Default
  public static Config allowExampleDotCom() {
    Config cfg = new Config();
    cfg.setString("auth", null, "type", "DEVELOPMENT_BECOME_ANY_ACCOUNT");
    cfg.setStringList(
        "site",
        null,
        "allowOriginRegex",
        ImmutableList.of("https?://(.+[.])?example[.]com", "http://friend[.]ly"));
    return cfg;
  }

  @Test
  public void missingOriginIsAllowedWithNoCorsResponseHeaders() throws Exception {
    Result change = createChange();
    String url = "/changes/" + change.getChangeId() + "/detail";
    RestResponse r = adminRestSession.get(url);
    r.assertOK();

    String allowOrigin = r.getHeader(ACCESS_CONTROL_ALLOW_ORIGIN);
    String allowCred = r.getHeader(ACCESS_CONTROL_ALLOW_CREDENTIALS);
    String maxAge = r.getHeader(ACCESS_CONTROL_MAX_AGE);
    String allowMethods = r.getHeader(ACCESS_CONTROL_ALLOW_METHODS);
    String allowHeaders = r.getHeader(ACCESS_CONTROL_ALLOW_HEADERS);

    assertWithMessage(ACCESS_CONTROL_ALLOW_ORIGIN).that(allowOrigin).isNull();
    assertWithMessage(ACCESS_CONTROL_ALLOW_CREDENTIALS).that(allowCred).isNull();
    assertWithMessage(ACCESS_CONTROL_MAX_AGE).that(maxAge).isNull();
    assertWithMessage(ACCESS_CONTROL_ALLOW_METHODS).that(allowMethods).isNull();
    assertWithMessage(ACCESS_CONTROL_ALLOW_HEADERS).that(allowHeaders).isNull();
  }

  @Test
  public void origins() throws Exception {
    Result change = createChange();
    String url = "/changes/" + change.getChangeId() + "/detail";

    check(url, true, "http://example.com");
    check(url, true, "https://sub.example.com");
    check(url, true, "http://friend.ly");

    check(url, false, "http://evil.attacker");
    check(url, false, "http://friendsly");
  }

  @Test
  public void originsOnNotFoundException() throws Exception {
    String url = "/changes/999/detail";
    check(url, true, "http://example.com", adminRestSession, 404);
    check(url, false, "http://friendsly", adminRestSession, 404);
  }

  @Test
  public void originsOnBadRequestException() throws Exception {
    String url = "/config/server/caches/?format=NONSENSE";
    check(url, true, "http://example.com", adminRestSession, 400);
    check(url, false, "http://friendsly", adminRestSession, 400);
  }

  @Test
  public void originsOnForbidden() throws Exception {
    Result change = createChange();
    // Make change private to hide it
    gApi.changes().id(change.getChangeId()).setPrivate(true, "now private");
    String url = "/changes/" + change.getChangeId() + "/detail";
    check(url, true, "http://example.com", anonymousRestSession, 404);
    check(url, false, "http://friendsly", anonymousRestSession, 404);
  }

  @Test
  public void putWithServerOriginAcceptedWithNoCorsResponseHeaders() throws Exception {
    Result change = createChange();
    String origin = adminRestSession.url();
    RestResponse r =
        adminRestSession.putWithHeader(
            "/changes/" + change.getChangeId() + "/topic", new BasicHeader(ORIGIN, origin), "A");
    r.assertOK();
    checkCors(r, false, origin);
    checkTopic(change, "A");
  }

  @Test
  public void putWithOtherOriginAccepted() throws Exception {
    Result change = createChange();
    String origin = "http://example.com";
    RestResponse r =
        adminRestSession.putWithHeader(
            "/changes/" + change.getChangeId() + "/topic", new BasicHeader(ORIGIN, origin), "A");
    r.assertOK();
    checkCors(r, true, origin);
  }

  @Test
  public void preflightOk() throws Exception {
    Result change = createChange();

    String origin = "http://example.com";
    Request req =
        Request.Options(adminRestSession.url() + "/a/changes/" + change.getChangeId() + "/detail");
    req.addHeader(ORIGIN, origin);
    req.addHeader(ACCESS_CONTROL_REQUEST_METHOD, "GET");
    req.addHeader(ACCESS_CONTROL_REQUEST_HEADERS, "X-Requested-With");

    RestResponse res = adminRestSession.execute(req);
    res.assertOK();

    String vary = res.getHeader(VARY);
    assertWithMessage(VARY).that(vary).isNotNull();
    assertThat(Splitter.on(", ").splitToList(vary))
        .containsExactly(ORIGIN, ACCESS_CONTROL_REQUEST_METHOD, ACCESS_CONTROL_REQUEST_HEADERS);
    checkCors(res, true, origin);
  }

  @Test
  public void preflightBadOrigin() throws Exception {
    Result change = createChange();
    Request req =
        Request.Options(adminRestSession.url() + "/a/changes/" + change.getChangeId() + "/detail");
    req.addHeader(ORIGIN, "http://evil.attacker");
    req.addHeader(ACCESS_CONTROL_REQUEST_METHOD, "GET");
    adminRestSession.execute(req).assertBadRequest();
  }

  @Test
  public void preflightBadMethod() throws Exception {
    Result change = createChange();
    Request req =
        Request.Options(adminRestSession.url() + "/a/changes/" + change.getChangeId() + "/detail");
    req.addHeader(ORIGIN, "http://example.com");
    req.addHeader(ACCESS_CONTROL_REQUEST_METHOD, "CALL");
    adminRestSession.execute(req).assertBadRequest();
  }

  @Test
  public void preflightBadHeader() throws Exception {
    Result change = createChange();
    Request req =
        Request.Options(adminRestSession.url() + "/a/changes/" + change.getChangeId() + "/detail");
    req.addHeader(ORIGIN, "http://example.com");
    req.addHeader(ACCESS_CONTROL_REQUEST_METHOD, "GET");
    req.addHeader(ACCESS_CONTROL_REQUEST_HEADERS, "X-Secret-Auth-Token");
    adminRestSession.execute(req).assertBadRequest();
  }

  @Test
  public void crossDomainPutTopic() throws Exception {
    Result change = createChange();
    BasicCookieStore cookies = new BasicCookieStore();
    Executor http = Executor.newInstance().use(cookies);

    Request req = Request.Get(canonicalWebUrl.get() + "/login/?account_id=" + admin.id().get());
    http.execute(req);
    String auth = null;
    for (Cookie c : cookies.getCookies()) {
      if ("GerritAccount".equals(c.getName())) {
        auth = c.getValue();
      }
    }
    assertWithMessage("GerritAccount cookie").that(auth).isNotNull();
    cookies.clear();

    UrlEncoded url =
        new UrlEncoded(canonicalWebUrl.get() + "/changes/" + change.getChangeId() + "/topic");
    url.put("$m", "PUT");
    url.put("$ct", "application/json; charset=US-ASCII");
    url.put("access_token", auth);

    String origin = "http://example.com";
    req = Request.Post(url.toString());
    req.setHeader(CONTENT_TYPE, "text/plain");
    req.setHeader(ORIGIN, origin);
    req.bodyByteArray("{\"topic\":\"test-xd\"}".getBytes(StandardCharsets.US_ASCII));

    HttpResponse r = http.execute(req).returnResponse();
    assertThat(r.getStatusLine().getStatusCode()).isEqualTo(200);

    Header vary = r.getFirstHeader(VARY);
    assertWithMessage(VARY).that(vary).isNotNull();
    assertWithMessage(VARY).that(Splitter.on(", ").splitToList(vary.getValue())).contains(ORIGIN);

    Header allowOrigin = r.getFirstHeader(ACCESS_CONTROL_ALLOW_ORIGIN);
    assertWithMessage(ACCESS_CONTROL_ALLOW_ORIGIN).that(allowOrigin).isNotNull();
    assertWithMessage(ACCESS_CONTROL_ALLOW_ORIGIN).that(allowOrigin.getValue()).isEqualTo(origin);

    Header allowAuth = r.getFirstHeader(ACCESS_CONTROL_ALLOW_CREDENTIALS);
    assertWithMessage(ACCESS_CONTROL_ALLOW_CREDENTIALS).that(allowAuth).isNotNull();
    assertWithMessage(ACCESS_CONTROL_ALLOW_CREDENTIALS)
        .that(allowAuth.getValue())
        .isEqualTo("true");

    checkTopic(change, "test-xd");
  }

  @Test
  public void crossDomainRejectsBadOrigin() throws Exception {
    Result change = createChange();
    UrlEncoded url =
        new UrlEncoded(canonicalWebUrl.get() + "/changes/" + change.getChangeId() + "/topic");
    url.put("$m", "PUT");
    url.put("$ct", "application/json; charset=US-ASCII");

    Request req = Request.Post(url.toString());
    req.setHeader(CONTENT_TYPE, "text/plain");
    req.setHeader(ORIGIN, "http://evil.attacker");
    req.bodyByteArray("{\"topic\":\"test-xd\"}".getBytes(StandardCharsets.US_ASCII));
    adminRestSession.execute(req).assertBadRequest();
    checkTopic(change, null);
  }

  private void checkTopic(Result change, @Nullable String topic) throws RestApiException {
    ChangeInfo info = gApi.changes().id(change.getChangeId()).get();
    StringSubject t = assertWithMessage("topic").that(info.topic);
    if (topic != null) {
      t.isEqualTo(topic);
    } else {
      t.isNull();
    }
  }

  private void check(String url, boolean accept, String origin) throws Exception {
    check(url, accept, origin, adminRestSession, HttpStatus.SC_OK);
  }

  private void check(
      String url, boolean accept, String origin, RestSession restSession, int httpStatusCode)
      throws Exception {
    Header hdr = new BasicHeader(ORIGIN, origin);
    RestResponse r = restSession.getWithHeader(url, hdr);
    r.assertStatus(httpStatusCode);
    checkCors(r, accept, origin);
  }

  private void checkCors(RestResponse r, boolean accept, String origin) {
    String vary = r.getHeader(VARY);
    assertWithMessage(VARY).that(vary).isNotNull();
    assertWithMessage(VARY).that(Splitter.on(", ").splitToList(vary)).contains(ORIGIN);

    String allowOrigin = r.getHeader(ACCESS_CONTROL_ALLOW_ORIGIN);
    String allowCred = r.getHeader(ACCESS_CONTROL_ALLOW_CREDENTIALS);
    String maxAge = r.getHeader(ACCESS_CONTROL_MAX_AGE);
    String allowMethods = r.getHeader(ACCESS_CONTROL_ALLOW_METHODS);
    String allowHeaders = r.getHeader(ACCESS_CONTROL_ALLOW_HEADERS);
    if (accept) {
      assertWithMessage(ACCESS_CONTROL_ALLOW_ORIGIN).that(allowOrigin).isEqualTo(origin);
      assertWithMessage(ACCESS_CONTROL_ALLOW_CREDENTIALS).that(allowCred).isEqualTo("true");
      assertWithMessage(ACCESS_CONTROL_MAX_AGE).that(maxAge).isEqualTo("600");

      assertWithMessage(ACCESS_CONTROL_ALLOW_METHODS).that(allowMethods).isNotNull();
      assertWithMessage(ACCESS_CONTROL_ALLOW_METHODS)
          .that(Splitter.on(", ").splitToList(allowMethods))
          .containsExactly("GET", "HEAD", "POST", "PUT", "DELETE", "OPTIONS");

      assertWithMessage(ACCESS_CONTROL_ALLOW_HEADERS).that(allowHeaders).isNotNull();
      assertWithMessage(ACCESS_CONTROL_ALLOW_HEADERS)
          .that(Splitter.on(", ").splitToList(allowHeaders))
          .containsExactlyElementsIn(
              Stream.of(AUTHORIZATION, CONTENT_TYPE, "X-Gerrit-Auth", "X-Requested-With")
                  .map(s -> s.toLowerCase(Locale.US))
                  .collect(ImmutableSet.toImmutableSet()));
    } else {
      assertWithMessage(ACCESS_CONTROL_ALLOW_ORIGIN).that(allowOrigin).isNull();
      assertWithMessage(ACCESS_CONTROL_ALLOW_CREDENTIALS).that(allowCred).isNull();
      assertWithMessage(ACCESS_CONTROL_MAX_AGE).that(maxAge).isNull();
      assertWithMessage(ACCESS_CONTROL_ALLOW_METHODS).that(allowMethods).isNull();
      assertWithMessage(ACCESS_CONTROL_ALLOW_HEADERS).that(allowHeaders).isNull();
    }
  }
}