// Copyright 2011 Google Inc. All Rights Reserved.
//
// 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.enterprise.adaptor;

import static org.junit.Assert.*;

import com.sun.net.httpserver.HttpExchange;

import org.junit.*;
import org.junit.rules.ExpectedException;

import java.io.*;
import java.net.*;
import java.nio.charset.Charset;
import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;

/**
 * Tests for {@link GsaCommunicationHandler}.
 */
public class GsaCommunicationHandlerTest {
  /**
   * Generated with {@code keytool -alias notadaptor -keystore
   * test/com/google/enterprise/adaptor/GsaCommunicationHandlerTest.valid.jks
   * -storepass notchangeit -genkeypair -keyalg RSA -keypass notchangeit
   * -validity 7300 -dname "CN=Unknown, OU=Unknown, O=Unknown, L=Unknown,
   *  ST=Unknown, C=Unknown"}.
   */
  private static final String KEYSTORE_VALID_FILENAME
      = "test/com/google/enterprise/adaptor/GsaCommunicationHandlerTest.valid.jks";

  private Config config;
  private GsaCommunicationHandler gsa;
  private NullAdaptor adaptor = new NullAdaptor();
  private MockHttpServer mockServer = new MockHttpServer();

  @Rule
  public ExpectedException thrown = ExpectedException.none();

  @Before
  public void setup() {
    config = new Config();
    config.setValue("gsa.hostname", "localhost");
    // Let the OS choose the port
    config.setValue("server.port", "0");
    config.setValue("server.dashboardPort", "0");
    // As hard-coded in MockHttpExchange
    config.setValue("server.fullAccessHosts", "127.0.0.3");
    gsa = new GsaCommunicationHandler(adaptor, config);
  }

  @After
  public void teardown() {
    gsa.stop(0, TimeUnit.SECONDS);
  }

  @Test
  public void testAdaptorContext() throws Exception {
    final AtomicReference<Throwable> error = new AtomicReference<Throwable>();
    class PollingIncrNullAdaptor extends NullAdaptor {
      @Override
      public void init(AdaptorContext context) {
        try {
          assertSame(config, context.getConfig());
          assertNotNull(context.getDocIdPusher());
          assertNotNull(context.getDocIdEncoder());
          assertNotNull(context.getSensitiveValueDecoder());
          ExceptionHandler originalHandler
              = context.getGetDocIdsFullErrorHandler();
          ExceptionHandler replacementHandler
              = ExceptionHandlers.exponentialBackoffHandler(
                  1, 1, TimeUnit.SECONDS);
          assertNotNull(originalHandler);
          context.setGetDocIdsFullErrorHandler(replacementHandler);
          assertSame(replacementHandler,
              context.getGetDocIdsFullErrorHandler());

          StatusSource source = new MockStatusSource("test",
              new MockStatus(Status.Code.NORMAL));
          context.addStatusSource(source);
          context.removeStatusSource(source);
        } catch (Throwable t) {
          error.set(t);
        }
      }
    }
    PollingIncrNullAdaptor adaptor = new PollingIncrNullAdaptor();
    gsa = new GsaCommunicationHandler(adaptor, config);
    gsa.start(mockServer, mockServer);
    Throwable t = error.get();
    if (t != null) {
      if (t instanceof Exception) {
        throw (Exception) t;
      } else if (t instanceof Error) {
        throw (Error) t;
      } else {
        throw new AssertionError();
      }
    }
  }

  @Test
  public void testPollingIncrementalAdaptor() throws Exception {
    class PollingIncrNullAdaptor extends NullAdaptor
        implements PollingIncrementalAdaptor {
      public final ArrayBlockingQueue<Object> queue
          = new ArrayBlockingQueue<Object>(1);

      @Override
      public void getModifiedDocIds(DocIdPusher pusher) {
        queue.offer(new Object());
      }
    }
    PollingIncrNullAdaptor adaptor = new PollingIncrNullAdaptor();
    gsa = new GsaCommunicationHandler(adaptor, config);
    gsa.start(mockServer, mockServer);
    assertNotNull(adaptor.queue.poll(1, TimeUnit.SECONDS));
  }

  @Test
  public void testFullPushAfterReload() throws Exception {
    NullAdaptor adaptor = new NullAdaptor();
    config.setValue("adaptor.pushDocIdsOnStartup", "false");
    gsa = new GsaCommunicationHandler(adaptor, config);
    gsa.start(mockServer, mockServer);
    gsa.stop(1, TimeUnit.SECONDS);
    gsa.start(mockServer, mockServer);
    assertTrue(gsa.checkAndScheduleImmediatePushOfDocIds());
  }

  @Test
  public void testFailOnceInitAdaptor() throws Exception {
    class FailFirstAdaptor extends NullAdaptor {
      private int count = 0;
      public boolean started = false;

      @Override
      public void init(AdaptorContext context) {
        if (count == 0) {
          count++;
          throw new RuntimeException();
        }
        started = true;
      }
    }
    FailFirstAdaptor adaptor = new FailFirstAdaptor();
    gsa = new GsaCommunicationHandler(adaptor, config);
    gsa.start(mockServer, mockServer);
    assertTrue(adaptor.started);
  }

  /**
   * Tests that Adaptor is properly initialized before HTTP serving is started.
   */
  @Test
  public void testInitBeforeServing() throws Exception {
    class SlowAdaptor extends NullAdaptor {
      public AtomicBoolean initHasFinished = new AtomicBoolean();
      public AtomicBoolean getCalledBeforeInitFinished = new AtomicBoolean();

      @Override
      public void init(AdaptorContext context) {
        try {
          Thread.sleep(500);  // the slowness of this adaptor
          initHasFinished.set(true);
        } catch (InterruptedException e) {
          throw new AssertionError(e);
        }
      }

      @Override
      public void getDocContent(Request req, Response resp)
          throws IOException {
        if (!initHasFinished.get()) {
          getCalledBeforeInitFinished.set(true);
        }
        resp.respondNotFound();
      }
    }
    SlowAdaptor adaptor = new SlowAdaptor();
    gsa = new GsaCommunicationHandler(adaptor, config);

    Thread tryFetch = new Thread(new Runnable() {
      @Override
      public void run() {
        while (true) {
          HttpExchange ex = mockServer.createExchange("GET", "/doc/1");
          if (ex != null) {
            try {
              mockServer.handle(ex);
            } catch (IOException e) {
              // We will already be retrying.
            }
          }

          try {
            Thread.sleep(20);
          } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            return;
          }
        }
      }
    });
    tryFetch.start();

    gsa.start(mockServer, mockServer);
    tryFetch.interrupt();
    tryFetch.join();

    assertEquals(false, adaptor.getCalledBeforeInitFinished.get());
  }

  @Test
  public void testMultiInstance() throws Exception {
    final Charset charset = Charset.forName("UTF-8");
    Adaptor adaptor = new NullAdaptor() {
      @Override
      public void getDocContent(Request req, Response resp)
          throws IOException {
        resp.getOutputStream().write(
            req.getDocId().getUniqueId().getBytes(charset));
      }
    };
    config.setValue("adaptor.pushDocIdsOnStartup", "false");
    gsa = new GsaCommunicationHandler(adaptor, config);
    gsa.start(mockServer, mockServer, "/path");
    GsaCommunicationHandler gsa2 = new GsaCommunicationHandler(adaptor, config);
    gsa2.start(mockServer, mockServer, "/path2");

    try {
      MockHttpExchange ex = mockServer.createExchange("GET", "/path/doc/1");
      mockServer.handle(ex);
      assertEquals("1", new String(ex.getResponseBytes(), charset));
      ex = mockServer.createExchange("GET", "/path2/doc/2");
      mockServer.handle(ex);
      assertEquals("2", new String(ex.getResponseBytes(), charset));
    } finally {
      gsa2.stop(0, TimeUnit.SECONDS);
      // gsa.stop() is called in @After, so no need for second finally for
      // shutting 'gsa' down.
    }
  }

  @Test
  public void testCreateTransformPipeline() {
    List<Map<String, String>> config = new ArrayList<Map<String, String>>();
    {
      Map<String, String> map = new HashMap<String, String>();
      map.put("name", "testing");
      map.put("factoryMethod", getClass().getName() + ".factoryMethod");
      config.add(map);
    }
    TransformPipeline pipeline
        = GsaCommunicationHandler.createTransformPipeline(config);
    assertEquals(1, pipeline.getDocumentTransforms().size());
    assertEquals(IdentityTransform.class, 
        pipeline.getDocumentTransforms().get(0).getClass());
    assertEquals("testing", pipeline.getNames().get(0));
  }

  @Test
  public void testCreateTransformPipelineEmpty() {
    assertNull(GsaCommunicationHandler.createTransformPipeline(
        Collections.<Map<String, String>>emptyList()));
  }

  @Test
  public void testCreateTransformPipelineNoClassSpecified() {
    List<Map<String, String>> config = new ArrayList<Map<String, String>>();
    {
      Map<String, String> map = new HashMap<String, String>();
      map.put("name", "testing");
      config.add(map);
    }
    thrown.expect(RuntimeException.class);
    TransformPipeline pipeline
        = GsaCommunicationHandler.createTransformPipeline(config);
  }

  @Test
  public void testCreateTransformPipelineMissingClass() {
    List<Map<String, String>> config = new ArrayList<Map<String, String>>();
    {
      Map<String, String> map = new HashMap<String, String>();
      map.put("name", "testing");
      map.put("factoryMethod", "adaptorlib.NotARealClass.fakeMethod");
      config.add(map);
    }
    thrown.expect(RuntimeException.class);
    TransformPipeline pipeline
        = GsaCommunicationHandler.createTransformPipeline(config);
  }

  @Test
  public void testCreateTransformPipelineNoGoodConstructor() throws Exception {
    List<Map<String, String>> config = new ArrayList<Map<String, String>>();
    {
      Map<String, String> map = new HashMap<String, String>();
      map.put("name", "testing");
      map.put("factoryMethod", getClass().getName() + ".wrongFactoryMethod");
      config.add(map);
    }
    thrown.expect(RuntimeException.class);
    TransformPipeline pipeline
        = GsaCommunicationHandler.createTransformPipeline(config);
  }

  @Test
  public void testCreateTransformPipelineConstructorFails() throws Exception {
    List<Map<String, String>> config = new ArrayList<Map<String, String>>();
    {
      Map<String, String> map = new HashMap<String, String>();
      map.put("name", "testing");
      map.put("factoryMethod",
          getClass().getName() + ".cantInstantiateFactoryMethod");
      config.add(map);
    }
    thrown.expect(RuntimeException.class);
    TransformPipeline pipeline
        = GsaCommunicationHandler.createTransformPipeline(config);
  }

  @Test
  public void testCreateTransformPipelineWrongType() throws Exception {
    List<Map<String, String>> config = new ArrayList<Map<String, String>>();
    {
      Map<String, String> map = new HashMap<String, String>();
      map.put("name", "testing");
      map.put("factoryMethod",
          getClass().getName() + ".wrongTypeFactoryMethod");
      config.add(map);
    }
    thrown.expect(ClassCastException.class);
    TransformPipeline pipeline
        = GsaCommunicationHandler.createTransformPipeline(config);
  }

  @Test
  public void testCreateTransformPipelineNoMethod() throws Exception {
    List<Map<String, String>> config = new ArrayList<Map<String, String>>();
    {
      Map<String, String> map = new HashMap<String, String>();
      map.put("name", "testing");
      map.put("factoryMethod", "noFactoryMethodToBeFound");
      config.add(map);
    }
    thrown.expect(RuntimeException.class);
    TransformPipeline pipeline
        = GsaCommunicationHandler.createTransformPipeline(config);
  }

  @Test
  public void testKeyStore() throws Exception {
    assertNotNull(GsaCommunicationHandler.getKeyPair("notadaptor",
        KEYSTORE_VALID_FILENAME, "JKS", "notchangeit"));
  }

  @Test
  public void testKeyStoreInvalidType() throws Exception {
    thrown.expect(RuntimeException.class);
    GsaCommunicationHandler.getKeyPair("notadaptor", KEYSTORE_VALID_FILENAME,
        "WRONG", "notchangeit");
  }

  @Test
  public void testKeyStoreMissing() throws Exception {
    thrown.expect(java.io.FileNotFoundException.class);
    GsaCommunicationHandler.getKeyPair("notadaptor", "notarealfile.jks", "JKS",
        "notchangeit");
  }

  @Test
  public void testKeyStoreNoAlias() throws Exception {
    thrown.expect(RuntimeException.class);
    GsaCommunicationHandler.getKeyPair("notherealalias",
        KEYSTORE_VALID_FILENAME, "JKS", "notchangeit");
  }

  private static class NullAdaptor extends AbstractAdaptor {
    private boolean inited;

    @Override
    public void init(AdaptorContext context) {
      inited = true;
    }

    @Override
    public void destroy() {
      inited = false;
    }

    @Override
    public void getDocIds(DocIdPusher pusher) {
      throw new UnsupportedOperationException();
    }

    @Override
    public void getDocContent(Request req, Response resp) throws IOException {
      throw new UnsupportedOperationException();
    }
  }

  static class IdentityTransform implements DocumentTransform {
    @Override
    public void transform(Metadata metadata, Map<String, String> params) {
    }
  }

  public static IdentityTransform factoryMethod(Map<String, String> config) {
    return new IdentityTransform();
  }

  public static IdentityTransform wrongFactoryMethod() {
    return factoryMethod(Collections.<String, String>emptyMap());
  }

  public static IdentityTransform cantInstantiateFactoryMethod(
      Map<String, String> config) {
    throw new RuntimeException("This always seems to happen");
  }

  public static Object wrongTypeFactoryMethod(Map<String, String> config) {
    return new Object();
  }
}