package org.infinispan.query.impl;

import static org.mockito.ArgumentMatchers.any;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.hibernate.search.query.engine.spi.EntityInfo;
import org.hibernate.search.spi.IndexedTypeIdentifier;
import org.infinispan.AdvancedCache;
import org.infinispan.query.ResultIterator;
import org.infinispan.query.backend.KeyTransformationHandler;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.Test;

/**
 * Test class for the {@link EagerIterator}.
 *
 * @author Navin Surtani
 */
@Test(groups = "functional", testName = "query.impl.EagerIteratorTest")
public class EagerIteratorTest {
   List<String> keys;
   List<EntityInfo> entityInfos;
   Map<String, String> dummyResults;
   ResultIterator<Object> iterator;
   AdvancedCache<String, String> cache;
   private KeyTransformationHandler keyTransformationHandler;

   @BeforeMethod
   public void setUp() throws Exception {
      keys = new ArrayList<>();
      dummyResults = new HashMap<>();

      entityInfos = new ArrayList<>();
      keyTransformationHandler = new KeyTransformationHandler(null);

      for (int i = 1; i <= 10; i++) {
         String key = "key" + i;
         keys.add(key);
         entityInfos.add(new MockEntityInfo(keyTransformationHandler.keyToString(key, 0)));
         dummyResults.put(key, "Result number " + i);
      }

      // create the instance of the iterator.
      cache = mock(AdvancedCache.class);

      when(cache.get(any())).thenAnswer(invocation -> {
         String k = invocation.getArguments()[0].toString();
         return dummyResults.get(k);
      });

      iterator = new EagerIterator<>(entityInfos, new EntityLoader(cache, keyTransformationHandler), getFetchSize());
   }

   protected int getFetchSize() {
      return 1;
   }

   @AfterMethod
   public void tearDown() {
      iterator.close();

      keys = null;
      dummyResults = null;
      iterator = null;
   }

   protected String resultAt(int index) {
      return dummyResults.get(keys.get(index));
   }

   public void testNextAndHasNext() {
      for (int i = 0; i < keys.size(); i++) {
         Object expectedValue = resultAt(i);
         assert iterator.hasNext(); // should have next as long as we are less than the number of elements.
         assert expectedValue == iterator.next(); // tests next()
      }
      assert !iterator.hasNext(); // this should now NOT be true.
   }

   private static class MockEntityInfo implements EntityInfo {

      private final String key;

      MockEntityInfo(String key) {
         this.key = key;
      }

      @Override
      public Serializable getId() {
         return key;
      }

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

      @Override
      public Object[] getProjection() {
         return new Object[0];
      }

      @Override
      public Object getEntityInstance() {
         return null;
      }

      @Override
      public void populateWithEntityInstance(Object entity) {
      }

      @Override
      public IndexedTypeIdentifier getType() {
         return null;
      }
   }
}
