/**
 * Copyright (C) 2007 Google Inc.
 *
 * 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.inject.spi;

import static com.google.inject.Asserts.assertContains;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.inject.AbstractModule;
import com.google.inject.Binder;
import com.google.inject.BindingAnnotation;
import com.google.inject.CreationException;
import com.google.inject.Guice;
import com.google.inject.Inject;
import com.google.inject.Injector;
import com.google.inject.Key;
import com.google.inject.Module;
import com.google.inject.Provider;
import com.google.inject.Provides;
import com.google.inject.Singleton;
import com.google.inject.internal.ProviderMethod;
import com.google.inject.internal.ProviderMethodsModule;
import com.google.inject.name.Named;
import com.google.inject.name.Names;
import com.google.inject.util.Types;

import junit.framework.TestCase;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import java.util.List;
import java.util.Set;
import java.util.concurrent.atomic.AtomicReference;
import java.util.logging.Logger;

/**
 * @author crazybob@google.com (Bob Lee)
 */
public class ProviderMethodsTest extends TestCase implements Module {

  @SuppressWarnings("unchecked")
  public void testProviderMethods() {
    Injector injector = Guice.createInjector(this);

    Bob bob = injector.getInstance(Bob.class);
    assertEquals("A Bob", bob.getName());

    Bob clone = injector.getInstance(Bob.class);
    assertEquals("A Bob", clone.getName());

    assertNotSame(bob, clone);
    assertSame(bob.getDaughter(), clone.getDaughter());

    Key soleBobKey = Key.get(Bob.class, Sole.class);
    assertSame(
        injector.getInstance(soleBobKey),
        injector.getInstance(soleBobKey)
    );
  }

  public void configure(Binder binder) {}

  interface Bob {
    String getName();
    Dagny getDaughter();
  }

  interface Dagny {
    int getAge();
  }

  @Provides
  Bob provideBob(final Dagny dagny) {
    return new Bob() {
      public String getName() {
        return "A Bob";
      }

      public Dagny getDaughter() {
        return dagny;
      }
    };
  }

  @Provides
  @Singleton
  @Sole
  Bob provideSoleBob(final Dagny dagny) {
    return new Bob() {
      public String getName() {
        return "Only Bob";
      }

      public Dagny getDaughter() {
        return dagny;
      }
    };
  }

  @Provides
  @Singleton
  Dagny provideDagny() {
    return new Dagny() {
      public int getAge() {
        return 1;
      }
    };
  }

  @Retention(RUNTIME)
  @Target({ ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD })
  @BindingAnnotation
  @interface Sole {}


// We'll have to make getProvider() support circular dependencies before this
// will work.
//
//  public void testCircularDependency() {
//    Injector injector = Guice.createInjector(new Module() {
//      public void configure(Binder binder) {
//        binder.install(ProviderMethods.from(ProviderMethodsTest.this));
//      }
//    });
//
//    Foo foo = injector.getInstance(Foo.class);
//    assertEquals(5, foo.getI());
//    assertEquals(10, foo.getBar().getI());
//    assertEquals(5, foo.getBar().getFoo().getI());
//  }
//
//  interface Foo {
//    Bar getBar();
//    int getI();
//  }
//
//  interface Bar {
//    Foo getFoo();
//    int getI();
//  }
//
//  @Provides Foo newFoo(final Bar bar) {
//    return new Foo() {
//
//      public Bar getBar() {
//        return bar;
//      }
//
//      public int getI() {
//        return 5;
//      }
//    };
//  }
//
//  @Provides Bar newBar(final Foo foo) {
//    return new Bar() {
//
//      public Foo getFoo() {
//        return foo;
//      }
//
//      public int getI() {
//        return 10;
//      }
//    };
//  }


  public void testMultipleBindingAnnotations() {
    try {
      Guice.createInjector(new AbstractModule() {
        @Override protected void configure() {}

        @Provides @Named("A") @Blue
        public String provideString() {
          return "a";
        }
      });
      fail();
    } catch (CreationException expected) {
      assertContains(expected.getMessage(),
          "more than one annotation annotated with @BindingAnnotation:", "Named", "Blue",
          "at " + getClass().getName(), ".provideString(ProviderMethodsTest.java:");
    }

  }

  @Retention(RUNTIME)
  @BindingAnnotation @interface Blue {}

  public void testGenericProviderMethods() {
    Injector injector = Guice.createInjector(
        new ProvideTs<String>("A", "B") {}, new ProvideTs<Integer>(1, 2) {});
    
    assertEquals("A", injector.getInstance(Key.get(String.class, Names.named("First"))));
    assertEquals("B", injector.getInstance(Key.get(String.class, Names.named("Second"))));
    assertEquals(ImmutableSet.of("A", "B"),
        injector.getInstance(Key.get(Types.setOf(String.class))));

    assertEquals(1, injector.getInstance(Key.get(Integer.class, Names.named("First"))).intValue());
    assertEquals(2, injector.getInstance(Key.get(Integer.class, Names.named("Second"))).intValue());
    assertEquals(ImmutableSet.of(1, 2),
        injector.getInstance(Key.get(Types.setOf(Integer.class))));
  }

  abstract class ProvideTs<T> extends AbstractModule {
    final T first;
    final T second;

    protected ProvideTs(T first, T second) {
      this.first = first;
      this.second = second;
    }

    @Override protected void configure() {}

    @Named("First") @Provides T provideFirst() {
      return first;
    }

    @Named("Second") @Provides T provideSecond() {
      return second;
    }

    @Provides Set<T> provideBoth(@Named("First") T first, @Named("Second") T second) {
      return ImmutableSet.of(first, second);
    }
  }
  
  public void testAutomaticProviderMethods() {
    Injector injector = Guice.createInjector((Module) new AbstractModule() {
      @Override protected void configure() { }
      private int next = 1;

      @Provides @Named("count")
      public Integer provideCount() {
        return next++;
      }
    });

    assertEquals(1, injector.getInstance(Key.get(Integer.class, Names.named("count"))).intValue());
    assertEquals(2, injector.getInstance(Key.get(Integer.class, Names.named("count"))).intValue());
    assertEquals(3, injector.getInstance(Key.get(Integer.class, Names.named("count"))).intValue());
  }

  /**
   * If the user installs provider methods for the module manually, that shouldn't cause a double
   * binding of the provider methods' types.
   */
  public void testAutomaticProviderMethodsDoNotCauseDoubleBinding() {
    Module installsSelf = new AbstractModule() {
      @Override protected void configure() {
        install(this);
        bind(Integer.class).toInstance(5);
      }
      @Provides public String provideString(Integer count) {
        return "A" + count;
      }
    };

    Injector injector = Guice.createInjector(installsSelf);
    assertEquals("A5", injector.getInstance(String.class));
  }
  
  public void testWildcardProviderMethods() {
    final List<String> strings = ImmutableList.of("A", "B", "C");
    final List<Number> numbers = ImmutableList.<Number>of(1, 2, 3);

    Injector injector = Guice.createInjector(new AbstractModule() {
      @Override protected void configure() {
        @SuppressWarnings("unchecked")
        Key<List<? super Integer>> listOfSupertypesOfInteger = (Key<List<? super Integer>>)
            Key.get(Types.listOf(Types.supertypeOf(Integer.class)));
        bind(listOfSupertypesOfInteger).toInstance(numbers);
      }
      @Provides public List<? extends CharSequence> provideCharSequences() {
        return strings;
      }
      @Provides public Class<?> provideType() {
        return Float.class;
      }
    });

    assertSame(strings, injector.getInstance(HasWildcardInjection.class).charSequences);
    assertSame(numbers, injector.getInstance(HasWildcardInjection.class).numbers);
    assertSame(Float.class, injector.getInstance(HasWildcardInjection.class).type);
  }

  static class HasWildcardInjection {
    @Inject List<? extends CharSequence> charSequences;
    @Inject List<? super Integer> numbers;
    @Inject Class<?> type;
  }

  public void testProviderMethodDependenciesAreExposed() {
    Injector injector = Guice.createInjector(new AbstractModule() {
      @Override protected void configure() {
        bind(Integer.class).toInstance(50);
        bindConstant().annotatedWith(Names.named("units")).to("Kg");
      }
      @Provides @Named("weight") String provideWeight(Integer count, @Named("units") String units) {
        return count + units;
      }
    });

    ProviderInstanceBinding<?> binding = (ProviderInstanceBinding<?>) injector.getBinding(
        Key.get(String.class, Names.named("weight")));
    assertEquals(ImmutableSet.<Dependency<?>>of(Dependency.get(Key.get(Integer.class)),
        Dependency.get(Key.get(String.class, Names.named("units")))),
        binding.getDependencies());
  }

  public void testNonModuleProviderMethods() {
    final Object methodsObject = new Object() {
      @Provides @Named("foo") String provideFoo() {
        return "foo-value";
      }
    };

    Module module = new AbstractModule() {
      @Override protected void configure() {
        install(ProviderMethodsModule.forObject(methodsObject));
      }
    };

    Injector injector = Guice.createInjector(module);

    Key<String> key = Key.get(String.class, Names.named("foo"));
    assertEquals("foo-value", injector.getInstance(key));

    // Test the provider method object itself. This makes sure getInstance works, since GIN uses it
    List<Element> elements = Elements.getElements(module);
    assertEquals(1, elements.size());

    Element element = elements.get(0);
    assertTrue(element + " instanceof ProviderInstanceBinding",
        element instanceof ProviderInstanceBinding);

    ProviderInstanceBinding binding = (ProviderInstanceBinding) element;
    Provider provider = binding.getProviderInstance();    
    assertEquals(ProviderMethod.class, provider.getClass());
    assertEquals(methodsObject, ((ProviderMethod) provider).getInstance());
  }

  public void testVoidProviderMethods() {
    try {
      Guice.createInjector(new AbstractModule() {
        @Override protected void configure() {}

        @Provides void provideFoo() {}
      });
      fail();
    } catch (CreationException expected) {
      assertContains(expected.getMessage(), 
          "1) Provider methods must return a value. Do not return void.",
          getClass().getName(), ".provideFoo(ProviderMethodsTest.java:");
    }
  }
  
  public void testInjectsJustOneLogger() {
    AtomicReference<Logger> loggerRef = new AtomicReference<Logger>();
    Injector injector = Guice.createInjector(new FooModule(loggerRef));
    
    assertNull(loggerRef.get());
    injector.getInstance(Integer.class);
    Logger lastLogger = loggerRef.getAndSet(null);
    assertNotNull(lastLogger);
    injector.getInstance(Integer.class);
    assertSame(lastLogger, loggerRef.get());
    
    assertEquals(FooModule.class.getName() + ".foo", lastLogger.getName());
  }
  
  private static class FooModule extends AbstractModule {
    private final AtomicReference<Logger> loggerRef;
    
    public FooModule(AtomicReference<Logger> loggerRef) {
      this.loggerRef = loggerRef;
    }

    @Override protected void configure() {}

    @SuppressWarnings("unused")
    @Provides Integer foo(Logger logger) {
      loggerRef.set(logger);
      return 42;
    }
  }
}