# ConstructorsModel.java

    /*
     * Copyright (c) 2008, Rickard Öberg. 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 org.qi4j.runtime.composite;

    import java.lang.annotation.Annotation;
    import java.lang.reflect.Constructor;
    import java.lang.reflect.Modifier;
    import java.lang.reflect.ParameterizedType;
    import java.lang.reflect.Type;
    import java.lang.reflect.TypeVariable;
    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.Comparator;
    import java.util.List;
    import org.qi4j.api.common.ConstructionException;
    import org.qi4j.api.composite.CompositeDescriptor;
    import org.qi4j.api.composite.InvalidCompositeException;
    import org.qi4j.api.injection.InjectionScope;
    import org.qi4j.api.injection.scope.Uses;
    import org.qi4j.api.util.Annotations;
    import org.qi4j.api.util.Classes;
    import org.qi4j.bootstrap.BindingException;
    import org.qi4j.functional.Function;
    import org.qi4j.functional.HierarchicalVisitor;
    import org.qi4j.functional.HierarchicalVisitorAdapter;
    import org.qi4j.functional.Iterables;
    import org.qi4j.functional.Specifications;
    import org.qi4j.functional.VisitableHierarchy;
    import org.qi4j.runtime.injection.Dependencies;
    import org.qi4j.runtime.injection.DependencyModel;
    import org.qi4j.runtime.injection.InjectedParametersModel;
    import org.qi4j.runtime.injection.InjectionContext;
    import org.qi4j.runtime.injection.ParameterizedTypeInstance;
    import org.qi4j.runtime.model.Binder;
    import org.qi4j.runtime.model.Resolution;

    import static org.qi4j.functional.Iterables.filter;
    import static org.qi4j.functional.Iterables.first;
    import static org.qi4j.functional.Iterables.iterable;

    /**
     * JAVADOC
     */
    public final class ConstructorsModel
        implements Binder, Dependencies, VisitableHierarchy<Object, Object>
    {
        @SuppressWarnings( "raw" )
        private final Class fragmentClass;
        private final List<ConstructorModel> constructorModels;
        private List<ConstructorModel> boundConstructors;

        @SuppressWarnings( { "raw", "unchecked" } )
        public ConstructorsModel( Class fragmentClass )
        {
            this.fragmentClass = fragmentClass;
            validate( fragmentClass );
            constructorModels = new ArrayList<>();
            Constructor[] realConstructors = this.fragmentClass.getDeclaredConstructors();
            Class injectionClass = FragmentClassLoader.getSourceClass( fragmentClass );
            for( Constructor constructor : realConstructors )
            {
                constructor.setAccessible( true );
                try
                {
                    Constructor injectionConstructor = injectionClass.getDeclaredConstructor( constructor.getParameterTypes() );
                    injectionConstructor.setAccessible( true );
                    ConstructorModel constructorModel = newConstructorModel( this.fragmentClass, constructor,
                                                                             injectionConstructor );
                    if( constructorModel != null )
                    {
                        constructorModels.add( constructorModel );
                    }
                }
                catch( NoSuchMethodException e )
                {
                    // Ignore and continue
                    e.printStackTrace();
                }
            }
        }

        @SuppressWarnings( "raw" )
        private void validate( Class fragmentClass )
        {
            // Ensure that the fragment class is not an inner class, in which case we should give a reasonable exception
            if( fragmentClass.getDeclaringClass() == null )
            {
                return;
            }
            if( Modifier.isStatic( fragmentClass.getModifiers() ) )
            {
                return;
            }
            throw new InvalidCompositeException( "Inner classes can not be used. Use static nested classes instead: " + fragmentClass );
        }

        @Override
        public Iterable<DependencyModel> dependencies()
        {
            Function<ConstructorModel, Iterable<DependencyModel>> constructorDependencies = new Function<ConstructorModel, Iterable<DependencyModel>>()
            {
                @Override
                public Iterable<DependencyModel> map( ConstructorModel constructorModel )
                {
                    return constructorModel.dependencies();
                }
            };

            return Iterables.flattenIterables( Iterables.map( constructorDependencies, boundConstructors == null ? constructorModels : boundConstructors ) );
        }

        @SuppressWarnings( "raw" )
        private ConstructorModel newConstructorModel( Class fragmentClass,
                                                      Constructor realConstructor,
                                                      Constructor injectedConstructor
        )
        {
            int idx = 0;
            InjectedParametersModel parameters = new InjectedParametersModel();
            Annotation[][] parameterAnnotations = injectedConstructor.getParameterAnnotations();
            for( Type type : injectedConstructor.getGenericParameterTypes() )
            {
                Annotation injectionAnnotation = first(
                    filter( Specifications.translate( Annotations.type(), Annotations.hasAnnotation( InjectionScope.class ) ), iterable( parameterAnnotations[ idx ] ) ) );

                if( injectionAnnotation == null )
                {
                    if( fragmentClass.getSuperclass().isMemberClass() )
                    {
                        injectionAnnotation = new Uses()
                        {
                            @Override
                            public Class<? extends Annotation> annotationType()
                            {
                                return Uses.class;
                            }
                        };
                    }
                    else
                    {
                        return null; // invalid constructor parameter
                    }
                }

                boolean optional = DependencyModel.isOptional( injectionAnnotation, parameterAnnotations[ idx ] );

                Type genericType = type;
                if( genericType instanceof ParameterizedType )
                {
                    genericType = new ParameterizedTypeInstance( ( (ParameterizedType) genericType ).getActualTypeArguments(), ( (ParameterizedType) genericType )
                        .getRawType(), ( (ParameterizedType) genericType ).getOwnerType() );

                    for( int i = 0; i < ( (ParameterizedType) genericType ).getActualTypeArguments().length; i++ )
                    {
                        Type typeArg = ( (ParameterizedType) genericType ).getActualTypeArguments()[ i ];
                        if( typeArg instanceof TypeVariable )
                        {
                            typeArg = Classes.resolveTypeVariable( (TypeVariable) typeArg, realConstructor.getDeclaringClass(), fragmentClass );
                            ( (ParameterizedType) genericType ).getActualTypeArguments()[ i ] = typeArg;
                        }
                    }
                }

                DependencyModel dependencyModel = new DependencyModel( injectionAnnotation, genericType, fragmentClass, optional,
                                                                       parameterAnnotations[ idx ] );
                parameters.addDependency( dependencyModel );
                idx++;
            }
            return new ConstructorModel( realConstructor, parameters );
        }

        @Override
        public <ThrowableType extends Throwable> boolean accept( HierarchicalVisitor<? super Object, ? super Object, ThrowableType> visitor )
            throws ThrowableType
        {
            if( visitor.visitEnter( this ) )
            {
                if( boundConstructors != null )
                {
                    for( ConstructorModel constructorModel : boundConstructors )
                    {
                        if( !constructorModel.accept( visitor ) )
                        {
                            break;
                        }
                    }
                }
                else
                {
                    for( ConstructorModel constructorModel : constructorModels )
                    {
                        if( !constructorModel.accept( visitor ) )
                        {
                            break;
                        }
                    }
                }
            }
            return visitor.visitLeave( this );
        }

        // Binding
        @Override
        public void bind( final Resolution resolution )
            throws BindingException
        {
            boundConstructors = new ArrayList<>();
            for( ConstructorModel constructorModel : constructorModels )
            {
                try
                {
                    constructorModel.accept( new HierarchicalVisitorAdapter<Object, Object, BindingException>()
                    {
                        @Override
                        public boolean visit( Object visitor )
                            throws BindingException
                        {
                            if( visitor instanceof Binder )
                            {
                                ( (Binder) visitor ).bind( resolution );
                            }
                            return true;
                        }
                    } );
                    boundConstructors.add( constructorModel );
                }
                catch( Exception e )
                {
                    // Ignore
                    e.printStackTrace();
                }
            }

            if( boundConstructors.isEmpty() )
            {
                StringBuilder messageBuilder = new StringBuilder( "Found no constructor that could be bound: " );
                if( resolution.model() instanceof CompositeDescriptor )
                {
                    messageBuilder.append( fragmentClass.getName() )
                        .append( " in " )
                        .append( resolution.model().toString() );
                }
                else
                {
                    messageBuilder.append( resolution.model().toString() );
                }

                if( messageBuilder.indexOf( "$" ) >= 0 )
                {
                    // This could be ok if instance is created manually
                    return;
    //                messageBuilder.append( "\nInner classes can not be used." );
                }
                String message = messageBuilder.toString();
                throw new BindingException( message );
            }

            // Sort based on parameter count
            Collections.sort( boundConstructors, new Comparator<ConstructorModel>()
            {
                @Override
                public int compare( ConstructorModel o1, ConstructorModel o2 )
                {
                    Integer model2ParametersCount = o2.constructor().getParameterTypes().length;
                    int model1ParametersCount = o1.constructor().getParameterTypes().length;
                    return model2ParametersCount.compareTo( model1ParametersCount );
                }
            } );
        }

        public Object newInstance( InjectionContext injectionContext )
        {
            // Try all bound constructors, in order
            ConstructionException exception = null;
            for( ConstructorModel constructorModel : boundConstructors )
            {
                try
                {
                    return constructorModel.newInstance( injectionContext );
                }
                catch( ConstructionException e )
                {
                    exception = e;
                }
            }

            throw exception;
        }
    }