// Copyright 2007, 2008, 2009, 2010, 2011 The Apache Software Foundation
//
// 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.apache.tapestry5.ioc.internal;

import org.apache.tapestry5.ioc.*;
import org.apache.tapestry5.ioc.annotations.EagerLoad;
import org.apache.tapestry5.ioc.annotations.Marker;
import org.apache.tapestry5.ioc.annotations.PreventServiceDecoration;
import org.apache.tapestry5.ioc.annotations.Scope;
import org.apache.tapestry5.ioc.def.ServiceDef;
import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
import org.apache.tapestry5.ioc.internal.util.InternalUtils;
import org.apache.tapestry5.ioc.internal.util.OneShotLock;
import org.apache.tapestry5.ioc.services.PlasticProxyFactory;

import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.Set;

@SuppressWarnings("all")
public class ServiceBinderImpl implements ServiceBinder, ServiceBindingOptions
{
    private final OneShotLock lock = new OneShotLock();

    private final Method bindMethod;

    private final ServiceDefAccumulator accumulator;

    private PlasticProxyFactory proxyFactory;

    private final Set<Class> defaultMarkers;

    private final boolean moduleDefaultPreventDecoration;

    public ServiceBinderImpl(ServiceDefAccumulator accumulator, Method bindMethod, PlasticProxyFactory proxyFactory,
                             Set<Class> defaultMarkers, boolean moduleDefaultPreventDecoration)
    {
        this.accumulator = accumulator;
        this.bindMethod = bindMethod;
        this.proxyFactory = proxyFactory;
        this.defaultMarkers = defaultMarkers;
        this.moduleDefaultPreventDecoration = moduleDefaultPreventDecoration;

        clear();
    }

    private String serviceId;

    private Class serviceInterface;

    private Class serviceImplementation;

    private final Set<Class> markers = CollectionFactory.newSet();

    private ObjectCreatorSource source;

    private boolean eagerLoad;

    private String scope;

    private boolean preventDecoration;

    private boolean preventReloading;

    public void finish()
    {
        lock.lock();

        flush();
    }

    protected void flush()
    {
        if (serviceInterface == null)
            return;

        // source will be null when the implementation class is provided; non-null when using
        // a ServiceBuilder callback

        if (source == null)
            source = createObjectCreatorSourceFromImplementationClass();

        // Combine service-specific markers with those inherited form the module.
        Set<Class> markers = CollectionFactory.newSet(defaultMarkers);
        markers.addAll(this.markers);

        ServiceDef serviceDef = new ServiceDefImpl(serviceInterface, serviceImplementation, serviceId, markers, scope,
                eagerLoad, preventDecoration, source);

        accumulator.addServiceDef(serviceDef);

        clear();
    }

    private void clear()
    {
        serviceId = null;
        serviceInterface = null;
        serviceImplementation = null;
        source = null;
        this.markers.clear();
        eagerLoad = false;
        scope = null;
        preventDecoration = moduleDefaultPreventDecoration;
        preventReloading = false;
    }

    private ObjectCreatorSource createObjectCreatorSourceFromImplementationClass()
    {
        if (InternalUtils.SERVICE_CLASS_RELOADING_ENABLED && !preventReloading && isProxiable() && reloadableScope()
                && InternalUtils.isLocalFile(serviceImplementation))
            return createReloadableConstructorBasedObjectCreatorSource();

        return createStandardConstructorBasedObjectCreatorSource();
    }

    private boolean isProxiable()
    {
        return serviceInterface.isInterface();
    }

    private boolean reloadableScope()
    {
        return scope.equalsIgnoreCase(ScopeConstants.DEFAULT);
    }

    private ObjectCreatorSource createStandardConstructorBasedObjectCreatorSource()
    {
        if (Modifier.isAbstract(serviceImplementation.getModifiers()))
            throw new RuntimeException(IOCMessages.abstractServiceImplementation(serviceImplementation, serviceId));
        final Constructor constructor = InternalUtils.findAutobuildConstructor(serviceImplementation);

        if (constructor == null)
            throw new RuntimeException(IOCMessages.noConstructor(serviceImplementation, serviceId));

        return new ObjectCreatorSource()
        {
            @Override
            public ObjectCreator constructCreator(ServiceBuilderResources resources)
            {
                return new ConstructorServiceCreator(resources, getDescription(), constructor);
            }

            @Override
            public String getDescription()
            {
                return String.format("%s via %s", proxyFactory.getConstructorLocation(constructor),
                        proxyFactory.getMethodLocation(bindMethod));
            }
        };
    }

    private ObjectCreatorSource createReloadableConstructorBasedObjectCreatorSource()
    {
        return new ReloadableObjectCreatorSource(proxyFactory, bindMethod, serviceInterface, serviceImplementation,
                eagerLoad);
    }

    @Override
    @SuppressWarnings("unchecked")
    public <T> ServiceBindingOptions bind(Class<T> serviceClass)
    {
        if (serviceClass.isInterface())
        {
            try
            {
                String expectedImplName = serviceClass.getName() + "Impl";

                ClassLoader classLoader = proxyFactory.getClassLoader();

                Class<T> implementationClass = (Class<T>) classLoader.loadClass(expectedImplName);

                if (!implementationClass.isInterface() && serviceClass.isAssignableFrom(implementationClass))
                {
                    return bind(
                            serviceClass, implementationClass);
                }
                throw new RuntimeException(IOCMessages.noServiceMatchesType(serviceClass));
            } catch (ClassNotFoundException ex)
            {
                throw new RuntimeException(String.format("Could not find default implementation class %sImpl. Please provide this class, or bind the service interface to a specific implementation class.",
                        serviceClass.getName()));
            }
        }

        return bind(serviceClass, serviceClass);
    }

    @Override
    public <T> ServiceBindingOptions bind(Class<T> serviceInterface, final ServiceBuilder<T> builder)
    {
        assert serviceInterface != null;
        assert builder != null;
        lock.check();

        flush();

        this.serviceInterface = serviceInterface;
        this.scope = ScopeConstants.DEFAULT;

        serviceId = serviceInterface.getSimpleName();

        this.source = new ObjectCreatorSource()
        {
            @Override
            public ObjectCreator constructCreator(final ServiceBuilderResources resources)
            {
                return new ObjectCreator()
                {
                    @Override
                    public Object createObject()
                    {
                        return builder.buildService(resources);
                    }
                };
            }

            @Override
            public String getDescription()
            {
                return proxyFactory.getMethodLocation(bindMethod).toString();
            }
        };

        return this;
    }

    @Override
    public <T> ServiceBindingOptions bind(Class<T> serviceInterface, Class<? extends T> serviceImplementation)
    {
        assert serviceInterface != null;
        assert serviceImplementation != null;
        lock.check();

        flush();

        this.serviceInterface = serviceInterface;

        this.serviceImplementation = serviceImplementation;

        // Set defaults for the other properties.

        eagerLoad = serviceImplementation.getAnnotation(EagerLoad.class) != null;

        serviceId = InternalUtils.getServiceId(serviceImplementation);

        if (serviceId == null)
        {
            serviceId = serviceInterface.getSimpleName();
        }

        Scope scope = serviceImplementation.getAnnotation(Scope.class);

        this.scope = scope != null ? scope.value() : ScopeConstants.DEFAULT;

        Marker marker = serviceImplementation.getAnnotation(Marker.class);

        if (marker != null)
        {
            InternalUtils.validateMarkerAnnotations(marker.value());
            markers.addAll(Arrays.asList(marker.value()));
        }

        preventDecoration |= serviceImplementation.getAnnotation(PreventServiceDecoration.class) != null;

        return this;
    }

    @Override
    public ServiceBindingOptions eagerLoad()
    {
        lock.check();

        eagerLoad = true;

        return this;
    }

    @Override
    public ServiceBindingOptions preventDecoration()
    {
        lock.check();

        preventDecoration = true;

        return this;
    }

    @Override
    public ServiceBindingOptions preventReloading()
    {
        lock.check();

        preventReloading = true;

        return this;
    }

    @Override
    public ServiceBindingOptions withId(String id)
    {
        assert InternalUtils.isNonBlank(id);
        lock.check();

        serviceId = id;

        return this;
    }

    @Override
    public ServiceBindingOptions withSimpleId()
    {
        if (serviceImplementation == null)
        {
            throw new IllegalArgumentException("No defined implementation class to generate simple id from.");
        }

        return withId(serviceImplementation.getSimpleName());
    }

    @Override
    public ServiceBindingOptions scope(String scope)
    {
        assert InternalUtils.isNonBlank(scope);
        lock.check();

        this.scope = scope;

        return this;
    }

    @Override
    public ServiceBindingOptions withMarker(Class<? extends Annotation>... marker)
    {
        lock.check();

        InternalUtils.validateMarkerAnnotations(marker);

        markers.addAll(Arrays.asList(marker));

        return this;
    }
}