/*******************************************************************************
 * Copyright (c) 2005, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Brad Reynolds - bug 164268, 171616
 *     Brad Reynolds - bug 147515
 *     Matthew Hall - bug 221704
 *     Thomas Kratz - bug 213787
 *******************************************************************************/
module org.eclipse.core.databinding.beans.BeansObservables;

import java.lang.all;

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;

import org.eclipse.core.databinding.BindingException;
import org.eclipse.core.databinding.observable.IObservable;
import org.eclipse.core.databinding.observable.Realm;
import org.eclipse.core.databinding.observable.list.IObservableList;
import org.eclipse.core.databinding.observable.map.IObservableMap;
import org.eclipse.core.databinding.observable.masterdetail.IObservableFactory;
import org.eclipse.core.databinding.observable.masterdetail.MasterDetailObservables;
import org.eclipse.core.databinding.observable.set.IObservableSet;
import org.eclipse.core.databinding.observable.value.IObservableValue;
import org.eclipse.core.internal.databinding.beans.BeanObservableListDecorator;
import org.eclipse.core.internal.databinding.beans.BeanObservableMapDecorator;
import org.eclipse.core.internal.databinding.beans.BeanObservableSetDecorator;
import org.eclipse.core.internal.databinding.beans.BeanObservableValueDecorator;
import org.eclipse.core.internal.databinding.beans.JavaBeanObservableList;
import org.eclipse.core.internal.databinding.beans.JavaBeanObservableMap;
import org.eclipse.core.internal.databinding.beans.JavaBeanObservableSet;
import org.eclipse.core.internal.databinding.beans.JavaBeanObservableValue;
import org.eclipse.core.internal.databinding.beans.JavaBeanPropertyObservableMap;
import org.eclipse.core.runtime.Assert;

/**
 * A factory for creating observable objects of Java objects that conform to the
 * <a href="http://java.sun.com/products/javabeans/docs/spec.html">JavaBean
 * specification</a> for bound properties.
 * 
 * @since 1.1
 * 
 */
final public class BeansObservables {

    /**
     * 
     */
    public static final bool DEBUG = true;

    /**
     * Returns an observable value in the default realm tracking the current
     * value of the named property of the given bean.
     * 
     * @param bean
     *            the object
     * @param propertyName
     *            the name of the property
     * @return an observable value tracking the current value of the named
     *         property of the given bean
     */
    public static IObservableValue observeValue(Object bean, String propertyName) {
        return observeValue(Realm.getDefault(), bean, propertyName);
    }

    /**
     * Returns an observable value in the given realm tracking the current value
     * of the named property of the given bean.
     * 
     * @param realm
     *            the realm
     * @param bean
     *            the object
     * @param propertyName
     *            the name of the property
     * @return an observable value tracking the current value of the named
     *         property of the given bean
     */
    public static IObservableValue observeValue(Realm realm, Object bean,
            String propertyName) {
        PropertyDescriptor descriptor = getPropertyDescriptor(bean.getClass(),
                propertyName);
        return new JavaBeanObservableValue(realm, bean, descriptor);
    }

    /**
     * Returns an observable map in the default realm tracking the current
     * values of the named property for the beans in the given set.
     * 
     * @param domain
     *            the set of bean objects
     * @param beanClass
     *            the common base type of bean objects that may be in the set
     * @param propertyName
     *            the name of the property
     * @return an observable map tracking the current values of the named
     *         property for the beans in the given domain set
     */
    public static IObservableMap observeMap(IObservableSet domain,
            Class beanClass, String propertyName) {
        PropertyDescriptor descriptor = getPropertyDescriptor(beanClass,
                propertyName);
        return new JavaBeanObservableMap(domain, descriptor);
    }

    /**
     * Returns an observable map in the given realm tracking the map-typed named
     * property of the given bean object.
     * 
     * @param realm
     *            the realm
     * @param bean
     *            the bean object
     * @param propertyName
     *            the name of the property
     * @return an observable map tracking the map-typed named property of the
     *         given bean object
     * @since 1.1
     */
    public static IObservableMap observeMap(Realm realm, Object bean,
            String propertyName) {
        PropertyDescriptor descriptor = getPropertyDescriptor(bean.getClass(),
                propertyName);
        return new JavaBeanPropertyObservableMap(realm, bean, descriptor);
    }

    /*package*/ static PropertyDescriptor getPropertyDescriptor(Class beanClass,
            String propertyName) {
        BeanInfo beanInfo;
        try {
            beanInfo = Introspector.getBeanInfo(beanClass);
        } catch (IntrospectionException e) {
            // cannot introspect, give up
            return null;
        }
        PropertyDescriptor[] propertyDescriptors = beanInfo
                .getPropertyDescriptors();
        for (int i = 0; i < propertyDescriptors.length; i++) {
            PropertyDescriptor descriptor = propertyDescriptors[i];
            if (descriptor.getName().equals(propertyName)) {
                return descriptor;
            }
        }
        throw new BindingException(
                "Could not find property with name " + propertyName + " in class " + beanClass); //$NON-NLS-1$ //$NON-NLS-2$
    }

    /**
     * Returns an array of observable maps in the default realm tracking the
     * current values of the named propertys for the beans in the given set.
     * 
     * @param domain
     *            the set of objects
     * @param beanClass
     *            the common base type of objects that may be in the set
     * @param propertyNames
     *            the array of property names
     * @return an array of observable maps tracking the current values of the
     *         named propertys for the beans in the given domain set
     */
    public static IObservableMap[] observeMaps(IObservableSet domain,
            Class beanClass, String[] propertyNames) {
        IObservableMap[] result = new IObservableMap[propertyNames.length];
        for (int i = 0; i < propertyNames.length; i++) {
            result[i] = observeMap(domain, beanClass, propertyNames[i]);
        }
        return result;
    }

    /**
     * Returns an observable list in the given realm tracking the
     * collection-typed named property of the given bean object. The returned
     * list is mutable.
     * 
     * @param realm
     *            the realm
     * @param bean
     *            the object
     * @param propertyName
     *            the name of the collection-typed property
     * @return an observable list tracking the collection-typed named property
     *         of the given bean object
     * @see #observeList(Realm, Object, String, Class)
     */
    public static IObservableList observeList(Realm realm, Object bean,
            String propertyName) {
        return observeList(realm, bean, propertyName, null);
    }

    /**
     * Returns an observable list in the given realm tracking the
     * collection-typed named property of the given bean object. The returned
     * list is mutable. When an item is added or removed the setter is invoked
     * for the list on the parent bean to provide notification to other
     * listeners via <code>PropertyChangeEvents</code>. This is done to
     * provide the same behavior as is expected from arrays as specified in the
     * bean spec in section 7.2.
     * 
     * @param realm
     *            the realm
     * @param bean
     *            the bean object
     * @param propertyName
     *            the name of the property
     * @param elementType
     *            type of the elements in the list. If <code>null</code> and
     *            the property is an array the type will be inferred. If
     *            <code>null</code> and the property type cannot be inferred
     *            element type will be <code>null</code>.
     * @return an observable list tracking the collection-typed named property
     *         of the given bean object
     */
    public static IObservableList observeList(Realm realm, Object bean,
            String propertyName, Class elementType) {
        PropertyDescriptor propertyDescriptor = getPropertyDescriptor(bean
                .getClass(), propertyName);
        elementType = getCollectionElementType(elementType, propertyDescriptor);

        return new JavaBeanObservableList(realm, bean, propertyDescriptor,
                elementType);
    }

    /**
     * Returns an observable set in the given realm tracking the
     * collection-typed named property of the given bean object
     * 
     * @param realm
     *            the realm
     * @param bean
     *            the bean object
     * @param propertyName
     *            the name of the property
     * @return an observable set tracking the collection-typed named property of
     *         the given bean object
     */
    public static IObservableSet observeSet(Realm realm, Object bean,
            String propertyName) {
        return observeSet(realm, bean, propertyName, null);
    }

    /**
     * Returns a factory for creating obervable values tracking the given
     * property of a particular bean object
     * 
     * @param realm
     *            the realm to use
     * @param propertyName
     *            the name of the property
     * @return an observable value factory
     */
    public static IObservableFactory valueFactory(final Realm realm,
            final String propertyName) {
        return new class() IObservableFactory {
            public IObservable createObservable(Object target) {
                return observeValue(realm, target, propertyName);
            }
        };
    }

    /**
     * Returns a factory for creating obervable lists tracking the given
     * property of a particular bean object
     * 
     * @param realm
     *            the realm to use
     * @param propertyName
     *            the name of the property
     * @param elementType
     * @return an observable list factory
     */
    public static IObservableFactory listFactory(final Realm realm,
            final String propertyName, final Class elementType) {
        return new class() IObservableFactory {
            public IObservable createObservable(Object target) {
                return observeList(realm, target, propertyName, elementType);
            }
        };
    }

    /**
     * Returns a factory for creating obervable sets tracking the given property
     * of a particular bean object
     * 
     * @param realm
     *            the realm to use
     * @param propertyName
     *            the name of the property
     * @return an observable set factory
     */
    public static IObservableFactory setFactory(final Realm realm,
            final String propertyName) {
        return new class() IObservableFactory {
            public IObservable createObservable(Object target) {
                return observeSet(realm, target, propertyName);
            }
        };
    }

    /**
     * Helper method for
     * <code>MasterDetailObservables.detailValue(master, valueFactory(realm,
     propertyName), propertyType)</code>
     * 
     * @param realm
     * @param master
     * @param propertyName
     * @param propertyType
     *            can be <code>null</code>
     * @return an observable value that tracks the current value of the named
     *         property for the current value of the master observable value
     * 
     * @see MasterDetailObservables
     */
    public static IObservableValue observeDetailValue(Realm realm,
            IObservableValue master, String propertyName, Class propertyType) {

        IObservableValue value = MasterDetailObservables.detailValue(master,
                valueFactory(realm, propertyName), propertyType);
        BeanObservableValueDecorator decorator = new BeanObservableValueDecorator(
                value, master, getValueTypePropertyDescriptor(master,
                        propertyName));

        return decorator;
    }

    /**
     * Helper method for
     * <code>MasterDetailObservables.detailValue(master, valueFactory(realm,
     * propertyName), propertyType)</code>.
     * This method returns an {@link IBeanObservable} with a
     * {@link PropertyDescriptor} based on the given master type and property
     * name.
     * 
     * @param realm
     *            the realm
     * @param master
     *            the master observable value, for example tracking the
     *            selection in a list
     * @param masterType
     *            the type of the master observable value
     * @param propertyName
     *            the property name
     * @param propertyType
     *            can be <code>null</code>
     * @return an observable value that tracks the current value of the named
     *         property for the current value of the master observable value
     * 
     * @see MasterDetailObservables
     * @since 1.1
     */
    public static IObservableValue observeDetailValue(Realm realm,
            IObservableValue master, Class masterType, String propertyName, Class propertyType) {
        Assert.isNotNull(masterType, "masterType cannot be null"); //$NON-NLS-1$
        IObservableValue value = MasterDetailObservables.detailValue(master,
                valueFactory(realm, propertyName), propertyType);
        BeanObservableValueDecorator decorator = new BeanObservableValueDecorator(
                value, master, getPropertyDescriptor(masterType,
                        propertyName));

        return decorator;
    }
    
    /**
     * Helper method for
     * <code>MasterDetailObservables.detailList(master, listFactory(realm,
     propertyName, propertyType), propertyType)</code>
     * 
     * @param realm
     * @param master
     * @param propertyName
     * @param propertyType
     *            can be <code>null</code>
     * @return an observable list that tracks the named property for the current
     *         value of the master observable value
     * 
     * @see MasterDetailObservables
     */
    public static IObservableList observeDetailList(Realm realm,
            IObservableValue master, String propertyName, Class propertyType) {
        IObservableList observableList = MasterDetailObservables.detailList(
                master, listFactory(realm, propertyName, propertyType),
                propertyType);
        BeanObservableListDecorator decorator = new BeanObservableListDecorator(
                observableList, master, getValueTypePropertyDescriptor(master,
                        propertyName));

        return decorator;
    }

    /**
     * Helper method for
     * <code>MasterDetailObservables.detailSet(master, setFactory(realm,
     propertyName), propertyType)</code>
     * 
     * @param realm
     * @param master
     * @param propertyName
     * @param propertyType
     *            can be <code>null</code>
     * @return an observable set that tracks the named property for the current
     *         value of the master observable value
     * 
     * @see MasterDetailObservables
     */
    public static IObservableSet observeDetailSet(Realm realm,
            IObservableValue master, String propertyName, Class propertyType) {

        IObservableSet observableSet = MasterDetailObservables.detailSet(
                master, setFactory(realm, propertyName, propertyType),
                propertyType);
        BeanObservableSetDecorator decorator = new BeanObservableSetDecorator(
                observableSet, master, getValueTypePropertyDescriptor(master,
                        propertyName));

        return decorator;
    }

    /**
     * Helper method for
     * <code>MasterDetailObservables.detailMap(master, mapFactory(realm, propertyName))</code>
     * 
     * @param realm
     *            the realm
     * @param master
     * @param propertyName
     * @return an observable map that tracks the map-type named property for the
     *         current value of the master observable value.
     * @since 1.1
     */
    public static IObservableMap observeDetailMap(Realm realm,
            IObservableValue master, String propertyName) {
        IObservableMap observableMap = MasterDetailObservables.detailMap(
                master, mapPropertyFactory(realm, propertyName));
        BeanObservableMapDecorator decorator = new BeanObservableMapDecorator(
                observableMap, master, getValueTypePropertyDescriptor(master,
                        propertyName));
        return decorator;
    }

    /**
     * @param realm
     * @param bean
     * @param propertyName
     * @param elementType
     *            can be <code>null</code>
     * @return an observable set that tracks the current value of the named
     *         property for given bean object
     */
    public static IObservableSet observeSet(Realm realm, Object bean,
            String propertyName, Class elementType) {
        PropertyDescriptor propertyDescriptor = getPropertyDescriptor(bean
                .getClass(), propertyName);
        elementType = getCollectionElementType(elementType, propertyDescriptor);

        return new JavaBeanObservableSet(realm, bean, propertyDescriptor,
                elementType);
    }

    /**
     * @param realm
     * @param propertyName
     * @param elementType
     *            can be <code>null</code>
     * @return an observable set factory for creating observable sets
     */
    public static IObservableFactory setFactory(final Realm realm,
            final String propertyName, final Class elementType) {
        return new class() IObservableFactory {
            public IObservable createObservable(Object target) {
                return observeSet(realm, target, propertyName, elementType);
            }
        };
    }

    /**
     * Returns a factory for creating an observable map. The factory, when
     * provided with an {@link IObservableSet}, will create an
     * {@link IObservableMap} in the same realm as the underlying set that
     * tracks the current values of the named property for the beans in the
     * given set.
     * 
     * @param beanClass
     *            the common base type of bean objects that may be in the set
     * @param propertyName
     *            the name of the property
     * @return a factory for creating {@link IObservableMap} objects
     *
     * @since 1.1
     */
    public static IObservableFactory setToMapFactory(final Class beanClass, final String propertyName) {
        return new class() IObservableFactory {
            public IObservable createObservable(Object target) {
                return observeMap(cast(IObservableSet) target, beanClass, propertyName);
            }
        };
    }
    
    /**
     * Returns a factory for creating an observable map. The factory, when
     * provided with a bean object, will create an {@link IObservableMap} in the
     * given realm that tracks the map-typed named property for the specified
     * bean.
     * 
     * @param realm
     *            the realm assigned to observables created by the returned
     *            factory.
     * @param propertyName
     *            the name of the property
     * @return a factory for creating {@link IObservableMap} objects.
     * @since 1.1
     */
    public static IObservableFactory mapPropertyFactory(final Realm realm,
            final String propertyName) {
        return new class() IObservableFactory {
            public IObservable createObservable(Object target) {
                return observeMap(realm, target, propertyName);
            }
        };
    }

    /**
     * @param elementType
     *            can be <code>null</code>
     * @param propertyDescriptor
     * @return type of the items in a collection/array property
     */
    /*package*/ static Class getCollectionElementType(Class elementType,
            PropertyDescriptor propertyDescriptor) {
        if (elementType is null) {
            Class propertyType = propertyDescriptor.getPropertyType();
            elementType = propertyType.isArray() ? propertyType
                    .getComponentType() : Object.class;
        }

        return elementType;
    }

    /**
     * @param observable
     * @param propertyName
     * @return property descriptor or <code>null</code>
     */
    /* package*/ static PropertyDescriptor getValueTypePropertyDescriptor(
            IObservableValue observable, String propertyName) {
        return (observable.getValueType() !is null) ? getPropertyDescriptor(
                cast(Class) observable.getValueType(), propertyName) : null;
    }
}