package summer.util;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;

import sun.reflect.ReflectionFactory;


@SuppressWarnings ( "restriction" )
public class Reflections {

    public static Field getField ( final Class<?> clazz, final String fieldName ) throws Exception {
        try {
            Field field = clazz.getDeclaredField(fieldName);
            if ( field != null ) {
                field.setAccessible(true);
            } else if ( clazz.getSuperclass() != null ) {
                field = getField(clazz.getSuperclass(), fieldName);
            }

            return field;
        }
        catch ( NoSuchFieldException e ) {
            if ( !clazz.getSuperclass().equals(Object.class) ) {
                return getField(clazz.getSuperclass(), fieldName);
            }
            throw e;
        }
    }


    public static void setFieldValue ( final Object obj, final String fieldName, final Object value ) throws Exception {
        final Field field = getField(obj.getClass(), fieldName);
        field.set(obj, value);
    }


    public static Object getFieldValue(final Object obj, final String fieldName, int i) throws Exception {
        final Field field = getField(obj.getClass(), fieldName);
        return field.get(obj);
    }


    public static Constructor<?> getFirstCtor ( final String name ) throws Exception {
        final Constructor<?> ctor = Class.forName(name).getDeclaredConstructors()[ 0 ];
        ctor.setAccessible(true);
        return ctor;
    }


    public static <T> T createWithoutConstructor ( Class<T> classToInstantiate )
            throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException {
        return createWithConstructor(classToInstantiate, Object.class, new Class[0], new Object[0]);
    }


    @SuppressWarnings ( {
            "unchecked"
    } )
    public static <T> T createWithConstructor ( Class<T> classToInstantiate, Class<? super T> constructorClass, Class<?>[] consArgTypes,
                                                Object[] consArgs ) throws NoSuchMethodException, InstantiationException, IllegalAccessException, InvocationTargetException {
        Constructor<? super T> objCons = constructorClass.getDeclaredConstructor(consArgTypes);
        objCons.setAccessible(true);
        Constructor<?> sc = ReflectionFactory.getReflectionFactory().newConstructorForSerialization(classToInstantiate, objCons);
        sc.setAccessible(true);
        return (T) sc.newInstance(consArgs);
    }

}
