package vul.util;

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

import sun.reflect.ReflectionFactory;

import com.nqzero.permit.Permit;

@SuppressWarnings ( "restriction" )
public class Reflections {

    public static void setAccessible(AccessibleObject member) {
        // quiet runtime warnings from JDK9+
        Permit.setAccessible(member);
    }

    public static Field getField(final Class<?> clazz, final String fieldName) {
        Field field = null;
        try {
            field = clazz.getDeclaredField(fieldName);
            setAccessible(field);
        }
        catch (NoSuchFieldException ex) {
            if (clazz.getSuperclass() != null) {
                field = getField(clazz.getSuperclass(), fieldName);
            }
        }
        return field;
    }

    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) 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];
        setAccessible(ctor);
        return ctor;
    }

    public static Object newInstance(String className, Object ... args) throws Exception {
        return getFirstCtor(className).newInstance(args);
    }

    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);
        setAccessible(objCons);
        Constructor<?> sc = ReflectionFactory.getReflectionFactory().newConstructorForSerialization(classToInstantiate, objCons);
        setAccessible(sc);
        return (T)sc.newInstance(consArgs);
    }

}
