package eu.mikroskeem.utils.reflect;

import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

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

/**
 * Reflection utils
 *
 * @author Mark
 */
public class Reflect {

    /**
     * Find class by name
     *
     * @param clazz Class to search
     * @return Class or null
     */
    @Nullable
    public static Class<?> getClass(@NotNull String clazz){
        try {
            return Class.forName(clazz);
        } catch (ClassNotFoundException e){
            return null;
        }
    }

    /**
     * Return whether class exists or not
     *
     * @param clazz Class to search
     * @return Whether class existed or not
     */
    public static boolean classExists(@NotNull String clazz){
        return getClass(clazz) != null;
    }

    /**
     * Get declared class method (public,protected,private)
     *
     * @param clazz Class to reflect
     * @param method Method to search
     * @param arguments Method arguments
     * @return Method or null
     */
    @Nullable
    public static Method getMethod(@NotNull Class<?> clazz, @NotNull String method, Class<?>... arguments){
        try {
            Method m = clazz.getDeclaredMethod(method, arguments);
            m.setAccessible(true);
            return m;
        } catch (NoSuchMethodException e){
            return null;
        }
    }

    /**
     * Invoke method and get result
     *
     * @param method Method to invoke
     * @param instance Instance where given method resides (null if static)
     * @param args Method arguments
     * @return Method result or null
     */
    @Nullable
    public static Object invokeMethod(@NotNull Method method, @Nullable Object instance, @Nullable Object... args){
        try {
            return method.invoke(instance, args);
        } catch (IllegalAccessException|InvocationTargetException e){
            return null;
        }
    }

    /**
     * Get declared class field (public,protected,private)
     *
     * @param clazz Class to reflect
     * @param field Field to search
     * @return Field or null
     */
    @Nullable
    public static Field getField(@NotNull Class<?> clazz, @NotNull String field){
        try {
            Field f = clazz.getDeclaredField(field);
            f.setAccessible(true);
            return f;
        } catch (NoSuchFieldException e){
            return null;
        }
    }

    /**
     * Read field
     *
     * @param field Field to read
     * @param instance Instance where to read (null if static)
     * @return Field contents or null;
     */
    @Nullable
    public static Object readField(@NotNull Field field, @Nullable Object instance){
        try {
            return field.get(instance);
        } catch (IllegalAccessException e){
            return null;
        }
    }

    /**
     * Write field
     *
     * @param field Field to write
     * @param instance Instance where field resides (null if static)
     * @param value Field new contents
     */
    public static void writeField(@NotNull Field field, @Nullable Object instance, @Nullable Object value){
        try {
            field.set(instance, value);
        } catch (IllegalAccessException e){}
    }
}