package endran.bridge;

import java.lang.reflect.InvocationTargetException;
import java.util.Random;

import org.bukkit.Location;
import org.bukkit.enchantments.Enchantment;
import org.bukkit.entity.Arrow;
import org.bukkit.entity.Entity;
import org.bukkit.entity.LivingEntity;
import org.bukkit.entity.Player;
import org.bukkit.entity.Projectile;
import org.bukkit.inventory.ItemStack;
import org.bukkit.util.Vector;

import com.comphenix.protocol.PacketType;
import com.comphenix.protocol.ProtocolLibrary;
import com.comphenix.protocol.events.PacketContainer;

public class Combat {
	public static void applyKnockback(LivingEntity livingEntity, Entity attacker, double resistance){
		Random random = new Random();
        if(random.nextDouble() >= resistance){
            double dist = (attacker instanceof Player && ((Player)attacker).isSprinting())? 1.5:1;
            dist += random.nextDouble()*0.4-0.2; // adds or subtract 0.2 to the distance
            int knockBackLevel = getKnockBackLevel(attacker);
            dist += 2*knockBackLevel;
            double mag = distanceToMagnitude(dist);
            Location location = getLocation(attacker);
            location.setPitch(location.getPitch()-15);
            Vector velocity = setMag(location.getDirection(),mag);
            livingEntity.setVelocity(velocity);
        }
    }

    private static Location getLocation(Entity entity){
        if(entity instanceof Projectile){
            Projectile projectile = (Projectile) entity;
            Location location = entity.getLocation();
            location.setDirection(projectile.getVelocity());
            return location;
        }else{
            return entity.getLocation();
        }
    }

    private static double distanceToMagnitude(double distance){
        return ((distance + 1.5)/5d);
    }

    private static Vector setMag(Vector vector, double mag){
        double x = vector.getX();
        double y = vector.getY();
        double z = vector.getZ();
        double denominator = Math.sqrt(x*x + y*y + z*z);
        if(denominator != 0 ){
            return vector.multiply(mag/denominator);
        }else{
            return vector;
        }
    }

    private static int getKnockBackLevel(Entity entity){
        if(entity instanceof LivingEntity){
            ItemStack mainHand = ((LivingEntity)entity).getEquipment().getItemInHand();
            if(mainHand != null && mainHand.hasItemMeta() && mainHand.getItemMeta().hasEnchants() && mainHand.getItemMeta().hasEnchant(Enchantment.KNOCKBACK)){
                return mainHand.getItemMeta().getEnchantLevel(Enchantment.KNOCKBACK);
            }else{
                return 0;
            }
        }else if(entity instanceof Arrow){
            Arrow arrow = (Arrow) entity;
            return arrow.getKnockbackStrength();
        }else{
            return 0;
        }
    }
    
	public static void sendDamageAnim(Entity target, Player p){
		PacketContainer damageAnim = ProtocolLibrary.getProtocolManager().createPacket(PacketType.Play.Server.ANIMATION);
		damageAnim.getIntegers().writeDefaults();
		damageAnim.getIntegers().write(0, target.getEntityId());
		damageAnim.getIntegers().write(1, 1);
		try {
			ProtocolLibrary.getProtocolManager().sendServerPacket(p, damageAnim);
		} catch (InvocationTargetException e1) {
			e1.printStackTrace();
		}
	}
}