package org.bukkit.entity;

import org.bukkit.Location;
import org.bukkit.block.Block;
import org.bukkit.inventory.EntityEquipment;
import org.bukkit.potion.PotionEffect;
import org.bukkit.potion.PotionEffectType;
import org.bukkit.projectiles.ProjectileSource;

import java.util.Collection;
import java.util.HashSet;
import java.util.List;

/**
 * Represents a living entity, such as a monster or player
 */
public interface LivingEntity extends Entity, Damageable, ProjectileSource
{

	/**
	 * Gets the height of the living entity's eyes above its Location.
	 *
	 * @return height of the living entity's eyes above its location
	 */
	public double getEyeHeight();

	/**
	 * Gets the height of the living entity's eyes above its Location.
	 *
	 * @param ignoreSneaking if set to true, the effects of sneaking will be
	 *                       ignored
	 * @return height of the living entity's eyes above its location
	 */
	public double getEyeHeight(boolean ignoreSneaking);

	/**
	 * Get a Location detailing the current eye position of the living entity.
	 *
	 * @return a location at the eyes of the living entity
	 */
	public Location getEyeLocation();

	/**
	 * Gets all blocks along the living entity's line of sight.
	 * <p>
	 * This list contains all blocks from the living entity's eye position to
	 * target inclusive.
	 *
	 * @param transparent HashSet containing all transparent block IDs (set to
	 *                    null for only air)
	 * @param maxDistance this is the maximum distance to scan (may be limited
	 *                    by server by at least 100 blocks, no less)
	 * @return list containing all blocks along the living entity's line of
	 * sight
	 * @deprecated Magic value
	 */
	@Deprecated
	public List<Block> getLineOfSight(HashSet<Byte> transparent, int maxDistance);

	/**
	 * Gets the block that the living entity has targeted.
	 *
	 * @param transparent HashSet containing all transparent block IDs (set to
	 *                    null for only air)
	 * @param maxDistance this is the maximum distance to scan (may be limited
	 *                    by server by at least 100 blocks, no less)
	 * @return block that the living entity has targeted
	 * @deprecated Magic value
	 */
	@Deprecated
	public Block getTargetBlock(HashSet<Byte> transparent, int maxDistance);

	/**
	 * Gets the last two blocks along the living entity's line of sight.
	 * <p>
	 * The target block will be the last block in the list.
	 *
	 * @param transparent HashSet containing all transparent block IDs (set to
	 *                    null for only air)
	 * @param maxDistance this is the maximum distance to scan. This may be
	 *                    further limited by the server, but never to less than 100 blocks
	 * @return list containing the last 2 blocks along the living entity's
	 * line of sight
	 * @deprecated Magic value
	 */
	@Deprecated
	public List<Block> getLastTwoTargetBlocks(HashSet<Byte> transparent, int maxDistance);

	/**
	 * Throws an egg from the living entity.
	 *
	 * @return the egg thrown
	 * @deprecated use launchProjectile(Egg.class) instead
	 */
	@Deprecated
	public Egg throwEgg();

	/**
	 * Throws a snowball from the living entity.
	 *
	 * @return the snowball thrown
	 * @deprecated use launchProjectile(Snowball.class) instead
	 */
	@Deprecated
	public Snowball throwSnowball();

	/**
	 * Shoots an arrow from the living entity.
	 *
	 * @return the arrow shot
	 * @deprecated use launchProjectile(Arrow.class) instead
	 */
	@Deprecated
	public Arrow shootArrow();

	/**
	 * Returns the amount of air that the living entity has remaining, in
	 * ticks.
	 *
	 * @return amount of air remaining
	 */
	public int getRemainingAir();

	/**
	 * Sets the amount of air that the living entity has remaining, in ticks.
	 *
	 * @param ticks amount of air remaining
	 */
	public void setRemainingAir(int ticks);

	/**
	 * Returns the maximum amount of air the living entity can have, in ticks.
	 *
	 * @return maximum amount of air
	 */
	public int getMaximumAir();

	/**
	 * Sets the maximum amount of air the living entity can have, in ticks.
	 *
	 * @param ticks maximum amount of air
	 */
	public void setMaximumAir(int ticks);

	/**
	 * Returns the living entity's current maximum no damage ticks.
	 * <p>
	 * This is the maximum duration in which the living entity will not take
	 * damage.
	 *
	 * @return maximum no damage ticks
	 */
	public int getMaximumNoDamageTicks();

	/**
	 * Sets the living entity's current maximum no damage ticks.
	 *
	 * @param ticks maximum amount of no damage ticks
	 */
	public void setMaximumNoDamageTicks(int ticks);

	/**
	 * Returns the living entity's last damage taken in the current no damage
	 * ticks time.
	 * <p>
	 * Only damage higher than this amount will further damage the living
	 * entity.
	 *
	 * @return damage taken since the last no damage ticks time period
	 */
	public double getLastDamage();

	/**
	 * This method exists for legacy reasons to provide backwards
	 * compatibility. It will not exist at runtime and should not be used
	 * under any circumstances.
	 */
	@Deprecated
	public int _INVALID_getLastDamage();

	/**
	 * Sets the damage dealt within the current no damage ticks time period.
	 *
	 * @param damage amount of damage
	 */
	public void setLastDamage(double damage);

	/**
	 * This method exists for legacy reasons to provide backwards
	 * compatibility. It will not exist at runtime and should not be used
	 * under any circumstances.
	 */
	@Deprecated
	public void _INVALID_setLastDamage(int damage);

	/**
	 * Returns the living entity's current no damage ticks.
	 *
	 * @return amount of no damage ticks
	 */
	public int getNoDamageTicks();

	/**
	 * Sets the living entity's current no damage ticks.
	 *
	 * @param ticks amount of no damage ticks
	 */
	public void setNoDamageTicks(int ticks);

	/**
	 * Gets the player identified as the killer of the living entity.
	 * <p>
	 * May be null.
	 *
	 * @return killer player, or null if none found
	 */
	public Player getKiller();

	/**
	 * Adds the given {@link PotionEffect} to the living entity.
	 * <p>
	 * Only one potion effect can be present for a given {@link
	 * PotionEffectType}.
	 *
	 * @param effect PotionEffect to be added
	 * @return whether the effect could be added
	 */
	public boolean addPotionEffect(PotionEffect effect);

	/**
	 * Adds the given {@link PotionEffect} to the living entity.
	 * <p>
	 * Only one potion effect can be present for a given {@link
	 * PotionEffectType}.
	 *
	 * @param effect PotionEffect to be added
	 * @param force  whether conflicting effects should be removed
	 * @return whether the effect could be added
	 */
	public boolean addPotionEffect(PotionEffect effect, boolean force);

	/**
	 * Attempts to add all of the given {@link PotionEffect} to the living
	 * entity.
	 *
	 * @param effects the effects to add
	 * @return whether all of the effects could be added
	 */
	public boolean addPotionEffects(Collection<PotionEffect> effects);

	/**
	 * Returns whether the living entity already has an existing effect of
	 * the given {@link PotionEffectType} applied to it.
	 *
	 * @param type the potion type to check
	 * @return whether the living entity has this potion effect active on them
	 */
	public boolean hasPotionEffect(PotionEffectType type);

	/**
	 * Removes any effects present of the given {@link PotionEffectType}.
	 *
	 * @param type the potion type to remove
	 */
	public void removePotionEffect(PotionEffectType type);

	/**
	 * Returns all currently active {@link PotionEffect}s on the living
	 * entity.
	 *
	 * @return a collection of {@link PotionEffect}s
	 */
	public Collection<PotionEffect> getActivePotionEffects();

	/**
	 * Checks whether the living entity has block line of sight to another.
	 * <p>
	 * This uses the same algorithm that hostile mobs use to find the closest
	 * player.
	 *
	 * @param other the entity to determine line of sight to
	 * @return true if there is a line of sight, false if not
	 */
	public boolean hasLineOfSight(Entity other);

	/**
	 * Returns if the living entity despawns when away from players or not.
	 * <p>
	 * By default, animals are not removed while other mobs are.
	 *
	 * @return true if the living entity is removed when away from players
	 */
	public boolean getRemoveWhenFarAway();

	/**
	 * Sets whether or not the living entity despawns when away from players
	 * or not.
	 *
	 * @param remove the removal status
	 */
	public void setRemoveWhenFarAway(boolean remove);

	/**
	 * Gets the inventory with the equipment worn by the living entity.
	 *
	 * @return the living entity's inventory
	 */
	public EntityEquipment getEquipment();

	/**
	 * Sets whether or not the living entity can pick up items.
	 *
	 * @param pickup whether or not the living entity can pick up items
	 */
	public void setCanPickupItems(boolean pickup);

	/**
	 * Gets if the living entity can pick up items.
	 *
	 * @return whether or not the living entity can pick up items
	 */
	public boolean getCanPickupItems();

	/**
	 * Sets a custom name on a mob. This name will be used in death messages
	 * and can be sent to the client as a nameplate over the mob.
	 * <p>
	 * Setting the name to null or an empty string will clear it.
	 * <p>
	 * This value has no effect on players, they will always use their real
	 * name.
	 *
	 * @param name the name to set
	 */
	public void setCustomName(String name);

	/**
	 * Gets the custom name on a mob. If there is no name this method will
	 * return null.
	 * <p>
	 * This value has no effect on players, they will always use their real
	 * name.
	 *
	 * @return name of the mob or null
	 */
	public String getCustomName();

	/**
	 * Sets whether or not to display the mob's custom name client side. The
	 * name will be displayed above the mob similarly to a player.
	 * <p>
	 * This value has no effect on players, they will always display their
	 * name.
	 *
	 * @param flag custom name or not
	 */
	public void setCustomNameVisible(boolean flag);

	/**
	 * Gets whether or not the mob's custom name is displayed client side.
	 * <p>
	 * This value has no effect on players, they will always display their
	 * name.
	 *
	 * @return if the custom name is displayed
	 */
	public boolean isCustomNameVisible();

	/**
	 * Returns whether the entity is currently leashed.
	 *
	 * @return whether the entity is leashed
	 */
	public boolean isLeashed();

	/**
	 * Gets the entity that is currently leading this entity.
	 *
	 * @return the entity holding the leash
	 * @throws IllegalStateException if not currently leashed
	 */
	public Entity getLeashHolder() throws IllegalStateException;

	/**
	 * Sets the leash on this entity to be held by the supplied entity.
	 * <p>
	 * This method has no effect on EnderDragons, Withers, Players, or Bats.
	 * Non-living entities excluding leashes will not persist as leash
	 * holders.
	 *
	 * @param holder the entity to leash this entity to
	 * @return whether the operation was successful
	 */
	public boolean setLeashHolder(Entity holder);
}