# Copyright (C) 2020 by ÿnérant, eichhornchen, nicomarg, charlse
# SPDX-License-Identifier: GPL-3.0-or-later

from random import choice, randint
from typing import Optional

from ..interfaces import Entity, FightingEntity, Map, InventoryHolder
from ..translations import gettext as _


class Item(Entity):
    """
    A class for items
    """
    held: bool
    held_by: Optional[InventoryHolder]
    price: int

    def __init__(self, held: bool = False,
                 held_by: Optional[InventoryHolder] = None,
                 price: int = 2, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.held = held
        self.held_by = held_by
        self.price = price

    def drop(self) -> None:
        """
        The item is dropped from the inventory onto the floor
        """
        if self.held:
            self.held_by.remove_from_inventory(self)
            self.held_by.map.add_entity(self)
            self.move(self.held_by.y, self.held_by.x)
            self.held = False
            self.held_by = None

    def use(self) -> None:
        """
        Indicates what should be done when the item is used.
        """

    def equip(self, armor: bool = False) -> None:
        """
        Indicates what should be done when the item is equipped.
        """
        if armor:
            if self.held_by.equipped_armor:
                self.held_by.equipped_armor.unequip()
            self.held_by.remove_from_inventory(self)
            self.held_by.equipped_armor = self
        else:
            if self.held_by.equipped_item:
                self.held_by.equipped_item.unequip()
            self.held_by.remove_from_inventory(self)
            self.held_by.equipped_item = self

    def unequip(self) -> None:
        """
        Indicates what should be done when the item is unequipped.
        """
        self.held_by.add_to_inventory(self)
        self.held_by.equipped_item = None

    def hold(self, holder: InventoryHolder) -> None:
        """
        The item is taken from the floor and put into the inventory
        """
        self.held = True
        self.held_by = holder
        self.held_by.map.remove_entity(self)
        holder.add_to_inventory(self)

    def save_state(self) -> dict:
        """
        Saves the state of the entity into a dictionary
        """
        d = super().save_state()
        d["held"] = self.held
        return d

    @staticmethod
    def get_all_items() -> list:
        return [BodySnatchPotion, Bomb, Heart, Shield, Sword]

    def be_sold(self, buyer: InventoryHolder, seller: InventoryHolder) -> bool:
        """
        Does all necessary actions when an object is to be sold.
        Is overwritten by some classes that cannot exist in the player's
        inventory
        """
        if buyer.hazel >= self.price:
            self.hold(buyer)
            seller.remove_from_inventory(self)
            buyer.change_hazel_balance(-self.price)
            seller.change_hazel_balance(self.price)
            return True
        else:
            return False


class Heart(Item):
    """
    A heart item to return health to the player
    """
    healing: int

    def __init__(self, name: str = "heart", healing: int = 5, price: int = 3,
                 *args, **kwargs):
        super().__init__(name=name, price=price, *args, **kwargs)
        self.healing = healing

    def hold(self, entity: InventoryHolder) -> None:
        """
        When holding a heart, heal the player and don't put item in inventory.
        """
        entity.health = min(entity.maxhealth, entity.health + self.healing)
        entity.map.remove_entity(self)

    def save_state(self) -> dict:
        """
        Saves the state of the header into a dictionary
        """
        d = super().save_state()
        d["healing"] = self.healing
        return d


class Bomb(Item):
    """
    A bomb item intended to deal damage to enemies at long range
    """
    damage: int = 5
    exploding: bool
    owner: Optional["InventoryHolder"]
    tick: int

    def __init__(self, name: str = "bomb", damage: int = 5,
                 exploding: bool = False, price: int = 4, *args, **kwargs):
        super().__init__(name=name, price=price, *args, **kwargs)
        self.damage = damage
        self.exploding = exploding
        self.tick = 4
        self.owner = None

    def use(self) -> None:
        """
        When the bomb is used, throw it and explodes it.
        """
        if self.held:
            self.owner = self.held_by
            super().drop()
            self.exploding = True

    def act(self, m: Map) -> None:
        """
        Special exploding action of the bomb
        """
        if self.exploding:
            if self.tick > 0:
                # The bomb will explode in <tick> moves
                self.tick -= 1
            else:
                # The bomb is exploding.
                # Each entity that is close to the bomb takes damages.
                # The player earn XP if the entity was killed.
                log_message = _("Bomb is exploding.")
                for e in m.entities.copy():
                    if abs(e.x - self.x) + abs(e.y - self.y) <= 3 and \
                            isinstance(e, FightingEntity):
                        log_message += " " + e.take_damage(self, self.damage)
                        if e.dead:
                            self.owner.add_xp(randint(3, 7))
                m.logs.add_message(log_message)
                m.entities.remove(self)

                # Add sparkles where the bomb exploded.
                explosion = Explosion(y=self.y, x=self.x)
                self.map.add_entity(explosion)

    def save_state(self) -> dict:
        """
        Saves the state of the bomb into a dictionary
        """
        d = super().save_state()
        d["exploding"] = self.exploding
        d["damage"] = self.damage
        return d


class Explosion(Item):
    """
    When a bomb explodes, the explosion is displayed.
    """
    def __init__(self, *args, **kwargs):
        super().__init__(name="explosion", *args, **kwargs)

    def act(self, m: Map) -> None:
        """
        The explosion instant dies.
        """
        m.remove_entity(self)

    def hold(self, player: InventoryHolder) -> None:
        """
        The player can't hold any explosion.
        """
        pass


class Weapon(Item):
    """
    Non-throwable items that improve player damage
    """
    damage: int

    def __init__(self, damage: int = 3, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.damage = damage

    def save_state(self) -> dict:
        """
        Saves the state of the weapon into a dictionary
        """
        d = super().save_state()
        d["damage"] = self.damage
        return d


class Sword(Weapon):
    """
    A basic weapon
    """
    def __init__(self, name: str = "sword", price: int = 20,
                 *args, **kwargs):
        super().__init__(name=name, price=price, *args, **kwargs)
        self.name = name

    def equip(self, armor: bool = False) -> None:
        """
        When a sword is equipped, the player gains strength.
        """
        super().equip()
        self.held_by.strength += self.damage

    def unequip(self) -> None:
        """
        Remove the strength earned by the sword.
        :return:
        """
        super().unequip()
        self.held_by.strength -= self.damage


class Shield(Item):
    constitution: int

    def __init__(self, constitution: int = 2, *args, **kwargs):
        super().__init__(name="shield", *args, **kwargs)
        self.constitution = constitution

    def equip(self, armor: bool = True) -> None:
        super().equip(armor)
        self.held_by.constitution += self.constitution

    def unequip(self) -> None:
        super().unequip()
        self.held_by.constitution -= self.constitution

    def save_state(self) -> dict:
        d = super().save_state()
        d["constitution"] = self.constitution
        return d


class BodySnatchPotion(Item):
    """
    The body-snatch potion allows to exchange all characteristics with a random
    other entity.
    """

    def __init__(self, name: str = "body_snatch_potion", price: int = 14,
                 *args, **kwargs):
        super().__init__(name=name, price=price, *args, **kwargs)

    def use(self) -> None:
        """
        Find a valid random entity, then exchange characteristics.
        """
        valid_entities = self.held_by.map.find_entities(FightingEntity)
        valid_entities.remove(self.held_by)
        entity = choice(valid_entities)
        entity_state = entity.save_state()
        player_state = self.held_by.save_state()
        self.held_by.__dict__.update(entity_state)
        entity.__dict__.update(player_state)
        self.held_by.map.currenty, self.held_by.map.currentx = self.held_by.y,\
            self.held_by.x

        self.held_by.map.logs.add_message(
            _("{player} exchanged its body with {entity}.").format(
                player=self.held_by.translated_name.capitalize(),
                entity=entity.translated_name))

        self.held_by.recalculate_paths()

        self.held_by.inventory.remove(self)