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

from enum import Enum, auto
from math import sqrt
from random import choice, randint
from typing import List, Optional, Union, Tuple

from .display.texturepack import TexturePack
from .translations import gettext as _


class Logs:
    """
    The logs object stores the messages to display. It is encapsulating a list
    of such messages, to allow multiple pointers to keep track of it even if
    the list was to be reassigned.
    """

    def __init__(self) -> None:
        self.messages = []

    def add_message(self, msg: str) -> None:
        self.messages.append(msg)

    def add_messages(self, msg: List[str]) -> None:
        self.messages += msg

    def clear(self) -> None:
        self.messages = []


class Slope():
    X: int
    Y: int

    def __init__(self, y: int, x: int) -> None:
        self.Y = y
        self.X = x

    def compare(self, other: Union[Tuple[int, int], "Slope"]) -> int:
        if isinstance(other, Slope):
            y, x = other.Y, other.X
        else:
            y, x = other
        return self.Y * x - self.X * y

    def __lt__(self, other: Union[Tuple[int, int], "Slope"]) -> bool:
        return self.compare(other) < 0

    def __eq__(self, other: Union[Tuple[int, int], "Slope"]) -> bool:
        return self.compare(other) == 0


class Map:
    """
    Object that represents a Map with its width, height
    and tiles, that have their custom properties.
    """
    width: int
    height: int
    start_y: int
    start_x: int
    tiles: List[List["Tile"]]
    visibility: List[List[bool]]
    entities: List["Entity"]
    logs: Logs
    # coordinates of the point that should be
    # on the topleft corner of the screen
    currentx: int
    currenty: int

    def __init__(self, width: int, height: int, tiles: list,
                 start_y: int, start_x: int):
        self.width = width
        self.height = height
        self.start_y = start_y
        self.start_x = start_x
        self.tiles = tiles
        self.visibility = [[False for _ in range(len(tiles[0]))]
                           for _ in range(len(tiles))]
        self.entities = []
        self.logs = Logs()

    def add_entity(self, entity: "Entity") -> None:
        """
        Register a new entity in the map.
        """
        self.entities.append(entity)
        entity.map = self

    def remove_entity(self, entity: "Entity") -> None:
        """
        Unregister an entity from the map.
        """
        self.entities.remove(entity)

    def find_entities(self, entity_class: type) -> list:
        return [entity for entity in self.entities
                if isinstance(entity, entity_class)]

    def is_free(self, y: int, x: int) -> bool:
        """
        Indicates that the case at the coordinates (y, x) is empty.
        """
        return 0 <= y < self.height and 0 <= x < self.width and \
            self.tiles[y][x].can_walk() and \
            not any(entity.x == x and entity.y == y for entity in self.entities)

    @staticmethod
    def load(filename: str) -> "Map":
        """
        Read a file that contains the content of a map, and build a Map object.
        """
        with open(filename, "r") as f:
            file = f.read()
        return Map.load_from_string(file)

    @staticmethod
    def load_from_string(content: str) -> "Map":
        """
        Load a map represented by its characters and build a Map object.
        """
        lines = content.split("\n")
        first_line = lines[0]
        start_y, start_x = map(int, first_line.split(" "))
        lines = [line for line in lines[1:] if line]
        height = len(lines)
        width = len(lines[0])
        tiles = [[Tile.from_ascii_char(c)
                  for x, c in enumerate(line)] for y, line in enumerate(lines)]

        return Map(width, height, tiles, start_y, start_x)

    @staticmethod
    def load_dungeon_from_string(content: str) -> List[List["Tile"]]:
        """
        Transforms a string into the list of corresponding tiles
        """
        lines = content.split("\n")
        tiles = [[Tile.from_ascii_char(c)
                  for x, c in enumerate(line)] for y, line in enumerate(lines)]
        return tiles

    def draw_string(self, pack: TexturePack) -> str:
        """
        Draw the current map as a string object that can be rendered
        in the window.
        """
        return "\n".join("".join(tile.char(pack) for tile in line)
                         for line in self.tiles)

    def spawn_random_entities(self, count: int) -> None:
        """
        Put randomly {count} hedgehogs on the map, where it is available.
        """
        for _ignored in range(count):
            y, x = 0, 0
            while True:
                y, x = randint(0, self.height - 1), randint(0, self.width - 1)
                tile = self.tiles[y][x]
                if tile.can_walk():
                    break
            entity = choice(Entity.get_all_entity_classes())()
            entity.move(y, x)
            self.add_entity(entity)

    def compute_visibility(self, y: int, x: int, max_range: int) -> None:
        """
        Sets the visible tiles to be the ones visible by an entity at point
        (y, x), using a twaked shadow casting algorithm
        """

        for line in self.visibility:
            for i in range(len(line)):
                line[i] = False
        self.visibility[y][x] = True
        for octant in range(8):
            self.compute_visibility_octant(octant, (y, x), max_range, 1,
                                           Slope(1, 1), Slope(0, 1))

    def crop_top_visibility(self, octant: int, origin: Tuple[int, int],
                            x: int, top: Slope) -> int:
        if top.X == 1:
            top_y = x
        else:
            top_y = ((x * 2 - 1) * top.Y + top.X) / (top.X * 2)
            if self.is_wall(top_y, x, octant, origin):
                if top >= (top_y * 2 + 1, x * 2) and not\
                        self.is_wall(top_y + 1, x, octant, origin):
                    top_y += 1
            else:
                ax = x * 2
                if self.is_wall(top_y + 1, x + 1, octant, origin):
                    ax += 1
                if top > (top_y * 2 + 1, ax):
                    top_y += 1
        return top_y

    def crop_bottom_visibility(self, octant: int, origin: Tuple[int, int],
                               x: int, bottom: Slope) -> int:
        if bottom.Y == 0:
            bottom_y = 0
        else:
            bottom_y = ((x * 2 + 1) * bottom.Y + bottom.X) /\
                (bottom.X * 2)
            if bottom >= (bottom_y * 2 + 1, x * 2) and\
                    self.is_wall(bottom_y, x, octant, origin) and\
                    not self.is_wall(bottom_y + 1, x, octant, origin):
                bottom_y += 1
        return bottom_y

    def compute_visibility_octant(self, octant: int, origin: Tuple[int, int],
                                  max_range: int, distance: int, top: Slope,
                                  bottom: Slope) -> None:
        for x in range(distance, max_range):
            top_y = self.crop_top_visibility(octant, origin, x, top)
            bottom_y = self.crop_bottom_visibility(octant, origin, x, bottom)
            was_opaque = -1
            for y in range(top_y, bottom_y - 1, -1):
                if sqrt(x**2 + y**2) > max_range:
                    continue
                is_opaque = self.is_wall(y, x, octant, origin)
                is_visible = is_opaque\
                    or ((y != top_y or top > (y * 4 - 1, x * 4 - 1))
                        and (y != bottom_y or bottom < (y * 4 + 1, x * 4 + 1)))
                if is_visible:
                    self.set_visible(y, x, octant, origin)
                if x == max_range:
                    continue
                if is_opaque and was_opaque == 0:
                    nx, ny = x * 2, y * 2 + 1
                    if self.is_wall(y + 1, x, octant, origin):
                        nx -= 1
                    if top > (ny, nx):
                        if y == bottom_y:
                            bottom = Slope(ny, nx)
                            break
                        else:
                            self.compute_visibility_octant(
                                octant, origin, max_range, x + 1, top,
                                Slope(ny, nx))
                    else:
                        if y == bottom_y:
                            return
                elif not is_opaque and was_opaque == 1:
                    nx, ny = x * 2, y * 2 + 1
                    if self.is_wall(y + 1, x + 1, octant, origin):
                        nx += 1
                    if bottom >= (ny, nx):
                        return
                was_opaque = is_opaque
            if was_opaque != 0:
                break

    @staticmethod
    def translate_coord(y: int, x: int, octant: int,
                        origin: Tuple[int, int]) -> Tuple[int, int]:
        ny, nx = origin
        if octant == 0:
            return nx + x, ny - y
        elif octant == 1:
            return nx + y, ny - x
        elif octant == 2:
            return nx - y, ny - x
        elif octant == 3:
            return nx - x, ny - y
        elif octant == 4:
            return nx - x, ny + y
        elif octant == 5:
            return nx - y, ny + x
        elif octant == 6:
            return nx + y, ny + x
        elif octant == 7:
            return nx + x, ny + y

    def is_wall(self, y: int, x: int, octant: int,
                origin: Tuple[int, int]) -> bool:
        y, x = self.translate_coord(y, x, octant, origin)
        return self.tiles[y][x].is_wall()

    def set_visible(self, y: int, x: int, octant: int,
                    origin: Tuple[int, int]) -> None:
        y, x = self.translate_coord(y, x, octant, origin)
        self.visibility[y][x] = True

    def tick(self) -> None:
        """
        Trigger all entity events.
        """
        for entity in self.entities:
            entity.act(self)

    def save_state(self) -> dict:
        """
        Saves the map's attributes to a dictionary
        """
        d = dict()
        d["width"] = self.width
        d["height"] = self.height
        d["start_y"] = self.start_y
        d["start_x"] = self.start_x
        d["currentx"] = self.currentx
        d["currenty"] = self.currenty
        d["entities"] = []
        for enti in self.entities:
            d["entities"].append(enti.save_state())
        d["map"] = self.draw_string(TexturePack.ASCII_PACK)
        return d

    def load_state(self, d: dict) -> None:
        """
        Loads the map's attributes from a dictionary
        """
        self.width = d["width"]
        self.height = d["height"]
        self.start_y = d["start_y"]
        self.start_x = d["start_x"]
        self.currentx = d["currentx"]
        self.currenty = d["currenty"]
        self.tiles = self.load_dungeon_from_string(d["map"])
        self.entities = []
        dictclasses = Entity.get_all_entity_classes_in_a_dict()
        for entisave in d["entities"]:
            self.add_entity(dictclasses[entisave["type"]](**entisave))


class Tile(Enum):
    """
    The internal representation of the tiles of the map
    """
    EMPTY = auto()
    WALL = auto()
    FLOOR = auto()

    @staticmethod
    def from_ascii_char(ch: str) -> "Tile":
        """
        Maps an ascii character to its equivalent in the texture pack
        """
        for tile in Tile:
            if tile.char(TexturePack.ASCII_PACK) == ch:
                return tile
        raise ValueError(ch)

    def char(self, pack: TexturePack) -> str:
        """
        Translates a Tile to the corresponding character according
        to the texture pack
        """
        return getattr(pack, self.name)

    def is_wall(self) -> bool:
        """
        Is this Tile a wall?
        """
        return self == Tile.WALL

    def can_walk(self) -> bool:
        """
        Check if an entity (player or not) can move in this tile.
        """
        return not self.is_wall() and self != Tile.EMPTY


class Entity:
    """
    An Entity object represents any entity present on the map
    """
    y: int
    x: int
    name: str
    map: Map

    # noinspection PyShadowingBuiltins
    def __init__(self, y: int = 0, x: int = 0, name: Optional[str] = None,
                 map: Optional[Map] = None, *ignored, **ignored2):
        self.y = y
        self.x = x
        self.name = name
        self.map = map

    def check_move(self, y: int, x: int, move_if_possible: bool = False)\
            -> bool:
        """
        Checks if moving to (y,x) is authorized
        """
        free = self.map.is_free(y, x)
        if free and move_if_possible:
            self.move(y, x)
        return free

    def move(self, y: int, x: int) -> bool:
        """
        Moves an entity to (y,x) coordinates
        """
        self.y = y
        self.x = x
        return True

    def move_up(self, force: bool = False) -> bool:
        """
        Moves the entity up one tile, if possible
        """
        return self.move(self.y - 1, self.x) if force else \
            self.check_move(self.y - 1, self.x, True)

    def move_down(self, force: bool = False) -> bool:
        """
        Moves the entity down one tile, if possible
        """
        return self.move(self.y + 1, self.x) if force else \
            self.check_move(self.y + 1, self.x, True)

    def move_left(self, force: bool = False) -> bool:
        """
        Moves the entity left one tile, if possible
        """
        return self.move(self.y, self.x - 1) if force else \
            self.check_move(self.y, self.x - 1, True)

    def move_right(self, force: bool = False) -> bool:
        """
        Moves the entity right one tile, if possible
        """
        return self.move(self.y, self.x + 1) if force else \
            self.check_move(self.y, self.x + 1, True)

    def act(self, m: Map) -> None:
        """
        Define the action of the entity that is ran each tick.
        By default, does nothing.
        """
        pass

    def distance_squared(self, other: "Entity") -> int:
        """
        Get the square of the distance to another entity.
        Useful to check distances since square root takes time.
        """
        return (self.y - other.y) ** 2 + (self.x - other.x) ** 2

    def distance(self, other: "Entity") -> float:
        """
        Get the cartesian distance to another entity.
        """
        return sqrt(self.distance_squared(other))

    def is_fighting_entity(self) -> bool:
        """
        Is this entity a fighting entity?
        """
        return isinstance(self, FightingEntity)

    def is_item(self) -> bool:
        """
        Is this entity an item?
        """
        from squirrelbattle.entities.items import Item
        return isinstance(self, Item)

    @property
    def translated_name(self) -> str:
        return _(self.name.replace("_", " "))

    @staticmethod
    def get_all_entity_classes():
        """
        Returns all entities subclasses
        """
        from squirrelbattle.entities.items import BodySnatchPotion, Bomb, Heart
        from squirrelbattle.entities.monsters import Tiger, Hedgehog, \
            Rabbit, TeddyBear
        return [BodySnatchPotion, Bomb, Heart, Hedgehog,
                Rabbit, TeddyBear, Tiger]

    @staticmethod
    def get_all_entity_classes_in_a_dict() -> dict:
        """
        Returns all entities subclasses in a dictionary
        """
        from squirrelbattle.entities.player import Player
        from squirrelbattle.entities.monsters import Tiger, Hedgehog, Rabbit, \
            TeddyBear
        from squirrelbattle.entities.items import BodySnatchPotion, Bomb, Heart
        return {
            "Tiger": Tiger,
            "Bomb": Bomb,
            "Heart": Heart,
            "BodySnatchPotion": BodySnatchPotion,
            "Hedgehog": Hedgehog,
            "Rabbit": Rabbit,
            "TeddyBear": TeddyBear,
            "Player": Player,
        }

    def save_state(self) -> dict:
        """
        Saves the coordinates of the entity
        """
        d = dict()
        d["x"] = self.x
        d["y"] = self.y
        d["type"] = self.__class__.__name__
        return d


class FightingEntity(Entity):
    """
    A FightingEntity is an entity that can fight, and thus has a health,
    level and stats
    """
    maxhealth: int
    health: int
    strength: int
    intelligence: int
    charisma: int
    dexterity: int
    constitution: int
    level: int

    def __init__(self, maxhealth: int = 0, health: Optional[int] = None,
                 strength: int = 0, intelligence: int = 0, charisma: int = 0,
                 dexterity: int = 0, constitution: int = 0, level: int = 0,
                 *args, **kwargs) -> None:
        super().__init__(*args, **kwargs)
        self.maxhealth = maxhealth
        self.health = maxhealth if health is None else health
        self.strength = strength
        self.intelligence = intelligence
        self.charisma = charisma
        self.dexterity = dexterity
        self.constitution = constitution
        self.level = level

    @property
    def dead(self) -> bool:
        return self.health <= 0

    def hit(self, opponent: "FightingEntity") -> str:
        """
        Deals damage to the opponent, based on the stats
        """
        return _("{name} hits {opponent}.")\
            .format(name=_(self.translated_name.capitalize()),
                    opponent=_(opponent.translated_name)) + " " + \
            opponent.take_damage(self, self.strength)

    def take_damage(self, attacker: "Entity", amount: int) -> str:
        """
        Take damage from the attacker, based on the stats
        """
        self.health -= amount
        if self.health <= 0:
            self.die()
        return _("{name} takes {amount} damage.")\
            .format(name=self.translated_name.capitalize(), amount=str(amount))\
            + (" " + _("{name} dies.")
               .format(name=self.translated_name.capitalize())
               if self.health <= 0 else "")

    def die(self) -> None:
        """
        If a fighting entity has no more health, it dies and is removed
        """
        self.map.remove_entity(self)

    def keys(self) -> list:
        """
        Returns a fighting entities specific attributes
        """
        return ["name", "maxhealth", "health", "level", "strength",
                "intelligence", "charisma", "dexterity", "constitution"]

    def save_state(self) -> dict:
        """
        Saves the state of the entity into a dictionary
        """
        d = super().save_state()
        for name in self.keys():
            d[name] = getattr(self, name)
        return d