"""Class for the various animals in the game"""

import random

from pgu.vid import Sprite
from pgu.algo import getline

import imagecache
import tiles
from misc import Position
import sound
import equipment

class Animal(Sprite):
    """Base class for animals"""

    STEALTH = 0

    def __init__(self, image_left, image_right, tile_pos):
        # Create the animal somewhere far off screen
        Sprite.__init__(self, image_left, (-1000, -1000))
        self.image_left = image_left
        self.image_right = image_right
        self.pos = Position(tile_pos[0], tile_pos[1])
        self.equipment = []
        self.abode = None

    def loop(self, tv, _sprite):
        ppos = tv.tile_to_view(self.pos.to_tuple())
        self.rect.x = ppos[0]
        self.rect.y = ppos[1]

    def move(self, state):
        """Given the game state, return a new position for the object"""
        # Default is not to move
        pass

    def set_pos(self, tile_pos):
        """Move an animal to the given tile_pos."""
        new_pos = Position(*tile_pos)
        self._fix_face(new_pos)
        self.pos = new_pos

    def _fix_face(self, final_pos):
        """Set the face correctly"""
        if final_pos.left_of(self.pos):
            self.setimage(self.image_left)
        elif final_pos.right_of(self.pos):
            self.setimage(self.image_right)

    def equip(self, item):
        self.equipment.append(item)

    def weapons(self):
        return [e for e in self.equipment if equipment.is_weapon(e)]

    def covers(self, tile_pos):
        return tile_pos[0] == self.pos.x and tile_pos[1] == self.pos.y

class Chicken(Animal):
    """A chicken"""

    def __init__(self, pos):
        image_left = imagecache.load_image('sprites/chkn.png')
        image_right = imagecache.load_image('sprites/chkn.png',
                ("right_facing",))
        Animal.__init__(self, image_left, image_right, pos)
        self.egg = False
        self.egg_counter = 0

    def move(self, gameboard):
        """A free chicken will move away from other free chickens"""
        pass

    def lay(self):
        """See if the chicken lays an egg"""
        if not self.egg:
            self.egg = True
            self.egg_counter = 2

    def hatch(self):
        """See if we have an egg to hatch"""
        if self.egg:
            self.egg_counter -= 1
            if self.egg_counter == 0:
                # Egg hatches
                self.egg = False
                return Chicken(self.pos.to_tuple())
        return None

    def _find_killable_fox(self, weapon, gameboard):
        """Choose a random fox within range of this weapon."""
        killable_foxes = []
        for fox in gameboard.foxes:
            if not visible(self, fox):
                continue
            if weapon.in_range(gameboard, self, fox):
                killable_foxes.append(fox)
        if not killable_foxes:
            return None
        return random.choice(killable_foxes)

    def attack(self, gameboard):
        """An armed chicken will attack a fox within range."""
        if not self.weapons():
            # Not going to take on a fox bare-winged.
            return
        # Choose the first weapon equipped.
        weapon = self.weapons()[0]
        fox = self._find_killable_fox(weapon, gameboard)
        if not fox:
            return
        if weapon.hit(gameboard, self, fox):
            sound.play_sound("kill-fox.ogg")
            gameboard.kill_fox(fox)

    def outside(self):
        return self.abode is None

class Egg(Animal):
    """An egg"""

    def __init__(self, pos):
        image = imagecache.load_image('sprites/egg.png')
        Animal.__init__(self, image, image, pos)

    # Eggs don't move

class Fox(Animal):
    """A fox"""

    STEALTH = 20

    costs = {
            # weighting for movement calculation
            'grassland' : 2,
            'woodland' : 1, # Try to keep to the woods if possible
            'broken fence' : 2,
            'fence' : 10,
            'guardtower' : 2, # We can pass under towers
            'henhouse' : 2,
            }

    def __init__(self, pos):
        image_left = imagecache.load_image('sprites/fox.png')
        image_right = imagecache.load_image('sprites/fox.png',
                ("right_facing",))
        Animal.__init__(self, image_left, image_right, pos)
        self.landmarks = [self.pos]
        self.hunting = True
        self.dig_pos = None
        self.tick = 0

    def _cost_tile(self, pos, gameboard):
        if gameboard.in_bounds(pos):
            this_tile = gameboard.tv.get(pos.to_tuple())
            cost = self.costs.get(tiles.TILE_MAP[this_tile], 100)
        else:
            cost = 100 # Out of bounds is expensive
        return cost

    def _cost_path(self, path, gameboard):
        """Calculate the cost of a path"""
        total = 0
        for pos in path:
            total += self._cost_tile(pos, gameboard)
        return total

    def _gen_path(self, start_pos, final_pos):
        """Construct a direct path from start_pos to final_pos,
           excluding start_pos"""
        if abs(start_pos.x - final_pos.x) < 2 and \
                abs(start_pos.y - final_pos.y) < 2:
            # pgu gets this case wrong on occasion.
            return [final_pos]
        start = start_pos.to_tuple()
        end = final_pos.to_tuple()
        points = getline(start, end)
        points.remove(start) # exclude start_pos
        if end not in points:
            # Rounding errors in getline cause this
            points.append(end)
        return [Position(x[0], x[1]) for x in points]

    def _find_best_path_step(self, final_pos, gameboard):
        """Find the cheapest path to final_pos, and return the next step
           along the path."""
        # We calculate the cost of the direct path
        direct_path = self._gen_path(self.pos, final_pos)
        min_cost = self._cost_path(direct_path, gameboard)
        min_path = direct_path
        # is there a point nearby that gives us a cheaper direct path?
        # This is delibrately not finding the optimal path, as I don't
        # want the foxes to be too intelligent, although the implementation
        # isn't well optimised yet
        poss = [Position(x, y) for x in range(self.pos.x - 3, self.pos.x + 4)
                for y in range(self.pos.y - 3, self.pos.y + 4)
                if (x, y) != (0,0)]
        for start in poss:
            cand_path = self._gen_path(self.pos, start) + \
                    self._gen_path(start, final_pos)
            cost = self._cost_path(cand_path, gameboard)
            if cost < min_cost:
                min_cost = cost
                min_path = cand_path
        if not min_path:
            return final_pos
        return min_path[0]

    def _find_path_to_woodland(self, gameboard):
        """Dive back to woodland through the landmarks"""
        # find the closest point to our current location in walked path
        if self.pos == self.landmarks[-1]:
            if len(self.landmarks) > 1:
                self.landmarks.pop() # Moving to the next landmark
            else:
                # Safely back at the start
                return self.pos
        return self._find_best_path_step(self.landmarks[-1], gameboard)

    def _find_path_to_chicken(self, gameboard):
        """Find the path to the closest chicken"""
        # Find the closest chicken
        min_dist = 999
        closest = None
        for chicken in gameboard.chickens:
            dist = chicken.pos.dist(self.pos)
            if dist < min_dist:
                min_dist = dist
                closest = chicken
        if not closest:
            # No more chickens, so leave
            self.hunting = False
            return self.pos
        if closest.pos == self.pos:
            # Caught a chicken
            self._catch_chicken(closest, gameboard)
            return self.pos
        return self._find_best_path_step(closest.pos, gameboard)

    def _catch_chicken(self, chicken, gameboard):
        """Catch a chicken"""
        sound.play_sound("kill-chicken.ogg")
        gameboard.remove_chicken(chicken)
        self.hunting = False

    def _update_pos(self, gameboard, new_pos):
        """Update the position, making sure we don't step on other foxes"""
        final_pos = new_pos
        moves = [Position(x, y) for x in range(self.pos.x-1, self.pos.x + 2)
                for y in range(self.pos.y-1, self.pos.y + 2)
                if (x,y) != (0,0)]
        blocked = False
        for fox in gameboard.foxes:
            if fox is not self and fox.pos == new_pos:
                blocked = True
            if fox.pos in moves:
                moves.remove(fox.pos)
        if blocked:
            # find the cheapest point in moves to new_pos that's not blocked
            final_pos = None
            min_cost = 1000
            for poss in moves:
                cost = self._cost_tile(poss, gameboard)
                if cost < min_cost:
                    min_cost = cost
                    final_pos = poss
        if gameboard.in_bounds(final_pos):
            this_tile = gameboard.tv.get(final_pos.to_tuple())
        else:
            this_tile = tiles.REVERSE_TILE_MAP['woodland']
        if tiles.TILE_MAP[this_tile] == 'broken fence' and self.hunting:
            # We'll head back towards the holes we make/find
            self.landmarks.append(final_pos)
        elif tiles.TILE_MAP[this_tile] == 'fence' and not self.dig_pos:
            self._dig(final_pos)
            return self.pos
        return final_pos

    def _dig(self, dig_pos):
        """Setup dig parameters, to be overridden if needed"""
        self.tick = 5
        self.dig_pos = dig_pos

    def _make_hole(self, gameboard):
        """Make a hole in the fence"""
        gameboard.tv.set(self.dig_pos.to_tuple(),
                tiles.REVERSE_TILE_MAP['broken fence'])
        self.dig_pos = None

    def move(self, gameboard):
        """Foxes will aim to move towards the closest henhouse or free
           chicken"""
        if self.dig_pos:
            if self.tick:
                self.tick -= 1
                # We're still digging through the fence
                # Check the another fox hasn't dug a hole for us
                # We're too busy digging to notice if a hole appears nearby,
                # but we'll notice if the fence we're digging vanishes
                this_tile = gameboard.tv.get(self.dig_pos.to_tuple())
                if tiles.TILE_MAP[this_tile] == 'broken fence':
                    self.tick = 0 
                return
            else:
                # We've dug through the fence, so make a hole
                self._make_hole(gameboard)
            return 
        if self.hunting:
            desired_pos = self._find_path_to_chicken(gameboard)
        else:
            desired_pos = self._find_path_to_woodland(gameboard)
        final_pos = self._update_pos(gameboard, desired_pos)
        self._fix_face(final_pos)
        self.pos = final_pos

class NinjaFox(Fox):
    """Ninja foxes are hard to see"""

    STEALTH = 60

class DemoFox(Fox):
    """Demolition Foxes destroy fences easily"""

class GreedyFox(Fox):
    """Greedy foxes eat more chickens"""

    def __init__(self, pos):
        Fox.__init__(self, pos)
        self.chickens_eaten = 0

    def _catch_chicken(self, chicken, gameboard):
        gameboard.remove_chicken(chicken)
        self.chickens_eaten += 1
        if self.chickens_eaten > 2:
            self.hunting = False

def visible(watcher, watchee):
    roll = random.randint(1, 100)
    distance = watcher.pos.dist(watchee.pos) - 1
    return roll > watchee.STEALTH + 10*distance