import importlib
import functools
import time

from astar import AStar

from mosfet.info import blocks
from mosfet import utils

class AStarTimeout(Exception):
    pass

BLOCK_ABOVE = (0, +1, 0)
BLOCK_ABOVE2 = (0, +2, 0)
BLOCK_ABOVE3 = (0, +3, 0)
BLOCK_ABOVE4 = (0, +4, 0)
BLOCK_BELOW = (0, -1, 0)
BLOCK_BELOW2 = (0, -2, 0)

TRAVERSE_NORTH = (0, 0, -1)
TRAVERSE_SOUTH = (0, 0, +1)
TRAVERSE_EAST = (+1, 0, 0)
TRAVERSE_WEST = (-1, 0, 0)
ASCEND_NORTH = (0, +1, -1)
ASCEND_SOUTH = (0, +1, +1)
ASCEND_EAST = (+1, +1, 0)
ASCEND_WEST = (-1, +1, 0)
DESCEND_EAST = (+1, -1, 0)
DESCEND_WEST = (-1, -1, 0)
DESCEND_NORTH = (0, -1, -1)
DESCEND_SOUTH = (0, -1, +1)
DESCEND2_EAST = (+1, -2, 0)
DESCEND2_WEST = (-1, -2, 0)
DESCEND2_NORTH = (0, -2, -1)
DESCEND2_SOUTH = (0, -2, +1)
DESCEND3_EAST = (+1, -3, 0)
DESCEND3_WEST = (-1, -3, 0)
DESCEND3_NORTH = (0, -3, -1)
DESCEND3_SOUTH = (0, -3, +1)
DIAGONAL_NORTHEAST = (+1, 0, -1)
DIAGONAL_NORTHWEST = (-1, 0, -1)
DIAGONAL_SOUTHEAST = (+1, 0, +1)
DIAGONAL_SOUTHWEST = (-1, 0, +1)
PARKOUR_NORTH = (0, 0, -2)
PARKOUR_SOUTH = (0, 0, +2)
PARKOUR_EAST = (+2, 0, 0)
PARKOUR_WEST = (-2, 0, 0)

CHECK_NORTH = (0, 0, -1)
CHECK_SOUTH = (0, 0, +1)
CHECK_EAST = (+1, 0, 0)
CHECK_WEST = (-1, 0, 0)

CHECK_DIRECTIONS = [
    CHECK_NORTH,
    CHECK_SOUTH,
    CHECK_EAST,
    CHECK_WEST,
]

TRAVERSE = [
    TRAVERSE_NORTH,
    TRAVERSE_SOUTH,
    TRAVERSE_EAST,
    TRAVERSE_WEST,
]

ASCEND = [
    ASCEND_NORTH,
    ASCEND_SOUTH,
    ASCEND_EAST,
    ASCEND_WEST,
]

DESCEND = [
    DESCEND_EAST,
    DESCEND_WEST,
    DESCEND_NORTH,
    DESCEND_SOUTH,
]

DESCEND2 = [
    DESCEND2_EAST,
    DESCEND2_WEST,
    DESCEND2_NORTH,
    DESCEND2_SOUTH,
]

DESCEND3 = [
    DESCEND3_EAST,
    DESCEND3_WEST,
    DESCEND3_NORTH,
    DESCEND3_SOUTH,
]

DIAGONAL = [
    DIAGONAL_NORTHEAST,
    DIAGONAL_NORTHWEST,
    DIAGONAL_SOUTHEAST,
    DIAGONAL_SOUTHWEST,
]

PARKOUR = [
    PARKOUR_NORTH,
    PARKOUR_SOUTH,
    PARKOUR_EAST,
    PARKOUR_WEST,
]

HALF_PARKOUR = {
    (0, 0, -2): (0, 0, -1),
    (0, 0, 2): (0, 0, 1),
    (2, 0, 0): (1, 0, 0),
    (-2, 0, 0): (-1, 0, 0),
}

# larger started being slower
BLOCK_CACHE_SIZE = 2**14

class Pathfinder(AStar):
    def __init__(self, g):
        self.g = g
        self.chunks = g.chunks
        self.start_time = time.time()

    @functools.lru_cache(maxsize=BLOCK_CACHE_SIZE)
    def bair(self, p):
        return self.chunks.get_block_at(*p) in blocks.NON_SOLID_IDS

    @functools.lru_cache(maxsize=BLOCK_CACHE_SIZE)
    def bavoid(self, p):
        return self.chunks.get_block_at(*p) in blocks.AVOID_IDS or p[1] < 0

    def check_traverse_crawling(self, node, offset):
        dest = utils.padd(node, offset)

        if not self.bair(dest):
            return False

        if self.bair(utils.padd(dest, BLOCK_BELOW)):
            return False

        if self.bavoid(dest):
            return False

        if self.bavoid(utils.padd(dest, BLOCK_BELOW)):
            return False

        return True

    def check_traverse(self, node, offset):
        dest = utils.padd(node, offset)

        if not self.bair(dest):
            return False

        if self.bair(utils.padd(dest, BLOCK_BELOW)):
            return False

        if not self.bair(utils.padd(dest, BLOCK_ABOVE)):
            return False

        if self.bavoid(dest):
            return False

        if self.bavoid(utils.padd(dest, BLOCK_BELOW)):
            return False

        if self.bavoid(utils.padd(dest, BLOCK_ABOVE)):
            return False

        return True

    def check_diagonal(self, node, offset):
        if not self.check_traverse(node, offset):
            return False

        dest = utils.padd(node, offset)
        thru1 = (node[0], node[1], dest[2])
        thru2 = (dest[0], node[1], node[2])

        if not self.bair(thru1):
            return False

        if not self.bair(utils.padd(thru1, BLOCK_ABOVE)):
            return False

        if self.bavoid(utils.padd(thru1, BLOCK_BELOW)):
            return False

        if not self.bair(thru2):
            return False

        if not self.bair(utils.padd(thru2, BLOCK_ABOVE)):
            return False

        if self.bavoid(utils.padd(thru2, BLOCK_BELOW)):
            return False

        return True

    def check_ascend(self, node, offset):
        dest = utils.padd(node, offset)

        if not self.bair(utils.padd(node, BLOCK_ABOVE2)):
            return False

        if not self.check_traverse(node, offset):
            return False

        return True

    def check_descend(self, node, offset):
        dest = utils.padd(node, offset)

        if not self.bair(utils.padd(dest, BLOCK_ABOVE2)):
            return False

        if not self.check_traverse(node, offset):
            return False

        return True

    def check_descend2(self, node, offset):
        dest = utils.padd(node, offset)

        if not self.bair(utils.padd(dest, BLOCK_ABOVE3)):
            return False

        if not self.check_descend(node, offset):
            return False

        return True

    def check_descend3(self, node, offset):
        dest = utils.padd(node, offset)

        if not self.bair(utils.padd(dest, BLOCK_ABOVE4)):
            return False

        if not self.check_descend2(node, offset):
            return False

        return True

    def check_parkour(self, node, offset):
        dest = utils.padd(node, offset)
        half_offset = HALF_PARKOUR[offset]
        middle = utils.padd(node, half_offset)

        # dont jump if we can walk instead
        if not self.bair(utils.padd(middle, BLOCK_BELOW)):
            return False

        if not self.check_ascend(node, offset):
            return False

        if not self.bair(utils.padd(dest, BLOCK_ABOVE2)):
            return False

        if not self.bair(utils.padd(middle, BLOCK_ABOVE)):
            return False

        if not self.bair(utils.padd(middle, BLOCK_ABOVE2)):
            return False

        return True

    def neighbors(self, node):
        results = []

        if self.g.crawling:
            for offset in TRAVERSE:
                if self.check_traverse_crawling(node, offset):
                    results.append(utils.padd(node, offset))
        else:
            for offset in TRAVERSE:
                if self.check_traverse(node, offset):
                    results.append(utils.padd(node, offset))
            for offset in DIAGONAL:
                if self.check_diagonal(node, offset):
                    results.append(utils.padd(node, offset))
            for offset in ASCEND:
                if self.check_ascend(node, offset):
                    results.append(utils.padd(node, offset))
            for offset in DESCEND:
                if self.check_descend(node, offset):
                    results.append(utils.padd(node, offset))
            for offset in DESCEND2:
                if self.check_descend2(node, offset):
                    results.append(utils.padd(node, offset))
            for offset in DESCEND3:
                if self.check_descend3(node, offset):
                    results.append(utils.padd(node, offset))
            for offset in PARKOUR:
                if self.check_parkour(node, offset):
                    results.append(utils.padd(node, offset))

        if not results:
            if time.time() - self.start_time > 2.0:
                raise(AStarTimeout)

        return results

    def distance_between(self, n1, n2):
        (x1, y1, z1) = n1
        (x2, y2, z2) = n2
        return utils.hypot(x2-x1, y2-y1, z2-z1)

    def heuristic_cost_estimate(self, n1, n2):
        (x1, y1, z1) = n1
        (x2, y2, z2) = n2
        return abs(x2-x1) + abs(y2-y1) + abs(z2-z1)