import math

from shapely.geometry import LineString
from shapely.geometry import Point as ShapelyPoint


def cut(line, distance, normalized=False):
    """ Cuts a LineString in two at a distance from its starting point.

    This is an example in the Shapely documentation.
    """
    if normalized:
        distance *= line.length

    if distance <= 0.0:
        return [None, line]
    elif distance >= line.length:
        return [line, None]

    coords = list(ShapelyPoint(p) for p in line.coords)
    traveled = 0
    last_point = coords[0]
    for i, p in enumerate(coords[1:], 1):
        traveled += p.distance(last_point)
        last_point = p
        if traveled == distance:
            return [
                LineString(coords[:i + 1]),
                LineString(coords[i:])]
        if traveled > distance:
            cp = line.interpolate(distance)
            return [
                LineString(coords[:i] + [(cp.x, cp.y)]),
                LineString([(cp.x, cp.y)] + coords[i:])]


def cut_path(points, length):
    """Return a subsection of at the start of the path that is length units long.

    Given a path denoted by a set of points, walk along it until we've travelled
    the specified length and return a new path up to that point.

    If the original path isn't that long, just return it as is.
    """

    if len(points) < 2:
        return points

    path = LineString(points)
    subpath, rest = cut(path, length)

    return [Point(*point) for point in subpath.coords]


def collapse_duplicate_point(geometry):
    if geometry.area < 0.01:
        return geometry.representative_point()

    return geometry


class Point:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def __json__(self):
        return vars(self)

    def __add__(self, other):
        return Point(self.x + other.x, self.y + other.y)

    def __sub__(self, other):
        return Point(self.x - other.x, self.y - other.y)

    def mul(self, scalar):
        return Point(self.x * scalar, self.y * scalar)

    def __mul__(self, other):
        if isinstance(other, Point):
            # dot product
            return self.x * other.x + self.y * other.y
        elif isinstance(other, (int, float)):
            return Point(self.x * other, self.y * other)
        else:
            raise ValueError("cannot multiply Point by %s" % type(other))

    def __neg__(self):
        return self * -1

    def __rmul__(self, other):
        if isinstance(other, (int, float)):
            return self.__mul__(other)
        else:
            raise ValueError("cannot multiply Point by %s" % type(other))

    def __div__(self, other):
        if isinstance(other, (int, float)):
            return self * (1.0 / other)
        else:
            raise ValueError("cannot divide Point by %s" % type(other))

    def __repr__(self):
        return "Point(%s,%s)" % (self.x, self.y)

    def length(self):
        return math.sqrt(math.pow(self.x, 2.0) + math.pow(self.y, 2.0))

    def distance(self, other):
        return (other - self).length()

    def unit(self):
        return self.mul(1.0 / self.length())

    def rotate_left(self):
        return Point(-self.y, self.x)

    def rotate(self, angle):
        return Point(self.x * math.cos(angle) - self.y * math.sin(angle), self.y * math.cos(angle) + self.x * math.sin(angle))

    def as_int(self):
        return Point(int(round(self.x)), int(round(self.y)))

    def as_tuple(self):
        return (self.x, self.y)

    def __getitem__(self, item):
        return self.as_tuple()[item]

    def __len__(self):
        return 2


def line_string_to_point_list(line_string):
    return [Point(*point) for point in line_string.coords]