"""
Computational geometry code for PySAL: Python Spatial Analysis Library.

"""

__author__ = "Sergio J. Rey, Xinyue Ye, Charles Schmidt, Andrew Winslow"
__credits__ = "Copyright (c) 2005-2009 Sergio J. Rey"

import doctest
import math
from warnings import warn
from sphere import arcdist
import numpy as np

__all__ = ['Point', 'LineSegment', 'Line', 'Ray', 'Chain', 'Polygon',
           'Rectangle', 'asShape']


def asShape(obj):
    """
    Returns a pysal shape object from obj.
    obj must support the __geo_interface__.
    """
    if isinstance(obj, (Point, LineSegment, Line, Ray, Chain, Polygon)):
        return obj
    if hasattr(obj, '__geo_interface__'):
        geo = obj.__geo_interface__
    else:
        geo = obj
    if hasattr(geo, 'type'):
        raise TypeError('%r does not appear to be a shape object' % (obj))
    geo_type = geo['type'].lower()
    #if geo_type.startswith('multi'):
    #    raise NotImplementedError, "%s are not supported at this time."%geo_type
    if geo_type in _geoJSON_type_to_Pysal_type:
        return _geoJSON_type_to_Pysal_type[geo_type].__from_geo_interface__(geo)
    else:
        raise NotImplementedError(
            "%s is not supported at this time." % geo_type)

class Geometry(object):
    """
    A base class to help implement is_geometry and make geometric types
    extendable.
    """
    def __init__(self):
        pass

class Point(Geometry):
    """
    Geometric class for point objects.

    Attributes
    ----------
    None
    """
    def __init__(self, loc):
        """
        Returns an instance of a Point object.

        __init__((number, number)) -> Point

        Test tag: <tc>#is#Point.__init__</tc>
        Test tag: <tc>#tests#Point.__init__</tc>

        Parameters
        ----------
        loc : tuple location (number x-tuple, x > 1)

        Attributes
        ----------

        Examples
        --------
        >>> p = Point((1, 3))
        """
        self.__loc = tuple(map(float, loc))

    @classmethod
    def __from_geo_interface__(cls, geo):
        return cls(geo['coordinates'])

    @property
    def __geo_interface__(self):
        return {'type': 'Point', 'coordinates': self.__loc}

    def __lt__(self, other):
        """
        Tests if the Point is < another object.

        __ne__(x) -> bool

        Parameters
        ----------
        other : an object to test equality against

        Attributes
        ----------

        Examples
        --------
        >>> Point((0,1)) < Point((0,1))
        False
        >>> Point((0,1)) < Point((1,1))
        True
        """
        return (self.__loc) < (other.__loc)

    def __le__(self, other):
        """
        Tests if the Point is <= another object.

        __ne__(x) -> bool

        Parameters
        ----------
        other : an object to test equality against

        Attributes
        ----------

        Examples
        --------
        >>> Point((0,1)) <= Point((0,1))
        True
        >>> Point((0,1)) <= Point((1,1))
        True
        """
        return (self.__loc) <= (other.__loc)

    def __eq__(self, other):
        """
        Tests if the Point is equal to another object.

        __eq__(x) -> bool

        Parameters
        ----------
        other : an object to test equality against

        Attributes
        ----------

        Examples
        --------
        >>> Point((0,1)) == Point((0,1))
        True
        >>> Point((0,1)) == Point((1,1))
        False
        """
        try:
            return (self.__loc) == (other.__loc)
        except AttributeError:
            return False

    def __ne__(self, other):
        """
        Tests if the Point is not equal to another object.

        __ne__(x) -> bool

        Parameters
        ----------
        other : an object to test equality against

        Attributes
        ----------

        Examples
        --------
        >>> Point((0,1)) != Point((0,1))
        False
        >>> Point((0,1)) != Point((1,1))
        True
        """
        try:
            return (self.__loc) != (other.__loc)
        except AttributeError:
            return True

    def __gt__(self, other):
        """
        Tests if the Point is > another object.

        __ne__(x) -> bool

        Parameters
        ----------
        other : an object to test equality against

        Attributes
        ----------

        Examples
        --------
        >>> Point((0,1)) > Point((0,1))
        False
        >>> Point((0,1)) > Point((1,1))
        False
        """
        return (self.__loc) > (other.__loc)

    def __ge__(self, other):
        """
        Tests if the Point is >= another object.

        __ne__(x) -> bool

        Parameters
        ----------
        other : an object to test equality against

        Attributes
        ----------

        Examples
        --------
        >>> Point((0,1)) >= Point((0,1))
        True
        >>> Point((0,1)) >= Point((1,1))
        False
        """
        return (self.__loc) >= (other.__loc)

    def __hash__(self):
        """
        Returns the hash of the Point's location.

        x.__hash__() -> hash(x)

        Parameters
        ----------
        None

        Attributes
        ----------

        Examples
        --------
        >>> hash(Point((0,1))) == hash(Point((0,1)))
        True
        >>> hash(Point((0,1))) == hash(Point((1,1)))
        False
        """
        return hash(self.__loc)

    def __getitem__(self, *args):
        """
        Return the coordinate for the given dimension.

        x.__getitem__(i) -> x[i]

        Parameters
        ----------
        i : index of the desired dimension.

        Attributes
        ----------

        Examples
        --------
        >>> p = Point((5.5,4.3))
        >>> p[0] == 5.5
        True
        >>> p[1] == 4.3
        True
        """
        return self.__loc.__getitem__(*args)

    def __getslice__(self, *args):
        """
        Return the coordinate for the given dimensions.

        x.__getitem__(i,j) -> x[i:j]

        Parameters
        ----------
        i : index to start slice
        j : index to end slice (excluded).

        Attributes
        ----------

        Examples
        --------
        >>> p = Point((3,6,2))
        >>> p[:2] == (3,6)
        True
        >>> p[1:2] == (6,)
        True
        """
        return self.__loc.__getslice__(*args)

    def __len__(self):
        """
        Returns the number of dimension in the point.

        __len__() -> int

        Parameters
        ----------
        None

        Attributes
        ----------

        Examples
        --------
        >>> len(Point((1,2)))
        2
        """
        return len(self.__loc)

    def __repr__(self):
        """
        Returns the string representation of the Point

        __repr__() -> string

        Parameters
        ----------
        None

        Attributes
        ----------

        Examples
        --------
        >>> Point((0,1))
        (0.0, 1.0)
        """
        return str(self)

    def __str__(self):
        """
        Returns a string representation of a Point object.

        __str__() -> string

        Test tag: <tc>#is#Point.__str__</tc>
        Test tag: <tc>#tests#Point.__str__</tc>

        Attributes
        ----------

        Examples
        --------
        >>> p = Point((1, 3))
        >>> str(p)
        '(1.0, 3.0)'
        """
        return str(self.__loc)
        return "POINT ({} {})".format(*self.__loc)


class LineSegment(Geometry):
    """
    Geometric representation of line segment objects.

    Parameters
    ----------

    start_pt     : Point
                   Point where segment begins
    end_pt       : Point
                   Point where segment ends

    Attributes
    ----------

    p1              : Point
                      Starting point
    p2              : Point
                      Ending point
    bounding_box    : tuple
                      The bounding box of the segment (number 4-tuple)
    len             : float
                      The length of the segment
    line            : Line
                      The line on which the segment lies

    """

    def __init__(self, start_pt, end_pt):
        """
        Creates a LineSegment object.

        __init__(Point, Point) -> LineSegment

        Test tag: <tc>#is#LineSegment.__init__</tc>
        Test tag: <tc>#tests#LineSegment.__init__</tc>


        Attributes
        ----------
        None

        Examples
        --------
        >>> ls = LineSegment(Point((1, 2)), Point((5, 6)))
        """
        self._p1 = start_pt
        self._p2 = end_pt
        self._reset_props()

    def __str__(self):
        return "LineSegment(" + str(self._p1) + ", " + str(self._p2) + ")"
        return "LINESTRING ({} {}, {} {})".format(self._p1[0], self._p1[1], 
                                                  self._p2[0], self._p2[1])

    def __eq__(self, other):
        """
        Returns true if self and other are the same line segment

        Examples
        --------
        >>> l1 = LineSegment(Point((1, 2)), Point((5, 6)))
        >>> l2 = LineSegment(Point((5, 6)), Point((1, 2)))
        >>> l1 == l2
        True
        >>> l2 == l1
        True
        """
        if not isinstance(other, self.__class__):
            return False
        if (other.p1 == self._p1 and other.p2 == self._p2):
            return True
        elif (other.p2 == self._p1 and other.p1 == self._p2):
            return True
        return False

    def intersect(self, other):
        """
        Test whether segment intersects with other segment

        Handles endpoints of segments being on other segment

        Examples
        --------

        >>> ls = LineSegment(Point((5,0)), Point((10,0)))
        >>> ls1 = LineSegment(Point((5,0)), Point((10,1)))
        >>> ls.intersect(ls1)
        True
        >>> ls2 = LineSegment(Point((5,1)), Point((10,1)))
        >>> ls.intersect(ls2)
        False
        >>> ls2 = LineSegment(Point((7,-1)), Point((7,2)))
        >>> ls.intersect(ls2)
        True
        >>>
        """
        ccw1 = self.sw_ccw(other.p2)
        ccw2 = self.sw_ccw(other.p1)
        ccw3 = other.sw_ccw(self.p1)
        ccw4 = other.sw_ccw(self.p2)

        return ccw1*ccw2 <= 0 and ccw3*ccw4 <=0



    def _reset_props(self):
        """
        HELPER METHOD. DO NOT CALL.

        Resets attributes which are functions of other attributes. The getters for these attributes (implemented as
        properties) then recompute their values if they have been reset since the last call to the getter.

        _reset_props() -> None

        Attributes
        ----------

        Examples
        --------
        >>> ls = LineSegment(Point((1, 2)), Point((5, 6)))
        >>> ls._reset_props()
        """
        self._bounding_box = None
        self._len = None
        self._line = False

    def _get_p1(self):
        """
        HELPER METHOD. DO NOT CALL.

        Returns the p1 attribute of the line segment.

        _get_p1() -> Point

        Attributes
        ----------

        Examples
        --------
        >>> ls = LineSegment(Point((1, 2)), Point((5, 6)))
        >>> r = ls._get_p1()
        >>> r == Point((1, 2))
        True
        """
        return self._p1

    def _set_p1(self, p1):
        """
        HELPER METHOD. DO NOT CALL.

        Sets the p1 attribute of the line segment.

        _set_p1(Point) -> Point

        Attributes
        ----------

        Examples
        --------
        >>> ls = LineSegment(Point((1, 2)), Point((5, 6)))
        >>> r = ls._set_p1(Point((3, -1)))
        >>> r == Point((3.0, -1.0))
        True
        """
        self._p1 = p1
        self._reset_props()
        return self._p1

    p1 = property(_get_p1, _set_p1)

    def _get_p2(self):
        """
        HELPER METHOD. DO NOT CALL.

        Returns the p2 attribute of the line segment.

        _get_p2() -> Point

        Attributes
        ----------

        Examples
        --------
        >>> ls = LineSegment(Point((1, 2)), Point((5, 6)))
        >>> r = ls._get_p2()
        >>> r == Point((5, 6))
        True
        """
        return self._p2

    def _set_p2(self, p2):
        """
        HELPER METHOD. DO NOT CALL.

        Sets the p2 attribute of the line segment.

        _set_p2(Point) -> Point

        Attributes
        ----------

        Examples
        --------
        >>> ls = LineSegment(Point((1, 2)), Point((5, 6)))
        >>> r = ls._set_p2(Point((3, -1)))
        >>> r == Point((3.0, -1.0))
        True
        """
        self._p2 = p2
        self._reset_props()
        return self._p2

    p2 = property(_get_p2, _set_p2)

    def is_ccw(self, pt):
        """
        Returns whether a point is counterclockwise of the segment. Exclusive.

        is_ccw(Point) -> bool

        Test tag: <tc>#is#LineSegment.is_ccw</tc>
        Test tag: <tc>#tests#LineSegment.is_ccw</tc>

        Parameters
        ----------
        pt : point lying ccw or cw of a segment

        Attributes
        ----------

        Examples
        --------
        >>> ls = LineSegment(Point((0, 0)), Point((5, 0)))
        >>> ls.is_ccw(Point((2, 2)))
        True
        >>> ls.is_ccw(Point((2, -2)))
        False
        """
        v1 = (self._p2[0] - self._p1[0], self._p2[1] - self._p1[1])
        v2 = (pt[0] - self._p1[0], pt[1] - self._p1[1])

        return v1[0] * v2[1] - v1[1] * v2[0] > 0

    def is_cw(self, pt):
        """
        Returns whether a point is clockwise of the segment. Exclusive.

        is_cw(Point) -> bool

        Test tag: <tc>#is#LineSegment.is_cw</tc>
        Test tag: <tc>#tests#LineSegment.is_cw</tc>

        Parameters
        ----------
        pt : point lying ccw or cw of a segment

        Attributes
        ----------

        Examples
        --------
        >>> ls = LineSegment(Point((0, 0)), Point((5, 0)))
        >>> ls.is_cw(Point((2, 2)))
        False
        >>> ls.is_cw(Point((2, -2)))
        True
        """
        v1 = (self._p2[0] - self._p1[0], self._p2[1] - self._p1[1])
        v2 = (pt[0] - self._p1[0], pt[1] - self._p1[1])
        return v1[0] * v2[1] - v1[1] * v2[0] < 0

    def sw_ccw(self, pt):
        """
        Sedgewick test for pt being ccw of segment

        Returns
        -------

        1 if turn from self.p1 to self.p2 to pt is ccw
        -1 if turn from self.p1 to self.p2 to pt is cw
        -1 if the points are collinear and self.p1 is in the middle
        1 if the points are collinear and self.p2 is in the middle
        0 if the points are collinear and pt is in the middle
        
        """

        p0 = self.p1
        p1 = self.p2
        p2 = pt

        dx1 = p1[0] - p0[0]
        dy1 = p1[1] - p0[1]
        dx2 = p2[0] - p0[0]
        dy2 = p2[1] - p0[1]

        if dy1*dx2 < dy2*dx1:
            return 1
        if dy1*dx2 > dy2*dx1:
            return -1
        if (dx1*dx2 < 0 or dy1*dy2 <0):
                return -1
        if dx1*dx1 + dy1*dy1 >= dx2*dx2 + dy2*dy2:
            return 0
        else:
            return 1




    def get_swap(self):
        """
        Returns a LineSegment object which has its endpoints swapped.

        get_swap() -> LineSegment

        Test tag: <tc>#is#LineSegment.get_swap</tc>
        Test tag: <tc>#tests#LineSegment.get_swap</tc>

        Attributes
        ----------

        Examples
        --------
        >>> ls = LineSegment(Point((1, 2)), Point((5, 6)))
        >>> swap = ls.get_swap()
        >>> swap.p1[0]
        5.0
        >>> swap.p1[1]
        6.0
        >>> swap.p2[0]
        1.0
        >>> swap.p2[1]
        2.0
        """
        return LineSegment(self._p2, self._p1)

    @property
    def bounding_box(self):
        """
        Returns the minimum bounding box of a LineSegment object.

        Test tag: <tc>#is#LineSegment.bounding_box</tc>
        Test tag: <tc>#tests#LineSegment.bounding_box</tc>

        bounding_box -> Rectangle

        Attributes
        ----------

        Examples
        --------
        >>> ls = LineSegment(Point((1, 2)), Point((5, 6)))
        >>> ls.bounding_box.left
        1.0
        >>> ls.bounding_box.lower
        2.0
        >>> ls.bounding_box.right
        5.0
        >>> ls.bounding_box.upper
        6.0
        """
        if self._bounding_box is None:  # If LineSegment attributes p1, p2 changed, recompute
            self._bounding_box = Rectangle(
                min([self._p1[0], self._p2[0]]), min([
                    self._p1[1], self._p2[1]]),
                max([self._p1[0], self._p2[0]]), max([self._p1[1], self._p2[1]]))
        return Rectangle(
            self._bounding_box.left, self._bounding_box.lower, self._bounding_box.right,
            self._bounding_box.upper)

    @property
    def len(self):
        """
        Returns the length of a LineSegment object.

        Test tag: <tc>#is#LineSegment.len</tc>
        Test tag: <tc>#tests#LineSegment.len</tc>

        len() -> number

        Attributes
        ----------

        Examples
        --------
        >>> ls = LineSegment(Point((2, 2)), Point((5, 2)))
        >>> ls.len
        3.0
        """
        if self._len is None:  # If LineSegment attributes p1, p2 changed, recompute
            self._len = math.hypot(self._p1[0] - self._p2[0],
                                   self._p1[1] - self._p2[1])
        return self._len

    @property
    def line(self):
        """
        Returns a Line object of the line which the segment lies on.

        Test tag: <tc>#is#LineSegment.line</tc>
        Test tag: <tc>#tests#LineSegment.line</tc>

        line() -> Line

        Attributes
        ----------

        Examples
        --------
        >>> ls = LineSegment(Point((2, 2)), Point((3, 3)))
        >>> l = ls.line
        >>> l.m
        1.0
        >>> l.b
        0.0
        """
        if self._line == False:
            dx = self._p1[0] - self._p2[0]
            dy = self._p1[1] - self._p2[1]
            if dx == 0 and dy == 0:
                self._line = None
            elif dx == 0:
                self._line = VerticalLine(self._p1[0])
            else:
                m = dy / float(dx)
                b = self._p1[1] - m * self._p1[0]  # y - mx
                self._line = Line(m, b)
        return self._line


class VerticalLine(Geometry):
    """
    Geometric representation of verticle line objects.

    Attributes
    ----------
    x       : float
              x-intercept
    """
    def __init__(self, x):
        """
        Returns a VerticalLine object.

        __init__(number) -> VerticalLine

        Parameters
        ----------
        x : the x-intercept of the line

        Attributes
        ----------

        Examples
        --------
        >>> ls = VerticalLine(0)
        >>> ls.m
        inf
        >>> ls.b
        nan
        """
        self._x = float(x)
        self.m = float('inf')
        self.b = float('nan')

    def x(self, y):
        """
        Returns the x-value of the line at a particular y-value.

        x(number) -> number

        Parameters
        ----------
        y : the y-value to compute x at

        Attributes
        ----------

        Examples
        --------
        >>> l = VerticalLine(0)
        >>> l.x(0.25)
        0.0
        """
        return self._x

    def y(self, x):
        """
        Returns the y-value of the line at a particular x-value.

        y(number) -> number

        Parameters
        ----------
        x : the x-value to compute y at

        Attributes
        ----------

        Examples
        --------
        >>> l = VerticalLine(1)
        >>> l.y(1)
        nan
        """
        return float('nan')


class Line(Geometry):
    """
    Geometric representation of line objects.

    Attributes
    ----------
    m       : float
              slope
    b       : float
              y-intercept

    """

    def __init__(self, m, b):
        """
        Returns a Line object.

        __init__(number, number) -> Line

        Test tag: <tc>#is#Line.__init__</tc>
        Test tag: <tc>#tests#Line.__init__</tc>

        Parameters
        ----------
        m : the slope of the line
        b : the y-intercept of the line

        Attributes
        ----------

        Examples
        --------
        >>> ls = Line(1, 0)
        >>> ls.m
        1.0
        >>> ls.b
        0.0
        """
        if m == float('inf') or m == float('inf'):
            raise ArithmeticError('Slope cannot be infinite.')
        self.m = float(m)
        self.b = float(b)

    def x(self, y):
        """
        Returns the x-value of the line at a particular y-value.

        x(number) -> number

        Parameters
        ----------
        y : the y-value to compute x at

        Attributes
        ----------

        Examples
        --------
        >>> l = Line(0.5, 0)
        >>> l.x(0.25)
        0.5
        """
        if self.m == 0:
            raise ArithmeticError('Cannot solve for X when slope is zero.')
        return (y - self.b) / self.m

    def y(self, x):
        """
        Returns the y-value of the line at a particular x-value.

        y(number) -> number

        Parameters
        ----------
        x : the x-value to compute y at

        Attributes
        ----------

        Examples
        --------
        >>> l = Line(1, 0)
        >>> l.y(1)
        1.0
        """
        if self.m == 0:
            return self.b
        return self.m * x + self.b


class Ray:
    """
    Geometric representation of ray objects.

    Attributes
    ----------

    o       : Point
              Origin (point where ray originates)
    p       : Point
              Second point on the ray (not point where ray originates)
    """

    def __init__(self, origin, second_p):
        """
        Returns a ray with the values specified.

        __init__(Point, Point) -> Ray

        Parameters
        ----------
        origin   : the point where the ray originates
        second_p : the second point specifying the ray (not the origin)

        Attributes
        ----------

        Examples
        --------
        >>> l = Ray(Point((0, 0)), Point((1, 0)))
        >>> str(l.o)
        '(0.0, 0.0)'
        >>> str(l.p)
        '(1.0, 0.0)'
        """
        self.o = origin
        self.p = second_p


class Chain(Geometry):
    """
    Geometric representation of a chain, also known as a polyline.

    Attributes
    ----------

    vertices    : list
                  List of Points of the vertices of the chain in order.
    len         : float
                  The geometric length of the chain.

    """

    def __init__(self, vertices):
        """
        Returns a chain created from the points specified.

        __init__(Point list or list of Point lists) -> Chain

        Parameters
        ----------
        vertices : list -- Point list or list of Point lists.

        Attributes
        ----------

        Examples
        --------
        >>> c = Chain([Point((0, 0)), Point((1, 0)), Point((1, 1)), Point((2, 1))])
        """
        if isinstance(vertices[0], list):
            self._vertices = [part for part in vertices]
        else:
            self._vertices = [vertices]
        self._reset_props()
    
    @classmethod
    def __from_geo_interface__(cls, geo):
        if geo['type'].lower() == 'linestring':
            verts = [Point(pt) for pt in geo['coordinates']]
        elif geo['type'].lower() == 'multilinestring':
            verts = [map(Point, part) for part in geo['coordinates']]
        else:
            raise TypeError('%r is not a Chain'%geo)
        return cls(verts)

    @property
    def __geo_interface__(self):
        if len(self.parts) == 1:
            return {'type': 'LineString', 'coordinates': self.vertices}
        else:
            return {'type': 'MultiLineString', 'coordinates': self.parts}

    def _reset_props(self):
        """
        HELPER METHOD. DO NOT CALL.

        Resets attributes which are functions of other attributes. The getters for these attributes (implemented as
        properties) then recompute their values if they have been reset since the last call to the getter.

        _reset_props() -> None

        Attributes
        ----------

        Examples
        --------
        >>> ls = Chain([Point((1, 2)), Point((5, 6))])
        >>> ls._reset_props()
        """
        self._len = None
        self._arclen = None
        self._bounding_box = None

    @property
    def vertices(self):
        """
        Returns the vertices of the chain in clockwise order.

        vertices -> Point list

        Attributes
        ----------

        Examples
        --------
        >>> c = Chain([Point((0, 0)), Point((1, 0)), Point((1, 1)), Point((2, 1))])
        >>> verts = c.vertices
        >>> len(verts)
        4
        """
        return sum([part for part in self._vertices], [])

    @property
    def parts(self):
        """
        Returns the parts of the chain.

        parts -> Point list

        Attributes
        ----------

        Examples
        --------
        >>> c = Chain([[Point((0, 0)), Point((1, 0)), Point((1, 1)), Point((0, 1))],[Point((2,1)),Point((2,2)),Point((1,2)),Point((1,1))]])
        >>> len(c.parts)
        2
        """
        return [[v for v in part] for part in self._vertices]

    @property
    def bounding_box(self):
        """
        Returns the bounding box of the chain.

        bounding_box -> Rectangle

        Attributes
        ----------

        Examples
        --------
        >>> c = Chain([Point((0, 0)), Point((2, 0)), Point((2, 1)), Point((0, 1))])
        >>> c.bounding_box.left
        0.0
        >>> c.bounding_box.lower
        0.0
        >>> c.bounding_box.right
        2.0
        >>> c.bounding_box.upper
        1.0
        """
        if self._bounding_box is None:
            vertices = self.vertices
            self._bounding_box = Rectangle(
                min([v[0] for v in vertices]), min([v[1] for v in vertices]),
                max([v[0] for v in vertices]), max([v[1] for v in vertices]))
        return self._bounding_box

    @property
    def len(self):
        """
        Returns the geometric length of the chain.

        len -> number

        Attributes
        ----------

        Examples
        --------
        >>> c = Chain([Point((0, 0)), Point((1, 0)), Point((1, 1)), Point((2, 1))])
        >>> c.len
        3.0
        >>> c = Chain([[Point((0, 0)), Point((1, 0)), Point((1, 1))],[Point((10,10)),Point((11,10)),Point((11,11))]])
        >>> c.len
        4.0
        """
        def dist(v1, v2):
            return math.hypot(v1[0] - v2[0], v1[1] - v2[1])

        def part_perimeter(part):
            return sum([dist(part[i], part[i + 1]) for i in xrange(len(part) - 1)])

        if self._len is None:
            self._len = sum([part_perimeter(part) for part in self._vertices])
        return self._len

    @property
    def arclen(self):
        """
        Returns the geometric length of the chain computed using arcdistance (meters).

        len -> number

        Attributes
        ----------

        Examples
        --------
        """
        def part_perimeter(part):
            return sum([arcdist(part[i], part[i + 1]) * 1000. for i in xrange(len(part) - 1)])
        if self._arclen is None:
            self._arclen = sum(
                [part_perimeter(part) for part in self._vertices])
        return self._arclen

    @property
    def segments(self):
        """
        Returns the segments that compose the Chain
        """
        return [[LineSegment(a, b) for (a, b) in zip(part[:-1], part[1:])] for part in self._vertices]


class Ring(Geometry):
    """
    Geometric representation of a Linear Ring

    Linear Rings must be closed, the first and last point must be the same. Open rings will be closed.

    This class exists primarily as a geometric primitive to form complex polygons with multiple rings and holes.

    The ordering of the vertices is ignored and will not be altered.

    Parameters
    ----------
    vertices : list -- a list of vertices

    Attributes
    __________
    vertices        : list
                      List of Points with the vertices of the ring
    len             : int
                      Number of vertices
    perimeter       : float
                      Geometric length of the perimeter of the ring
    bounding_box    : Rectangle
                      Bounding box of the ring
    area            : float
                      area enclosed by the ring
    centroid        : tuple
                      The centroid of the ring defined by the 'center of gravity' or 'center or mass'
    """
    def __init__(self, vertices):
        if vertices[0] != vertices[-1]:
            vertices = vertices[:] + vertices[0:1]
            #raise ValueError, "Supplied vertices do not form a closed ring, the first and last vertices are not the same"
        self.vertices = tuple(vertices)
        self._perimeter = None
        self._bounding_box = None
        self._area = None
        self._centroid = None

    def __len__(self):
        return len(self.vertices)

    @property
    def len(self):
        return len(self)

    @staticmethod
    def dist(v1, v2):
        return math.hypot(v1[0] - v2[0], v1[1] - v2[1])

    @property
    def perimeter(self):
        if self._perimeter is None:
            dist = self.dist
            v = self.vertices
            self._perimeter = sum([dist(v[i], v[i + 1])
                                   for i in xrange(-1, len(self) - 1)])
        return self._perimeter

    @property
    def bounding_box(self):
        """
        Returns the bounding box of the ring

        bounding_box -> Rectangle

        Examples
        --------
        >>> r = Ring([Point((0, 0)), Point((2, 0)), Point((2, 1)), Point((0, 1)), Point((0,0))])
        >>> r.bounding_box.left
        0.0
        >>> r.bounding_box.lower
        0.0
        >>> r.bounding_box.right
        2.0
        >>> r.bounding_box.upper
        1.0
        """
        if self._bounding_box is None:
            vertices = self.vertices
            x = [v[0] for v in vertices]
            y = [v[1] for v in vertices]
            self._bounding_box = Rectangle(min(x), min(y), max(x), max(y))
        return self._bounding_box

    @property
    def area(self):
        """
        Returns the area of the ring.

        area -> number

        Examples
        --------
        >>> r = Ring([Point((0, 0)), Point((2, 0)), Point((2, 1)), Point((0, 1)), Point((0,0))])
        >>> r.area
        2.0
        """
        return abs(self.signed_area)

    @property
    def signed_area(self):
        if self._area is None:
            vertices = self.vertices
            x = [v[0] for v in vertices]
            y = [v[1] for v in vertices]
            N = len(self)

            A = 0.0
            for i in xrange(N - 1):
                A += (x[i] + x[i + 1]) * \
                    (y[i] - y[i + 1])
            A = A * 0.5
            self._area = -A
        return self._area

    @property
    def centroid(self):
        """
        Returns the centroid of the ring.

        centroid -> Point

        Notes
        -----
        The centroid returned by this method is the geometric centroid.
        Also known as the 'center of gravity' or 'center of mass'.


        Examples
        --------
        >>> r = Ring([Point((0, 0)), Point((2, 0)), Point((2, 1)), Point((0, 1)), Point((0,0))])
        >>> str(r.centroid)
        '(1.0, 0.5)'
        """
        if self._centroid is None:
            vertices = self.vertices
            x = [v[0] for v in vertices]
            y = [v[1] for v in vertices]
            A = self.signed_area
            N = len(self)
            cx = 0
            cy = 0
            for i in xrange(N - 1):
                f = (x[i] * y[i + 1] - x[i + 1] * y[i])
                cx += (x[i] + x[i + 1]) * f
                cy += (y[i] + y[i + 1]) * f
            cx = 1.0 / (6 * A) * cx
            cy = 1.0 / (6 * A) * cy
            self._centroid = Point((cx, cy))
        return self._centroid

    def contains_point(self, point):
        """
        Point containment using winding number

        Implementation based on: http://www.engr.colostate.edu/~dga/dga/papers/point_in_polygon.pdf
        """

        x, y = point

        # bbox check
        if x < self.bounding_box.left:
            return False
        if x > self.bounding_box.right:
            return False
        if y < self.bounding_box.lower:
            return False
        if y > self.bounding_box.upper:
            return False


        rn = len(self.vertices)
        xs = [ self.vertices[i][0] - point[0] for i in xrange(rn) ]
        ys = [ self.vertices[i][1] - point[1] for i in xrange(rn) ]
        w = 0
        for i in xrange(len(self.vertices) - 1):
            yi = ys[i]
            yj = ys[i+1]
            xi = xs[i]
            xj = xs[i+1]
            if yi*yj < 0:
                r = xi + yi * (xj-xi) / (yi - yj)
                if r > 0:
                    if yi < 0:
                        w += 1
                    else:
                        w -= 1
            elif yi==0 and xi > 0:
                if yj > 0:
                    w += 0.5
                else:
                    w -= 0.5
            elif yj == 0 and xj > 0:
                if yi < 0:
                    w += 0.5
                else:
                    w -= 0.5
        if w==0:
            return False
        else:
            return True




class Polygon(Geometry):
    """
    Geometric representation of polygon objects.

    Attributes
    ----------
    vertices        : list
                      List of Points with the vertices of the Polygon in
                      clockwise order
    len             : int
                      Number of vertices including holes
    perimeter       : float
                      Geometric length of the perimeter of the Polygon
    bounding_box    : Rectangle
                      Bounding box of the polygon
    bbox            : List
                      [left, lower, right, upper]
    area            : float
                      Area enclosed by the polygon
    centroid        : tuple
                      The 'center of gravity', i.e. the mean point of the polygon.
    """

    def __init__(self, vertices, holes=None):
        """
        Returns a polygon created from the objects specified.

        __init__(Point list or list of Point lists, holes list ) -> Polygon

        Parameters
        ----------
        vertices : list -- a list of vertices or a list of lists of vertices.
        holes    : list -- a list of sub-polygons to be considered as holes.

        Attributes
        ----------

        Examples
        --------
        >>> p1 = Polygon([Point((0, 0)), Point((1, 0)), Point((1, 1)), Point((0, 1))])
        """
        self._part_rings = []
        self._hole_rings = []

        def clockwise(part):
            if standalone.is_clockwise(part):
                return part[:]
            else:
                return part[::-1]

        if isinstance(vertices[0], list):
            self._part_rings = map(Ring, vertices)
            self._vertices = [clockwise(part) for part in vertices]
        else:
            self._part_rings = [Ring(vertices)]
            self._vertices = [clockwise(vertices)]
        if holes is not None and holes != []:
            if isinstance(holes[0], list):
                self._hole_rings = map(Ring, holes)
                self._holes = [clockwise(hole) for hole in holes]
            else:
                self._hole_rings = [Ring(holes)]
                self._holes = [clockwise(holes)]
        else:
            self._holes = [[]]
        self._reset_props()

    @classmethod
    def __from_geo_interface__(cls, geo):
        """
        While pysal does not differentiate polygons and multipolygons GEOS,Shapely and geoJSON do.
        In GEOS, etc, polygons may only have a single exterior ring, all other parts are holes.
        MultiPolygons are simply a list of polygons.
        """
        geo_type = geo['type'].lower()
        if geo_type == 'multipolygon':
            parts = []
            holes = []
            for polygon in geo['coordinates']:
                verts = [[Point(pt) for pt in part] for part in polygon]
                parts += verts[0:1]
                holes += verts[1:]
            if not holes:
                holes = None
            return cls(parts, holes)
        else:
            verts = [[Point(pt) for pt in part] for part in geo['coordinates']]
            return cls(verts[0:1], verts[1:])

    @property
    def __geo_interface__(self):
        if len(self.parts) > 1:
            geo = {'type': 'MultiPolygon', 'coordinates': [[
                part] for part in self.parts]}
            if self._holes[0]:
                geo['coordinates'][0] += self._holes
            return geo
        if self._holes[0]:
            return {'type': 'Polygon', 'coordinates': self._vertices + self._holes}
        else:
            return {'type': 'Polygon', 'coordinates': self._vertices}

    def _reset_props(self):
        self._perimeter = None
        self._bounding_box = None
        self._bbox = None
        self._area = None
        self._centroid = None
        self._len = None

    def __len__(self):
        return self.len

    @property
    def len(self):
        """
        Returns the number of vertices in the polygon.

        len -> int

        Attributes
        ----------

        Examples
        --------
        >>> p1 = Polygon([Point((0, 0)), Point((0, 1)), Point((1, 1)), Point((1, 0))])
        >>> p1.len
        4
        >>> len(p1)
        4
        """
        if self._len is None:
            self._len = len(self.vertices)
        return self._len

    @property
    def vertices(self):
        """
        Returns the vertices of the polygon in clockwise order.

        vertices -> Point list

        Attributes
        ----------

        Examples
        --------
        >>> p1 = Polygon([Point((0, 0)), Point((0, 1)), Point((1, 1)), Point((1, 0))])
        >>> len(p1.vertices)
        4
        """
        return sum([part for part in self._vertices], []) + sum([part for part in self._holes], [])

    @property
    def holes(self):
        """
        Returns the holes of the polygon in clockwise order.

        holes -> Point list

        Attributes
        ----------

        Examples
        --------
        >>> p = Polygon([Point((0, 0)), Point((10, 0)), Point((10, 10)), Point((0, 10))], [Point((1, 2)), Point((2, 2)), Point((2, 1)), Point((1, 1))])
        >>> len(p.holes)
        1
        """
        return [[v for v in part] for part in self._holes]

    @property
    def parts(self):
        """
        Returns the parts of the polygon in clockwise order.

        parts -> Point list

        Attributes
        ----------

        Attributes
        ----------

        Examples
        --------
        >>> p = Polygon([[Point((0, 0)), Point((1, 0)), Point((1, 1)), Point((0, 1))], [Point((2,1)),Point((2,2)),Point((1,2)),Point((1,1))]])
        >>> len(p.parts)
        2
        """
        return [[v for v in part] for part in self._vertices]

    @property
    def perimeter(self):
        """
        Returns the perimeter of the polygon.

        perimeter() -> number

        Attributes
        ----------

        Examples
        --------
        >>> p = Polygon([Point((0, 0)), Point((1, 0)), Point((1, 1)), Point((0, 1))])
        >>> p.perimeter
        4.0
        """
        def dist(v1, v2):
            return math.hypot(v1[0] - v2[0], v1[1] - v2[1])

        def part_perimeter(part):
            return sum([dist(part[i], part[i + 1]) for i in xrange(-1, len(part) - 1)])

        if self._perimeter is None:
            self._perimeter = (sum([part_perimeter(part) for part in self._vertices]) +
                               sum([part_perimeter(hole) for hole in self._holes]))
        return self._perimeter

    @property
    def bbox(self):
        """
        Returns the bounding box of the polygon as a list

        See also bounding_box
        """
        if self._bbox is None:
            self._bbox = [ self.bounding_box.left,
                    self.bounding_box.lower,
                    self.bounding_box.right,
                    self.bounding_box.upper]
        return self._bbox


    @property
    def bounding_box(self):
        """
        Returns the bounding box of the polygon.

        bounding_box -> Rectangle

        Attributes
        ----------

        Examples
        --------
        >>> p = Polygon([Point((0, 0)), Point((2, 0)), Point((2, 1)), Point((0, 1))])
        >>> p.bounding_box.left
        0.0
        >>> p.bounding_box.lower
        0.0
        >>> p.bounding_box.right
        2.0
        >>> p.bounding_box.upper
        1.0
        """
        if self._bounding_box is None:
            vertices = self.vertices
            self._bounding_box = Rectangle(
                min([v[0] for v in vertices]), min([v[1] for v in vertices]),
                max([v[0] for v in vertices]), max([v[1] for v in vertices]))
        return self._bounding_box

    @property
    def area(self):
        """
        Returns the area of the polygon.

        area -> number

        Attributes
        ----------

        Examples
        --------
        >>> p = Polygon([Point((0, 0)), Point((1, 0)), Point((1, 1)), Point((0, 1))])
        >>> p.area
        1.0
        >>> p = Polygon([Point((0, 0)), Point((10, 0)), Point((10, 10)), Point((0, 10))],[Point((2,1)),Point((2,2)),Point((1,2)),Point((1,1))])
        >>> p.area
        99.0
        """
        def part_area(part_verts):
            area = 0
            for i in xrange(-1, len(part_verts) - 1):
                area += (part_verts[i][0] + part_verts[i + 1][0]) * \
                    (part_verts[i][1] - part_verts[i + 1][1])
            area = area * 0.5
            if area < 0:
                area = -area
            return area

        return (sum([part_area(part) for part in self._vertices]) -
                sum([part_area(hole) for hole in self._holes]))

    @property
    def centroid(self):
        """
        Returns the centroid of the polygon

        centroid -> Point

        Notes
        -----
        The centroid returned by this method is the geometric centroid and respects multipart polygons with holes.
        Also known as the 'center of gravity' or 'center of mass'.


        Examples
        --------
        >>> p = Polygon([Point((0, 0)), Point((10, 0)), Point((10, 10)), Point((0, 10))], [Point((1, 1)), Point((1, 2)), Point((2, 2)), Point((2, 1))])
        >>> p.centroid
        (5.0353535353535355, 5.0353535353535355)
        """
        CP = [ring.centroid for ring in self._part_rings]
        AP = [ring.area for ring in self._part_rings]
        CH = [ring.centroid for ring in self._hole_rings]
        AH = [-ring.area for ring in self._hole_rings]

        A = AP + AH
        cx = sum([pt[0] * area for pt, area in zip(CP + CH, A)]) / sum(A)
        cy = sum([pt[1] * area for pt, area in zip(CP + CH, A)]) / sum(A)
        return cx, cy

    def contains_point(self, point):
        """
        Test if polygon contains point

        Examples
        --------
        >>> p = Polygon([Point((0,0)), Point((4,0)), Point((4,5)), Point((2,3)), Point((0,5))])
        >>> p.contains_point((3,3))
        1
        >>> p.contains_point((0,6))
        0
        >>> p.contains_point((2,2.9))
        1
        >>> p.contains_point((4,5))
        0
        >>> p.contains_point((4,0))
        0
        >>>

        Handles holes

        >>> p = Polygon([Point((0, 0)), Point((0, 10)), Point((10, 10)), Point((10, 0))], [Point((2, 2)), Point((4, 2)), Point((4, 4)), Point((2, 4))])
        >>> p.contains_point((3.0,3.0))
        False
        >>> p.contains_point((1.0,1.0))
        True
        >>>


        Notes
        -----
        Points falling exactly on polygon edges may yield unpredictable
        results
        """

        for ring in self._hole_rings:
            if ring.contains_point(point):
                return False

        for ring in self._part_rings:
            if ring.contains_point(point):
                return True

        return False



class Rectangle(Geometry):
    """
    Geometric representation of rectangle objects.

    Attributes
    ----------

    left    : float
              Minimum x-value of the rectangle
    lower   : float
              Minimum y-value of the rectangle
    right   : float
              Maximum x-value of the rectangle
    upper   : float
              Maximum y-value of the rectangle
    """

    def __init__(self, left, lower, right, upper):
        """
        Returns a Rectangle object.

        __init__(number, number, number, number) -> Rectangle

        Parameters
        ----------
        left  : the minimum x-value of the rectangle
        lower : the minimum y-value of the rectangle
        right : the maximum x-value of the rectangle
        upper : the maximum y-value of the rectangle

        Attributes
        ----------

        Examples
        --------
        >>> r = Rectangle(-4, 3, 10, 17)
        >>> r.left #minx
        -4.0
        >>> r.lower #miny
        3.0
        >>> r.right #maxx
        10.0
        >>> r.upper #maxy
        17.0
        """
        if right < left or upper < lower:
            raise ArithmeticError('Rectangle must have positive area.')
        self.left = float(left)
        self.lower = float(lower)
        self.right = float(right)
        self.upper = float(upper)

    def __nonzero__(self):
        """
        ___nonzero__ is used "to implement truth value testing and the built-in operation bool()" -- http://docs.python.org/reference/datamodel.html

        Rectangles will evaluate to Flase if they have Zero Area.
        >>> r = Rectangle(0,0,0,0)
        >>> bool(r)
        False
        >>> r = Rectangle(0,0,1,1)
        >>> bool(r)
        True
        """
        return bool(self.area)

    def __eq__(self, other):
        if other:
            return self[:] == other[:]
        return False

    def __add__(self, other):
        x, y, X, Y = self[:]
        x1, y2, X1, Y1 = other[:]
        return Rectangle(min(self.left, other.left), min(self.lower, other.lower), max(self.right, other.right), max(self.upper, other.upper))

    def __getitem__(self, key):
        """
        >>> r = Rectangle(-4, 3, 10, 17)
        >>> r[:]
        [-4.0, 3.0, 10.0, 17.0]
        """
        l = [self.left, self.lower, self.right, self.upper]
        return l.__getitem__(key)

    def set_centroid(self, new_center):
        """
        Moves the rectangle center to a new specified point.

        set_centroid(Point) -> Point

        Parameters
        ----------
        new_center : the new location of the centroid of the polygon

        Attributes
        ----------

        Examples
        --------
        >>> r = Rectangle(0, 0, 4, 4)
        >>> r.set_centroid(Point((4, 4)))
        >>> r.left
        2.0
        >>> r.right
        6.0
        >>> r.lower
        2.0
        >>> r.upper
        6.0
        """
        shift = (new_center[0] - (self.left + self.right) / 2,
                 new_center[1] - (self.lower + self.upper) / 2)
        self.left = self.left + shift[0]
        self.right = self.right + shift[0]
        self.lower = self.lower + shift[1]
        self.upper = self.upper + shift[1]

    def set_scale(self, scale):
        """
        Rescales the rectangle around its center.

        set_scale(number) -> number

        Parameters
        ----------
        scale : the ratio of the new scale to the old scale (e.g. 1.0 is current size)

        Attributes
        ----------

        Examples
        --------
        >>> r = Rectangle(0, 0, 4, 4)
        >>> r.set_scale(2)
        >>> r.left
        -2.0
        >>> r.right
        6.0
        >>> r.lower
        -2.0
        >>> r.upper
        6.0
        """
        center = ((self.left + self.right) / 2, (self.lower + self.upper) / 2)
        self.left = center[0] + scale * (self.left - center[0])
        self.right = center[0] + scale * (self.right - center[0])
        self.lower = center[1] + scale * (self.lower - center[1])
        self.upper = center[1] + scale * (self.upper - center[1])

    @property
    def area(self):
        """
        Returns the area of the Rectangle.

        area -> number

        Attributes
        ----------

        Examples
        --------
        >>> r = Rectangle(0, 0, 4, 4)
        >>> r.area
        16.0
        """
        return (self.right - self.left) * (self.upper - self.lower)

    @property
    def width(self):
        """
        Returns the width of the Rectangle.

        width -> number

        Attributes
        ----------

        Examples
        --------
        >>> r = Rectangle(0, 0, 4, 4)
        >>> r.width
        4.0
        """
        return self.right - self.left

    @property
    def height(self):
        """
        Returns the height of the Rectangle.

        height -> number

        Examples
        --------
        >>> r = Rectangle(0, 0, 4, 4)
        >>> r.height
        4.0
        """
        return self.upper - self.lower


_geoJSON_type_to_Pysal_type = {'point': Point, 'linestring': Chain, 'multilinestring': Chain,
                               'polygon': Polygon, 'multipolygon': Polygon}
import standalone  # moving this to top breaks unit tests !


