#! /usr/bin/env python
'''Libraries for moving objects, trajectories...'''

import utils;

from shapely.geometry import Polygon

__metaclass__ = type

#class MovingObject:

class TimeInterval:
    '''Temporal interval'''
    def __init__(self, first=0, last=-1):
        self.first=first
        self.last=last

    def __str__(self):
        return '%d %d'%(self.first, self.last)

    def empty(self):
        '''
        >>> TimeInterval().empty()
        True
        >>> TimeInterval(0,1).empty()
        False
        '''
        return self.first > self.last

    def length(self):
        '''Returns the length of the interval
        
        >>> TimeInterval(0,1).length()
        2
        >>> TimeInterval(10,8).length()
        0
        '''
        return max(0,self.last-self.first+1)

    def getList(self):
        return [self.first, self.last]

    def contains(self, instant):
        return (self.first<=instant and self.last>=instant)

    def inside(self, interval2):
        'indicates if the temporal interval of self is comprised in interval2'
        return (self.first >= interval2.first) and (self.last <= interval2.last)

    def union(self, interval2):
        '''Largest interval comprising self and interval2'''
        return TimeInterval(min(self.first, interval2.first), max(self.last, interval2.last))
        
    def intersection(self, interval2):
        '''Largest interval comprising self and interval2'''
        return TimeInterval(max(self.first, interval2.first), min(self.last, interval2.last))


# class BoundingPolygon:
#     '''Class for a polygon bounding a set of points
#     with methods to create intersection, unions...
#     '''
# We will use the polygon class of Shapely

class STObject:
    '''Class for spatio-temporal object
    i.e. with temporal and spatial existence 
    (time interval and bounding polygon for positions (e.g. rectangle)).
    It does not mean that the object is defined 
    for all time instants within the time interval'''

    def __init__(self, num = None, timeInterval = None, boundingPolygon = None):
        self.num = num
        self.timeInterval = timeInterval
        self.boundingPolygon = boundingPolygon

    def empty(self):
        return self.timeInterval.empty() or not self.boudingPolygon

    def getFirstInstant(self):
        return self.timeInterval.first()

    def getLastInstant(self):
        return self.timeInterval.first()

class Trajectory:
    '''Class for trajectories
    i.e. a temporal sequence of positions'''

    def __init__(self, positions = None):
        self.positions = positions

    def addPosition(self, point):
        if not self.positions:
            self.positions = [[point[0]],[point[1]]]
        else:
            self.positions[0].append(point[0])
            self.positions[1].append(point[1])

    def draw(self):
        from matplotlib.pylab import plot
        plot(self.positions[0], self.positions[1])

class MovingObject(STObject):
    '''Class for moving objects
    i.e. with a trajectory and a geometry (volume)
    and a type (e.g. road user)
    '''

    def __init__(self, num = None, timeInterval = None, trajectory = None, geometry = None, type = None):
        STObject.__init__(self, num, timeInterval)
        self.trajectory = trajectory
        self.geometry = geometry
        self.type = type
        # compute bounding polygon from trajectory

    # def computeVelocities(self):

class TemporalIndicator:
    '''Class for temporal indicators
    i.e. indicators that take a value at specific instants'''
    pass

if __name__ == "__main__":
    import doctest
    import unittest
    #suite = doctest.DocFileSuite('tests/ubc_utils.txt')
    suite = doctest.DocTestSuite()
    unittest.TextTestRunner().run(suite)
    #doctest.testmod()
    #doctest.testfile("example.txt")