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

import utils;

__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 STObject:
    '''Class for spatio-temporal object
    i.e. with temporal and spatial existence 
    (time interval and bounding polygon for positions (e.g. rectangle)'''

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

    def empty(self):
        return self.timeInterval.empty()

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

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

    
        
# return bounding box, and generic polygon, that defaults to box

class Track(STObject):
    '''Class for trajectories
    i.e. sequence of positions'''
    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")