from fuel.transformers import Transformer, Filter, Mapping
import numpy
import theano
import random
import data

def at_least_k(k, v, pad_at_begin, is_longitude):
    if len(v) == 0:
        v = numpy.array([data.porto_center[1 if is_longitude else 0]], dtype=theano.config.floatX)
    if len(v) < k:
        if pad_at_begin:
            v = numpy.concatenate((numpy.full((k - len(v),), v[0]), v))
        else:
            v = numpy.concatenate((v, numpy.full((k - len(v),), v[-1])))
    return v


class Select(Transformer):
    def __init__(self, data_stream, sources):
        super(Select, self).__init__(data_stream)
        self.ids = [data_stream.sources.index(source) for source in sources]
        self.sources=sources

    def get_data(self, request=None):
        if request is not None:
            raise ValueError
        data=next(self.child_epoch_iterator)
        return [data[id] for id in self.ids]
        

class first_k(object):
    def __init__(self, k, id_latitude, id_longitude):
        self.k = k
        self.id_latitude = id_latitude
        self.id_longitude = id_longitude
    def __call__(self, data): 
        return (numpy.array(at_least_k(self.k, data[self.id_latitude], False, False)[:self.k],
                            dtype=theano.config.floatX),
                numpy.array(at_least_k(self.k, data[self.id_longitude], False, True)[:self.k],
                            dtype=theano.config.floatX))
def add_first_k(k, stream):
    id_latitude = stream.sources.index('latitude')
    id_longitude = stream.sources.index('longitude')
    return Mapping(stream, first_k(k, id_latitude, id_longitude), ('first_k_latitude', 'first_k_longitude'))

class random_k(object):
    def __init__(self, k, id_latitude, id_longitude):
        self.k = k
        self.id_latitude = id_latitude
        self.id_longitude = id_longitude
    def __call__(self, x):
        lat = at_least_k(self.k, x[self.id_latitude], True, False)
        lon = at_least_k(self.k, x[self.id_longitude], True, True)
        loc = random.randrange(len(lat)-self.k+1)
        return (numpy.array(lat[loc:loc+self.k], dtype=theano.config.floatX),
                numpy.array(lon[loc:loc+self.k], dtype=theano.config.floatX))
def add_random_k(k, stream):
    id_latitude = stream.sources.index('latitude')
    id_longitude = stream.sources.index('longitude')
    return Mapping(stream, random_k(k, id_latitude, id_longitude), ('last_k_latitude', 'last_k_longitude'))

class last_k(object):
    def __init__(self, k, id_latitude, id_longitude):
        self.k = k
        self.id_latitude = id_latitude
        self.id_longitude = id_longitude
    def __call__(self, data):
        return (numpy.array(at_least_k(self.k, data[self.id_latitude], True, False)[-self.k:],
                            dtype=theano.config.floatX),
                numpy.array(at_least_k(self.k, data[self.id_longitude], True, True)[-self.k:],
                            dtype=theano.config.floatX))
def add_last_k(k, stream):
    id_latitude = stream.sources.index('latitude')
    id_longitude = stream.sources.index('longitude')
    return Mapping(stream, last_k(k, id_latitude, id_longitude), ('last_k_latitude', 'last_k_longitude'))

class destination(object):
    def __init__(self, id_latitude, id_longitude):
        self.id_latitude = id_latitude
        self.id_longitude = id_longitude
    def __call__(self, data):
        return (numpy.array(at_least_k(1, data[self.id_latitude], True, False)[-1],
                            dtype=theano.config.floatX),
                numpy.array(at_least_k(1, data[self.id_longitude], True, True)[-1],
                            dtype=theano.config.floatX))
def add_destination(stream):
    id_latitude = stream.sources.index('latitude')
    id_longitude = stream.sources.index('longitude')
    return Mapping(stream, destination(id_latitude, id_longitude), ('destination_latitude', 'destination_longitude'))