import logging
import urllib
import urllib2

try:
    import json
except ImportError:
    import simplejson as json

MAX_PEOPLE_REQ_SIZE = 100
DEFAULT_URL = "http://whoisi.com/"

def split_seq(seq, size):
    """
    Split up the given sequence into pieces of the given size.

    Taken from http://code.activestate.com/recipes/425044/.
    """

    return [seq[i:i+size] for i in range(0, len(seq), size)]

class WhoisiServer(object):
    def __init__(self, url=DEFAULT_URL, urlopen=urllib2.urlopen):
        self._urlopen = urlopen
        self.url = url

    def _call_api_method(self, name, query_args):
        full_url = "%sapi/%s?%s" % (self.url, name,
                                    urllib.urlencode(query_args))
        logging.debug('retrieving %s' % full_url)
        return json.loads(self._urlopen(full_url).read())

    def get_person(self, app, person):
        return self._call_api_method('getPerson',
                                     [('app', app),
                                      ('person', str(person))])

    def get_people(self, app, first, last):
        return self._call_api_method('getPeople',
                                     [('app', app),
                                      ('first', str(first)),
                                      ('last', str(last))])

    def get_max_person_id(self, app):
        return self._call_api_method('getMaxPersonID',
                                     [('app', app)])

class WhoisiCache(object):
    APP_NAME = "whoisi-cache"

    def __init__(self, server, storage, batch_size=MAX_PEOPLE_REQ_SIZE):
        self.server = server
        self.batch_size = batch_size
        self.people = storage

    def refresh_people(self, people_ids):
        for person_id in people_ids:
            result = self.server.get_person(self.APP_NAME, person_id + 1)
            self.people[person_id] = result['person']

    def update(self):
        pid = self.server.get_max_person_id(app=self.APP_NAME)
        interval = range(len(self.people) + 1, pid + 1)
        subintervals = split_seq(interval, self.batch_size)
        for subinterval in subintervals:
            first = subinterval[0]
            last = subinterval[-1]
            result = self.server.get_people(app=self.APP_NAME,
                                            first=first,
                                            last=last)
            for person_id in range(first, last + 1):
                self.people.append(result['people'][str(person_id)])