tweet_updates.py

from time import sleep
from datetime import datetime, timedelta
from requests.exceptions import ConnectionError
from polybot import Bot
import tempfile
from geonames import GeoNamesGeocoder
from epic import EPIC
from processing import process_image


def suffix(d):
    return 'th' if 11 <= d <= 13 else {1: 'st', 2: 'nd', 3: 'rd'}.get(d % 10, 'th')


class TweetEPIC(Bot):
    def __init__(self):
        super().__init__('tweet_epic')
        self.parser.add_argument('--now', action='store_true',
                                 help="Tweet the next image now")
        self.epic = EPIC()
        self.geocoder = GeoNamesGeocoder()
        self.state = {'image_queue': {},
                      'last_posted_image': datetime(2015, 9, 1),
                      'last_post_time': datetime(2015, 9, 1)}
        self.post_interval = timedelta(minutes=60)
        self.post_interval_fast = timedelta(minutes=45)

    def poll(self):
        try:
            most_recent = sorted(self.state['image_queue'].keys())[-1]
        except IndexError:
            most_recent = self.state['last_posted_image']

        try:
            images = self.epic.get_recent_images(most_recent, 20)
        except (ConnectionError, ValueError):
            self.log.exception("Unable to fetch images")
            images = []

        added = 0
        for image in images:
            if (image['date'] not in self.state['image_queue'] and
               image['date'] > self.state['last_posted_image']):
                self.state['image_queue'][image['date']] = image
                added += 1
        if added > 0:
            self.log.info("Added %s images to queue", added)

        if len(self.state['image_queue']) > 20:
            to_drop = len(self.state['image_queue']) - 20
            self.log.info("Dropping %s images from queue", to_drop)
            for key in sorted(self.state['image_queue'])[0:to_drop]:
                del self.state['image_queue'][key]

        if len(self.state['image_queue']) > 12:
            interval = self.post_interval_fast
        else:
            interval = self.post_interval

        if self.state['last_post_time'] < (datetime.now() - interval) \
           and len(self.state['image_queue']) > 0:
            try:
                self.do_tweet()
            except ConnectionError:
                self.log.exception("Unable to fetch image file")
            self.save_state()

    def do_tweet(self):
        image_date = sorted(self.state['image_queue'].keys())[0]
        image = self.state['image_queue'][image_date]
        self.log.info("Tweeting an image")

        with tempfile.NamedTemporaryFile(suffix='.png') as imagefile:
            self.fetch_image(image, imagefile)
            self.post_tweet(image, imagefile)

        del self.state['image_queue'][image_date]
        self.state['last_posted_image'] = image_date
        self.state['last_post_time'] = datetime.now()
        self.log.info("One image tweeted, %s left in queue", len(self.state['image_queue']))

    def post_tweet(self, image, imagefile):
        lat = image['centroid_coordinates']['lat']
        lon = image['centroid_coordinates']['lon']
        self.log.info("Geocoding %s, %s", lat, lon)

        geocoded = self.geocoder.geocode(lat, lon)
        if geocoded[0] is not None:
            place = " ".join(geocoded)

        datestring = "%s %s%s" % (image['date'].strftime("%H:%M on %A %B"),
                                  image['date'].day, suffix(image['date'].day))

        if geocoded[0] is not None:
            text = "%s, %s" % (datestring, place)
        else:
            text = datestring
        self.post(text, imagefile=imagefile, lat=lat, lon=lon)

    def fetch_image(self, image, destfile):
        with tempfile.NamedTemporaryFile(suffix='.png') as downloadfile:
            self.epic.download_image(image, downloadfile)
            process_image(downloadfile.name, destfile.name)

    def main(self):
        if self.args.now:
            self.state['last_post_time'] = datetime(2015, 9, 1)
        while True:
            self.poll()
            sleep(120)


TweetEPIC().run()