import json
import requests
from mastodon import Mastodon
import config

def get_images(album_api):
    return requests.get(album_api).json()['result']['images']

def get_next_image(images, previous_id):
    tail = [image for image in images if image['id']>previous_id]
    return tail and sorted(tail, key=lambda image: image['id'])[0] or None

def get_previous_id():
   try: 
       return int(json.load(open("previous_id.txt")))
   except Exception:
       return 0

def set_previous_id(previous_id):
    json.dump(previous_id, open("previous_id.txt", "w"))

def toot_next_image():
    mastodon = Mastodon(access_token="secrets.txt")
    image = get_next_image(get_images(config.ALBUM_API), get_previous_id())
    if image:
        if image['comment'] is None:
            image['comment'] = ""  # Better not mess up templates when no comment.
        media = mastodon.media_post(
            requests.get(
                image["derivatives"][config.MEDIA_SIZE]["url"]).content,
            mime_type="image/jpeg",
            description = config.ALT_TEXT_TEMPLATE.format(**image))
        mastodon.status_post(
            config.TOOT_TEMPLATE.format(**image),
            media_ids=[media],
            visibility=config.TOOT_VISIBILITY,
            language=config.TOOT_LANGUAGE)
        set_previous_id(image['id'])

if __name__=='__main__':
    toot_next_image()