''' activitystream api and books '''
from django.core.exceptions import ObjectDoesNotExist
from django.core.files.base import ContentFile
import re
import requests

from fedireads.models import Author, Book
from fedireads.settings import OL_URL


def book_search(query):
    ''' look up a book '''
    response = requests.get('%s/search.json' % OL_URL, params={'q': query})
    if not response.ok:
        response.raise_for_status()
    data = response.json()
    results = []

    for doc in data['docs'][:5]:
        key = doc['key']
        key = key.split('/')[-1]
        results.append({
            'title': doc.get('title'),
            'olkey': key,
            'year': doc.get('first_publish_year'),
            'author': doc.get('author_name')[0],
        })
    return results


def get_or_create_book(olkey, user=None, update=False):
    ''' add a book by looking up its open library "work" key. I'm conflating
    "book" and "work" here a bit; the table is called "book" in fedireads, but
    in open library parlance, it's a "work," which is the canonical umbrella
    item that contains all the editions ("book"s) '''
    # check if this is in the format of an OL book identifier
    if not re.match(r'^OL\d+W$', olkey):
        raise ValueError('Invalid OpenLibrary work ID')

    # get the existing entry from our db, if it exists
    try:
        book = Book.objects.get(openlibrary_key=olkey)
        if not update:
            return book
        # we have the book, but still want to update it from OL
    except ObjectDoesNotExist:
        # no book was found, so we start creating a new one
        book = Book(openlibrary_key=olkey)

    # load the book json from openlibrary.org
    response = requests.get('%s/works/%s.json' % (OL_URL, olkey))
    if not response.ok:
        response.raise_for_status()

    data = response.json()
    book.data = data

    if user and user.is_authenticated:
        book.added_by = user

    # great, we can update our book.
    book.save()

    # we also need to know the author get the cover
    for author_blob in data['authors']:
        # this id starts as "/authors/OL1234567A" and we want just "OL1234567A"
        author_id = author_blob['author']['key']
        author_id = author_id.split('/')[-1]
        book.authors.add(get_or_create_author(author_id))

    if data['covers'] and len(data['covers']):
        book.cover.save(*get_cover(data['covers'][0]), save=True)

    return book


def get_cover(cover_id):
    ''' ask openlibrary for the cover '''
    # TODO: get medium and small versions
    image_name = '%s-M.jpg' % cover_id
    url = 'https://covers.openlibrary.org/b/id/%s' % image_name
    response = requests.get(url)
    if not response.ok:
        response.raise_for_status()
    image_content = ContentFile(requests.get(url).content)
    return [image_name, image_content]


def get_or_create_author(olkey, update=False):
    ''' load that author '''
    if not re.match(r'^OL\d+A$', olkey):
        raise ValueError('Invalid OpenLibrary author ID')
    try:
        author = Author.objects.get(openlibrary_key=olkey)
        if not update:
            return author
    except ObjectDoesNotExist:
        pass

    response = requests.get('%s/authors/%s.json' % (OL_URL, olkey))
    if not response.ok:
        response.raise_for_status()

    data = response.json()
    author = Author(openlibrary_key=olkey, data=data)
    author.save()
    return author