''' using another fedireads instance as a source of book data '''
import re
from uuid import uuid4

from django.core.exceptions import ObjectDoesNotExist
from django.core.files.base import ContentFile
from django.db import transaction
import requests

from fedireads import models
from .abstract_connector import AbstractConnector, SearchResult
from .abstract_connector import update_from_mappings, get_date, get_data


class Connector(AbstractConnector):
    ''' interact with other instances '''
    def __init__(self, identifier):
        self.key_mappings = {
            'isbn_13': ('isbn_13', None),
            'isbn_10': ('isbn_10', None),
            'oclc_numbers': ('oclc_number', None),
            'lccn': ('lccn', None),
        }
        self.book_mappings = self.key_mappings.copy()
        self.book_mappings.update({
            'published_date': ('published_date', get_date),
            'first_published_date': ('first_published_date', get_date),
        })
        super().__init__(identifier)


    def format_search_result(self, search_result):
        return SearchResult(**search_result)


    def parse_search_data(self, data):
        return data


    def get_or_create_book(self, remote_id):
        ''' pull up a book record by whatever means possible '''
        # re-construct a remote id from the int and books_url
        if re.match(r'^\d+$', remote_id):
            remote_id = self.books_url + '/' + remote_id
        book = models.Book.objects.select_subclasses().filter(
            remote_id=remote_id
        ).first()
        if book:
            if isinstance(book, models.Work):
                return book.default_edition
            return book

        # no book was found, so we start creating a new one
        data = get_data(remote_id)

        if data['book_type'] == 'work':
            work_data = data
            try:
                edition_data = data['editions'][0]
            except KeyError:
                # hack: re-use the work data as the edition data
                edition_data = data
        else:
            edition_data = data
            try:
                work_data = data['work']
            except KeyError:
                # hack: re-use the work data as the edition data
                work_data = data

        with transaction.atomic():
            # create both work and a default edition
            work_key = work_data.get('url')
            work = self.create_book(work_key, work_data, models.Work)

            ed_key = edition_data.get('url')
            edition = self.create_book(ed_key, edition_data, models.Edition)
            edition.default = True
            edition.parent_work = work
            edition.save()

        return edition


    def get_cover_from_data(self, data):
        cover_data = data.get('attachment')
        if not cover_data:
            return None
        cover_url = cover_data[0].get('url')
        response = requests.get(cover_url)
        if not response.ok:
            response.raise_for_status()

        image_name = str(uuid4()) + cover_url.split('.')[-1]
        image_content = ContentFile(response.content)
        return [image_name, image_content]


    def get_authors_from_data(self, data):
        authors = []

        for author_url in data.get('authors', []):
            authors.append(self.get_or_create_author(author_url))
        return authors


    def get_or_create_author(self, remote_id):
        ''' load that author '''
        try:
            return models.Author.objects.get(remote_id=remote_id)
        except ObjectDoesNotExist:
            pass

        data = get_data(remote_id)

        # ingest a new author
        author = models.Author(remote_id=remote_id)
        mappings = {
            'born': ('born', get_date),
            'died': ('died', get_date),
        }
        author = update_from_mappings(author, data, mappings)
        author.save()

        return author


    def expand_book_data(self, book):
        # TODO
        pass


def get_cover(cover_url):
    ''' ask openlibrary for the cover '''
    image_name = cover_url.split('/')[-1]
    response = requests.get(cover_url)
    if not response.ok:
        response.raise_for_status()
    image_content = ContentFile(response.content)
    return [image_name, image_content]