''' select and call a connector for whatever book task needs doing '''
import importlib
from urllib.parse import urlparse

from requests import HTTPError

from bookwyrm import models
from bookwyrm.connectors import ConnectorException
from bookwyrm.tasks import app


def get_edition(book_id):
    ''' look up a book in the db and return an edition '''
    book = models.Book.objects.select_subclasses().get(id=book_id)
    if isinstance(book, models.Work):
        book = book.default_edition
    return book


def get_or_create_connector(remote_id):
    ''' get the connector related to the author's server '''
    url = urlparse(remote_id)
    identifier = url.netloc
    if not identifier:
        raise ValueError('Invalid remote id')

    try:
        connector_info = models.Connector.objects.get(identifier=identifier)
    except models.Connector.DoesNotExist:
        connector_info = models.Connector.objects.create(
            identifier=identifier,
            connector_file='bookwyrm_connector',
            base_url='https://%s' % identifier,
            books_url='https://%s/book' % identifier,
            covers_url='https://%s/images/covers' % identifier,
            search_url='https://%s/search?q=' % identifier,
            priority=2
        )

    return load_connector(connector_info)


@app.task
def load_more_data(book_id):
    ''' background the work of getting all 10,000 editions of LoTR '''
    book = models.Book.objects.select_subclasses().get(id=book_id)
    connector = load_connector(book.connector)
    connector.expand_book_data(book)


def search(query, min_confidence=0.1):
    ''' find books based on arbitary keywords '''
    results = []
    dedup_slug = lambda r: '%s/%s/%s' % (r.title, r.author, r.year)
    result_index = set()
    for connector in get_connectors():
        try:
            result_set = connector.search(query, min_confidence=min_confidence)
        except (HTTPError, ConnectorException):
            continue

        result_set = [r for r in result_set \
                if dedup_slug(r) not in result_index]
        # `|=` concats two sets. WE ARE GETTING FANCY HERE
        result_index |= set(dedup_slug(r) for r in result_set)
        results.append({
            'connector': connector,
            'results': result_set,
        })

    return results


def local_search(query, min_confidence=0.1):
    ''' only look at local search results '''
    connector = load_connector(models.Connector.objects.get(local=True))
    return connector.search(query, min_confidence=min_confidence)


def first_search_result(query, min_confidence=0.1):
    ''' search until you find a result that fits '''
    for connector in get_connectors():
        result = connector.search(query, min_confidence=min_confidence)
        if result:
            return result[0]
    return None


def get_connectors():
    ''' load all connectors '''
    for info in models.Connector.objects.order_by('priority').all():
        yield load_connector(info)


def load_connector(connector_info):
    ''' instantiate the connector class '''
    connector = importlib.import_module(
        'bookwyrm.connectors.%s' % connector_info.connector_file
    )
    return connector.Connector(connector_info.identifier)