''' interface with whatever connectors the app has '''
import importlib
import re
from urllib.parse import urlparse

from requests import HTTPError

from bookwyrm import models
from bookwyrm.tasks import app


class ConnectorException(HTTPError):
    ''' when the connector can't do what was asked '''


def search(query, min_confidence=0.1):
    ''' find books based on arbitary keywords '''
    results = []

    # Have we got a ISBN ?
    isbn = re.sub('[\W_]', '', query)
    maybe_isbn = len(isbn) in [10, 13] # ISBN10 or ISBN13

    dedup_slug = lambda r: '%s/%s/%s' % (r.title, r.author, r.year)
    result_index = set()
    for connector in get_connectors():
        result_set = None
        if maybe_isbn:
            # Search on ISBN
            if not connector.isbn_search_url or connector.isbn_search_url == '': 
                result_set = []
            else:
                try:
                    result_set = connector.isbn_search(isbn)
                except (HTTPError, ConnectorException):
                    pass

        # if no isbn search or results, we fallback to generic search
        if result_set == None or result_set == []:
            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, raw=False):
    ''' only look at local search results '''
    connector = load_connector(models.Connector.objects.get(local=True))
    return connector.search(query, min_confidence=min_confidence, raw=raw)


def isbn_local_search(query, raw=False):
    ''' only look at local search results '''
    connector = load_connector(models.Connector.objects.get(local=True))
    return connector.isbn_search(query, raw=raw)


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 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(connector_id, book_id):
    ''' background the work of getting all 10,000 editions of LoTR '''
    connector_info = models.Connector.objects.get(id=connector_id)
    connector = load_connector(connector_info)
    book = models.Book.objects.select_subclasses().get(id=book_id)
    connector.expand_book_data(book)


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)