# -*- coding: utf-8 -*-
from argparse import ArgumentParser
from ArangoDb import ArangoDb
from backend.AbstractBackend import AbstractBackend
from Feed import Feed
from FeedEntry import FeedEntry
from FeedUpdater import FeedUpdater
from Preferences import Preferences
from pyArango.connection import Connection

"""
Backend that uses ArangoDB for persistence
"""
class ArangoBackend(AbstractBackend):
    def __init__(self):
        super(ArangoBackend, self).__init__()
        args = self._parse_arguments()
        connection = Connection(arangoURL=args.dburl, username=args.user, password=args.password)
        self.database = ArangoDb(connection[args.dbname])
        self.prefs = None

    def _parse_arguments(self):
        parser = ArgumentParser()
        parser.add_argument('--dburl', nargs='?', help='URL of the database', default='http://127.0.0.1:8529')
        parser.add_argument('--dbname', nargs='?', help='name of the database', default='feedworm')
        parser.add_argument('--user', nargs='?', help='username for authenticating the database connection', required=True)
        parser.add_argument('--password', nargs='?', help='password for authenticating the database connection', required=True)
        return parser.parse_known_args()[0]

    def preferences(self):
        if self.prefs is None:
            self.prefs = Preferences(self.database)
        return self.prefs

    def getUnreadFeeds(self):
        return Feed.get_unread(self.database)
    
    def _retrieveEntriesForSelectedFeed(self, hideReadEntries):
        base_query = """
            FOR feed_entry_doc in feed_entry
                FILTER feed_entry_doc.feed == @feed_key"""
        if hideReadEntries:
            query = base_query + " AND feed_entry_doc.read == false "
        query = query + " SORT feed_entry_doc.updated RETURN feed_entry_doc"
        bind_vars = { 'feed_key': self.selectedFeed._key }
        results = self.database.AQLQuery(query, bind_vars=bind_vars)
        return [FeedEntry(doc) for doc in results]

    def _markSelectedFeedEntryRead(self):
        self.selectedFeedEntry.markRead()
            
    def updateAllFeeds(self):
        for feed in Feed.all_pending_update(self.database):
            FeedUpdater(self.database, self.preferences()).update(feed)