from jsonmodels import models
from jsonmodels.errors import ValidationError
from jsonmodels.fields import StringField
from mongoengine import register_connection
from mongoengine.connection import get_connection

from config import config
from .defs import Database
from .utils import get_items

log = config.logger(__file__)

strict = config.get('apiserver.mongo.strict', True)

_entries = []


class DatabaseEntry(models.Base):
    host = StringField(required=True)
    alias = StringField()

    @property
    def health_alias(self):
        return '__health__' + self.alias


def initialize():
    db_entries = config.get('hosts.mongo', {})
    missing = []
    log.info('Initializing database connections')
    for key, alias in get_items(Database).items():
        if key not in db_entries:
            missing.append(key)
            continue
        entry = DatabaseEntry(alias=alias, **db_entries.get(key))
        try:
            entry.validate()
            log.info('Registering connection to %(alias)s (%(host)s)' % entry.to_struct())
            register_connection(alias=alias, host=entry.host)

            _entries.append(entry)
        except ValidationError as ex:
            raise Exception('Invalid database entry `%s`: %s' % (key, ex.args[0]))
    if missing:
        raise ValueError('Missing database configuration for %s' % ', '.join(missing))


def get_entries():
    return _entries


def get_aliases():
    return [entry.alias for entry in get_entries()]


def reconnect():
    for entry in get_entries():
        get_connection(entry.alias, reconnect=True)