import json
import logging

from jsonschema import validate
from wrapt import synchronized

logger = logging.getLogger(__name__)

_cur_conf = None


# Required json-schema for user specified config
_conf_schema = {
    'type': 'object',
    'properties': {
        'max_open_trades': {'type': 'integer'},
        'stake_currency': {'type': 'string'},
        'stake_amount': {'type': 'number'},
        'dry_run': {'type': 'boolean'},
        'minimal_roi': {
            'type': 'object',
            'patternProperties': {
                '^[0-9.]+$': {'type': 'number'}
            },
            'minProperties': 1
        },
        'poloniex': {'$ref': '#/definitions/exchange'},
        'bittrex': {'$ref': '#/definitions/exchange'},
        'telegram': {
            'type': 'object',
            'properties': {
                'enabled': {'type': 'boolean'},
                'token': {'type': 'string'},
                'chat_id': {'type': 'string'},
            },
            'required': ['enabled', 'token', 'chat_id']
        }
    },
    'definitions': {
        'exchange': {
            'type': 'object',
            'properties': {
                'enabled': {'type': 'boolean'},
                'key': {'type': 'string'},
                'secret': {'type': 'string'},
                'pair_whitelist': {
                    'type': 'array',
                    'items': {'type': 'string'},
                    'uniqueItems': True
                }
            },
            'required': ['enabled', 'key', 'secret', 'pair_whitelist']
        }
    },
    'anyOf': [
        {'required': ['poloniex']},
        {'required': ['bittrex']}
    ],
    'required': [
        'max_open_trades',
        'stake_currency',
        'stake_amount',
        'dry_run',
        'minimal_roi',
        'telegram'
    ]
}


@synchronized
def get_conf(filename: str='config.json') -> dict:
    """
    Loads the config into memory validates it
    and returns the singleton instance
    :return: dict
    """
    global _cur_conf
    if not _cur_conf:
        with open(filename) as file:
            _cur_conf = json.load(file)
            validate(_cur_conf, _conf_schema)
    return _cur_conf