# coding=utf8
## Copyright (c) 2020 Arseniy Kuznetsov
##
## This program is free software; you can redistribute it and/or
## modify it under the terms of the GNU General Public License
## as published by the Free Software Foundation; either version 2
## of the License, or (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.


from prometheus_client.core import GaugeMetricFamily, CounterMetricFamily, InfoMetricFamily
from mktxp.cli.config.config import MKTXPConfigKeys
     

def get_values(record, labels, default=''):
    """Get a set of metrics by label.
    None values are replaced with a default value.
    
    >>> get_values(
    ...     {'interface': 'cap3', 'tx_rate': '12 Mbps', 'rx_rate': '390 Mbps', 'comment': None},
    ...     ['interface', 'tx_rate', 'rx_rate', 'comment']
    ... )
    {'interface': 'cap3', 'tx_rate': '12 Mbps', 'rx_rate': '390 Mbps', 'comment': ''}
    """
    values = {}
    for label in labels:
        val = record.get(label)
        if val is None:
            val = default
        values[label] = val
    
    return values

     
class BaseCollector:
    ''' Base Collector methods
        For use by custom collector
    '''
    @staticmethod
    def info_collector(name, decription, router_records, metric_labels=None):
        if metric_labels is None:
            metric_labels = []
        BaseCollector._add_id_labels(metric_labels)
        collector = InfoMetricFamily(f'mktxp_{name}', decription)

        for router_record in router_records:
            label_values = get_values(router_record, metric_labels)
            collector.add_metric(metric_labels, label_values)
        return collector

    @staticmethod
    def counter_collector(name, decription, router_records, metric_key, metric_labels=None):
        if metric_labels is None:
            metric_labels = []
        BaseCollector._add_id_labels(metric_labels)
        collector = CounterMetricFamily(f'mktxp_{name}', decription, labels=metric_labels)

        for router_record in router_records:           
            label_values = get_values(router_record, metric_labels)
            collector.add_metric(label_values, router_record.get(metric_key, 0))
        return collector

    @staticmethod
    def gauge_collector(name, decription, router_records, metric_key, metric_labels=None, add_id_labels = True):
        if metric_labels is None:
            metric_labels = []        
        if add_id_labels:
            BaseCollector._add_id_labels(metric_labels)
        collector = GaugeMetricFamily(f'mktxp_{name}', decription, labels=metric_labels)

        for router_record in router_records:       
            label_values = get_values(router_record, metric_labels)
            collector.add_metric(label_values, router_record.get(metric_key, 0))
        return collector


    # Helpers
    @staticmethod
    def _add_id_labels(metric_labels):
        metric_labels.append(MKTXPConfigKeys.ROUTERBOARD_NAME)
        metric_labels.append(MKTXPConfigKeys.ROUTERBOARD_ADDRESS)