# -*- coding: utf-8 -*-
"""
Display Graphite metrics.

Configuration parameters:
    cache_timeout: how often we refresh this module in seconds.
        (default 120)
    datapoint_selection: when multiple data points are returned,
        use "max" or "min" to determine which one to display.
        (default "max")
    format: you MUST use placeholders here to display data, see below.
        (default '')
    graphite_url: URL to your graphite server. (default '')
    http_timeout: HTTP query timeout to graphite.
        (default 10)
    proxy: You can configure the proxy with HTTP or HTTPS.
        examples:
            proxy = 'https://myproxy.example.com:1234/'
            proxy = 'http://user:passwd@myproxy.example.com/'
            proxy = 'socks5://user:passwd@host:port'
        (proxy_socks is available after an 'pip install requests[socks]')
        (default None)
    targets: semicolon separated list of targets to query graphite for.
        (default '')
    threshold_bad: numerical threshold,
        if set will send a notification and colorize the output.
        (default None)
    threshold_degraded: numerical threshold,
        if set will send a notification and colorize the output.
        (default None)
    timespan: time range to query graphite for.
        (default "-2minutes")
    value_comparator: choose between "max" and "min" to compare thresholds
        to the data point value.
        (default "max")
    value_format: pretty format long numbers with "K", "M" etc.
        (default True)
    value_round: round values so they're not displayed as floats.
        (default True)

Dynamic format placeholders:
        The "format" parameter placeholders are dynamically based on the data
        points names returned by the "targets" query to graphite.

    For example if your target is `"carbon.agents.localhost-a.memUsage"`,
    you'd get a JSON result like this:

        ```
        {
            "target": "carbon.agents.localhost-a.memUsage",
            "datapoints": [[19693568.0, 1463663040]]
        }
        ```

    So the placeholder you could use on your "format" config is:
        `format = "{carbon.agents.localhost-a.memUsage}"`

    TIP: use aliases !
        ```
        targets = "alias(carbon.agents.localhost-a.memUsage, 'local_memuse')"
        format = "local carbon mem usage: {local_memuse} bytes"
        ```

Color options:
    color_bad: threshold_bad has been exceeded
    color_degraded: threshold_degraded has been exceeded

@author ultrabug
"""
from requests import get
from syslog import syslog, LOG_INFO


def format_value(num, value_round=True):
    for unit in ['', 'K', 'M', 'G', 'T', 'P', 'E', 'Z']:
        if abs(num) < 1000.0:
            if value_round:
                return '%1.0f%s' % (num, unit)
            else:
                return '%3.1f%s' % (num, unit)
        num /= 1000.0
    if value_round:
        return '%.0f%s' % (num, 'Y')
    else:
        return '%.1f%s' % (num, 'Y')


class Py3status:
    """
    """
    # available configuration parameters
    cache_timeout = 120
    datapoint_selection = 'max'
    format = ''
    graphite_url = ''
    http_timeout = 10
    proxy = None
    targets = ''
    threshold_bad = None
    threshold_degraded = None
    timespan = '-2minutes'
    value_comparator = 'max'
    value_format = True
    value_round = True

    def post_config_hook(self):
        self._validate_config()

    def _reset_notifications(self):
        """
        """
        self.notification_level = 'info'
        self.notifications = []

    def _validate_config(self):
        """
        """
        if not self.format:
            raise ValueError('missing "format" configuration')
        if not self.graphite_url:
            raise ValueError('missing "graphite_url" configuration')
        if not self.targets:
            raise ValueError('missing "targets" configuration')
        if self.datapoint_selection not in ['max', 'min']:
            raise ValueError('invalid "datapoint_selection" configuration')
        if self.value_comparator not in ['max', 'min']:
            raise ValueError('invalid "value_comparator" configuration')

    def _render_graphite_json(self):
        """
        """
        params = [('format', 'json'), ('from', self.timespan)]
        for target in self.targets.split(';'):
            params.append(('target', target))

        proxies = {}
        if self.proxy:
            if self.proxy.startswith('https'):
                proxies['https'] = self.proxy
            else:
                proxies['http'] = self.proxy

        r = get('{}/render'.format(self.graphite_url),
                params,
                timeout=self.http_timeout,
                proxies=proxies)
        if r.status_code != 200:
            raise Exception('HTTP error {}'.format(r.status_code))
        else:
            color_key = 'good'
            r_json = {}
            for metric in r.json():
                value = None
                target = metric['target']
                for datapoint_list in metric['datapoints']:
                    point, timestamp = datapoint_list
                    if point is not None:
                        if value is None:
                            value = point
                        elif self.datapoint_selection == 'max':
                            value = max(value, point)
                        elif self.datapoint_selection == 'min':
                            value = min(value, point)

                if value is None:
                    syslog(
                        LOG_INFO,
                        'graphite module: no data for target {} with configuration {}'.format(
                            target, self.targets))
                    continue

                if self.value_format:
                    displayed_value = format_value(value, self.value_round)
                else:
                    displayed_value = value

                # compare this value to the configured thresholds
                # and use the worst color to display
                _color = self._check_threshold_and_get_color(displayed_value,
                                                             target, value)
                if _color == 'bad':
                    color_key = 'bad'
                elif _color == 'degraded' and color_key != 'bad':
                    color_key = 'degraded'

                r_json[target] = displayed_value
            return color_key, r_json

    def _store_notification(self, target, threshold, value):
        """
        """
        if self.value_comparator == 'max':
            msg = '{}: {} > {}'.format(target, value, threshold)
        elif self.value_comparator == 'min':
            msg = '{}: {} < {}'.format(target, value, threshold)
        self.notifications.append(msg)

    def _notify_user(self):
        """
        """
        if self.notifications:
            self.py3.notify_user('\n'.join(self.notifications),
                                 level=self.notification_level)

    def _check_threshold_and_get_color(self, displayed_value, target, value):
        """
        """
        if self.threshold_bad:
            if eval('{}(self.threshold_bad, value) == value'.format(
                    self.value_comparator)):
                self._store_notification(target, self.threshold_bad,
                                         displayed_value)
                self.notification_level = 'error'
                return 'bad'
        if self.threshold_degraded:
            if eval('{}(self.threshold_degraded, value) == value'.format(
                    self.value_comparator)):
                self._store_notification(target, self.threshold_degraded,
                                         displayed_value)
                return 'degraded'
        return 'good'

    def graphite(self):
        """
        """
        self._reset_notifications()

        color_key, r_json = self._render_graphite_json()
        self._notify_user()

        response = {
            'cached_until': self.py3.time_in(self.cache_timeout),
            'color': getattr(self.py3, 'COLOR_{}'.format(color_key.upper())),
            'full_text': self.py3.safe_format(self.format, r_json)
        }
        return response


if __name__ == "__main__":
    """
    Run module in test mode.
    """
    from py3status.module_test import module_test
    module_test(Py3status)
