#!/usr/lib/python3
from configparser import ConfigParser
import requests

COMPONENT_PATH = "%(cachet_url)s/api/v1/components/%(component_id)s"


def checker(config, section):
    """Main entry point to check  and update a target status

    :param dict config: a dict like object with whole configuration
    :param str section: the section to check
    """
    config_section = config[section]
    result = http_checker(config_section)
    update(config, section, result)


def http_checker(conf):
    """Check an http/https endpoint

    :param dict conf: a dict like object with the target configuration
    :rtype: boolean
    :returns: True if the target was reachable witin timeout and the status
        code was 200 or 204
    """
    url = conf["url"]
    timeout = conf.get('timeout', 2)
    try:
        result = requests.get(url, timeout=timeout)
    except requests.exceptions.Timeout:
        return False
    return result.status_code in (200, 204)


def update(config, section, result):
    """Update the cachet instance with the given result
    """
    cachet_url = config["cachetupdater"]["url"]
    cachet_token = config["cachetupdater"]["token"]
    component_id = config[section]["id"]
    status = 1 if result else 4
    url = COMPONENT_PATH % {
        "cachet_url": cachet_url,
        "component_id": component_id,
    }

    if need_update(url, status):
        headers = {
            "Content-Type": "application/json",
            "X-Cachet-Token": cachet_token,
        }
        payload = {
            "status": 1 if result else 4
        }
        requests.request("PUT", url, json=payload, headers=headers)


def need_update(url, status):
    response = requests.request("GET", url)
    current = response.json()
    current_status = int(current.get("data", {}).get("status", None))
    if current_status == status or current_status not in (1, 4):
        return False
    else:
        return True


def main(args):
    """Entry point for the script

    :param configParser args: tha argmuents given via the command line
    """
    config = get_configuration(args.configuration)
    for section in config.sections():
        if section != "cachetupdater":
            checker(config, section)


def get_configuration(config_path):
    """Reads the configuration and returns it

    :param str config_path: path to retrieve the configuration file
    :rtype: a dict like object
    :returns: a dict like object containing the configuration
    """
    config = ConfigParser()
    config.read(config_path)
    return config


if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser()
    parser.add_argument("configuration", help="path to the config file")
    main(parser.parse_args())