import threading
from http.server import HTTPServer
import socket
import time
import datetime
from prometheus.collectors import Gauge
from prometheus.registry import Registry
from prometheus.exporter import PrometheusMetricHandler


PORT_NUMBER = 9999
seconds = 0


def seconds_elapsed():
    return seconds


def time_elapsed():
    return datetime.timedelta(seconds=seconds_elapsed())


def gather_data(registry):
    """Gathers the metrics"""
    global seconds

    # Acquire the name of host
    host = socket.gethostname()
    fqdn = socket.getfqdn(host)

    # Create our collectors
    time_metric = Gauge("host_time_epoch", "")

    fqdn_metric = Gauge("fully_qualified_domain_name", "")

    # register the metric collectors
    registry.register(time_metric)
    registry.register(fqdn_metric)

    # Start gathering metrics every second
    while True:
        time.sleep(1)
        seconds += 1
        time_metric.set({'type': 'Timestamp'}, time_elapsed())
        time_metric.set({'type': 'Seconds'}, seconds)
        fqdn_metric.set("", fqdn)


if __name__ == "__main__":
    # Create the registry
    registry = Registry()

    # Create the thread that gathers the data while we serve it
    thread = threading.Thread(target=gather_data, args=(registry,))
    thread.start()

    # Set a server to export (expose to prometheus) the data (in a thread)
    try:
        # We make this to set the registry in the handler
        def handler(*args, **kwargs):
            PrometheusMetricHandler(registry, *args, **kwargs)


        server = HTTPServer(('0.0.0.0', PORT_NUMBER), handler)
        server.serve_forever()

    except KeyboardInterrupt:
        server.socket.close()
thread.join()