import signal
import sys
import os
import logger
from server import Server

def _handle_exit(sig, frame):
    print("Exiting...")
    sys.exit(0)

def _get_environment_variable(key: str) -> str:
    value = os.getenv(key)

    if not value:
        logger.error("Environment variable '" + key + "' must be set")

    return value

def _parse_environment_variable(key: str, value: str) -> int | None:
    try:
        return int(value)
    except ValueError:
        logger.error("Environment variable '" + key + "' must be an integer")

def main():
    signal.signal(signal.SIGTERM, _handle_exit)
    signal.signal(signal.SIGINT, _handle_exit)

    host = _get_environment_variable("HOST")
    port = _get_environment_variable("PORT")
    cache_duration = _get_environment_variable("CACHE_DURATION")
    ics_url = _get_environment_variable("ICS_URL")

    port_int = _parse_environment_variable("PORT", port)
    cache_duration_int = _parse_environment_variable("CACHE_DURATION", cache_duration)

    server = Server(host, port_int, cache_duration_int, ics_url)
    server.serve()

if __name__ == "__main__":
    main()