import time

from caproto.sync.client import read, write
from ioc.pystartioc import startioc
import pytest

from common import read_config

TIMEOUT_IOC_STARTUP = 10
TIMEOUT_READ = 2


@pytest.fixture(autouse=True)
def prepare_ioc():

    config = read_config()
    pvprefix = config['pvprefix']

    """
    This function checks if the test IOC is already running and attempts to
    start it, if that is not the case.
    """
    try:
        read(f'{pvprefix}:IOCREADY', timeout=TIMEOUT_READ)

        # Reading the check recird was successfull -> We assume that the IOC
        # is running
        return
    except TimeoutError:
        # Received a timeout error -> Start the IOC
        startioc()

        # Check periodically if the IOC started successfully
        now = time.time()
        while now + TIMEOUT_IOC_STARTUP > time.time():
            try:
                read(f'{pvprefix}:IOCREADY', timeout=TIMEOUT_READ)
                return
            except TimeoutError:
                time.sleep(0.5)

        # IOC startup failed in the given time -> Raise an error
        raise TimeoutError(
            f'Starting the IOC within {TIMEOUT_IOC_STARTUP} seconds failed.')