"""Timeout information for generating tasks."""
import math
from datetime import timedelta
from inspect import getframeinfo, currentframe
from typing import NamedTuple, Optional

import structlog

from buildscripts.patch_builds.task_generation import TimeoutInfo

LOGGER = structlog.getLogger(__name__)

AVG_SETUP_TIME = int(timedelta(minutes=5).total_seconds())
MIN_TIMEOUT_SECONDS = int(timedelta(minutes=5).total_seconds())
MAX_EXPECTED_TIMEOUT = int(timedelta(hours=48).total_seconds())


def calculate_timeout(avg_runtime: float, scaling_factor: int) -> int:
    """
    Determine how long a runtime to set based on average runtime and a scaling factor.

    :param avg_runtime: Average runtime of previous runs.
    :param scaling_factor: scaling factor for timeout.
    :return: timeout to use (in seconds).
    """

    def round_to_minute(runtime):
        """Round the given seconds up to the nearest minute."""
        distance_to_min = 60 - (runtime % 60)
        return int(math.ceil(runtime + distance_to_min))

    return max(MIN_TIMEOUT_SECONDS, round_to_minute(avg_runtime)) * scaling_factor + AVG_SETUP_TIME


class TimeoutEstimate(NamedTuple):
    """Runtime estimates used to calculate timeouts."""

    max_test_runtime: Optional[float]
    expected_task_runtime: Optional[float]

    @classmethod
    def no_timeouts(cls) -> "TimeoutEstimate":
        """Create an instance with no estimation data."""
        return cls(max_test_runtime=None, expected_task_runtime=None)

    def is_specified(self) -> bool:
        """Determine if any specific timeout value has been specified."""
        return self.max_test_runtime is not None or self.expected_task_runtime is not None

    def calculate_test_timeout(self, repeat_factor: int) -> Optional[int]:
        """
        Calculate the timeout to use for tests.

        :param repeat_factor: How many times the suite will be repeated.
        :return: Timeout value to use for tests.
        """
        if self.max_test_runtime is None:
            return None

        timeout = calculate_timeout(self.max_test_runtime, 3) * repeat_factor
        LOGGER.debug("Setting timeout", timeout=timeout, max_runtime=self.max_test_runtime,
                     factor=repeat_factor)
        return timeout

    def calculate_task_timeout(self, repeat_factor: int) -> Optional[int]:
        """
        Calculate the timeout to use for tasks.

        :param repeat_factor: How many times the suite will be repeated.
        :return: Timeout value to use for tasks.
        """
        if self.expected_task_runtime is None:
            return None

        exec_timeout = calculate_timeout(self.expected_task_runtime, 3) * repeat_factor
        LOGGER.debug("Setting exec_timeout", exec_timeout=exec_timeout,
                     suite_runtime=self.expected_task_runtime, factor=repeat_factor)
        return exec_timeout

    def generate_timeout_cmd(self, is_patch: bool, repeat_factor: int,
                             use_default: bool = False) -> TimeoutInfo:
        """
        Create the timeout info to use to create a timeout shrub command.

        :param is_patch: Whether the command is being created in a patch build.
        :param repeat_factor: How many times the suite will be repeated.
        :param use_default: Should the default timeout be used.
        :return: Timeout info for the task.
        """

        if not self.is_specified or use_default:
            return TimeoutInfo.default_timeout()

        test_timeout = self.calculate_test_timeout(repeat_factor)
        task_timeout = self.calculate_task_timeout(repeat_factor)

        if is_patch and (test_timeout > MAX_EXPECTED_TIMEOUT
                         or task_timeout > MAX_EXPECTED_TIMEOUT):
            frameinfo = getframeinfo(currentframe())
            LOGGER.error(
                "This task looks like it is expected to run far longer than normal. This is "
                "likely due to setting the suite 'repeat' value very high. If you are sure "
                "this is something you want to do, comment this check out in your patch build "
                "and resubmit", repeat_value=repeat_factor, timeout=test_timeout,
                exec_timeout=task_timeout, code_file=frameinfo.filename, code_line=frameinfo.lineno,
                max_timeout=MAX_EXPECTED_TIMEOUT)
            raise ValueError("Failing due to expected runtime.")

        return TimeoutInfo.overridden(timeout=test_timeout, exec_timeout=task_timeout)