"""Throttlers."""

from datetime import datetime, timezone
import random
import time

import psutil
import sentry_sdk

from video import config
from video.connectors import cloudwatch as cloudwatch_connector
from video.constants import exceptions
from video.utils import exception as exception_utils


def _is_resource_utilization_ok():
    """Check if resource utilization is ok."""
    cpu_utilization_percent = psutil.cpu_percent()
    memory_utilization_percent = psutil.virtual_memory().percent

    cpu_utilization_ok = (
        cpu_utilization_percent <= config.MAX_ALLOWED_CPU_UTILIZATION_PERCENT)
    memory_utilization_ok = (
        memory_utilization_percent <= config.MAX_ALLOWED_MEMORY_UTILIZATION_PERCENT)  # noqa

    _log_custom_metrics_to_cloudwatch(
        cpu_utilization_percent, memory_utilization_percent)

    return cpu_utilization_ok and memory_utilization_ok


def is_handling_worker_activated():
    """Indicate if handler worker is activated."""
    time.sleep(
        config.MAX_TIMEOUT_BEFORE_PICKING_UP_WORK_SECONDS * random.random())

    while not _is_resource_utilization_ok():
        time.sleep(
            config.MAX_TIMEOUT_BETWEEN_RESOURCE_UTILIZATION_CHECKS_SECONDS * random.random())  # noqa

    return True


def is_polling_worker_activated():
    """Indicate if polling worker is activated."""
    while not _is_resource_utilization_ok():
        time.sleep(
            config.MAX_TIMEOUT_BETWEEN_RESOURCE_UTILIZATION_CHECKS_SECONDS * random.random())  # noqa

    return True


def handling_worker_throttler():
    """Throttle handler worker."""
    time.sleep(
        random.random() * config.MAX_TIMEOUT_BETWEEN_PICKING_UP_WORK_AND_HANDLING_SECONDS)  # noqa

    if not _is_resource_utilization_ok():
        exception_utils.raise_exception(exceptions.NotCurrentlyAcceptingWork)


def _log_custom_metrics_to_cloudwatch(
        cpu_utilization_percent, memory_utilization_percent):
    """Log custom metrics to cloudwatch.

    Args:
        cpu_utilization_percent: CPU utilization percent.
        memory_utilization_percent: Memory utilization percent.
    """
    cloudwatch_client = cloudwatch_connector.get_cloudwatch_client()

    try:
        cloudwatch_client.put_metric_data(
            Namespace=config.CLOUDWATCH_NAMESPACE,
            MetricData=[
                {
                    'MetricName': config.CUSTOM_METRIC_CPU_USAGE_PERCENT,
                    'Dimensions': [
                        {
                            'Name': 'Environment',
                            'Value': config.ENVIRONMENT
                        },
                    ],
                    'Timestamp': datetime.now(timezone.utc).replace(tzinfo=None),
                    'Value': cpu_utilization_percent,
                    'Unit': 'Percent',
                    'StorageResolution': 1,
                },
                {
                    'MetricName': config.CUSTOM_METRIC_MEMORY_USAGE_PERCENT,
                    'Dimensions': [
                        {
                            'Name': 'Environment',
                            'Value': config.ENVIRONMENT
                        },
                    ],
                    'Timestamp': datetime.now(timezone.utc).replace(tzinfo=None),
                    'Value': memory_utilization_percent,
                    'Unit': 'Percent',
                    'StorageResolution': 1,
                },
            ]
        )
    except Exception:
        sentry_sdk.capture_exception()