import fastapi
import re
import numpy
import subprocess
import fastapi.responses
import pydantic_settings
import logging

logger = logging.getLogger(__name__)

from online.fxreader.pr34.commands_typed import metrics as pr34_metrics

from typing import Optional, Any, ClassVar


class Settings(pydantic_settings.BaseSettings):
	checks_hosts: list[str]

	_singleton: ClassVar[Optional['Settings']] = None

	@classmethod
	def singleton(cls) -> 'Settings':
		if cls._singleton is None:
			cls._singleton = Settings.model_validate({})

		return cls._singleton


def ping_stats(host: str) -> Optional[float]:
	try:
		ping_output = subprocess.check_output(
			[
				'ping',
				'-i',
				'0.1',
				'-c',
				'3',
				'-w',
				'1',
				host,
			]
		).decode('utf-8')
	except:
		logger.exception('')

		ping_output = ''

	r1 = re.compile(r'time=(\d+\.\d+)\sms')

	spend_time = [float(o[1]) for o in r1.finditer(ping_output)]

	if len(spend_time) == 0:
		return None
	else:
		return float(numpy.mean(spend_time))


async def metrics_get() -> fastapi.responses.Response:
	ping_res = {h: ping_stats(h) for h in Settings.singleton().checks_hosts}

	metrics = [
		pr34_metrics.Metric.model_validate(
			dict(
				name='ping_mean',
				type='gauge',
				help='ping to host, 3 counts, up to 1 second',
				samples=[
					dict(
						value=str(v),
						parameters=dict(
							host=k,
						),
					)
				],
			)
		)
		for k, v in ping_res.items()
		if not v is None
	]
	serialize_res = pr34_metrics.serialize(metrics)

	return fastapi.responses.Response(
		content=serialize_res.json2,
		headers={
			'Content-Type': serialize_res.content_type,
		},
	)


def get_router() -> fastapi.APIRouter:
	router = fastapi.APIRouter()

	router.get('/metrics')(metrics_get)

	return router