"""Read experiment temperature history from the local tempproxy service.

Example:
    client = TemperatureProxyClient()
    temperature = client.get_history(start_epoch, end_epoch)
"""

import http.client
import json
import logging
from urllib.parse import urlencode
from urllib.request import urlopen

from damaris.data.Temperature import TemperatureResult


logger = logging.getLogger(__name__)


class TemperatureProxyClient:
    """Retrieve experiment-bounded readings from ``localhost:8000``."""

    URL = "http://localhost:8000/v1/readings"
    TIMEOUT = 5

    def get_history(self, start_epoch: float, end_epoch: float) -> TemperatureResult | None:
        """Return temperature history relative to the experiment start, or ``None``.

        Readings retain the proxy's ``pv`` units; an empty result or failed
        request returns ``None``.

        Example:
            temperature = TemperatureProxyClient().get_history(1000.0, 1060.0)
        """
        query = urlencode({"start": start_epoch, "end": end_epoch})
        url = f"{self.URL}?{query}"

        try:
            with urlopen(url, timeout=self.TIMEOUT) as response:
                payload = json.loads(response.read())

            readings = payload["readings"]
            if not isinstance(readings, list):
                raise ValueError("response 'readings' must be a list")
            if not readings:
                return None

            x = [float(reading["t"]) - start_epoch for reading in readings]
            y = [float(reading["pv"]) for reading in readings]
            return TemperatureResult(x=x, y=y)
        except (OSError, http.client.HTTPException, ValueError, TypeError, KeyError) as error:
            logger.warning("Unable to retrieve temperature history from tempproxy: %s", error)
            return None