import datetime
from typing import Dict, List

import pytimeparse
import requests

from matrix_alertbot.cache import Cache
from matrix_alertbot.errors import AlertNotFoundError


class AlertmanagerClient:
    def __init__(self, url: str, cache: Cache) -> None:
        self.api_url = f"{url}/api/v2"
        self.cache = cache

    def get_alerts(self) -> List[Dict]:
        response = requests.get(f"{self.api_url}/alerts")
        response.raise_for_status()
        return response.json()

    def get_alert_labels(self, fingerprint: str) -> Dict[str, str]:
        if fingerprint not in self.cache:
            alerts = self.get_alerts()
            alert = self._find_alert(alerts, fingerprint)
            self.cache[fingerprint] = alert["labels"]
        return self.cache[fingerprint]

    def create_silence(self, fingerprint: str, duration: str, user: str) -> str:
        labels = self.get_alert_labels(fingerprint)
        matchers = []
        for label_name, label_value in labels.items():
            matchers.append(
                {"name": label_name, "value": label_value, "isRegex": False}
            )

        start_time = datetime.datetime.now()
        duration_seconds = pytimeparse.parse(duration)
        duration_delta = datetime.timedelta(seconds=duration_seconds)
        end_time = start_time + duration_delta

        silence = {
            "matchers": matchers,
            "startsAt": start_time.isoformat(),
            "endsAt": end_time.isoformat(),
            "createdBy": user,
            "comment": "Acknowledge alert from Matrix",
        }
        response = requests.post(f"{self.api_url}/silences", json=silence)
        response.raise_for_status()
        data = response.json()
        return data["silenceID"]

    @staticmethod
    def _find_alert(alerts: List[Dict], fingerprint: str) -> Dict:
        for alert in alerts:
            if alert["fingerprint"] == fingerprint:
                return alert
        raise AlertNotFoundError(f"Cannot find alert with fingerprint {fingerprint}")