import os

import yaml

from ...models import DesiredRecord
from ...normalizer import normalize_hostname, normalize_ipv4


class Plugin:
    name = "file"

    def __init__(self, config):
        self.config = config
        self.path = os.getenv("DNS_SYNC_FILE")
        if not self.path:
            raise RuntimeError("DNS_SYNC_FILE is required when PROXY=file")

    def discover(self):
        try:
            with open(self.path, "r", encoding="utf-8") as fh:
                data = yaml.safe_load(fh)
        except (OSError, yaml.YAMLError) as exc:
            raise RuntimeError(f"Could not read desired-state file {self.path}: {exc}") from exc

        if not isinstance(data, dict) or not isinstance(data.get("records"), dict):
            raise RuntimeError("Desired-state YAML must contain a top-level records mapping")

        result = []
        for raw_hostname, raw_ip in data["records"].items():
            hostname, wildcard = normalize_hostname(str(raw_hostname), allow_wildcard=True)
            result.append(
                DesiredRecord(
                    hostname=hostname,
                    ip=normalize_ipv4(str(raw_ip), hostname),
                    wildcard=wildcard,
                    source=self.name,
                )
            )
        return result