"""Persistenter Zustand: wann lief welche Gruppe zuletzt?"""

from __future__ import annotations

import json
import logging
import os
from datetime import datetime

log = logging.getLogger("pvesnap.state")

_TIME_FORMAT = "%Y-%m-%dT%H:%M:%S"


class State:
    def __init__(self, path):
        self.path = path
        self.data = {"version": 1, "groups": {}}
        self._dirty = False

    # -- Laden / Speichern ------------------------------------------------

    def load(self):
        if not os.path.exists(self.path):
            return self
        try:
            with open(self.path, "r", encoding="utf-8") as handle:
                data = json.load(handle)
            if isinstance(data, dict) and isinstance(data.get("groups"), dict):
                self.data = data
                self.data.setdefault("version", 1)
        except (OSError, ValueError) as exc:
            log.warning("Zustandsdatei %s nicht lesbar (%s) - starte mit leerem Zustand",
                        self.path, exc)
        return self

    def save(self, force=False):
        if not self._dirty and not force:
            return
        directory = os.path.dirname(os.path.abspath(self.path))
        try:
            os.makedirs(directory, exist_ok=True)
            tmp = self.path + ".tmp"
            with open(tmp, "w", encoding="utf-8") as handle:
                json.dump(self.data, handle, indent=2, ensure_ascii=False)
                handle.write("\n")
                handle.flush()
                os.fsync(handle.fileno())
            os.replace(tmp, self.path)
            self._dirty = False
        except OSError as exc:
            log.error("Zustand konnte nicht gespeichert werden (%s): %s", self.path, exc)

    # -- Zugriff ----------------------------------------------------------

    def _entry(self, group_name):
        return self.data["groups"].setdefault(group_name, {})

    def last_run(self, group_name):
        raw = self._entry(group_name).get("last_run")
        if not raw:
            return None
        try:
            return datetime.strptime(raw, _TIME_FORMAT)
        except ValueError:
            return None

    def record_run(self, group_name, moment, created=0, deleted=0, errors=None):
        entry = self._entry(group_name)
        entry["last_run"] = moment.strftime(_TIME_FORMAT)
        entry["created"] = created
        entry["deleted"] = deleted
        entry["errors"] = list(errors or [])
        entry["status"] = "error" if errors else "ok"
        entry["total_runs"] = int(entry.get("total_runs") or 0) + 1
        self._dirty = True

    def info(self, group_name):
        return dict(self._entry(group_name))

    def forget(self, group_name):
        if group_name in self.data["groups"]:
            del self.data["groups"][group_name]
            self._dirty = True

    def prune_unknown(self, known_names):
        known = set(known_names)
        for name in [n for n in self.data["groups"] if n not in known]:
            del self.data["groups"][name]
            self._dirty = True