"""Dnsmasq config persistence for Vacuum Wall.

Provides load/save for the declarative JSON config and upstream-management
helpers used by the sync bus and network handler.  All mutation and
apply logic lives in daemon/handlers/dnsmasq.py.
"""

import logging
from copy import deepcopy
from pathlib import Path
from typing import Any

from lib.common import deep_merge, ensure_dirs, load_json, save_json

logger = logging.getLogger(__name__)

PROJECT_DIR = Path(__file__).resolve().parent.parent
CONFIG_DIR = PROJECT_DIR / "config" / "dnsmasq"
DATA_DIR = PROJECT_DIR / "data" / "dnsmasq"
CONFIG_PATH = CONFIG_DIR / "config.json"
FRAGMENTS_DIR = DATA_DIR / "fragments"

DEFAULT_CFG: dict[str, Any] = {
    "dhcp": {
        "ranges": [],
        "static_leases": [],
    },
    "dns": {
        "upstreams": ["8.8.8.8", "1.1.1.1"],
        "domain": None,
        "custom_records": [],
    },
}


# ───────── config lifecycle ──────────────────────────────────────────


def get_config() -> dict[str, Any]:
    """Load current dnsmasq config from JSON state file."""
    ensure_dirs(CONFIG_DIR, DATA_DIR, FRAGMENTS_DIR)
    raw = load_json(CONFIG_PATH)
    if not raw:
        return deepcopy(DEFAULT_CFG)
    return deep_merge(deepcopy(DEFAULT_CFG), raw)


def save_config(cfg: dict[str, Any]) -> None:
    """Persist config to JSON (does NOT touch on-disk dnsmasq config)."""
    ensure_dirs(CONFIG_DIR, DATA_DIR, FRAGMENTS_DIR)
    merged = deep_merge(deepcopy(DEFAULT_CFG), cfg)
    save_json(CONFIG_PATH, merged)
    logger.info("dnsmasq config saved")


# ───────── upstream helpers ──────────────────────────────────────────


def set_upstreams(servers: list[str]) -> None:
    """Set the list of upstream DNS forwarders."""
    cfg = get_config()
    cfg["dns"]["upstreams"] = list(servers)
    save_config(cfg)
    logger.info("DNS upstreams set to %s", servers)


def set_domain(domain: str | None) -> None:
    """Set (or clear) the local DNS domain."""
    cfg = get_config()
    cfg["dns"]["domain"] = domain if domain else None
    save_config(cfg)
    logger.info("DNS domain set to '%s'", domain)


__all__ = [
    "get_config",
    "save_config",
    "set_domain",
    "set_upstreams",
]