from __future__ import annotations

import logging
from pathlib import Path

from app.config import Config
from app.models import Mirror
from app.services.host import host_path, run_on_host

logger = logging.getLogger(__name__)

DROPIN_FILENAME = "mirror-manager.conf"


def read_current_dns() -> dict:
    dropin = host_path("etc/systemd/resolved.conf.d", DROPIN_FILENAME)
    main_conf = host_path("etc/systemd/resolved.conf")
    return {
        "dropin_exists": dropin.exists(),
        "dropin_path": str(dropin),
        "main_conf_exists": main_conf.exists(),
        "content": dropin.read_text(encoding="utf-8") if dropin.exists() else None,
    }


def apply_dns(mirror: Mirror) -> dict:
    ips = mirror.get_ips()
    if not ips:
        return {"success": False, "error": "آدرس DNS تعریف نشده"}

    dropin_dir = host_path("etc/systemd/resolved.conf.d")
    dropin_dir.mkdir(parents=True, exist_ok=True)
    dropin_path = dropin_dir / DROPIN_FILENAME

    dns_line = " ".join(ips)
    content = f"""# Managed by Mirror Manager - do not edit manually
[Resolve]
DNS={dns_line}
FallbackDNS=1.1.1.1 8.8.8.8
DNSStubListener=yes
"""

    dropin_path.write_text(content, encoding="utf-8")

    result = run_on_host(["systemctl", "restart", "systemd-resolved"])
    if result.returncode != 0:
        return {
            "success": False,
            "error": result.stderr or "خطا در restart systemd-resolved",
            "applied_content": content,
        }

    return {
        "success": True,
        "message": f"DNS اعمال شد: {mirror.name}",
        "ips": ips,
        "path": str(dropin_path),
    }


def remove_dns_dropin() -> None:
    dropin = host_path("etc/systemd/resolved.conf.d", DROPIN_FILENAME)
    if dropin.exists():
        dropin.unlink()
    run_on_host(["systemctl", "restart", "systemd-resolved"])