"""Probe remote host and register in SAC before agent deploy (WinRM / SSH)."""

from __future__ import annotations

import re
from datetime import datetime, timezone

from sqlalchemy import select
from sqlalchemy.orm import Session

from app.models import Host
from app.services.agent_update_settings import PRODUCT_RDP, PRODUCT_SSH
from app.services.linux_admin_settings import get_effective_linux_admin_config
from app.services.ssh_connect import _is_ipv4, _ssh_output_hostname, test_ssh_connection
from app.services.win_admin_settings import get_effective_win_admin_config
from app.services.winrm_connect import test_winrm_connection

_IPV4_RE = re.compile(r"^\d{1,3}(?:\.\d{1,3}){3}$")


class ManualHostAddError(Exception):
    pass


def validate_windows_target(target: str) -> str:
    text = (target or "").strip()
    if not text:
        raise ManualHostAddError("Укажите имя Windows-ПК")
    if _IPV4_RE.match(text):
        raise ManualHostAddError(
            "Для Windows укажите имя ПК (NetBIOS/DNS), не IP — WinRM с Kerberos по IP ненадёжен"
        )
    short = text.split(".")[0].split("\\")[-1].strip()
    if not short or " " in short:
        raise ManualHostAddError("Некорректное имя хоста")
    return short


def validate_linux_target(target: str) -> str:
    text = (target or "").strip()
    if not text:
        raise ManualHostAddError("Укажите IP или hostname Linux-хоста")
    return text


def probe_windows_host(db: Session, hostname: str) -> str:
    cfg = get_effective_win_admin_config(db)
    if not cfg.configured:
        raise ManualHostAddError("Windows domain admin не настроен в SAC")
    probe = test_winrm_connection(
        target=hostname,
        user=cfg.user,
        password=cfg.password,
    )
    if not probe.ok:
        raise ManualHostAddError(probe.message)
    return (probe.hostname or hostname).strip()


def probe_linux_host(db: Session, target: str) -> tuple[str, str | None]:
    cfg = get_effective_linux_admin_config(db)
    if not cfg.configured:
        raise ManualHostAddError("Linux SSH admin не настроен в SAC")
    probe = test_ssh_connection(
        target=target,
        user=cfg.user,
        password=cfg.password,
    )
    if not probe.ok:
        raise ManualHostAddError(probe.message)
    hostname = _ssh_output_hostname(probe.stdout) or target
    ipv4 = target if _is_ipv4(target) else None
    return hostname, ipv4


def get_or_create_manual_host(
    db: Session,
    *,
    hostname: str,
    product: str,
    os_family: str,
    ipv4: str | None = None,
) -> Host:
    host = db.scalar(
        select(Host).where(Host.hostname == hostname, Host.product == product).limit(1)
    )
    now = datetime.now(timezone.utc)
    if host is None:
        host = Host(
            hostname=hostname,
            os_family=os_family,
            product=product,
            ipv4=ipv4,
            last_seen_at=now,
        )
        db.add(host)
    else:
        host.os_family = os_family
        if ipv4:
            host.ipv4 = ipv4
        host.last_seen_at = now
    db.flush()
    return host


def prepare_manual_host_add(db: Session, *, platform: str, target: str) -> Host:
    platform_norm = (platform or "").strip().lower()
    if platform_norm == "windows":
        win_target = validate_windows_target(target)
        hostname = probe_windows_host(db, win_target)
        return get_or_create_manual_host(
            db,
            hostname=hostname,
            product=PRODUCT_RDP,
            os_family="windows",
        )
    if platform_norm == "linux":
        linux_target = validate_linux_target(target)
        hostname, ipv4 = probe_linux_host(db, linux_target)
        return get_or_create_manual_host(
            db,
            hostname=hostname,
            product=PRODUCT_SSH,
            os_family="linux",
            ipv4=ipv4,
        )
    raise ManualHostAddError("platform должен быть windows или linux")