import logging

from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy import select
from sqlalchemy.orm import Session

from .. import models, proxmox_client as pve, schemas
from ..config import settings
from ..database import get_db
from ..deps import get_current_user
from ..proxmox_actions import delete_guest, get_live_stats, guest_action

logger = logging.getLogger(__name__)
router = APIRouter(prefix="/instances", tags=["instances"])


def _get_owned_instance(db: Session, user: models.User, instance_id: int) -> models.Instance:
    """Возвращает инстанс с проверкой владельца."""
    instance = db.get(models.Instance, instance_id)
    if instance is None or instance.status == models.InstanceStatus.deleted:
        raise HTTPException(status_code=404, detail="Инстанс не найден")
    if user.role != models.UserRole.admin and instance.owner_id != user.id:
        raise HTTPException(status_code=404, detail="Инстанс не найден")
    return instance


@router.get("", response_model=list[schemas.InstanceOut])
def list_instances(db: Session = Depends(get_db), user: models.User = Depends(get_current_user)):
    """Клиент видит только свои инстансы, администратор — все."""
    query = select(models.Instance).where(models.Instance.status != models.InstanceStatus.deleted)
    if user.role != models.UserRole.admin:
        query = query.where(models.Instance.owner_id == user.id)
    return list(db.scalars(query.order_by(models.Instance.created_at.desc())))


@router.get("/{instance_id}/stats")
def instance_stats(instance_id: int, db: Session = Depends(get_db), user: models.User = Depends(get_current_user)):
    """Возвращает актуальные CPU/RAM/диск/uptime из Proxmox."""
    instance = _get_owned_instance(db, user, instance_id)
    try:
        return get_live_stats(instance.guest_type.value, instance.vmid)
    except Exception as exc:
        logger.warning("Ошибка статистики instance_id=%s: %s", instance_id, exc)
        raise HTTPException(status_code=502, detail="Не удалось получить статистику Proxmox")


@router.post("/{instance_id}/action")
def instance_action(instance_id: int, payload: schemas.InstanceAction, db: Session = Depends(get_db), user: models.User = Depends(get_current_user)):
    """Запускает, останавливает или перезапускает VM/LXC."""
    instance = _get_owned_instance(db, user, instance_id)
    try:
        guest_action(instance.guest_type.value, instance.vmid, payload.action)
    except Exception as exc:
        logger.warning("Ошибка action=%s instance_id=%s: %s", payload.action, instance_id, exc)
        raise HTTPException(status_code=502, detail="Не удалось выполнить действие в Proxmox")
    if payload.action == "start":
        instance.status = models.InstanceStatus.running
    elif payload.action in {"stop", "shutdown"}:
        instance.status = models.InstanceStatus.stopped
    db.commit()
    return {"ok": True, "action": payload.action}


def _save_error(db: Session, instance: models.Instance, exc: Exception) -> None:
    """Помечает инстанс ошибочным без выдачи деталей Proxmox."""
    instance.status = models.InstanceStatus.error
    db.commit()
    logger.exception("Ошибка провижининга instance_id=%s: %s", instance.id, exc)


@router.post("", response_model=schemas.InstanceCreateOut, status_code=status.HTTP_201_CREATED)
def create_instance(payload: schemas.InstanceCreate, db: Session = Depends(get_db), user: models.User = Depends(get_current_user)):
    """Создаёт и запускает VM/LXC из активного шаблона."""
    template = db.scalar(select(models.Template).where(models.Template.id == payload.template_id, models.Template.is_active.is_(True)))
    if template is None:
        raise HTTPException(status_code=404, detail="Активный шаблон не найден")
    try:
        vmid = pve.next_vmid()
    except Exception as exc:
        logger.exception("Не удалось получить VMID из Proxmox: %s", exc)
        raise HTTPException(status_code=502, detail="Proxmox недоступен")
    instance = models.Instance(name=payload.name, vmid=vmid, node=settings.pve_node, guest_type=template.guest_type, status=models.InstanceStatus.creating, owner_id=user.id, template_id=template.id)
    db.add(instance); db.commit(); db.refresh(instance)
    try:
        if template.guest_type == models.GuestType.vm:
            pve.provision_vm(template.source_vmid, vmid, payload.name, template.cores, template.memory_mb, template.disk_gb, payload.username, payload.password)
        else:
            pve.provision_lxc(template.source_template, vmid, payload.name, template.cores, template.memory_mb, template.disk_gb, payload.password)
    except Exception as exc:
        _save_error(db, instance, exc)
        raise HTTPException(status_code=502, detail="Не удалось создать инстанс в Proxmox")
    instance.status = models.InstanceStatus.running; db.commit(); db.refresh(instance)
    return schemas.InstanceCreateOut(**schemas.InstanceOut.model_validate(instance).model_dump(), initial_password=payload.password)


@router.delete("/{instance_id}")
def delete_instance(instance_id: int, db: Session = Depends(get_db), user: models.User = Depends(get_current_user)):
    """Удаляет принадлежащую пользователю VM/LXC."""
    instance = _get_owned_instance(db, user, instance_id)
    if instance.vmid is None:
        raise HTTPException(status_code=409, detail="У инстанса отсутствует VMID")
    instance.status = models.InstanceStatus.deleting; db.commit()
    try:
        delete_guest(instance.guest_type.value, instance.vmid)
    except Exception as exc:
        instance.status = models.InstanceStatus.error; db.commit()
        logger.exception("Ошибка удаления instance_id=%s: %s", instance.id, exc)
        raise HTTPException(status_code=502, detail="Не удалось удалить инстанс в Proxmox")
    instance.status = models.InstanceStatus.deleted; db.commit()
    return {"ok": True}