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

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


@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())))


def _save_error(db: Session, instance: models.Instance, exc: Exception) -> None:
    """Помечает инстанс ошибочным без сохранения деталей Proxmox пользователю."""
    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(
                source_vmid=template.source_vmid, vmid=vmid, name=payload.name,
                cores=template.cores, memory_mb=template.memory_mb, disk_gb=template.disk_gb,
                username=payload.username, password=payload.password,
            )
        else:
            pve.provision_lxc(
                source_template=template.source_template, vmid=vmid, name=payload.name,
                cores=template.cores, memory_mb=template.memory_mb, disk_gb=template.disk_gb,
                password=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 и отмечает запись deleted."""
    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")
    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}