# SPDX-License-Identifier: GPL-2.0-or-later
# Copyright (C) 2026 Bryan Joshua Pedini
import logging

from django.contrib import messages
from django.contrib.auth.mixins import PermissionRequiredMixin
from django.shortcuts import get_object_or_404, redirect
from django.views import View

from core.choices import ObjectChangeActionChoices
from virtualization.choices import VirtualMachineStatusChoices
from virtualization.models import VirtualMachine

from .proxmox import ProxmoxError, power_action

logger = logging.getLogger("proxmox_power_button")

VALID_ACTIONS = {"start", "stop", "reboot"}


def _log_changelog_only(request, vm, message):
    """
    Record a changelog entry for an operation that changes no field.

    Used for reboot: the VM stays powered on, so there is nothing to save. We
    build the ObjectChange by hand (pre == post, no field diff) rather than
    touching the object, and attribute it to the current request/user exactly
    like ChangeLoggingMiddleware would.
    """
    vm.snapshot()
    objectchange = vm.to_objectchange(ObjectChangeActionChoices.ACTION_UPDATE)
    objectchange.message = message
    objectchange.user = request.user
    objectchange.request_id = request.id
    objectchange.save()


def _save_with_changelog(request, vm, status, message):
    """
    Apply a status change; the post_save signal writes a single changelog
    entry carrying our message.
    """
    vm.snapshot()
    vm._changelog_message = message
    vm.status = status
    vm.save()


class VMPowerActionView(PermissionRequiredMixin, View):
    """
    POST-only action endpoint (Post/Redirect/Get) — renders no page.

    Performs the Proxmox power action, records exactly one changelog entry per
    state change, and logs every outcome (including failures).
    """

    permission_required = "virtualization.change_virtualmachine"

    def get(self, request, pk, action):
        # Not a real page — just bounce back to the VM.
        return redirect("virtualization:virtualmachine", pk=pk)

    def post(self, request, pk, action):
        # Scope the lookup through NetBox's object-permission system: a user
        # whose change_virtualmachine permission is constraint-scoped gets a
        # 404 on VMs outside their scope, exactly like core NetBox views.
        vm = get_object_or_404(
            VirtualMachine.objects.restrict(request.user, "change"), pk=pk
        )

        if action not in VALID_ACTIONS:
            logger.error("user=%s vm=%s: unknown power action '%s'", request.user, vm.name, action)
            messages.error(request, f"Unknown power action '{action}'.")
            return redirect("virtualization:virtualmachine", pk=vm.pk)

        try:
            result = power_action(vm, action)
        except ProxmoxError as exc:
            logger.error("user=%s vm=%s: %s failed: %s", request.user, vm.name, action, exc)
            # Don't echo raw Proxmox/network errors to the browser — they can
            # leak internal hostnames, URLs, and response bodies. Full detail
            # is in the log line above.
            messages.error(
                request,
                f"Proxmox {action} failed for {vm.name} — see the NetBox log for details.",
            )
            return redirect("virtualization:virtualmachine", pk=vm.pk)

        if action == "start":
            if result == "running":
                _save_with_changelog(
                    request, vm,
                    VirtualMachineStatusChoices.STATUS_ACTIVE,
                    "Powered on via Proxmox (confirmed running)",
                )
                logger.info("user=%s vm=%s: powered on (confirmed running)", request.user, vm.name)
                messages.success(request, f"{vm.name} is powered on (confirmed running).")
            else:
                # Command accepted but the VM is not running yet: no state
                # change, so no changelog entry — log only.
                state = result or "unknown"
                logger.warning(
                    "user=%s vm=%s: start sent but not confirmed running (state=%s)",
                    request.user, vm.name, state,
                )
                messages.warning(
                    request,
                    f"Start sent to {vm.name}, but it is not reporting 'running' yet "
                    f"({state}); status left unchanged.",
                )
        elif action == "stop":
            _save_with_changelog(
                request, vm,
                VirtualMachineStatusChoices.STATUS_OFFLINE,
                "Powered off via Proxmox (shutdown sent)",
            )
            logger.info("user=%s vm=%s: stop (shutdown) sent", request.user, vm.name)
            messages.success(request, f"Stop sent to {vm.name}.")
        else:  # reboot — VM stays powered on: changelog entry, but no save
            _log_changelog_only(request, vm, "Rebooted via Proxmox")
            logger.info("user=%s vm=%s: reboot sent", request.user, vm.name)
            messages.success(request, f"Reboot sent to {vm.name}.")

        return redirect("virtualization:virtualmachine", pk=vm.pk)