from django.core import signing
from django.contrib import messages
from django.core.exceptions import PermissionDenied, ValidationError
from django.shortcuts import get_object_or_404, redirect, render
from django.views.decorators.cache import never_cache
from django.views.decorators.http import require_http_methods

from .dispatch_responses import can_open_responses, open_dispatch_responses, render_opening_sms, response_control
from .models import GroupDispatch
from apps.notifications.models import SMSTemplate
from .views import staff_required


@staff_required
@require_http_methods(["GET", "POST"])
@never_cache
def open_responses(request, public_id):
    dispatch = get_object_or_404(GroupDispatch.objects.select_related("unit"), public_id=public_id)
    control = response_control(dispatch)
    if not control or control.mode != "SEALED" or not can_open_responses(request.user, dispatch):
        raise PermissionDenied
    if control.opened_at:
        return redirect("staff_tickets:dispatch_detail", public_id=public_id)
    if request.method == "POST":
        try:
            proof = signing.loads(request.POST.get("confirmation", ""), salt="dispatch-opening", max_age=600)
            if proof["user"] != request.user.pk or proof["dispatch"] != str(public_id):
                raise signing.BadSignature
            open_dispatch_responses(dispatch, request.user, proof["sms"])
        except (signing.BadSignature, KeyError):
            messages.error(request, "تأیید معتبر نیست یا مهلت آن پایان یافته؛ دوباره بررسی کنید.")
        except (ValidationError, ValueError, SMSTemplate.DoesNotExist) as error:
            messages.error(request, str(error))
        else:
            messages.success(request, "پاسخ‌ها هم‌زمان بازگشایی شدند؛ وضعیت پیامک را در گزارش بررسی کنید.")
            return redirect("staff_tickets:dispatch_detail", public_id=public_id)
    try:
        sms = render_opening_sms(dispatch) if control.notify_sms else ""
    except (SMSTemplate.DoesNotExist, ValueError):
        messages.error(request, "قالب پیامک بازگشایی معتبر یا فعال نیست؛ تنظیمات قالب را بررسی کنید.")
        return redirect("staff_tickets:dispatch_detail", public_id=public_id)
    from .dispatch_responses import _respondents
    proof = signing.dumps({"user": request.user.pk, "dispatch": str(public_id), "sms": sms}, salt="dispatch-opening")
    return render(request, "tickets/dispatch_open_confirm.html", {"dispatch": dispatch, "control": control,
        "opening_sms": sms, "respondent_count": len(_respondents(dispatch)), "confirmation": proof})