import json
import logging

from django.conf import settings
from django.contrib.auth.decorators import login_required
from django.http import HttpResponse, HttpResponseBadRequest, JsonResponse
from django.shortcuts import render
from django.views.decorators.csrf import csrf_exempt
from django.views.decorators.http import require_http_methods

from pos_sync.models import POSConnection, SyncEvent
from pos_sync.services import POSSyncError, apply_inbound_sale

logger = logging.getLogger(__name__)


def _authorized(request) -> bool:
    expected = (settings.POS_WEBHOOK_SECRET or "").strip()
    if not expected:
        conn = POSConnection.objects.filter(is_active=True).exclude(
            webhook_secret=""
        ).first()
        expected = (conn.webhook_secret if conn else "").strip()
    if not expected:
        return False
    header = request.headers.get("Authorization", "")
    token = ""
    if header.startswith("Bearer "):
        token = header[7:].strip()
    token = token or request.GET.get("token") or ""
    return token == expected


@login_required
def event_list(request):
    events = SyncEvent.objects.select_related("connection")[:200]
    connections = POSConnection.objects.all()
    return render(
        request,
        "pos_sync/list.html",
        {"events": events, "connections": connections},
    )


@csrf_exempt
@require_http_methods(["POST"])
def inventory_webhook(request):
    if not _authorized(request):
        return HttpResponse("unauthorized", status=401)
    try:
        payload = json.loads(request.body.decode() or "{}")
    except json.JSONDecodeError:
        return HttpResponseBadRequest("invalid json")
    sku = payload.get("sku") or payload.get("SKU") or ""
    try:
        quantity = int(payload.get("quantity") or payload.get("qty") or 0)
    except (TypeError, ValueError):
        return HttpResponseBadRequest("invalid quantity")
    external_id = str(payload.get("external_id") or payload.get("id") or "")
    try:
        event = apply_inbound_sale(
            sku=sku,
            quantity=quantity,
            external_id=external_id,
            payload=payload,
        )
    except POSSyncError as exc:
        logger.warning("POS inbound rejected: %s", exc)
        return JsonResponse({"ok": False, "error": str(exc)}, status=400)
    return JsonResponse({"ok": True, "id": str(event.pk), "status": event.status})