import json

from django.http import FileResponse, HttpResponseNotAllowed, JsonResponse
from django.shortcuts import get_object_or_404
from django.views.decorators.csrf import csrf_exempt

from .models import Project


def _auth(request):
    """None if logged in, else a 401 JSON response (so fetch() doesn't get a
    login redirect)."""
    if not request.user.is_authenticated:
        return JsonResponse({"detail": "authentication required"}, status=401)
    return None


def _owned(request, pk):
    return get_object_or_404(Project, pk=pk, owner=request.user)


def projects(request):
    """GET /api/projects/ — the current user's projects."""
    if (resp := _auth(request)):
        return resp
    rows = Project.objects.filter(owner=request.user).values("id", "name", "fps", "updated")
    return JsonResponse(list(rows), safe=False)


@csrf_exempt  # dev convenience: session-auth API without a CSRF token round-trip
def scene(request, pk):
    """GET/PUT /api/projects/<pk>/scene/ — read or replace the timeline scene."""
    if (resp := _auth(request)):
        return resp
    project = _owned(request, pk)
    if request.method == "GET":
        return JsonResponse({"fps": project.fps, "scene": project.scene})
    if request.method == "PUT":
        data = json.loads(request.body or "{}")
        if "scene" in data:
            project.scene = data["scene"]
        if "fps" in data:
            project.fps = data["fps"]
        project.save(update_fields=["scene", "fps", "updated"])
        return JsonResponse({"ok": True, "updated": project.updated})
    return HttpResponseNotAllowed(["GET", "PUT"])


def otio(request, pk):
    """GET /api/projects/<pk>/otio/ — serve the uploaded OTIO file."""
    if (resp := _auth(request)):
        return resp
    project = _owned(request, pk)
    if not project.otio:
        return JsonResponse({"detail": "no otio uploaded"}, status=404)
    return FileResponse(project.otio.open("rb"), content_type="application/json")