tl/scenes/views.py

import json

from django.contrib.auth import authenticate, login as dj_login, logout as dj_logout
from django.db.models import Q
from django.http import HttpResponseNotAllowed, JsonResponse
from django.shortcuts import get_object_or_404
from django.utils import timezone
from django.views.decorators.csrf import csrf_exempt

from .attribution import annotation_layer, apply_attribution
from .models import Project, Revision

MAX_CLIP_BYTES = 100 * 1024 * 1024


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 _visible(request):
    """Projects the user owns or collaborates on."""
    return Project.objects.filter(
        Q(owner=request.user) | Q(collaborators=request.user)).distinct()


def _editable(request, pk):
    """The project if the user may edit it (owner/collaborator), else 404."""
    return get_object_or_404(_visible(request), pk=pk)


def _meta(request, project):
    return {
        "id": project.pk,
        "name": project.name,
        "fps": project.fps,
        "owner": project.owner.get_username(),
        "otio": request.build_absolute_uri(project.otio.url) if project.otio else None,
        "clip": request.build_absolute_uri(project.clip.url) if project.clip else None,
    }


def _who(user):
    return {"authenticated": user.is_authenticated,
            "username": user.get_username() if user.is_authenticated else None}


def me(request):
    """GET /api/me/ — who the browser is logged in as (for the UI to gate edits)."""
    return JsonResponse(_who(request.user))


@csrf_exempt
def login_view(request):
    """POST /api/login/ {username, password} — start a session (httpOnly cookie)."""
    if request.method != "POST":
        return HttpResponseNotAllowed(["POST"])
    data = json.loads(request.body or "{}")
    user = authenticate(request, username=data.get("username"), password=data.get("password"))
    if user is None:
        return JsonResponse({"detail": "invalid username or password"}, status=400)
    dj_login(request, user)
    return JsonResponse(_who(user))


@csrf_exempt
def logout_view(request):
    """POST /api/logout/ — end the session."""
    dj_logout(request)
    return JsonResponse(_who(request.user))


@csrf_exempt
def projects(request):
    """GET — the user's projects; POST — create one from an uploaded otio + clip."""
    if (resp := _auth(request)):
        return resp
    if request.method == "GET":
        rows = list(_visible(request).values("id", "name", "fps", "updated", "owner__username"))
        return JsonResponse(rows, safe=False)
    if request.method == "POST":
        name = (request.POST.get("name") or "").strip()
        otio = request.FILES.get("otio")
        clip = request.FILES.get("clip")
        if not (name and otio and clip):
            return JsonResponse({"detail": "name, otio and clip are required"}, status=400)
        if clip.size > MAX_CLIP_BYTES:
            return JsonResponse({"detail": "clip exceeds 100 MB"}, status=400)
        project = Project.objects.create(owner=request.user, name=name, otio=otio, clip=clip)
        return JsonResponse(_meta(request, project), status=201)
    return HttpResponseNotAllowed(["GET", "POST"])


def project(request, pk):
    """GET /api/projects/<pk>/ — project metadata + media URLs (public to view)."""
    return JsonResponse(_meta(request, get_object_or_404(Project, pk=pk)))


@csrf_exempt  # dev convenience: session-auth API without a CSRF token round-trip
def scene(request, pk):
    """GET (public) the scene; PUT (owner/collaborator) merges a delta into it."""
    if request.method == "GET":
        p = get_object_or_404(Project, pk=pk)
        return JsonResponse({"fps": p.fps, "scene": p.scene})
    if request.method == "PUT":
        if (resp := _auth(request)):
            return resp
        p = _editable(request, pk)
        # A delta, not the whole scene: {changed: {gid: annotation}, deleted: [gid]}.
        # Merging per-id means two users editing different annotations both land
        # (no clobber); same-annotation edits are last-write-wins by arrival.
        data = json.loads(request.body or "{}")
        changed = data.get("changed") or {}
        deleted = data.get("deleted") or []
        summary = None
        if changed or deleted:
            groups = dict((p.scene or {}).get("groups", {}))
            groups.update(changed)
            for gid in deleted:
                groups.pop(gid, None)
            merged = dict(p.scene or {}, groups=groups)
            p.scene, summary, counts = apply_attribution(
                p.scene, merged, request.user.get_username(), timezone.now().isoformat())
            if any(counts.values()):       # don't log a no-op save
                Revision.objects.create(project=p, user=request.user, summary=summary,
                                        annotations=annotation_layer(p.scene))
        if "fps" in data:
            p.fps = data["fps"]
        p.save(update_fields=["scene", "fps", "updated"])
        return JsonResponse({"ok": True, "updated": p.updated, "summary": summary,
                             "annotations": annotation_layer(p.scene)})
    return HttpResponseNotAllowed(["GET", "PUT"])


def revisions(request, pk):
    """GET /api/projects/<pk>/revisions/ — the save history (who/when/what)."""
    if (resp := _auth(request)):
        return resp
    p = _editable(request, pk)
    rows = p.revisions.values("id", "user__username", "created", "summary")
    return JsonResponse(list(rows), safe=False)