From a3ae769a2ca3d4a9e3d1f47c67df3350dfd432c7 Mon Sep 17 00:00:00 2001
From: Tom Hacohen <tom@stosb.com>
Date: Sun, 27 Dec 2020 17:58:15 +0200
Subject: [PATCH] Implement fetch_updates.

---
 etebase_fastapi/collection.py     | 42 ++++++++++++++++++++++++++++++-
 etebase_fastapi/stoken_handler.py |  2 +-
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/etebase_fastapi/collection.py b/etebase_fastapi/collection.py
index 3a9ca8b..7679ed6 100644
--- a/etebase_fastapi/collection.py
+++ b/etebase_fastapi/collection.py
@@ -15,7 +15,7 @@ from django_etebase import models
 from .authentication import get_authenticated_user
 from .exceptions import ValidationError, transform_validation_error
 from .msgpack import MsgpackRoute, MsgpackResponse
-from .stoken_handler import filter_by_stoken_and_limit, get_stoken_obj
+from .stoken_handler import filter_by_stoken_and_limit, filter_by_stoken, get_stoken_obj, get_queryset_stoken
 
 User = get_user_model()
 collection_router = APIRouter(route_class=MsgpackRoute)
@@ -133,6 +133,11 @@ class CollectionItemListResponse(BaseModel):
     done: bool
 
 
+class CollectionItemBulkGetIn(BaseModel):
+    uid: str
+    etag: t.Optional[str]
+
+
 class ItemDepIn(BaseModel):
     etag: str
     uid: str
@@ -417,6 +422,41 @@ def item_bulk_common(data: ItemBatchIn, user: User, stoken: t.Optional[str], uid
         return MsgpackResponse({})
 
 
+@collection_router.post("/{collection_uid}/item/fetch_updates/")
+def fetch_updates(
+    collection_uid: str,
+    data: t.List[CollectionItemBulkGetIn],
+    stoken: t.Optional[str] = None,
+    prefetch: Prefetch = PrefetchQuery,
+    user: User = Depends(get_authenticated_user),
+):
+    _, queryset = get_item_queryset(user, collection_uid)
+    # FIXME: make configurable?
+    item_limit = 200
+
+    if len(data) > item_limit:
+        raise ValidationError("too_many_items", "Request has too many items.", status_code=status.HTTP_400_BAD_REQUEST)
+
+    queryset, stoken_rev = filter_by_stoken(stoken, queryset, models.CollectionItem.stoken_annotation)
+
+    uids, etags = zip(*[(item.uid, item.etag) for item in data])
+    revs = models.CollectionItemRevision.objects.filter(uid__in=etags, current=True)
+    queryset = queryset.filter(uid__in=uids).exclude(revisions__in=revs)
+
+    new_stoken_obj = get_queryset_stoken(queryset)
+    new_stoken = new_stoken_obj and new_stoken_obj.uid
+    stoken = stoken_rev and getattr(stoken_rev, "uid", None)
+    new_stoken = new_stoken or stoken
+
+    context = Context(user, prefetch)
+    ret = CollectionItemListResponse(
+        data=[CollectionItemOut.from_orm_context(item, context) for item in queryset],
+        stoken=new_stoken,
+        done=True,  # we always return all the items, so it's always done
+    )
+    return MsgpackResponse(ret)
+
+
 @collection_router.post("/{collection_uid}/item/transaction/")
 def item_transaction(
     collection_uid: str, data: ItemBatchIn, stoken: t.Optional[str] = None, user: User = Depends(get_authenticated_user)
diff --git a/etebase_fastapi/stoken_handler.py b/etebase_fastapi/stoken_handler.py
index fb89651..a976830 100644
--- a/etebase_fastapi/stoken_handler.py
+++ b/etebase_fastapi/stoken_handler.py
@@ -33,7 +33,7 @@ def filter_by_stoken(
     return queryset, stoken_rev
 
 
-def get_queryset_stoken(queryset: list) -> t.Optional[Stoken]:
+def get_queryset_stoken(queryset: t.Iterable[t.Any]) -> t.Optional[Stoken]:
     maxid = -1
     for row in queryset:
         rowmaxid = getattr(row, "max_stoken") or -1