private static async Task <List <RssItem> > SyncCoreAsync(LocalDbContext ctx, ISyncSource syncSource, SyncSourceInfo syncInfo,
CancellationToken cancellationToken)
{
if (syncInfo is null)
{
syncInfo = new SyncSourceInfo {
SyncSourceId = syncSource.SyncSourceId
};
ctx.Add(syncInfo);
}
var page = await syncSource.TryGetItemsAsync(syncInfo.LastSyncId, cancellationToken)
.ConfigureAwait(false);
if (page.LastId is int lastId)
{
syncInfo.LastSyncId = lastId;
}
var newItems = page.GetItems().Select(z =>
{
var r = new RssItem();
r.UpdateFrom(z);
return(r);
}).ToList();
return(ctx.AddOrIgnoreRange(newItems));
}