1	import Base
2	import ../../change_tick.bend as Tick
3	import ../../deferred_command.bend as Deferred
4	import domains.bend as D
5	import routing.bend as Route
6	import ../../world.bend as W
7	
8	type BarrierState<S: Data,C: Type,R: Type,E: Data> is Type:
9	  BarrierState{world: W.World<S,C,R,E>,domains: List<&2,D.Domain<S,E>>,tick: Nat}
10	
11	def collected(~S: Data,~C: Type,~R: Type,~E: Data,joined: W.World<S,C,R,E> & List<&2,D.Domain<S,E>>,tick: Nat) -> BarrierState<S,C,R,E>:
12	  (world,domains) = joined
13	  BarrierState{world,domains,tick}
14	
15	def command_collected(~S: Data,~C: Type,~R: Type,~E: Data,~classify: E -> Maybe<D.DescriptorKey<S>>,command: Deferred.Command<W.World<S,C,R,E>>,state: BarrierState<S,C,R,E>) -> BarrierState<S,C,R,E>:
16	  match state:
17	    case BarrierState{world,domains,+tick}: collected(~S,~C,~R,~E,Route.collect(~S,~C,~R,~E,~classify,Deferred.run_disabled(~W.World<S,C,R,E>,command,world),tick,domains),tick)
18	
19	def closed(~S:Data,~C:Type,~R:Type,~E:Data,state:BarrierState<S,C,R,E>) -> BarrierState<S,C,R,E>:
20	  match state:
21	    case BarrierState{world,domains,tick}:BarrierState{W.leave_run(~S,~C,~R,~E,world),domains,tick}
22	def drain(~S: Data,~C: Type,~R: Type,~E: Data,~classify: E -> Maybe<D.DescriptorKey<S>>,commands: List<Deferred.Command<W.World<S,C,R,E>>>,state: BarrierState<S,C,R,E>) -> BarrierState<S,C,R,E>:
23	  match commands:
24	    case []: closed(~S,~C,~R,~E,state)
25	    case command <> rest: drain(~S,~C,~R,~E,~classify,rest,command_collected(~S,~C,~R,~E,~classify,command,state))
26	
27	# The deferred barrier advances the actual World clock once. Every command
28	# publishes a distinct batch stamped with that same barrier tick.
29	def opened(~S: Data,~C: Type,~R: Type,~E: Data,~classify: E -> Maybe<D.DescriptorKey<S>>,advanced: W.World<S,C,R,E> & Tick.Tick,domains: List<&2,D.Domain<S,E>>) -> BarrierState<S,C,R,E>:
30	  (world,+tick) = advanced
31	  match world:
32	    case W.World{+namespace,allocator,store,resource,+events,pending,+registrations,+nextSystemId,+clock}: drain(~S,~C,~R,~E,~classify,List.reverse(&1,Deferred.Command<W.World<S,C,R,E>>,pending),BarrierState{W.World{namespace,allocator,store,resource,events,[],registrations,nextSystemId,clock},domains,Tick.total(tick)})
33	
34	def barrier(~S: Data,~C: Type,~R: Type,~E: Data,~classify: E -> Maybe<D.DescriptorKey<S>>,world: W.World<S,C,R,E>,domains: List<&2,D.Domain<S,E>>) -> BarrierState<S,C,R,E>:
35	  opened(~S,~C,~R,~E,~classify,W.enter_run(~S,~C,~R,~E,world),domains)