1	import Base
2	import queue.bend as Q
3	import domains.bend as D
4	import ../../event_runtime.bend as Ev
5	
6	type KeyReading<S: Data,E: Data> is Data:
7	  KeyReading{key: D.DescriptorKey<S>,values: List<&2,E>,lagged: Bool}
8	
9	def queue_reading(~S: Data,~E: Data,key: D.DescriptorKey<S>,queue: Q.Queue<E>,position: Ev.Position) -> KeyReading<S,E>:
10	  match queue position:
11	    case Q.Queue{+front,+back,+size,+dropped} Ev.Position{_,+cursor,+registered}: KeyReading{key,Q.read(~E,Q.Queue{front,back,size,dropped},cursor),Nat.is_lt(Nat.max(cursor,registered),dropped)}
12	
13	def select(~S: Data,~E: Data,same: Bool,key: D.DescriptorKey<S>,queue: Q.Queue<E>,position: Ev.Position,ih: Unit -> KeyReading<S,E>) -> KeyReading<S,E>:
14	  match same:
15	    case True{}: queue_reading(~S,~E,key,queue,position)
16	    case False{}: ih(Unit{})
17	
18	def one(~S: Data,~E: Data,domains: List<&2,D.Domain<S,E>>,+wanted: D.DescriptorKey<S>,+position: Ev.Position) -> KeyReading<S,E>:
19	  match domains:
20	    case []: KeyReading{wanted,[],False{}}
21	    case D.Domain{+key,queue,_} <> rest: select(~S,~E,D.key_equal(~S,key,wanted),key,queue,position,_ => one(~S,~E,rest,wanted,position))
22	
23	def all(~S: Data,~E: Data,keys: List<&2,D.DescriptorKey<S>>,+domains: List<&2,D.Domain<S,E>>,+position: Ev.Position) -> List<&2,KeyReading<S,E>>:
24	  match keys:
25	    case []: []
26	    case key <> rest: one(~S,~E,domains,key,position) <> all(~S,~E,rest,domains,position)
27	
28	def activate(~S: Data,~E: Data,keys: List<&2,D.DescriptorKey<S>>,domains: List<&2,D.Domain<S,E>>,+id: U32) -> List<&2,D.Domain<S,E>>:
29	  match keys:
30	    case []: domains
31	    case key <> rest: activate(~S,~E,rest,D.activate_one(~S,~E,domains,key,id),id)