reagent filter backend

code/__DEFINES/reagents/reagent.dm

@@ -18,3 +18,13 @@ DEFINE_SHARED_BITFIELD(reagent_guidebook_flags, list(
 	BITFIELD(REAGENT_GUIDEBOOK_UNLISTED),
 	BITFIELD(REAGENT_GUIDEBOOK_HIDDEN),
 ))
+
+//* flags for /datum/reagent/var/reagent_filter_flags *//
+
+/// the default flag that reagents have by default.
+#define REAGENT_FILTER_GENERIC (1<<0)
+
+/// **disallow** from common medical machinery, like sleepers.
+///
+/// * high-end reagents filtration / systems should be able to hit this
+#define REAGENT_FILTER_NO_COMMON_BIOANALYSIS (1<<23)

code/game/machinery/Sleeper.dm

@@ -178,6 +178,9 @@
 	idle_power_usage = 15
 	active_power_usage = 200 //builtin health analyzer, dialysis machine, injectors.
 
+	/// filter flags we use for dialysis
+	var/dialysis_reagent_filter_flags = ~REAGENT_FILTER_NO_COMMON_BIOANALYSIS
+
 /obj/machinery/sleeper/Initialize(mapload)
 	. = ..()
 	beaker = new /obj/item/reagent_containers/glass/beaker/large(src)
@@ -243,21 +246,32 @@
 
 		if(filtering > 0)
 			if(beaker)
-				if(beaker.reagents.total_volume < beaker.reagents.maximum_volume)
-					var/pumped = 0
-					for(var/datum/reagent/x in occupant.reagents.reagent_list)
-						occupant.reagents.trans_to_obj(beaker, 3)
-						pumped++
-					if(ishuman(occupant))
-						occupant.vessel.trans_to_obj(beaker, pumped + 1)
+				// filter 3 units per chem-type inside them, or remaining volume, whichever is lesser
+				// we will also pump out 1/3 of that volume as their blood.
+				var/remaining_beaker_volume_for_dialysis = beaker.reagents.maximum_volume - beaker.reagents.total_volume
+				var/filtered_volume = occupant.reagents?.filter_to_holder(
+					beaker.reagents,
+					min(
+						remaining_beaker_volume_for_dialysis * (3 / 4),
+						length(occupant.reagents.reagent_list) * 3,
+					),
+					dialysis_reagent_filter_flags,
+				)
+				occupant.vessel.trans_to_holder(beaker.reagents, filtered_volume * (1 / 3))
 			else
 				toggle_filter()
 
 		if(pumping > 0)
 			if(beaker)
-				if(beaker.reagents.total_volume < beaker.reagents.maximum_volume)
-					for(var/datum/reagent/x in occupant.ingested.reagent_list)
-						occupant.ingested.trans_to_obj(beaker, 3)
+				// filter 3 units per chem-type inside them, or remaining volume, whichever is lesser
+				occupant.ingested?.filter_to_holder(
+					beaker.reagents,
+					min(
+						beaker.reagents.maximum_volume - beaker.reagents.total_volume,
+						length(occupant.ingested.reagent_list) * 3,
+					),
+					dialysis_reagent_filter_flags,
+				)
 			else
 				toggle_pump()
 

code/modules/reagents/chemistry/reagent.dm

@@ -17,6 +17,14 @@ GLOBAL_LIST_INIT(name2reagent, build_name2reagent())
 	/// reagent flags - see [code/__DEFINES/reagents/flags.dm]
 	var/reagent_flags = NONE
 
+	//* Filtering *//
+	/// reagent filter flags - dynamic flags used for simulations of filtration/identification/detection
+	///
+	/// * used for a lot of things
+	/// * REAGENT_FILTER_GENERIC is a default because this allows us to have a single 'flags' on filter,
+	///   instead of a 'include flags' and 'exclude flags'.
+	var/reagent_filter_flags = REAGENT_FILTER_GENERIC
+
 	//* Identity
 	/// our name - visible from guidebooks and to admins
 	var/name = "Reagent"

code/modules/reagents/chemistry/reagent_holder.dm

@@ -539,6 +539,49 @@
 		R.on_update (A)
 	update_total()
 
+//* Filtering *//
+
+/**
+ * Filters chemicals by `reagent_filter_flags`
+ *
+ * @params
+ * * transfer_to - where to transfer to
+ * * amount - volume limit
+ * * flags - only these flags are allowed
+ */
+/datum/reagent_holder/proc/filter_to_holder(datum/reagent_holder/transfer_to, amount = INFINITY, flags)
+	if(amount <= 0)
+		return
+	var/list/filtering_ids = list()
+	for(var/datum/reagent/reagent in reagent_list)
+		if(!(reagent.reagent_filter_flags & flags))
+			continue
+		filtering_ids += reagent.id
+	return transfer_to_holder(transfer_to, filtering_ids, amount)
+
+/**
+ * Filters chemicals by `reagent_filter_flags`
+ *
+ * @params
+ * * amount - volume limit
+ * * flags - only these flags are allowed
+ */
+/datum/reagent_holder/proc/filter_to_void(amount = INFINITY, flags)
+	if(amount <= 0)
+		return
+	var/total_filterable = 0
+	var/list/datum/reagent/filtering = list()
+	for(var/datum/reagent/reagent in reagent_list)
+		if(!(reagent.reagent_filter_flags & flags))
+			continue
+		total_filterable += reagent.volume
+		filtering += reagent
+	var/ratio = amount / total_filterable
+	for(var/datum/reagent/to_filter in filtering)
+		remove_reagent(to_filter.id, to_filter.volume * ratio, TRUE)
+	reconsider_reactions()
+	return min(amount, total_filterable)
+
 //* Queries *//
 
 /**
@@ -620,7 +663,7 @@
 	if(!total_volume)
 		return
 	if(!reagents)
-		var/ratio = min(1, (target.maximum_volume - target.total_volume) / total_volume)
+		var/ratio = min(1, min(amount, target.maximum_volume - target.total_volume) / total_volume)
 		. = total_volume * ratio
 		if(!copy)
 			for(var/datum/reagent/R as anything in reagent_list)
@@ -646,7 +689,7 @@
 			reagents_transferring += R
 		if(!total_transferable)
 			return 0
-		var/ratio = min(1, (target.maximum_volume - target.total_volume) / total_transferable)
+		var/ratio = min(1, min(amount, target.maximum_volume - target.total_volume) / total_transferable)
 		. = total_transferable * ratio
 		if(!copy)
 			for(var/datum/reagent/R as anything in reagents_transferring)