added prototype

main.lua

@@ -0,0 +1,74 @@
+
+
+local function send_train_between(stations, r_station_i, p_station_i)
+	stations[r_station_i].last_p_station_i = p_station_i
+	stations[p_station_i].last_r_station_i = r_station_i
+end
+
+
+local function tick(stations)
+	--psuedocode
+
+	local r_stations = {}
+
+	for station_i, station in ipairs(stations) do
+		local r_item = station.item
+		if -r_item.amount >= station.requester_limit then
+			r_stations[#r_stations + 1] = station_i
+		end
+	end
+
+	local p_stations = {}
+
+	for station_i, station in ipairs(stations) do
+		local p_item = station.item
+		if p_item.amount >= station.provider_limit then
+			p_stations[#p_stations + 1] = station_i
+		end
+	end
+
+	--we do not dispatch more than one train per station per tick
+	if #r_stations > 0 and #p_stations > 0 then
+		if #r_stations <= #p_stations then
+			local last_p_station_i = stations[r_stations[1]].last_p_station_i
+			local i = 1
+			while true do
+				if i > #p_stations then
+					i = 1
+					break
+				elseif p_stations[i] > last_p_station_i then
+					break
+				else
+					i = i + 1
+				end
+			end
+			for j = 1, #r_stations do
+				send_train_between(stations, r_stations[j], p_stations[i])
+
+				i = i%#p_stations + 1
+			end
+		else
+			local last_r_station_i = stations[p_stations[1]].last_r_station_i
+			local i = 1
+			while true do
+				if i > #r_stations then
+					i = 1
+					break
+				elseif r_stations[i] > last_r_station_i then
+					break
+				else
+					i = i + 1
+				end
+			end
+			for j = 1, #p_stations do
+				send_train_between(stations, r_stations[i], p_stations[j])
+
+				i = i%#p_stations + 1
+			end
+
+		end
+	end
+end
+
+
+tick()