--Environment Code
F.error = function(set)
	local error_indicator = POS(-4025,13,-2671)
	if set ~= nil then
		setstate(error_indicator,(set and "on") or "off")
	end
	return (getstate(error_indicator) == "on") or false
end

F.yard_active = function(set) --if set == true then yard = active
	local yard_indicator = POS(-4025,14,-2659)
	if set ~= nil then
		setstate(yard_indicator,(set and "on") or "off")
	end
	return (getstate(yard_indicator) == "on") or false
end

F.dir = function(set) -- if set == true then dir = pointing north
	local dir_indicator = POS(-4025,13,-2665)
	if set ~= nil then
		setstate(dir_indicator,(set and "on") or "off")
	end
	return (getstate(dir_indicator) == "on") or false
end

F.get_rc_safe = function()
	return get_rc() or ""
end

F.has_rc = function(query,rc_list) -- query eg: "rc1"
	if rc_list == "" or query == nil or query=="" then return false end
	if not rc_list then rc_list = F.get_rc_safe() end
	for word in rc_list:gmatch("[^%s]+") do
		if word == query then return true end
	end
	return false
end

F.remove_rc = function(rc_list,arrow_mode) -- rc_list eg: {"rc1","rc2"}
	-- rc_list MUST be a table of rc codes to remove
	-- eg: {"rc1","rc2"}
	-- Arrow Modes:
	-- true: with arrow direction
	-- false: against arrow direction
	-- nil: ignores arrow direction
	
	if not atc_id then return false end
	if (arrow_mode == nil) or (atc_arrow == arrow_mode) then
		local rc = F.get_rc_safe()
		rc_list = rc_list or {}
		local rc_remove = {}
		for _,v in pairs(rc_list) do
			rc_remove[v] = true
		end
		-- remove codes from train's rc
		local reinsert = {}
		for token in rc:gmatch("[^%s]+") do
			if not rc_remove[token] then
				table.insert(reinsert,token)
			end
		end
		-- insert new string to train's rc
		set_rc(table.concat(reinsert," "))
	end
	return reinsert
end

F.add_rc = function(rc_list) -- rc_list eg {"rc1","rc2"} OR "rc1 rc2"
	if not atc_id then return false end
	if type(rc_list) == "table" then
		rc_list = table.concat(rc_list," ")
	end
	set_rc(F.get_rc_safe().." "..rc_list)
	return true
end

-- EOL function
F.EOL = function(this_dir)
	-- this_dir == true for north end, false for south end
	if not F.yard_active() then return end
	if atc_arrow then
		if F.dir() == this_dir then --train has bounced and needs to leave the rake or depart with it
			if F.has_rc("TY_FINAL_COLLECT") then -- take the whole rake to the exit
				F.remove({"TY_FINAL_COLLECT"})
				F.add_rc({"TY_DEPART"})
			else -- disconnect loco and return to pickup
				split_off_locomotive("A0B0")
				F.add_rc({"TY_PICKUP"})
			end
			F.add_rc({"TY_HEADSHUNT"})
		else --train needs to bounce
			atc_send("B0WRD1S4")
		end
	else
		if F.dir() == this_dir then
			--train is clasifying wagons, let it pass and couple to the rest of the rake
			local rm = {}
			for v in F.get_rc_safe():gmatch("(TY_CLASS_%S-)") do
				table.insert(rm,v)
			end
			F.remove_rc(rm)
		else --this should never come into play as it means the train has entered from the wrong end somehow
			atc_send("BBOL") --stop the train and open the doors (if available) to signify assistance required
			F.error(true)
		end
	end
end