Allow read of Distributor slot status

Add support for reading distributor slot status. This action
is complementary to already present filter setting function.
'port' distributor message is modified to accept filter color
only (without '=on/off'), device returns selected filter state.
A wrapper function ($get_filter(...)) for Lua Controller and
condition selector for ICTA Controller are implemented as well.

Signed-off-by: Michal Cieslakiewicz <michal.cieslakiewicz@wp.pl>

basic_machines/distributor.lua

@@ -27,7 +27,7 @@ local STANDBY_TICKS = 3
 local COUNTDOWN_TICKS = 4
 local CYCLE_TIME = 4
 
-local INFO = [[Turn port on/off: command = 'port', payload = red/green/blue/yellow=on/off]]
+local INFO = [[Turn port on/off or read its state: command = 'port', payload = red/green/blue/yellow{=on/off}]]
 
 
 --local Side2Color = {B="red", L="green", F="blue", R="yellow"}
@@ -374,6 +374,13 @@ local function change_filter_settings(pos, slot, val)
 	return true
 end
 
+-- techage command to read filter channel status (on/off)
+local function read_filter_settings(pos, slot)
+	local slots = {["red"] = 1, ["green"] = 2, ["blue"] = 3, ["yellow"] = 4}
+	local filter = minetest.deserialize(M(pos):get_string("filter"))
+	return filter[slots[slot]] and "on" or "off"
+end
+
 local function can_dig(pos, player)
 	if minetest.is_protected(pos, player:get_player_name()) then
 		return false
@@ -437,7 +444,11 @@ local tubing = {
 		elseif topic == "port" then
 			-- "red"/"green"/"blue"/"yellow" = "on"/"off"
 			local slot, val = techage.ident_value(payload)
-			return change_filter_settings(pos, slot, val)
+			if val == "" then
+				return read_filter_settings(pos, slot)
+			else
+				return change_filter_settings(pos, slot, val)
+			end
 		else		
 			return CRD(pos).State:on_receive_message(pos, topic, payload)
 		end

icta_controller/commands.lua

@@ -744,3 +744,52 @@ techage.icta_register_action("set_filter", {
 		end
 	end,
 })
+
+techage.icta_register_condition("get_filter", {
+	title = "read state of a Distributor filter slot",
+	formspec = {
+		{
+			type = "number",
+			name = "number",
+			label = "distri number",
+			default = "",
+		},
+		{
+			type = "textlist",
+			name = "color",
+			label = "filter port",
+			choices = "red,green,blue,yellow",
+			default = "red",
+		},
+		{
+			type = "textlist",
+			name = "operand",
+			choices = "is,is not",
+			default = "is",
+		},
+		{
+			type = "textlist",
+			name = "value",
+			label = "state",
+			choices = "on,off",
+			default = "off",
+		},
+		{
+			type = "label",
+			name = "lbl",
+			label = "Read state of a Distributor filter slot.\n",
+		},
+	},
+	button = function(data, environ)  -- default button label
+		return 'fltr('..techage.fmt_number(data.number)..","..data.color..' '..data.operand..' '..data.value..')'
+	end,
+	code = function(data, environ)
+		local condition = function(env, idx)
+			return techage.send_single(environ.number, data.number, "port", data.color)
+		end
+		local result = function(val)
+			return techage.compare(val, data.value, data.operand)
+		end
+		return condition, result
+	end,
+})

lua_controller/commands.lua

@@ -105,6 +105,19 @@ techage.lua_ctlr.register_action("set_filter", {
 		' example: $set_filter("1234", "red", "off")'
 })
 
+techage.lua_ctlr.register_action("get_filter", {
+	cmnd = function(self, num, slot)
+		num = tostring(num or "")
+		slot = tostring(slot or "red")
+		if not_protected(self.meta.owner, num) then
+			return techage.send_single(self.meta.number, num, "port", slot)
+		end
+	end,
+	help = " $get_filter(num, slot)\n"..
+		' Read state of a Distributor filter slot.\n'..
+		' Return value is "on" or "off".\n'..
+		' example: state = $get_filter("1234", "red")'
+})
 
 techage.lua_ctlr.register_action("display", {
 	cmnd = function(self, num, row, text)