Make Buffers become implicitly their own TCBs and signals when interlocking is enabled

5 files changed, 198 insertions, 21 deletions

diff --git a/advtrains_interlocking/database.lua b/advtrains_interlocking/database.lua
index e77d073..75247de 100644
--- a/advtrains_interlocking/database.lua
+++ b/advtrains_interlocking/database.lua
@@ -802,10 +802,18 @@ function ildb.create_tcb_at(pos)
 end
 
 -- Remove TCB at the position and update/repair the now joined section
-function ildb.remove_tcb_at(pos)
+--   skip_tsrepair: should be set to true when the rail node at the TCB position is already gone.
+--                  Assumes the track sections are now separated and does not attempt the repair process.
+function ildb.remove_tcb_at(pos, pname, skip_tsrepair)
 	--atdebug("remove_tcb_at",pos)
 	local pts = advtrains.encode_pos(pos)
 	local old_tcb = track_circuit_breaks[pts]
+	-- unassign signals if defined
+	for connid=1,2 do
+		if old_tcb[connid].signal then
+			ildb.set_sigd_for_signal(old_tcb[connid].signal, nil)
+		end
+	end
 	track_circuit_breaks[pts] = nil
 	-- purge the track sections adjacent
 	if old_tcb[1].ts_id then
@@ -823,7 +831,9 @@ function ildb.remove_tcb_at(pos)
 	end
 	advtrains.interlocking.remove_tcb_marker(pos)
 	-- If needed, merge the track sections here
-	ildb.check_and_repair_ts_at_pos(pos, nil)
+	if not skip_tsrepair then
+		ildb.check_and_repair_ts_at_pos(pos, pname)
+	end
 	return true
 end
 
@@ -973,11 +983,34 @@ function ildb.get_sigd_for_signal(pos)
 	end
 	return nil
 end
-function ildb.set_sigd_for_signal(pos, sigd)
+function ildb.set_sigd_for_signal(pos, sigd) -- do not use!
 	local pts = advtrains.roundfloorpts(pos)
 	signal_assignments[pts] = sigd
 end
 
+-- Assign the signal at pos to the given TCB side.
+function ildb.assign_signal_to_tcbs(pos, sigd)
+	local tcbs = ildb.get_tcbs(sigd)
+	assert(tcbs, "assign_signal_to_tcbs invalid sigd!")
+	tcbs.signal = pos
+	if not tcbs.routes then
+		tcbs.routes = {}
+	end
+	ildb.set_sigd_for_signal(pos, sigd)
+end
+
+-- unassign the signal from the given sigd (looks in tcbs.signal for the signalpos)
+function ildb.unassign_signal_for_tcbs(sigd)
+	local tcbs = advtrains.interlocking.db.get_tcbs(sigd)
+	if not tcbs then return end
+	local pos = tcbs.signal
+	if not pos then return end
+	ildb.set_sigd_for_signal(pos, nil)
+	tcbs.signal = nil
+	tcbs.route_aspect = nil
+	tcbs.route_remote = nil
+end
+
 -- checks if there's any influence point set to this position
 -- if purge is true, checks whether the associated signal still exists
 -- and deletes the ip if not.
@@ -987,7 +1020,7 @@ function ildb.is_ip_at(pos, purge)
 		if purge then
 			-- is there still a signal assigned to it?
 			for connid, sigpos in pairs(influence_points[pts]) do
-				local asp = advtrains.interlocking.signal_get_aspect(sigpos)
+				local asp = advtrains.interlocking.signal.get_aspect(sigpos)
 				if not asp then
 					atlog("Clearing orphaned signal influence point", pts, "/", connid)
 					ildb.clear_ip_signal(pts, connid)
diff --git a/advtrains_interlocking/mod.conf b/advtrains_interlocking/mod.conf
index 3b2d029..9191dd9 100644
--- a/advtrains_interlocking/mod.conf
+++ b/advtrains_interlocking/mod.conf
@@ -4,4 +4,4 @@ description=Interlocking system for Advanced Trains
 author=orwell96
 
 depends=advtrains
-optional_depends=advtrains_train_track
+#optional_depends=advtrains_train_track
diff --git a/advtrains_interlocking/route_prog.lua b/advtrains_interlocking/route_prog.lua
index 2f0f8ee..3bdf6d6 100644
--- a/advtrains_interlocking/route_prog.lua
+++ b/advtrains_interlocking/route_prog.lua
@@ -535,9 +535,12 @@ minetest.register_on_punchnode(function(pos, node, player, pointed_thing)
 			-- show formspec
 			
 			show_routing_form(pname, tcbpos)
-			
 			advtrains.interlocking.visualize_route(rp.origin, rp.route, "prog_"..pname, rp.tmp_lcks, pname)
-			
+			return
+		elseif advtrains.interlocking.database.get_tcb(pos) then
+			-- the punched node itself is a TCB
+			show_routing_form(pname, pos)
+			advtrains.interlocking.visualize_route(rp.origin, rp.route, "prog_"..pname, rp.tmp_lcks, pname)
 			return
 		end
 		if advtrains.is_passive(pos) then
diff --git a/advtrains_interlocking/signal_api.lua b/advtrains_interlocking/signal_api.lua
index 9b0479f..8347b1c 100644
--- a/advtrains_interlocking/signal_api.lua
+++ b/advtrains_interlocking/signal_api.lua
@@ -400,7 +400,8 @@ end
 -- 0: not a signal at all
 -- 1: signal has get_aspect_info() but the aspect is not variable (e.g. a sign)
 -- 2: signal has apply_aspect() but does not have main aspects (e.g. a pure distant signal)
--- 3: Full capabilities, signal has main aspects and can be used as main/shunt signal (can be start/endpoint of a route)
+-- 3: signal has main signal role but can only ever display a halt aspect, such as a bumper (can be endpoint, but not startpoint, of a route)
+-- 4: Full capabilities, signal has main aspects and can be used as main/shunt signal (can be start/endpoint of a route)
 function signal.get_signal_cap_level(pos)
 	local node = advtrains.ndb.get_node_or_nil(pos)
 	local ndef = node and minetest.registered_nodes[node.name]
@@ -408,6 +409,10 @@ function signal.get_signal_cap_level(pos)
 	if ndefat and ndefat.get_aspect_info then
 		if ndefat.apply_aspect  then
 			if ndefat.main_aspects then
+				-- if the table contains anything, 4, otherwise 3
+				for _,_ in pairs(ndefat.main_aspects) do
+					return 4
+				end
 				return 3
 			end
 			return 2
@@ -419,9 +424,17 @@ end
 
 ----------------
 
-function signal.can_dig(pos)
+function signal.can_dig(pos, player)
 	local sigd = advtrains.interlocking.db.get_sigd_for_signal(pos)
 	if sigd then
+		-- check privileges
+		if not player or not minetest.check_player_privs(player:get_player_name(), "interlocking") then
+			if not player then -- intermediate debug to uncover hard-to-find bugz
+				atdebug("advtrains.interlocking.signal.can_dig(",pos,") called with player==nil!")
+			end
+			return false
+		end
+		-- check if route is set
 		local tcbs = advtrains.interlocking.db.get_tcbs(sigd)
 		if tcbs.routeset then
 			return false
@@ -434,11 +447,7 @@ function signal.after_dig(pos, oldnode, oldmetadata, player)
 	-- unassign signal if necessary
 	local sigd = advtrains.interlocking.db.get_sigd_for_signal(pos)
 	if sigd then
-		local tcbs = advtrains.interlocking.db.get_tcbs(sigd)
-		advtrains.interlocking.db.set_sigd_for_signal(pos, nil)
-		tcbs.signal = nil
-		tcbs.route_aspect = nil
-		tcbs.route_remote = nil
+		advtrains.interlocking.db.unassign_signal_for_tcbs(sigd)
 		minetest.chat_send_player(player:get_player_name(), "Signal has been unassigned. Name and routes are kept for reuse.")
 	end
 	-- TODO clear influence point
diff --git a/advtrains_interlocking/tcb_ts_ui.lua b/advtrains_interlocking/tcb_ts_ui.lua
index 1cdbb29..2b93234 100755
--- a/advtrains_interlocking/tcb_ts_ui.lua
+++ b/advtrains_interlocking/tcb_ts_ui.lua
@@ -156,7 +156,7 @@ minetest.register_on_punchnode(function(pos, node, player, pointed_thing)
 	local tcbnpos = players_assign_tcb[pname]
 	if tcbnpos then
 		if vector.distance(pos, tcbnpos)<=20 then
-			local node_ok, conns, rhe = advtrains.get_rail_info_at(pos, advtrains.all_tracktypes)
+			local node_ok, conns, rhe = advtrains.get_rail_info_at(pos)
 			if node_ok and #conns == 2 then
 				-- if there is already a tcb here, reassign it
 				if ildb.get_tcb(pos) then
@@ -189,11 +189,7 @@ minetest.register_on_punchnode(function(pos, node, player, pointed_thing)
 				if ndef and ndef.advtrains and ndef.advtrains.apply_aspect then
 					local tcbs = ildb.get_tcbs(sigd)
 					if tcbs then
-						tcbs.signal = pos
-						if not tcbs.routes then
-							tcbs.routes = {}
-						end
-						ildb.set_sigd_for_signal(pos, sigd)
+						ildb.assign_signal_to_tcbs(pos, sigd)
 						minetest.chat_send_player(pname, "Configuring TCB: Successfully assigned signal.")
 						advtrains.interlocking.show_ip_form(pos, pname, true)
 					else
@@ -212,6 +208,138 @@ minetest.register_on_punchnode(function(pos, node, player, pointed_thing)
 	end
 end)
 
+-- "Self-contained TCB"
+-- 2024-11-25: Buffers should become their own TCB (and signal) automatically to permit setting routes to them
+-- These are support functions for this kind of node.
+
+-- Create an after_place_node callback for a self-contained TCB node. The parameters control additional behavior:
+-- fail_silently_on_noprivs: (boolean) Does not give an error in case the placer does not have the interlocking privilege
+-- auto_create_self_signal: (boolean) Automatically assign this same node as signal to the A side of the newly-created TCB
+--                          (this is useful for buffers as they serve both as TCB and as an always-halt signal)
+function advtrains.interlocking.self_tcb_make_after_place_callback(fail_silently_on_noprivs, auto_create_self_signal)
+	return function(pos, player, itemstack, pointed_thing)
+		atdebug("selftcb apn ",pos, player, itemstack, pointed_thing)
+		local pname = player:get_player_name()
+		if not minetest.check_player_privs(pname, "interlocking") then
+			if not fail_silently_on_noprivs then
+				minetest.chat_send_player(pname, "Insufficient privileges to use this!")
+			end
+			return
+		end
+		if ildb.get_tcb(pos) then
+			minetest.chat_send_player(pname, "TCB already existed at this position, now linked to this node")
+		else
+			ildb.create_tcb_at(pos, pname)
+		end
+		if auto_create_self_signal then
+			local sigd = { p = pos, s = 1 }
+			local tcbs = ildb.get_tcbs(sigd)
+			-- make sure signal doesn't already exist
+			if tcbs.signal then
+				minetest.chat_send_player(pname, "Signal on B side already assigned!")
+				return
+			end
+			ildb.assign_signal_to_tcbs(pos, sigd)
+			-- assign influence point to itself
+			ildb.set_ip_signal(advtrains.roundfloorpts(pos), 1, pos)
+		end
+	end
+end
+
+-- Create an can_dig callback for a self-contained TCB node. The parameters control additional behavior:
+-- is_signal: (boolean) Whether this node is also a signal (in addition to being a TCB), e.g. when auto_create_self_signal was set.
+--            Causes also the signal API's can_dig to be called
+function advtrains.interlocking.self_tcb_make_can_dig_callback(is_signal)
+	return function(pos, player)
+		local pname = player and player:get_player_name() or ""
+		-- need to duplicate logic of the regular "can_dig_or_modify_track()" function in core/tracks.lua
+		if advtrains.get_train_at_pos(pos) then
+			minetest.chat_send_player(pname, "Can't remove track, a train is here!")
+			return false
+		end
+		-- end of standard checks
+		local tcb = ildb.get_tcb(pos)
+		if not tcb then
+			-- digging always allowed because the TCB hasn't been created (unless signal callback interjects)
+			if is_signal then
+				return advtrains.interlocking.signal.can_dig(pos, player)
+			else
+				return true
+			end
+		end
+		-- TCB exists
+		if not minetest.check_player_privs(pname, "interlocking") then
+			return false
+		end
+		-- fine to remove (unless signal callback interjects)
+		if is_signal then
+			return advtrains.interlocking.signal.can_dig(pos, player)
+		else
+			return true
+		end
+	end
+end
+
+-- Create an after_dig_node callback for a self-contained TCB node. The parameters control additional behavior:
+-- is_signal: (boolean) Whether this node is also a signal (in addition to being a TCB), e.g. when auto_create_self_signal was set.
+--            Causes also the signal API's after_dig_node to be called
+function advtrains.interlocking.self_tcb_make_after_dig_callback(is_signal)
+	return function(pos, oldnode, oldmetadata, player)
+		local pname = player:get_player_name()
+		if is_signal then
+			-- "dig" the signal first
+			advtrains.interlocking.signal.after_dig(pos, oldnode, oldmetadata, player)
+		end
+		if ildb.get_tcb(pos) then
+			-- remove the TCB
+			ildb.remove_tcb_at(pos, pname, true)
+		end
+	end
+end
+
+-- Create an on_rightclick callback for a self-contained TCB node. The rightclick callback tries to repeat the TCB assignment
+-- if necessary and otherwise shows the TCB formspec. The parameters control additional behavior:
+-- fail_silently_on_noprivs: (boolean) Does not give an error in case the placer does not have the interlocking privilege
+-- auto_create_self_signal: (boolean) Automatically assign this same node as signal to the B side of the
+--                           newly-created TCB if that has not already happened during place.
+--                           Otherwise, opens the signal dialog instead of the TCB dialog on rightclick
+function advtrains.interlocking.self_tcb_make_on_rightclick_callback(fail_silently_on_noprivs, auto_create_self_signal)
+	return function(pos, node, player, itemstack, pointed_thing)
+		local pname = player:get_player_name()
+		if not minetest.check_player_privs(pname, "interlocking") then
+			if not fail_silently_on_noprivs then
+				minetest.chat_send_player(pname, "Insufficient privileges to use this!")
+			end
+			return
+		end
+		if ildb.get_tcb(pos) then
+			-- TCB already here. go on
+		else
+			-- otherwise create tcb
+			ildb.create_tcb_at(pos, pname)
+		end
+		if auto_create_self_signal then
+			local sigd = { p = pos, s = 1 }
+			local tcbs = ildb.get_tcbs(sigd)
+			-- make sure signal doesn't already exist
+			if not tcbs.signal then
+				-- go ahead and assign signal
+				ildb.assign_signal_to_tcbs(pos, sigd)
+				-- assign influence point to itself
+				ildb.set_ip_signal(advtrains.roundfloorpts(pos), 1, pos)
+			end
+			-- in any case open the signalling form nouw
+			local control = player:get_player_control()
+			advtrains.interlocking.show_signal_form(pos, node, pname, control.aux1)
+			return
+		else
+			-- not an autosignal. Then show the TCB form
+			advtrains.interlocking.show_tcb_form(pos, pname)
+			return
+		end
+	end
+end
+
 -- TCB Form
 
 local function mktcbformspec(pos, side, tcbs, offset, pname)
@@ -666,7 +794,7 @@ function advtrains.interlocking.show_signalling_form(sigd, pname, sel_rte, calle
 				-- no route is active, and no route is so far defined
 				if not tcbs.signal then atwarn("signalling form missing signal?!", pos) return end -- safeguard, nothing else in this function checks tcbs.signal
 				local caps = advtrains.interlocking.signal.get_signal_cap_level(tcbs.signal)
-				if caps >= 3 then
+				if caps >= 4 then
 					-- offer user the "block signal mode"
 					form = form.."label[0.5,2.5;No routes are yet defined.]"
 					if hasprivs then
@@ -683,6 +811,10 @@ function advtrains.interlocking.show_signalling_form(sigd, pname, sel_rte, calle
 								.."Sets a route into the section ahead with auto-working set on\n"
 								.."Short block: This signal becomes distant signal for next signal.]"
 					end
+				elseif caps >= 3 then
+					-- it's a buffer!
+					form = form.."label[0.5,2.5;This is an always-halt signal (e.g. a buffer)\n"
+								.."No routes can be set from here.]"
 				else
 					-- signal caps say it cannot be route start/end
 					form = form.."label[0.5,2.5;This is a Non-Halt signal (e.g. pure distant signal)\n"