-- New track registration helper
-- Retains the old table-template-based definition format, but adapts it to the new (advtrains 2.5)
-- track definition system
-- Note to future: This is actually just a work-saver, avoiding me to port over all the crossing nodes as well as the linetrack tracks.
-- Future track mods should please directly use the appropriate advtrains.register_node_4rot() API and not rely on this!

--definition preparation
local function conns(c1, c2, r1, r2) return {{c=c1, y=r1}, {c=c2, y=r2}} end
local function conns3(c1, c2, c3, r1, r2, r3) return {{c=c1, y=r1}, {c=c2, y=r2}, {c=c3, y=r3}} end

advtrains.ap={}
advtrains.ap.t_30deg_flat={
	v25_format = true,
	regstep=1,
	variant={
		st={
			conns = conns(0,8),
			desc = "straight",
			tpdouble = true,
			tpsingle = true,
			trackworker = "cr",
		},
		cr={
			conns = conns(0,7),
			desc = "curve",
			tpdouble = true,
			trackworker = "swlst",
		},
		swlst={
			conns = conns3(0,8,7),
			desc = "left switch (straight)",
			trackworker = "swrst",
			switchalt = "cr",
			switchmc = "on",
			switchst = "st",
			switchprefix = "swl",
			conn_map = {2,1,1},
			stmref = "swl",
		},
		swlcr={
			conns = conns3(0,8,7),
			desc = "left switch (curve)",
			trackworker = "swrcr",
			switchalt = "st",
			switchmc = "off",
			switchst = "cr",
			switchprefix = "swl",
			conn_map = {3,1,1},
			stmref = "swl",
		},
		swrst={
			conns = conns3(0,8,9),
			desc = "right switch (straight)",
			trackworker = "st",
			switchalt = "cr",
			switchmc = "on",
			switchst = "st",
			switchprefix = "swr",
			conn_map = {2,1,1},
			stmref = "swr",
		},
		swrcr={
			conns = conns3(0,8,9),
			desc = "right switch (curve)",
			trackworker = "st",
			switchalt = "st",
			switchmc = "off",
			switchst = "cr",
			switchprefix = "swr",
			conn_map = {3,1,1},
			stmref = "swr",
		},
	},
	regtp=true,
	tpdefault="st",
	trackworker={
		["swrcr"]="st",
		["swrst"]="st",
		["cr"]="swlst",
		["swlcr"]="swrcr",
		["swlst"]="swrst",
	},
	rotation={"", "_30", "_45", "_60"},
	statemaps = {
		swl = { st = "swlst", cr = "swlcr"},
		swr = { st = "swrst", cr = "swrcr"}
	}
}
advtrains.ap.t_yturnout={
	v25_format = true,
	regstep=1,
	variant={
		l={
			conns = conns3(0,7,9),
			desc = "Y-turnout (left)",
			switchalt = "r",
			switchmc = "off",
			switchst = "l",
			switchprefix = "",
			conn_map = {2,1,1},
			stmref = "sw",
			tpsingle = true,
		},
		r={
			conns = conns3(0,7,9),
			desc = "Y-turnout (right)",
			switchalt = "l",
			switchmc = "on",
			switchst = "r",
			switchprefix = "",
			conn_map = {3,1,1},
			stmref = "sw",
		}
	},
	regtp=true,
	tpdefault="l",
	rotation={"", "_30", "_45", "_60"},
	statemaps = {
		sw = { l = "l", r = "r"}
	}
}
advtrains.ap.t_s3way={
	v25_format = true,
	regstep=1,
	variant={
		l={
			conns = { {c=0}, {c=7}, {c=8}, {c=9}},
			desc = "3-way turnout (left)",
			switchalt = "s",
			switchst="l",
			switchprefix = "",
			conn_map = {2,1,1},
			stmref = "sw",
		},
		s={
			conns = { {c=0}, {c=7}, {c=8}, {c=9}},
			desc = "3-way turnout (straight)",
			switchalt ="r",
			switchst = "s",
			switchprefix = "",
			conn_map = {3,1,1},
			stmref = "sw",
			tpsingle = true,
		},
		r={
			conns = { {c=0}, {c=7}, {c=8}, {c=9}},
			desc = "3-way turnout (right)",
			switchalt = "l",
			switchst="r",
			switchprefix = "",
			conn_map = {4,1,1},
			stmref = "sw",
		}
	},
	regtp=true,
	tpdefault="l",
	rotation={"", "_30", "_45", "_60"},
	statemaps = {
		sw = { l = "l", s = "s", r = "r"}
	}
}
advtrains.ap.t_30deg_slope={
	v25_format = true,
	regstep=1,
	variant={
		vst1={conns = conns(8,0,0,0.5), rail_y = 0.25, desc = "steep uphill 1/2", slope=true},
		vst2={conns = conns(8,0,0.5,1), rail_y = 0.75, desc = "steep uphill 2/2", slope=true},
		vst31={conns = conns(8,0,0,0.33), rail_y = 0.16, desc = "uphill 1/3", slope=true},
		vst32={conns = conns(8,0,0.33,0.66), rail_y = 0.5, desc = "uphill 2/3", slope=true},
		vst33={conns = conns(8,0,0.66,1), rail_y = 0.83, desc = "uphill 3/3", slope=true},
	},
	regsp=true,
	slopeplacer={
		[2]={"vst1", "vst2"},
		[3]={"vst31", "vst32", "vst33"},
		max=3,--highest entry
	},
	slopeplacer_45={
		[2]={"vst1_45", "vst2_45"},
		max=2,
	},
	rotation={"", "_30", "_45", "_60"},
	trackworker={},
	increativeinv={},
}
advtrains.ap.t_30deg_straightonly={
	v25_format = true,
	regstep=1,
	variant={
		st={
			conns = conns(0,8),
			desc = "straight",
			tpdouble = true,
			tpsingle = true,
			trackworker = "st",
		},
	},
	regtp=true,
	tpdefault="st",
	rotation={"", "_30", "_45", "_60"},
}
advtrains.ap.t_30deg_straightonly_noplacer={
	v25_format = true,
	regstep=1,
	variant={
		st={
			conns = conns(0,8),
			desc = "straight",
			tpdouble = true,
			tpsingle = true,
			trackworker = "st",
		},
	},
	tpdefault="st",
	rotation={"", "_30", "_45", "_60"},
}
advtrains.ap.t_45deg={
	v25_format = true,
	regstep=2,
	variant={
		st={
			conns = conns(0,8),
			desc = "straight",
			tpdouble = true,
			tpsingle = true,
			trackworker = "cr",
		},
		cr={
			conns = conns(0,6),
			desc = "curve",
			tpdouble = true,
			trackworker = "swlst",
		},
		swlst={
			conns = conns3(0,8,6),
			desc = "left switch (straight)",
			trackworker = "swrst",
			switchalt = "cr",
			switchmc = "on",
			switchst = "st",
		},
		swlcr={
			conns = conns3(0,6,8),
			desc = "left switch (curve)",
			trackworker = "swrcr",
			switchalt = "st",
			switchmc = "off",
			switchst = "cr",
		},
		swrst={
			conns = conns3(0,8,10),
			desc = "right switch (straight)",
			trackworker = "st",
			switchalt = "cr",
			switchmc = "on",
			switchst = "st",
		},
		swrcr={
			conns = conns3(0,10,8),
			desc = "right switch (curve)",
			trackworker = "st",
			switchalt = "st",
			switchmc = "off",
			switchst = "cr",
		},
	},
	regtp=true,
	tpdefault="st",
	trackworker={
		["swrcr"]="st",
		["swrst"]="st",
		["cr"]="swlst",
		["swlcr"]="swrcr",
		["swlst"]="swrst",
	},
	rotation={"", "_30", "_45", "_60"},
}
advtrains.ap.t_perpcrossing={
	v25_format = true,
	regstep = 1,
	variant={
		st={
			conns = { {c=0}, {c=8}, {c=4}, {c=12} },
			desc = "perpendicular crossing",
			tpdouble = true,
			tpsingle = true,
			trackworker = "st",
			conn_map = {2,1,4,3},
		},
	},
	regtp=true,
	tpdefault="st",
	rotation={"", "_30", "_45", "_60"},
}
advtrains.ap.t_90plusx_crossing={
	v25_format = true,
	regstep = 1,
	variant={
		["30l"]={
			conns = { {c=0}, {c=8}, {c=1}, {c=9} },
			desc = "30/90 degree crossing (left)",
			tpdouble = true,
			tpsingle = true,
			trackworker = "45l",
			conn_map = {2,1,4,3},
		},
		["45l"]={
			conns = { {c=0}, {c=8}, {c=2}, {c=10} },
			desc = "45/90 degree crossing (left)",
			tpdouble = true,
			tpsingle = true,
			trackworker = "60l",
			conn_map = {2,1,4,3},
		},
		["60l"]={
			conns = { {c=0}, {c=8}, {c=3}, {c=11}},
			desc = "60/90 degree crossing (left)",
			tpdouble = true,
			tpsingle = true,
			trackworker = "60r",
			conn_map = {2,1,4,3},
		},
		["60r"]={
			conns = { {c=0}, {c=8}, {c=5}, {c=13} },
			desc = "60/90 degree crossing (right)",
			tpdouble = true,
			tpsingle = true,
			trackworker = "45r",
			conn_map = {2,1,4,3},
		},
		["45r"]={
			conns = { {c=0}, {c=8}, {c=6}, {c=14} },
			desc = "45/90 degree crossing (right)",
			tpdouble = true,
			tpsingle = true,
			trackworker = "30r",
			conn_map = {2,1,4,3},
		},
		["30r"]={
			conns = { {c=0}, {c=8}, {c=7}, {c=15}},
			desc = "30/90 degree crossing (right)",
			tpdouble = true,
			tpsingle = true,
			trackworker = "30l",
			conn_map = {2,1,4,3},
		},
	},
	regtp=true,
	tpdefault="30l",
	rotation={""},
	trackworker = {
		["30l"] = "45l",
		["45l"] = "60l",
		["60l"] = "60r",
		["60r"] = "45r",
		["45r"] = "30r",
		["30r"] = "30l",
	}
}

advtrains.ap.t_diagonalcrossing = {
	v25_format = true,
	regstep=1,
	variant={
		["30l45r"]={
			conns = {{c=1}, {c=9}, {c=6}, {c=14}},
			desc = "30left-45right diagonal crossing",
			tpdouble=true,
			tpsingle=true,
			trackworker="60l30l",
			conn_map = {2,1,4,3},
		},
		["60l30l"]={
			conns = {{c=3}, {c=11}, {c=1}, {c=9}},
			desc = "30left-60right diagonal crossing",
			tpdouble=true,
			tpsingle=true,
			trackworker="60l45r",
			conn_map = {2,1,4,3},
		},
		["60l45r"]={
			conns = {{c=3}, {c=11}, {c=6}, {c=14}},
			desc = "60left-45right diagonal crossing",
			tpdouble=true,
			tpsingle=true,
			trackworker="60l60r",
			conn_map = {2,1,4,3},
		},
		["60l60r"]={
			conns = {{c=3}, {c=11}, {c=5}, {c=13}},
			desc = "60left-60right diagonal crossing",
			tpdouble=true,
			tpsingle=true,
			trackworker="60r45l",
			conn_map = {2,1,4,3},
		},
		--If 60l60r had a mirror image, it would be here, but it's symmetric.
		-- 60l60r is also equivalent to 30l30r but rotated 90 degrees.
		["60r45l"]={
			conns = {{c=5}, {c=13}, {c=2}, {c=10}},
			desc = "60right-45left diagonal crossing",
			tpdouble=true,
			tpsingle=true,
			trackworker="60r30r",
			conn_map = {2,1,4,3},
		},
		["60r30r"]={
			conns = {{c=5}, {c=13}, {c=7}, {c=15}},
			desc = "60right-30right diagonal crossing",
			tpdouble=true,
			tpsingle=true,
			trackworker="30r45l",
			conn_map = {2,1,4,3},
		},
		["30r45l"]={
			conns = {{c=7}, {c=15}, {c=2}, {c=10}},
			desc = "30right-45left diagonal crossing",
			tpdouble=true,
			tpsingle=true,
			trackworker="30l45r",
			conn_map = {2,1,4,3},
		},

	},
	regtp=true,
	tpdefault="30l45r",
	rotation={""},
	trackworker = {
		["30l45r"] = "60l30l",
		["60l30l"] = "60l45r",
		["60l45r"] = "60l60r",
		["60l60r"] = "60r45l",
		["60r45l"] = "60r30r",
		["60r30r"] = "30r45l",
		["30r45l"] = "30l45r",
	}
}

advtrains.trackpresets = advtrains.ap

--definition format: ([] optional)
--[[{
	nodename_prefix
	texture_prefix
	[shared_texture]
	models_prefix
	models_suffix (with dot)
	[shared_model]
	formats={
		st,cr,swlst,swlcr,swrst,swrcr,vst1,vst2
		(each a table with indices 0-3, for if to register a rail with this 'rotation' table entry. nil is assumed as 'all', set {} to not register at all)
	}
	common={} change something on common rail appearance
}
[18.12.17] Note on new connection system:
In order to support real rail crossing nodes and finally make the trackplacer respect switches, I changed the connection system.
There can be a variable number of connections available. These are specified as tuples {c=<connection>, y=<rely>}
The table "at_conns" consists of {<conn1>, <conn2>...}
the "at_rail_y" property holds the value that was previously called "railheight"
Depending on the number of connections:
2 conns: regular rail
3 conns: switch:
	- when train passes in at conn1, will move out of conn2
	- when train passes in at conn2 or conn3, will move out of conn1
4 conns: cross (or cross switch, depending on arrangement of conns):
	- conn1 <> conn2
	- conn3 <> conn4
]]

-- Notify the user if digging the rail is not allowed
local function can_dig_callback(pos, player)
	local ok, reason = advtrains.can_dig_or_modify_track(pos)
	if not ok and player then
		minetest.chat_send_player(player:get_player_name(), attrans("This track can not be removed!") .. " " .. reason)
	end
	return ok
end

local function append_statemap_suffix(state_map, nnpref, rot)
	local t = {}
	for state, nn in pairs(state_map) do
		t[state] = nnpref .. "_" .. nn .. rot
	end
	return t
end

function advtrains.register_tracks(tracktype, def, preset)
	if not preset.v25_format then
		error("advtrains.register_tracks(): A track preset for pre-v2.5 is used with advtrains 2.5+. Mod probably defines own track preset instead of using it from the advtrains.ap table! Please check track mod compatibility!")
	end

	if preset.regtp then
		local nnprefix = def.nodename_prefix
		minetest.register_craftitem(":"..nnprefix.."_placer", {
			description = def.description,
			inventory_image = def.texture_prefix.."_placer.png",
			wield_image = def.texture_prefix.."_placer.png",
			groups={advtrains_trackplacer=1, digtron_on_place=1},
			liquids_pointable = false,
			on_place = function(itemstack, placer, pointed_thing)
				local name = placer:get_player_name()
				if not name then
				   return itemstack, false
				end
				if pointed_thing.type=="node" then
					local pos=pointed_thing.above
					local upos=vector.subtract(pointed_thing.above, {x=0, y=1, z=0})
					if not advtrains.check_track_protection(pos, name) then
						return itemstack, false
					end
					if minetest.registered_nodes[minetest.get_node(pos).name] and minetest.registered_nodes[minetest.get_node(pos).name].buildable_to then
						local s = minetest.registered_nodes[minetest.get_node(upos).name] and minetest.registered_nodes[minetest.get_node(upos).name].walkable
						if s then
	--						minetest.chat_send_all(nnprefix)
							local yaw = placer:get_look_horizontal()
							advtrains.trackplacer.place_track(pos, nnprefix, name, yaw)
							if not advtrains.is_creative(name) then
								itemstack:take_item()
							end
						end
					end
				end
				return itemstack, true
			end,
		})
		
		advtrains.trackplacer.set_default_place_candidate(def.nodename_prefix, def.nodename_prefix.."_"..preset.tpdefault)
	end
	if preset.regsp then
		advtrains.slope.register_placer(def, preset)			
	end
	
	for suffix, var in pairs(preset.variant) do
		for rotid, rotation in ipairs(preset.rotation) do
			if not def.formats[suffix] or def.formats[suffix][rotid] then
				local img_suffix = suffix..rotation
				local ndef = advtrains.merge_tables({
					description=def.description.."("..(var.desc or "any")..rotation..")",
					drawtype = "mesh",
					paramtype="light",
					paramtype2="facedir",
					walkable = false,
					selection_box = {
						type = "fixed",
						fixed = {-1/2-1/16, -1/2, -1/2, 1/2+1/16, -1/2+2/16, 1/2},
					},
					
					mesh = def.shared_model or (def.models_prefix.."_"..img_suffix..def.models_suffix),
					tiles = {def.shared_texture or (def.texture_prefix.."_"..img_suffix..".png"), def.second_texture},
					
					groups = {
						attached_node = advtrains.IGNORE_WORLD and 0 or 1,
						advtrains_track=1,
						["advtrains_track_"..tracktype]=1,
						save_in_at_nodedb=1,
						dig_immediate=2,
						not_in_creative_inventory=1,
						not_blocking_trains=1,
					},
						
					can_dig = advtrains.track_can_dig_callback,
					after_dig_node = advtrains.track_update_callback,
					after_place_node = advtrains.track_update_callback,
					
					at_rail_y = var.rail_y
				}, def.common or {})
				
				if preset.regtp then
					ndef.drop = def.nodename_prefix.."_placer"
				end
				if preset.regsp and var.slope then
					ndef.drop = def.nodename_prefix.."_slopeplacer"
				end
				
				--connections
				ndef.at_conns = advtrains.rotate_conn_by(var.conns, (rotid-1)*preset.regstep)
				-- NEW since 2.5
				ndef.at_conn_map = var.conn_map
				
				local ndef_avt_table = {}
				
				if var.switchalt and var.switchst then
					-- NEW since 2.5
					ndef.on_rightclick = advtrains.state_node_on_rightclick_callback
					ndef_avt_table.node_state = var.switchst
					ndef_avt_table.node_next_state = var.switchalt
					-- obtain and build statemap
					local state_map = preset.statemaps[var.stmref]
					if not state_map then error("On registering "..def.nodename_prefix.."_"..suffix..rotation..", stmref of variant doesn't reference entry in preset.statemaps") end
					ndef_avt_table.node_state_map = append_statemap_suffix(state_map, def.nodename_prefix, rotation)
					
					if var.switchmc then
						local vswitchalt = var.switchalt
						ndef.mesecons = {effector = {
							["action_"..var.switchmc] = function(pos, node) 
								advtrains.setstate(pos, vswitchalt, node)
							end,
							rules=advtrains.meseconrules
						}}
					end
				end
				
				local adef={}
				if def.get_additional_definiton then
					adef=def.get_additional_definiton(def, preset, suffix, rotation)
				end
				ndef = advtrains.merge_tables(ndef, adef)
				
				-- insert getstate/setstate functions after merging the additional definitions
				if ndef_avt_table then
					ndef.advtrains = advtrains.merge_tables(ndef.advtrains or {}, ndef_avt_table)
				end
				
				-- NEW since 2.5: add appropriate fields for trackworker rotation
				-- get the next rotation step
				local num_rots = #preset.rotation
				if rotid >= num_rots then
					ndef.advtrains.trackworker_next_rot = def.nodename_prefix.."_"..suffix..preset.rotation[1]
					ndef.advtrains.trackworker_rot_incr_param2 = true
				else
					ndef.advtrains.trackworker_next_rot = def.nodename_prefix.."_"..suffix..preset.rotation[rotid+1]
				end
				if var.trackworker then
					ndef.advtrains.trackworker_next_var = def.nodename_prefix.."_"..var.trackworker..rotation
				end

				local the_node_name = def.nodename_prefix.."_"..suffix..rotation
				
				--trackplacer
				if preset.regtp and (var.tpsingle or var.tpdouble) then
					advtrains.trackplacer.register_candidate(
						def.nodename_prefix,
						the_node_name,
						ndef,
						var.tpsingle,
						var.tpdouble,
						true)
				end
				
				-- All set, go ahead and register node!
				--atdebug("track_reg_helper: Registering ",the_node_name," as",ndef)
				minetest.register_node(":"..the_node_name, ndef)
				
			end
		end
	end
end

-- slope placer. Defined in register_tracks.
--crafted with rail and gravel
local sl={}
function sl.register_placer(def, preset)
	minetest.register_craftitem(":"..def.nodename_prefix.."_slopeplacer",{
		description = attrans("@1 Slope", def.description),
		inventory_image = def.texture_prefix.."_slopeplacer.png",
		wield_image = def.texture_prefix.."_slopeplacer.png",
		groups={},
		on_place = sl.create_slopeplacer_on_place(def, preset)
	})
end
--(itemstack, placer, pointed_thing)
function sl.create_slopeplacer_on_place(def, preset)
	return function(istack, player, pt)
		if not pt.type=="node" then 
			minetest.chat_send_player(player:get_player_name(), attrans("Can't place: not pointing at node"))
			return istack 
		end
		local pos=pt.above
		if not pos then 
			minetest.chat_send_player(player:get_player_name(), attrans("Can't place: not pointing at node"))
			return istack
		end
		local node=minetest.get_node(pos)
		if not minetest.registered_nodes[node.name] or not minetest.registered_nodes[node.name].buildable_to then
			minetest.chat_send_player(player:get_player_name(), attrans("Can't place: space occupied!"))
			return istack
		end
		if not advtrains.check_track_protection(pos, player:get_player_name()) then 
			minetest.record_protection_violation(pos, player:get_player_name())
			return istack
		end
		--determine player orientation (only horizontal component)
		--get_look_horizontal may not be available
		local yaw=player.get_look_horizontal and player:get_look_horizontal() or (player:get_look_yaw() - math.pi/2)
		
		--rounding unit vectors is a nice way for selecting 1 of 8 directions since sin(30°) is 0.5.
		local dirvec={x=math.floor(math.sin(-yaw)+0.5), y=0, z=math.floor(math.cos(-yaw)+0.5)}
		--translate to direction to look up inside the preset table
		local param2, rot45=({
			[-1]={
				[-1]=2,
				[0]=3,
				[1]=3,
				},
			[0]={
				[-1]=2,
				[1]=0,
				},
			[1]={
				[-1]=1,
				[0]=1,
				[1]=0,
				},
		})[dirvec.x][dirvec.z], dirvec.x~=0 and dirvec.z~=0
		local lookup=preset.slopeplacer
		if rot45 then lookup=preset.slopeplacer_45 end
		
		--go unitvector forward and look how far the next node is
		local step=1
		while step<=lookup.max do
			local node=minetest.get_node(vector.add(pos, dirvec))
			--next node solid?
			if not minetest.registered_nodes[node.name] or not minetest.registered_nodes[node.name].buildable_to or advtrains.is_protected(pos, player:get_player_name()) then 
				--do slopes of this distance exist?
				if lookup[step] then
					if minetest.settings:get_bool("creative_mode") or istack:get_count()>=step then
						--start placing
						local placenodes=lookup[step]
						while step>0 do
							minetest.set_node(pos, {name=def.nodename_prefix.."_"..placenodes[step], param2=param2})
							if not minetest.settings:get_bool("creative_mode") then
								istack:take_item()
							end
							step=step-1
							pos=vector.subtract(pos, dirvec)
						end
					else
						minetest.chat_send_player(player:get_player_name(), attrans("Can't place: Not enough slope items left (@1 required)", step))
					end
				else
					minetest.chat_send_player(player:get_player_name(), attrans("Can't place: There's no slope of length @1",step))
				end
				return istack
			end
			step=step+1
			pos=vector.add(pos, dirvec)
		end
		minetest.chat_send_player(player:get_player_name(), attrans("Can't place: no supporting node at upper end."))
		return itemstack
	end
end

advtrains.slope=sl