local lot = os.clock()
minetest.log("action", "[advtrains] Loading...")

-- Boilerplate to support localized strings if intllib mod is installed.
if minetest.get_modpath("intllib") then
    attrans = intllib.Getter()
else
    attrans = function(s,a,...)a={a,...}return s:gsub("@(%d+)",function(n)return a[tonumber(n)]end)end
end

--advtrains

DUMP_DEBUG_SAVE = false
GENERATE_ATRICIFIAL_LAG = false

--Constant for maximum connection value/division of the circle
AT_CMAX = 16

advtrains = {trains={}, player_to_train_mapping={}}

--pcall
local no_action=false

local function reload_saves()
	atwarn("Restoring saved state in 1 second...")
	no_action=true
	advtrains.lock_path_inval = false
	--read last save state and continue, as if server was restarted
	for aoi, le in pairs(minetest.luaentities) do
		if le.is_wagon then
			le.object:remove()
		end
	end
	minetest.after(1, function()
		advtrains.load()
		atwarn("Reload successful!")
		advtrains.ndb.restore_all()
	end)
end

function advtrains.pcall(fun)
	if no_action then return end
	
	local succ, return1, return2, return3, return4=xpcall(fun, function(err)
			atwarn("Lua Error occured: ", err)
			atwarn(debug.traceback())
			if advtrains.atprint_context_tid then
				advtrains.path_print(advtrains.trains[advtrains.atprint_context_tid], atdebug)
				atwarn(advtrains.trains[advtrains.atprint_context_tid].debug)
			end
		end)
	if not succ then
		reload_saves()
	else
		return return1, return2, return3, return4
	end
end


advtrains.modpath = minetest.get_modpath("advtrains")

--Advtrains dump (special treatment of pos and sigd)
function atdump(t, intend)
	local str
	if type(t)=="table" then
		if t.x and t.y and t.z then
			str=minetest.pos_to_string(t)
		elseif t.p and t.s then -- interlocking sigd
			str="S["..minetest.pos_to_string(t.p).."/"..t.s.."]"
		elseif advtrains.lines and t.s and t.m then -- RwT
			str=advtrains.lines.rwt.to_string(t)
		else
			str="{"
			local intd = (intend or "") .. "  "
			for k,v in pairs(t) do
				if type(k)~="string" or not string.match(k, "^path[_]?") then
					-- do not print anything path-related
					str = str .. "\n" .. intd .. atdump(k, intd) .. " = " ..atdump(v, intd)
				end
			end
			str = str .. "\n" .. (intend or "") .. "}"
		end
	elseif type(t)=="boolean" then
		if t then
			str="true"
		else
			str="false"
		end
	elseif type(t)=="function" then
		str="<function>"
	elseif type(t)=="userdata" then
		str="<userdata>"
	else
		str=""..t
	end
	return str
end

function advtrains.print_concat_table(a)
	local str=""
	local stra=""
	local t
	for i=1,20 do
		t=a[i]
		if t==nil then
			stra=stra.."nil "
		else
			str=str..stra
			stra=""
			str=str..atdump(t).." "
		end
	end
	return str
end

atprint=function() end
atlog=function(t, ...)
	local text=advtrains.print_concat_table({t, ...})
	minetest.log("action", "[advtrains]"..text)
end
atwarn=function(t, ...)
	local text=advtrains.print_concat_table({t, ...})
	minetest.log("warning", "[advtrains]"..text)
	minetest.chat_send_all("[advtrains] -!- "..text)
end
sid=function(id) if id then return string.sub(id, -6) end end


--ONLY use this function for temporary debugging. for consistent debug prints use atprint
atdebug=function(t, ...)
	local text=advtrains.print_concat_table({t, ...})
	minetest.log("action", "[advtrains]"..text)
	minetest.chat_send_all("[advtrains]"..text)
end

if minetest.settings:get_bool("advtrains_enable_debugging") then
	atprint=function(t, ...)
		local context=advtrains.atprint_context_tid or ""
		if not context then return end
		local text=advtrains.print_concat_table({t, ...})
		advtrains.drb_record(context, text)
		
		--atlog("@@",advtrains.atprint_context_tid,t,...)
	end
	dofile(advtrains.modpath.."/debugringbuffer.lua")
	
end

function assertt(var, typ)
	if type(var)~=typ then
		error("Assertion failed, variable has to be of type "..typ)
	end
end

dofile(advtrains.modpath.."/helpers.lua");
--dofile(advtrains.modpath.."/debugitems.lua");

advtrains.meseconrules = 
{{x=0,  y=0,  z=-1},
 {x=1,  y=0,  z=0},
 {x=-1, y=0,  z=0},
 {x=0,  y=0,  z=1},
 {x=1,  y=1,  z=0},
 {x=1,  y=-1, z=0},
 {x=-1, y=1,  z=0},
 {x=-1, y=-1, z=0},
 {x=0,  y=1,  z=1},
 {x=0,  y=-1, z=1},
 {x=0,  y=1,  z=-1},
 {x=0,  y=-1, z=-1},
 {x=0, y=-2, z=0}}

advtrains.fpath=minetest.get_worldpath().."/advtrains"

dofile(advtrains.modpath.."/path.lua")
dofile(advtrains.modpath.."/trainlogic.lua")
dofile(advtrains.modpath.."/trainhud.lua")
dofile(advtrains.modpath.."/trackplacer.lua")
dofile(advtrains.modpath.."/tracks.lua")
dofile(advtrains.modpath.."/occupation.lua")
dofile(advtrains.modpath.."/atc.lua")
dofile(advtrains.modpath.."/wagons.lua")
dofile(advtrains.modpath.."/protection.lua")

dofile(advtrains.modpath.."/trackdb_legacy.lua")
dofile(advtrains.modpath.."/nodedb.lua")
dofile(advtrains.modpath.."/couple.lua")

dofile(advtrains.modpath.."/signals.lua")
dofile(advtrains.modpath.."/misc_nodes.lua")
dofile(advtrains.modpath.."/crafting.lua")
dofile(advtrains.modpath.."/craft_items.lua")

dofile(advtrains.modpath.."/log.lua")
dofile(advtrains.modpath.."/passive.lua")

dofile(advtrains.modpath.."/lzb.lua")


--load/save

-- backup variables, used if someone should accidentally delete a sub-mod
local MDS_interlocking, MDS_lines


advtrains.fpath=minetest.get_worldpath().."/advtrains"
dofile(advtrains.modpath.."/log.lua")
function advtrains.read_component(name)
	local path = advtrains.fpath.."_"..name
	minetest.log("action", "[advtrains] loading "..path)
	local file, err = io.open(path, "r")
	if not file then
		minetest.log("warning", " Failed to read advtrains save data from file "..path..": "..(err or "Unknown Error"))
		minetest.log("warning", " (this is normal when first enabling advtrains on this world)")
		return
	end
	local tbl =  minetest.deserialize(file:read("*a"))
	file:close()
	return tbl
end

function advtrains.avt_load()
	-- check for new, split advtrains save file
	
	local version = advtrains.read_component("version")
	local tbl
	if version and version == 3 then
		-- we are dealing with the new, split-up system
		minetest.log("action", "[advtrains] loading savefiles version 3")
		local il_save = {
			tcbs = true,
			ts = true,
			signalass = true,
			rs_locks = true,
			rs_callbacks = true,
			influence_points = true,
			npr_rails = true,
		}
		tbl={
			trains = true,
			wagon_save = true,
			ptmap = true,
			atc = true,
			ndb = true,		
			lines = true,
			version = 2,
		}
		for i,k in pairs(il_save) do
			il_save[i] = advtrains.read_component("interlocking_"..i)
		end
		for i,k in pairs(tbl) do
			tbl[i] = advtrains.read_component(i)
		end
		tbl["interlocking"] = il_save
	else	
		local file, err = io.open(advtrains.fpath, "r")
		if not file then
			minetest.log("warning", " Failed to read advtrains save data from file "..advtrains.fpath..": "..(err or "Unknown Error"))
			minetest.log("warning", " (this is normal when first enabling advtrains on this world)")
			return
		else
			tbl = minetest.deserialize(file:read("*a"))
			file:close()
		end
	end
	if type(tbl) == "table" then
		if tbl.version then
			--congrats, we have the new save format.
			advtrains.trains = tbl.trains
			--Save the train id into the train table to avoid having to pass id around
			for id, train in pairs(advtrains.trains) do
				train.id = id
			end
			advtrains.wagons = tbl.wagon_save
			advtrains.player_to_train_mapping = tbl.ptmap or {}
			advtrains.ndb.load_data(tbl.ndb)
			advtrains.atc.load_data(tbl.atc)
			if advtrains.interlocking then
				advtrains.interlocking.db.load(tbl.interlocking)
			else
				MDS_interlocking = tbl.interlocking
			end
			if advtrains.lines then
				advtrains.lines.load(tbl.lines)
			else
				MDS_lines = tbl.lines
			end
			--remove wagon_save entries that are not part of a train
			local todel=advtrains.merge_tables(advtrains.wagon_save)
			for tid, train in pairs(advtrains.trains) do
				train.id = tid
				for _, wid in ipairs(train.trainparts) do
					todel[wid]=nil
				end
			end
			for wid, _ in pairs(todel) do
				atwarn("Removing unused wagon", wid, "from wagon_save table.")
				advtrains.wagon_save[wid]=nil
			end
		else
			--oh no, its the old one...
			advtrains.trains=tbl
			--load ATC
			advtrains.fpath_atc=minetest.get_worldpath().."/advtrains_atc"
			local file, err = io.open(advtrains.fpath_atc, "r")
			if not file then
				local er=err or "Unknown Error"
				atprint("Failed loading advtrains atc save file "..er)
			else
				local tbl = minetest.deserialize(file:read("*a"))
				if type(tbl) == "table" then
					advtrains.atc.controllers=tbl.controllers
				end
				file:close()
			end
			--load wagon saves
			advtrains.fpath_ws=minetest.get_worldpath().."/advtrains_wagon_save"
			local file, err = io.open(advtrains.fpath_ws, "r")
			if not file then
				local er=err or "Unknown Error"
				atprint("Failed loading advtrains save file "..er)
			else
				local tbl = minetest.deserialize(file:read("*a"))
				if type(tbl) == "table" then
					advtrains.wagon_save=tbl
				end
				file:close()
			end
		end
	else
		minetest.log("error", " Failed to deserialize advtrains save data: Not a table!")
	end
end

advtrains.save_component = function (tbl, name)
	-- Saves each component of the advtrains file separately
	--
	-- required for now to shrink the advtrains db to overcome lua
	-- limitations.
	local datastr = minetest.serialize(tbl)
	if not datastr then
		minetest.log("error", " Failed to serialize advtrains save data!")
		return
	end
	local temppath = advtrains.fpath.."_"..name.."~"
	local file, err = io.open(temppath, "w")
	if err then
		minetest.log("error", " Failed to write advtrains save data to file "..temppath..": "..(err or "Unknown Error"))
		return
	end
	file:write(datastr)
	file:close()
	os.rename(temppath, advtrains.fpath.."_"..name)
	
end

advtrains.avt_save = function(remove_players_from_wagons)
	--atprint("saving")
	
	if remove_players_from_wagons then
		for w_id, data in pairs(advtrains.wagons) do
			data.seatp={}
		end
		advtrains.player_to_train_mapping={}
	end
	
	local tmp_trains={}
	for id, train in pairs(advtrains.trains) do
		--first, deep_copy the train
		if #train.trainparts > 0 then
			local v=advtrains.save_keys(train, {
				"last_pos", "last_connid", "last_frac", "velocity", "tarvelocity",
				"trainparts", "recently_collided_with_env",