local map_def={
	example = {
		p1x=168,
		p1z=530,
		p2x=780,
		p2z=1016,
		background="itm_example.png",
	},
}

local itm_cache={}
local itm_pdata={}
local itm_conf_mindia=0.1

minetest.register_privilege("itm", { description = "Allows to display train map", give_to_singleplayer = true, default = false })

local function create_map_form_with_bg--Minetest
--Copyright (C) 2016 T4im
--
--This program is free software; you can redistribute it and/or modify
--it under the terms of the GNU Lesser General Public License as published by
--the Free Software Foundation; either version 2.1 of the License, or
--(at your option) any later version.
--
--This program is distributed in the hope that it will be useful,
--but WITHOUT ANY WARRANTY; without even the implied warranty of
--MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
--GNU Lesser General Public License for more details.
--
--You should have received a copy of the GNU Lesser General Public License along
--with this program; if not, write to the Free Software Foundation, Inc.,
--51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
local setmetatable = setmetatable
local pairs, format = pairs, string.format
local min, max, huge = math.min, math.max, math.huge
local core = core

local profiler = ...
-- Split sampler and profile up, to possibly allow for rotation later.
local sampler = {}
local profile
local stats_total
local logged_time, logged_data

local _stat_mt = {
	get_time_avg = function(self)
		return self.time_all/self.samples
	end,
	get_part_avg = function(self)
		if not self.part_all then
			return 100 -- Extra handling for "total"
		end
		return self.part_all/self.samples
	end,
}
_stat_mt.__index = _stat_mt

function sampler.reset()
	-- Accumulated logged time since last sample.
	-- This helps determining, the relative time a mod used up.
	logged_time = 0
	-- The measurements taken through instrumentation since last sample.
	logged_data = {}

	profile = {
		-- Current mod statistics (max/min over the entire mod lifespan)
		-- Mod specific instrumentation statistics are nested within.
		stats = {},
		-- Current stats over all mods.
		stats_total = setmetatable({
			samples = 0,
			time_min = huge,
			time_max = 0,
			time_all = 0,
			part_min = 100,
			part_max = 100
		}, _stat_mt)
	}
	stats_total = profile.stats_total

	-- Provide access to the most recent profile.
	sampler.profile = profile
end

---
-- Log a measurement for the sampler to pick up later.
-- Keep `log` and its often called functions lean.
-- It will directly add to the instrumentation overhead.
--
function sampler.log(modname, instrument_name, time_diff)
	if time_diff <= 0 then
		if time_diff < 0 then
			-- This **might** have happened on a semi-regular basis with huge mods,
			-- resulting in negative statistics (perhaps midnight time jumps or ntp corrections?).
			core.log("warning", format(
					"Time travel of %s::%s by %dµs.",
					modname, instrument_name, time_diff
			))
		end
		-- Throwing these away is better, than having them mess with the overall result.
		return
	end

	local mod_data = logged_data[modname]
	if mod_data == nil then
		mod_data = {}
		logged_data[modname] = mod_data
	end

	mod_data[instrument_name] = (mod_data[instrument_name] or 0) + time_diff
	-- Update logged time since last sample.
	logged_time = logged_time + time_diff
end

---
-- Return a requested statistic.
-- Initialize if necessary.
--
local function get_statistic(stats_table, name)
	local statistic = stats_table[name]
	if statistic == nil then
		statistic = setmetatable({
			samples = 0,
			time_min = huge,
			time_max = 0,
			time_all = 0,
			part_min = 100,
			part_max = 0,
			part_all = 0,
		}, _stat_mt)
		stats_table[name] = statistic
	end
	return statistic
end

---
-- Update a statistic table
--
local function update_statistic(stats_table, time)
	stats_table.samples = stats_table.samples + 1

	-- Update absolute time (µs) spend by the subject
	stats_table.time_min = min(stats_table.time_min, time)
	stats_table.time_max = max(stats_table.time_max, time)
	stats_table.time_all = stats_table.time_all + time

	-- Update relative time (%) of this sample spend by the subject
	local current_part = (time/logged_time) * 100
	stats_table.part_min = min(stats_table.part_min, current_part)
	stats_table.part_max = max(stats_table.part_max, current_part)
	stats_table.part_all = stats_table.part_all + current_part
end

---
-- Sample all logged measurements each server step.
-- Like any globalstep function, this should not be too heavy,
-- but does not add to the instrumentation overhead.
--
local function sample(dtime)
	-- Rare, but happens and is currently of no informational value.
	if logged_time == 0 then
		return
	end

	for modname, instruments in pairs(logged_data) do
		local mod_stats = get_statistic(profile.stats, modname)
		if mod_stats.instruments == nil then
			-- Current statistics for each instrumentation component
			mod_stats.instruments = {}
		end

		local mod_time = 0
		for instrument_name, time in pairs(instruments) do
			if time > 0 then
				mod_time = mod_time + time
				local instrument_stats = get_statistic(mod_stats.instruments, instrument_name)

				-- Update time of this sample spend by the instrumented function.
				update_statistic(instrument_stats, time)
				-- Reset logged data for the next sample.
				instruments[instrument_name] = 0
			end
		end

		-- Update time of this sample spend by this mod.
		update_statistic(mod_stats, mod_time)="hl opt">]
			minetest.show_formspec(name, "itrainmap", create_map_form(d))
			return true, "Showing train map: "..mdef
		end
		local x1, z1, x2, z2=string.match(param, "^(%S+) (%S+) (%S+) (%S+)$")
		if not (x1 and z1 and x2 and z2) then
			if worldedit then
				local wep1, wep2=worldedit.pos1[name], worldedit.pos2[name]
				if wep1 and wep2 then
					x1, z1, x2, z2=wep1.x, wep1.z, wep2.x, wep2.z
				end
			end
		end
		if not (x1 and z1 and x2 and z2) then
			return false, "Invalid parameters and no WE positions set"
		end
		local d={p1x=x1, p1z=z1, p2x=x2, p2z=z2}
		itm_pdata[name]=d
		minetest.show_formspec(name, "itrainmap", create_map_form(d))
		return true, "Showing ("..x1..","..z1..")-("..x2..","..z2..")"
	end,
})
minetest.register_chatcommand("itm_cache_ndb", {
	params="",
	description="Cache advtrains node database again. Run when tracks changed.",
	privs={itm=true},
	func = function(name, param)
		cache_ndb()
		return true, "Done caching node database."
	end,
})

local timer=0
function advtrains_itm_mainloop(dtime)
	timer=timer-math.min(dtime, 0.1)
	if timer<=0 then
		for pname,d in pairs(itm_pdata) do
			minetest.show_formspec(pname, "itrainmap", create_map_form(d))
		end
		timer=2
	end
end
minetest.register_on_player_receive_fields(function(player, formname, fields)
	if formname=="itrainmap" and fields.quit then
		itm_pdata[player:get_player_name()]=nil
	end
end)

function advtrains_itm_init()
	--automatically run itm_cache_ndb
	minetest.after(2, cache_ndb)
end