init.lua

--[[

  Timer - a high precision, saveable timer class

  Copyright (C) 2017 - Auke Kok <sofar@foo-projects.org

  "timer" 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.

]]--

---
--- static data: active timers
---

local timers = {}

---
--- Timer class
---

Timer = {}
Timer.__index = Timer

setmetatable(Timer, {
	__call = function(c, ...)
		return c.new(...)
	end,
})

function Timer.new(name_or_table, interval, repeats)
print("new")
	local self = setmetatable({}, Timer)

	self.modname = minetest.get_current_modname()

	if type(name_or_table) == "table" then
		self.name = name_or_table.name
		self.interval = name_or_table.interval
		self.repeats = name_or_table.repeats

		self.active = name_or_table.active
		if self.active then
			self.elapsed = name_or_table.elapsed or 0.0
		end
	elseif type(name_or_table) == "string" then
		self.name = name_or_table
		self.interval = interval
		self.repeats = repeats or true

		self.active = false
		self.elapsed = 0.0
	else
		minetest.log("error", self.modname ..  "Can't create new Timer without valid parameters")
		return nil
	end


	if self.name == nil then
		minetest.log("error", "Can't create new Timer without function name")
		return false
	elseif _G[self.name] == nil or type(_G[self.name]) ~= "function" then
		minetest.log("error", "Can't create new Timer - incorrect function name passed")
		return false
	end

	if type(name_or_table) == "table" and self.active then
		self:start()
	end

	return self
end

function Timer:start()
print("start")
	if self.active then
		return
	end

	self.fn = _G[self.name]
	self.active = true
	self.registration = function(dtime)
print("step")
		if self.active then
			self.elapsed = self.elapsed + dtime
			if self.elapsed > self.interval then
				self:expire()
			end
		end
	end

	timers[self.registration] = true
end

function Timer:stop()
print("stop")
	if self.active then
		self.active = false
	end
	timers[self.registration] = nil
	self.registration = nil
end

function Timer:set_interval(interval)
	assert(self.active == false)
	self.interval = interval
end

function Timer:expire()
print("expire")
	self.fn()
	self.elapsed = 0.0 + (self.interval - self.elapsed)
end
	

function Timer:to_table()
	return {
		name = self.name,
		interval = self.interval,
		repeats = self.repeats,
		active = self.active,
		elapsed = self.elapsed,
	}
end

---
--- our globalstep function
---


minetest.register_globalstep(function(dtime)
	for k, _ in pairs(timers) do
		k(dtime)
	end
end)