Save status into playereffects.mt on shutdown

The file is stored in the world path. It is loaded again when the server starts again.
If the file does not exist, playereffects starts with an empty set of effects.

init.lua

@@ -18,6 +18,27 @@ playereffects.inactive_effects = {}
 -- Variable for counting the effect_id
 playereffects.last_effect_id = 0
 
+--[=[ Load inactive_effects and last_effect_id from playereffects.mt, if this file exists  ]=]
+do
+	local filepath = minetest.get_worldpath().."/playereffects.mt"
+	local file = io.open(filepath, "r")
+	local string
+	if file then
+		minetest.log("action", "[playereffects] playereffects.mt opened.")
+		local string = file:read()
+		io.close(file)
+		if(string ~= nil) then
+			savetable = minetest.deserialize(string)
+			playereffects.inactive_effects = savetable.inactive_effects
+			minetest.debug("[playereffects] playereffects.mt successfully read.")
+			minetest.debug("[playereffects] inactive_effects = "..dump(playereffects.inactive_effects))
+			playereffects.last_effect_id = savetable.last_effect_id
+			minetest.debug("[playereffects] last_effect_id = "..dump(playereffects.last_effect_id))
+			
+		end
+	end
+end
+
 function playereffects.next_effect_id()
 	playereffects.last_effect_id = playereffects.last_effect_id + 1
 	return playereffects.last_effect_id
@@ -155,8 +176,7 @@ minetest.register_on_leaveplayer(function(player)
 		playereffects.inactive_effects[playername] = {}
 	end
 	for e=1,#effects do
-		local start_time = effects[e].start_time
+		local new_duration = effects[e].time_left - os.difftime(leave_time, effects[e].start_time)
-		local new_duration = os.difftime(leave_time, start_time)
 		local new_effect = effects[e]
 		new_effect.time_left = new_duration
 		table.insert(playereffects.inactive_effects[playername], new_effect)
@@ -164,6 +184,39 @@ minetest.register_on_leaveplayer(function(player)
 	end
 end)
 
+minetest.register_on_shutdown(function()
+	minetest.log("action", "[playereffects] Server shuts down. Rescuing data into playereffects.mt")
+	local shutdown_time = os.time()
+	local savetable = {}
+	local effects = playereffects.effects
+	local inactive_effects = playereffects.inactive_effects
+	for id,effect in pairs(effects) do
+		local new_duration = effect.time_left - os.difftime(shutdown_time, effect.start_time)
+		local new_effect = effect
+		new_effect.time_left = new_duration
+		if(inactive_effects[effect.playername] == nil) then
+			inactive_effects[effect.playername] = {}
+		end
+		table.insert(inactive_effects[effect.playername], new_effect)
+		playereffects.cancel_effect(effect.effect_id)
+	end
+
+	savetable.inactive_effects = inactive_effects
+	savetable.last_effect_id = playereffects.last_effect_id
+
+	savestring = minetest.serialize(savetable)
+
+	local filepath = minetest.get_worldpath().."/playereffects.mt"
+	local file = io.open(filepath, "w")
+	if file then
+		file:write(savestring)
+		io.close(file)
+		minetest.log("action", "[playereffects] Wrote playereffects data into "..filepath..".")
+	else
+		minetest.log("error", "[playereffects] Failed to write playereffects data into "..filepath..".")
+	end
+	
+end)
 
 minetest.register_on_joinplayer(function(player)
 	minetest.after(0, playereffects.join0, player)
@@ -190,11 +243,8 @@ minetest.register_globalstep(function()
 	end
 end)
 
---[[
+
-minetest.register_on_shutdown(function()
+
-	
-end)
-]]
 
 --[=[ HUD ]=]
 function playereffects.hud_update(player)
@@ -245,4 +295,4 @@ end
 
 -- EXAMPLES
 -- uncomment the line below if you want to try out the examples
--- dofile(minetest.get_modpath(minetest.get_current_modname()).."/examples.lua")
+dofile(minetest.get_modpath(minetest.get_current_modname()).."/examples.lua")