Erinfest/mods/PLAYER/mcl_hunger/init.lua

local modname = minetest.get_current_modname()
local modpath = minetest.get_modpath(modname)

local S = minetest.get_translator(modname)

mcl_hunger = {}

--[[ This variable tells you if the hunger gameplay mechanic is active.
The state of the hunger mechanic will be determined at game start.
Hunger is enabled when damage is enabled.
If the damage setting is changed within the game, this does NOT
update the hunger mechanic, so the game must be restarted for this
to take effect. ]]
if minetest.settings:get_bool("enable_damage") == true then
	mcl_hunger.active = true
else
	mcl_hunger.active = false
end

mcl_hunger.HUD_TICK = 0.1

-- Exhaustion increase
mcl_hunger.EXHAUST_DIG = 5  -- after digging node
mcl_hunger.EXHAUST_JUMP = 50 -- jump
mcl_hunger.EXHAUST_SPRINT_JUMP = 200 -- jump while sprinting
mcl_hunger.EXHAUST_ATTACK = 100 -- hit an enemy
mcl_hunger.EXHAUST_SWIM = 10 -- player movement in water
mcl_hunger.EXHAUST_SPRINT = 100 -- sprint (per node)
mcl_hunger.EXHAUST_DAMAGE = 100 -- taking damage (protected by armor)
mcl_hunger.EXHAUST_REGEN = 6000 -- Regenerate 1 HP
mcl_hunger.EXHAUST_LVL = 4000 -- at what exhaustion player saturation gets lowered

mcl_hunger.SATURATION_INIT = 5 -- Initial saturation for new/respawning players

-- Debug Mode. If enabled, saturation and exhaustion are shown as well.
-- NOTE: Only updated when settings are loaded.
mcl_hunger.debug = false

-- Cooldown timers for each player, to force a short delay between consuming 2 food items
mcl_hunger.last_eat = {}

dofile(modpath.."/api.lua")
dofile(modpath.."/hunger.lua")
dofile(modpath.."/register_foods.lua")

--[[ IF HUNGER IS ENABLED ]]
if mcl_hunger.active == true then

-- Read debug mode setting
-- The setting should only be read at the beginning, this mod is not
-- prepared to change this setting later.
mcl_hunger.debug = minetest.settings:get_bool("mcl_hunger_debug")
if mcl_hunger.debug == nil then
	mcl_hunger.debug = false
end

--[[ Data value format notes:
	Hunger values is identical to Minecraft's and ranges from 0 to 20.
	Exhaustion and saturation values are stored as integers, unlike in Minecraft.
	Exhaustion is Minecraft exhaustion times 1000 and ranges from 0 to 4000.
	Saturation is Minecraft saturation and ranges from 0 to 20.

	Food saturation is stored in the custom item definition field _mcl_saturation.
	This field uses the original Minecraft value.
]]

-- Count number of poisonings a player has at once
mcl_hunger.poison_hunger = {} -- food poisoning, increasing hunger

-- HUD
local function init_hud(player)
	hb.init_hudbar(player, "hunger", mcl_hunger.get_hunger(player))
	if mcl_hunger.debug then
		hb.init_hudbar(player, "saturation", mcl_hunger.get_saturation(player), mcl_hunger.get_hunger(player))
		hb.init_hudbar(player, "exhaustion", mcl_hunger.get_exhaustion(player))
	end
end

-- HUD updating functions for Debug Mode. No-op if not in Debug Mode
function mcl_hunger.update_saturation_hud(player, saturation, hunger)
	if mcl_hunger.debug then
		hb.change_hudbar(player, "saturation", saturation, hunger)
	end
end
function mcl_hunger.update_exhaustion_hud(player, exhaustion)
	if mcl_hunger.debug then
		hb.change_hudbar(player, "exhaustion", exhaustion)
	end
end

-- register saturation hudbar
hb.register_hudbar("hunger", 0xFFFFFF, S("Food"), { icon = "hbhunger_icon.png", bgicon = "hbhunger_bgicon.png",  bar = "hbhunger_bar.png" }, 1, 20, 20, false)
if mcl_hunger.debug then
	hb.register_hudbar("saturation", 0xFFFFFF, S("Saturation"), { icon = "mcl_hunger_icon_saturation.png", bgicon = "mcl_hunger_bgicon_saturation.png", bar = "mcl_hunger_bar_saturation.png" }, 1, mcl_hunger.SATURATION_INIT, 200, false)
	hb.register_hudbar("exhaustion", 0xFFFFFF, S("Exhaust."), { icon = "mcl_hunger_icon_exhaustion.png", bgicon = "mcl_hunger_bgicon_exhaustion.png", bar = "mcl_hunger_bar_exhaustion.png" }, 1, 0, mcl_hunger.EXHAUST_LVL, false)
end

minetest.register_on_joinplayer(function(player)
	local name = player:get_player_name()
	mcl_hunger.init_player(player)
	init_hud(player)
	mcl_hunger.poison_hunger[name] = 0
	mcl_hunger.last_eat[name] = -1
end)

minetest.register_on_respawnplayer(function(player)
	-- reset hunger, related values and poison
	local name = player:get_player_name()

	mcl_hunger.stop_poison(player)
	mcl_hunger.last_eat[name] = -1

	local h, s, e = 20, mcl_hunger.SATURATION_INIT, 0
	mcl_hunger.set_hunger(player, h, false)
	mcl_hunger.set_saturation(player, s, false)
	mcl_hunger.set_exhaustion(player, e, false)
	hb.change_hudbar(player, "hunger", h)
	mcl_hunger.update_saturation_hud(player, s, h)
	mcl_hunger.update_exhaustion_hud(player, e)
end)

-- PvP combat exhaustion
minetest.register_on_punchplayer(function(victim, puncher, time_from_last_punch, tool_capabilities, dir, damage)
	if puncher:is_player() then
		mcl_hunger.exhaust(puncher:get_player_name(), mcl_hunger.EXHAUST_ATTACK)
	end
end)

-- Exhaust on taking damage
minetest.register_on_player_hpchange(function(player, hp_change)
	if hp_change < 0 then
		local name = player:get_player_name()
		mcl_hunger.exhaust(name, mcl_hunger.EXHAUST_DAMAGE)
	end
end)

local food_tick_timers = {} -- one food_tick_timer per player, keys are the player-objects
minetest.register_globalstep(function(dtime)
	for _,player in pairs(minetest.get_connected_players()) do

		local food_tick_timer = food_tick_timers[player] and food_tick_timers[player] + dtime or 0
		local player_name = player:get_player_name()
		local food_level = mcl_hunger.get_hunger(player)
		local food_saturation_level = mcl_hunger.get_saturation(player)
		local player_health = player:get_hp()

		if food_tick_timer > 4.0 then
			food_tick_timer = 0

			if food_level >= 18 then -- slow regenration
				if player_health > 0 and player_health < 20 then
					player:set_hp(player_health+1)
					mcl_hunger.exhaust(player_name, mcl_hunger.EXHAUST_REGEN)
					mcl_hunger.update_exhaustion_hud(player, mcl_hunger.get_exhaustion(player))
				end

			elseif food_level == 0 then -- starvation
				-- the amount of health at which a player will stop to get
				-- harmed by starvation (10 for Easy, 1 for Normal, 0 for Hard)
				local maximum_starvation = 1
				-- TODO: implement Minecraft-like difficulty modes and the update maximumStarvation here
				if player_health > maximum_starvation then
					mcl_util.deal_damage(player, 1, {type = "starve"})
				end
			end

		elseif food_tick_timer > 0.5 and food_level == 20 and food_saturation_level >= 6 then -- fast regeneration
			if player_health > 0 and player_health < 20 then
				food_tick_timer = 0
				player:set_hp(player_health+1)
				mcl_hunger.exhaust(player_name, mcl_hunger.EXHAUST_REGEN)
				mcl_hunger.update_exhaustion_hud(player, mcl_hunger.get_exhaustion(player))
			end
		end

		food_tick_timers[player] = food_tick_timer -- update food_tick_timer table
	end
end)

--[[ IF HUNGER IS NOT ENABLED ]]
else

minetest.register_on_joinplayer(function(player)
	mcl_hunger.init_player(player)
	mcl_hunger.last_eat[player:get_player_name()] = -1
end)

end