VoxeLibre/mods/ENTITIES/mcl_mobs/api/mob_functions/interaction.lua

local minetest_after      = minetest.after
local minetest_sound_play = minetest.sound_play

local math_floor  = math.floor
local math_min    = math.min
local math_random = math.random

local vector_direction = vector.direction
local vector_multiply  = vector.multiply

mobs.feed_tame = function(self)
    return nil
end

-- Code to execute before custom on_rightclick handling
local on_rightclick_prefix = function(self, clicker)

	local item = clicker:get_wielded_item()

	-- Name mob with nametag
	if not self.ignores_nametag and item:get_name() == "mcl_mobs:nametag" then

		local tag = item:get_meta():get_string("name")
		if tag ~= "" then
			if string.len(tag) > MAX_MOB_NAME_LENGTH then
				tag = string.sub(tag, 1, MAX_MOB_NAME_LENGTH)
			end
			self.nametag = tag

			update_tag(self)

			if not mobs.is_creative(clicker:get_player_name()) then
				item:take_item()
				clicker:set_wielded_item(item)
			end
			return true
		end

	end
	return false
end

-- I have no idea what this does
mobs.create_mob_on_rightclick = function(on_rightclick)
	return function(self, clicker)
		--don't allow rightclicking dead mobs
		if self.health <= 0 then
			return
		end
		local stop = on_rightclick_prefix(self, clicker)
		if (not stop) and (on_rightclick) then
			on_rightclick(self, clicker)
		end
	end
end


-- deal damage and effects when mob punched
mobs.mob_punch = function(self, hitter, tflp, tool_capabilities, dir)

	--don't do anything if the mob is already dead
	if self.health <= 0 then
		return
	end

	--neutral passive mobs switch to neutral hostile
	if self.neutral then

		--drop in variables for attacking (stops crash)
		self.attacking   = hitter
		self.punch_timer = 0

		self.hostile = true
		--hostile_cooldown timer is initialized here
		self.hostile_cooldown_timer = self.hostile_cooldown

		--initialize the group attack (check for other mobs in area, make them neutral hostile)
		if self.group_attack then
			mobs.group_attack_initialization(self)
		end
	end


	-- custom punch function
	if self.do_punch then
		-- when false skip going any further
		if self.do_punch(self, hitter, tflp, tool_capabilities, dir) == false then
			return
		end
	end

	--don't do damage until pause timer resets
	if self.pause_timer > 0 then
		return
	end 

	
	-- error checking when mod profiling is enabled
	if not tool_capabilities then
		minetest.log("warning", "[mobs_mc] Mod profiling enabled, damage not enabled")
		return
	end


	local is_player = hitter:is_player()


	-- punch interval
	local weapon = hitter:get_wielded_item()

	local punch_interval = 1.4

	-- exhaust attacker
	if mod_hunger and is_player then
		mcl_hunger.exhaust(hitter:get_player_name(), mcl_hunger.EXHAUST_ATTACK)
	end

	-- calculate mob damage
	local damage = 0
	local armor = self.object:get_armor_groups() or {}
	local tmp

	--calculate damage groups
	for group,_ in pairs( (tool_capabilities.damage_groups or {}) ) do
		damage = damage + (tool_capabilities.damage_groups[group] or 0) * ((armor[group] or 0) / 100.0)
	end

	if weapon then
		local fire_aspect_level = mcl_enchanting.get_enchantment(weapon, "fire_aspect")
		if fire_aspect_level > 0 then
			mcl_burning.set_on_fire(self.object, fire_aspect_level * 4)
		end
	end

	-- check for tool immunity or special damage
	for n = 1, #self.immune_to do
		if self.immune_to[n][1] == weapon:get_name() then
			damage = self.immune_to[n][2] or 0
			break
		end
	end

	-- healing
	if damage <= -1 then
		self.health = self.health - math_floor(damage)
		return
	end

	if tool_capabilities then
		punch_interval = tool_capabilities.full_punch_interval or 1.4
	end

	-- add weapon wear manually
	-- Required because we have custom health handling ("health" property)
	--minetest_is_creative_enabled("") ~= true --removed for now
	if tool_capabilities then
		if tool_capabilities.punch_attack_uses then
			-- Without this delay, the wear does not work. Quite hacky ...
			minetest_after(0, function(name)
				local player = minetest.get_player_by_name(name)
				if not player then return end
				local weapon = hitter:get_wielded_item(player)
				local def = weapon:get_definition()
				if def.tool_capabilities and def.tool_capabilities.punch_attack_uses then
					local wear = math_floor(65535/tool_capabilities.punch_attack_uses)
					weapon:add_wear(wear)
					hitter:set_wielded_item(weapon)
				end
			end, hitter:get_player_name())
		end
	end


	--if player is falling multiply damage by 1.5
	--critical hit
	if hitter:get_velocity().y < 0 then
		damage = damage * 1.5
		mobs.critical_effect(self)
	end

	local die = false

	-- only play hit sound and show blood effects if damage is 1 or over; lower to 0.1 to ensure armor works appropriately.
	if damage >= 0.1 then

		-- weapon sounds
		if weapon:get_definition().sounds ~= nil then

			local s = math_random(0, #weapon:get_definition().sounds)

			minetest_sound_play(weapon:get_definition().sounds[s], {
				object = self.object, --hitter,
				max_hear_distance = 8
			}, true)
		else
			minetest_sound_play("default_punch", {
				object = self.object,
				max_hear_distance = 5
			}, true)
		end

		--damage_effect(self, damage)

		-- do damage
		self.health = self.health - damage

		-- skip future functions if dead, except alerting others
		--if check_for_death(self, "hit", {type = "punch", puncher = hitter}) then
		--	die = true
		--end

		-- knock back effect
		local velocity = self.object:get_velocity()
		
		--2d direction
		local pos1 = self.object:get_pos()
		pos1.y = 0
		local pos2 = hitter:get_pos()
		pos2.y = 0

		local dir = vector.direction(pos2,pos1)

		local up = 3

		-- if already in air then dont go up anymore when hit
		if velocity.y ~= 0 then
			up = 0
		end


		--0.75 for perfect distance to not be too easy, and not be too hard
		local multiplier = 0.75 

		-- check if tool already has specific knockback value
		local knockback_enchant = mcl_enchanting.get_enchantment(hitter:get_wielded_item(), "knockback")
		if knockback_enchant and knockback_enchant > 0 then
			multiplier = knockback_enchant + 1 --(starts from 1, 1 would be no change)
		end

		
		local luaentity

		--[[ --why does this multiply it again???
		if hitter then
			luaentity = hitter:get_luaentity()
		end
		if hitter and is_player then
			local wielditem = hitter:get_wielded_item()
			kb = kb + 3 * mcl_enchanting.get_enchantment(wielditem, "knockback")
		elseif luaentity and luaentity._knockback then
			kb = kb + luaentity._knockback
		end
		]]--

		dir = vector_multiply(dir,multiplier)

		dir.y = up

		--add velocity breaks momentum - use set velocity
		self.object:set_velocity(dir)

		--0.4 seconds until you can hurt the mob again
		self.pause_timer = 0.4
	end
	 -- END if damage

	-- if skittish then run away
	--[[
	if not die and self.runaway == true and self.state ~= "flop" then

		local lp = hitter:get_pos()
		local s = self.object:get_pos()
		local vec = {
			x = lp.x - s.x,
			y = lp.y - s.y,
			z = lp.z - s.z
		}

		local yaw = (atan(vec.z / vec.x) + 3 * math_pi / 2) - self.rotate

		if lp.x > s.x then
			yaw = yaw + math_pi
		end

		yaw = set_yaw(self, yaw, 6)
		self.state = "runaway"
		self.runaway_timer = 0
		self.following = nil
	end

	]]--
end

--do internal per mob projectile calculations
mobs.shoot_projectile = function(self)

	local pos1 = self.object:get_pos()
	--add mob eye height
	pos1.y = pos1.y + self.eye_height

	local pos2 = self.attacking:get_pos()
	--add player eye height
	pos2.y = pos2.y + self.attacking:get_properties().eye_height

	--get direction
	local dir = vector_direction(pos1,pos2)

	--call internal shoot_arrow function
	self.shoot_arrow(self,pos1,dir)
end