Generate a YGOPro Lua script for the following Yu-Gi-Oh card effect:
Monsters you control gain 300 ATK for each different Attribute you control. "Charmer" and "Familiar-Possessed" monsters you control cannot be destroyed by card effects. If a Spellcaster monster(s) with 1850 original ATK is Normal or Special Summoned to your field: Draw 1 card. You can only use this effect of "Awakening of the Possessed" once per turn.
--憑依覚醒
--Awakening of the Possessed
--Scripted by AlphaKretin
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_FREE_CHAIN)
	c:RegisterEffect(e1)
	--Monsters you control gain 300 ATK for each different Attribute you control
	local e2=Effect.CreateEffect(c)
	e2:SetType(EFFECT_TYPE_FIELD)
	e2:SetCode(EFFECT_UPDATE_ATTACK)
	e2:SetRange(LOCATION_SZONE)
	e2:SetTargetRange(LOCATION_MZONE,0)
	e2:SetValue(s.atkval)
	c:RegisterEffect(e2)
	--"Charmer" and "Familiar-Possessed" monsters you control cannot be destroyed by card effects
	local e3=Effect.CreateEffect(c)
	e3:SetType(EFFECT_TYPE_FIELD)
	e3:SetCode(EFFECT_INDESTRUCTABLE_EFFECT)
	e3:SetRange(LOCATION_SZONE)
	e3:SetTargetRange(LOCATION_MZONE,0)
	e3:SetTarget(s.indtg)
	e3:SetValue(1)
	c:RegisterEffect(e3)
	--Draw 1 card
	local e4=Effect.CreateEffect(c)
	e4:SetDescription(aux.Stringid(id,0))
	e4:SetCategory(CATEGORY_DRAW)
	e4:SetType(EFFECT_TYPE_FIELD+EFFECT_TYPE_TRIGGER_F)
	e4:SetCode(EVENT_SUMMON_SUCCESS)
	e4:SetRange(LOCATION_SZONE)
	e4:SetCondition(s.drcon)
	e4:SetTarget(s.drtg)
	e4:SetOperation(s.drop)
	e4:SetCountLimit(1,id)
	c:RegisterEffect(e4)
	local e5=e4:Clone()
	e5:SetCode(EVENT_SPSUMMON_SUCCESS)
	c:RegisterEffect(e5)
end
s.listed_series={SET_CHARMER,SET_FAMILIAR_POSSESSED}
function s.atkval(e,c)
	local g=Duel.GetMatchingGroup(Card.IsFaceup,e:GetHandlerPlayer(),LOCATION_MZONE,0,nil)
	return 300*g:GetBinClassCount(Card.GetAttribute)
end
function s.indtg(e,c)
	return c:IsFaceup() and c:IsSetCard({SET_CHARMER,SET_FAMILIAR_POSSESSED})
end
function s.cfilter(c,tp)
	return c:IsFaceup() and c:IsControler(tp) and c:GetBaseAttack()==1850 and c:IsRace(RACE_SPELLCASTER)
end
function s.drcon(e,tp,eg,ep,ev,re,r,rp)
	return eg:IsExists(s.cfilter,1,nil,tp)
end
function s.drtg(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return true end
	Duel.SetTargetPlayer(tp)
	Duel.SetTargetParam(1)
	Duel.SetOperationInfo(0,CATEGORY_DRAW,nil,0,tp,1)
end
function s.drop(e,tp,eg,ep,ev,re,r,rp)
	local p,d=Duel.GetChainInfo(0,CHAININFO_TARGET_PLAYER,CHAININFO_TARGET_PARAM)
	Duel.Draw(p,d,REASON_EFFECT)
end