--かっぱの川流し
--Kappa's River Flow
--scripted by YoshiDuels
local s,id=GetID()
function s.initial_effect(c)
	--Activate
	local e1=Effect.CreateEffect(c)
	e1:SetDescription(aux.Stringid(id,0))
	e1:SetCategory(CATEGORY_ATKCHANGE)
	e1:SetType(EFFECT_TYPE_ACTIVATE)
	e1:SetCode(EVENT_ATTACK_ANNOUNCE)
	e1:SetCondition(s.condition)
	e1:SetCost(s.cost)
	e1:SetOperation(s.activate)
	c:RegisterEffect(e1)
end
function s.condition(e,tp,eg,ep,ev,re,r,rp)
	local ac=Duel.GetAttacker()
	return ac:IsControler(1-tp)
end
function s.cfilter(c)
	return c:IsMonster() and c:IsRace(RACE_AQUA) and c:IsAbleToDeckOrExtraAsCost()
end
function s.cost(e,tp,eg,ep,ev,re,r,rp,chk)
	if chk==0 then return Duel.IsExistingMatchingCard(s.cfilter,tp,LOCATION_GRAVE,0,2,nil) end
end
function s.filter(c)
	return c:IsFaceup() and c:IsType(TYPE_NORMAL)
end
function s.activate(e,tp,eg,ep,ev,re,r,rp)
	--Requirement
	local c=e:GetHandler()
	Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_TODECK)
	local g=Duel.SelectMatchingCard(tp,s.cfilter,tp,LOCATION_GRAVE,0,2,2,nil)
	if #g==0 then return end
	Duel.HintSelection(g,true)
	if Duel.SendtoDeck(g,nil,SEQ_DECKSHUFFLE,REASON_EFFECT)~=2 then return end
	--Effect
	local ac=Duel.GetAttacker()
	if ac:IsFaceup() and ac:IsRelateToBattle() then
		--Decrease ATK
		local e1=Effect.CreateEffect(c)
		e1:SetType(EFFECT_TYPE_SINGLE)
		e1:SetCode(EFFECT_UPDATE_ATTACK)
		e1:SetReset(RESETS_STANDARD_PHASE_END)
		e1:SetValue(-800)
		ac:RegisterEffect(e1)
	end
	if Duel.IsExistingMatchingCard(aux.FilterMaximumSideFunctionEx(s.filter),tp,0,LOCATION_MZONE,1,nil) and Duel.SelectYesNo(tp,aux.Stringid(id,1)) then
		Duel.Hint(HINT_SELECTMSG,tp,HINTMSG_FACEUP)
		local g=Duel.SelectMatchingCard(tp,aux.FilterMaximumSideFunctionEx(s.filter),tp,0,LOCATION_MZONE,1,1,nil)
		if #g>0 then
			Duel.HintSelection(g)
			local e1=Effect.CreateEffect(c)
			e1:SetType(EFFECT_TYPE_SINGLE)
			e1:SetCode(EFFECT_UPDATE_ATTACK)
			e1:SetValue(-800)
			e1:SetReset(RESETS_STANDARD_PHASE_END)
			g:GetFirst():RegisterEffect(e1)
		end
	end
end
