Tierd Discount by Cart Value Script Adjustment to Exclude a Specific Collection

[LCCCHRIS]

Hello all, I am a script novice, and am currently using the following script to apply tiered discounts based on total cart value. We are about to add a subscription service to our Shopify store and would like the subscription products to be excluded from the total car value, as well as the discount applied. What changes would be needed to this script?

Thanks in Advance

# ================================ Customizable Settings ================================
# ================================================================
# Tiered Cart Discounts by Spend Threshold
#
# If the cart total is greater than (or equal to) an entered
# threshold, the associated discount is applied to the cart. The
# discount will be spread, as evenly as possible, across all items.
#
# - 'threshold' is the spend amount needed to qualify
# - 'discount_amount' is the dollar discount to apply to the
# cart
# - 'discount_message' is the message to show when a discount
# is applied
# ================================================================
SPENDING_THRESHOLDS = [
{
threshold: 150,
discount_amount: 6.99,
discount_message: 'Spend $150 and get free shipping',
},
#{
# threshold: 200,
# discount_amount: 21.99,
# discount_message: 'Spend $200 and get $20 off & Free Shipping!',
#},
#{
# threshold: 400,
# discount_amount: 75,
# discount_message: 'Spend $400 and get $75 off!',
#},
]

# ================================ Script Code (do not edit) ================================
# ================================================================
# DollarDiscountApplicator
#
# Applies the entered discount to the supplied line item.
# ================================================================
class DollarDiscountApplicator
def initialize(discount_message)
@discount_message = discount_message
end

def apply(line_item, discount_amount)
new_line_price = line_item.line_price - discount_amount
line_item.change_line_price(new_line_price, message: @discount_message)
end
end

# ================================================================
# TieredCartDiscountBySpendCampaign
#
# If the cart total is greater than (or equal to) an entered
# threshold, the associated discount is applied to the cart. The
# discount will be spread, as evenly as possible, across all items.
# ================================================================
class TieredCartDiscountBySpendCampaign
def initialize(tiers)
@Tiers = tiers.sort_by { |tier| tier[:threshold] }.reverse
end

def run(cart)
applicable_tier = @Tiers.find { |tier| cart.subtotal_price >= (Money.new(cents: 100) * tier[:threshold]) }
return if applicable_tier.nil?

discount_applicator = DollarDiscountApplicator.new(applicable_tier[:discount_message])
discount_amount = applicable_tier[:discount_amount]
items = cart.line_items.sort_by { |line_item| line_item.variant.price }
self.loop_items(cart, items, discount_amount, discount_applicator)
end

def loop_items(cart, line_items, discount_amount, discount_applicator)
avg_discount = (discount_amount.to_f * (1 / line_items.map(&:quantity).reduce(0, :+))).round(2)
avg_discount = Money.new(cents: 100) * avg_discount
discount_amount = Money.new(cents: 100) * discount_amount

line_items.each_with_index do |line_item, index|
break if discount_amount <= Money.zero

line_discount = avg_discount * line_item.quantity

if discount_amount < line_discount || index == (line_items.size - 1)
discount_update = line_item.line_price > discount_amount ? discount_amount : line_item.line_price
else
discount_update = line_item.line_price > line_discount ? line_discount : line_item.line_price
end

discount_amount -= discount_update
discount_applicator.apply(line_item, discount_update)
end
end
end

CAMPAIGNS = [
TieredCartDiscountBySpendCampaign.new(SPENDING_THRESHOLDS),
]

CAMPAIGNS.each do |campaign|
campaign.run(Input.cart)
end

Output.cart = Input.cart