Days reduction offer in booking website

The job consists in a days discount during a booking process. Admin area is partially done. There is an existing admin panel area where discounts are created and stored into database with this data: Minimum days to get the discount Days to be discounted from total Booking dates Accommodation dates Combinable checkbox Name and description The job consists in apply those discounts to the booking process as follows: In first step of the booking, obtain the average price of stay dividing the total by the days of stay (daily price).The result will be multiplied by the number of days to deduct. This is the amount to be discounted from the total. The discount only must be applied if minimum days, reservation dates and accommodation dates are meet. The discount only will be applied once. Per example: A days reduction discount has been created for october. Stay 7 days and pay 6, Another days reduction discount for the same dates is created but for more days. Stay 14 days and pay 12. The discount to be applied is the one that meets or exceeds the stay. If the booking is for 15 days, the amount of 2 days will be discounted. If the booking is for 10 days, the amount of 1 day will be discounted. If it is less than 7 days none discount to be applied. There is also an existing campaign discount and promo codes area. If combinable checkbox is marked in days reduction discount, this discount must be added to any existing campaign, if not, the days reduction discount will not be applied. Discount banner must appear in booking process as appear the other discount campaigns. Also discount details must appear in booking details.