UK tax 2019

BEGIN{

    basic_rate = 0.2
    higher_rate = 0.4
    upper_rate = 0.45

    for(salary=1; salary < 400000; salary+=100){

        if(ubi){
            newsalary = (salary + 20000) * (1-0.47)
            tax = salary - newsalary
        }
        else{

            taxable = salary
            net = 0


            personal_allowance = 12500

            if(salary > 100000){
                personal_allowance -= (salary-100000)/2;
                if(personal_allowance < 0)
                    personal_allowance = 0;
            }
            else if(salary < personal_allowance)
                personal_allowance = salary;


            net += personal_allowance
            taxable -= personal_allowance
            income_tax = 0

            if(taxable <= 37500)
                income_tax = taxable * basic_rate
            else if(taxable <= 150000){
                income_tax += 37500*basic_rate
                income_tax += (taxable - 37500) * higher_rate
            }
            else{
                income_tax += 37500*basic_rate
                income_tax += (150000 - 37500) * higher_rate
                income_tax += (taxable - 150000) * upper_rate
            }

            monthly = salary / 12
            ni=0
            if(monthly <= 166)
                ni=0
            else if(monthly <= 962){
                ni = (monthly - 166) * 0.12
            }
            else {
                ni = (962 - 166) * 0.12
                ni += (monthly - 962) * 0.02
            }
            ni *=12


            tax = ni + income_tax
        }

        print salary, 100 * (1- (salary - tax)/salary)
        #print salary, ni
    }

}