import math
import math.big { Integer }
import crypto.rand

struct SSS {
mut:
	prime Integer = big.integer_from_string('115792089237316195423570985008687907853269984665640564039457584007913129639747')!
}

// random returns a random number from the range (0, prime-1) inclusive
fn (s SSS) random() !Integer {
	mut result := big.zero_int + s.prime
	result = result - big.one_int
	return rand.int_big(result)
}

// mod_inverse computes the multiplicative inverse of the number on the field
// prime; more specifically, number * inverse == 1; Note: number should never be
// zero
fn mod_inverse(number Integer) Integer {
	s := SSS{}
	copy := number % s.prime
	pcopy := s.prime

	_, _, y := math.egcd(pcopy.int(), copy.int())

	return (s.prime + big.integer_from_i64(y)) % s.prime
}

fn main() {
	mod_inverse(big.integer_from_string('1')!)
}