Foop

(ns spiral.core
    (:require [cljs.nodejs :as nodejs]))

(enable-console-print!)
(nodejs/enable-util-print!)

(defn is_prime? [nval]
    (if (< nval 2)
        false
        (if (or (= nval 2) (= nval 3))
            true
            (if (or (= (mod nval 2) 0) (not (or (= (mod nval 6) 1) (= (mod nval 6) 5))))
                false
                (loop [n 5]
                    (if (> n (Math/sqrt nval))
                        true
                        (if (= (mod nval n) 0)
                            false
                            (recur (+ n 2)))))))))

(defn nth_diags [n]
 (let [interval (* 2 (Math/ceil (/ n 4))) side (inc interval)]
    (- (* side side) (* (- 3 (mod (+ n 3) 4)) interval))))

(defn gen_diags
    ([] (gen_diags 0))
    ([n] (lazy-seq (cons (nth_diags n) (gen_diags (inc n))))))

(defn ratio [n]
    (let [llist (take n (gen_diags))]
        (/ (apply + (for [p llist :when (is_prime? p)] 1)) (count llist))))

(defn square_list [n]
        (take (inc (* 4 (dec n))) (gen_diags)))

(defn square_ratio [n]
    (ratio (inc (* 4 (dec n)))))

(defn -main [& args]
    (loop [n 2]
        (if (>= (square_ratio n) 0.1)
            (do
                (println n "square:" (dec (* 2 n)) "square ratio:" (square_ratio n))
                (recur (inc n)))
            (println n "answer:" (dec (* 2 n)) "square ratio:" (square_ratio n))
        )))