(ns day7
  (:require [clojure.string :as string]
            [helpers :refer [get-input]]))

(def example
"190: 10 19
3267: 81 40 27
83: 17 5
156: 15 6
7290: 6 8 6 15
161011: 16 10 13
192: 17 8 14
21037: 9 7 18 13
292: 11 6 16 20")

(def input
  (->>
   ;example
   (get-input 7)
   string/split-lines))

(defn permutation->operator [p]
  (concat
   (map #(if (even? %) + *) p)
   (map #(if (odd? %) + *) p)))

(defn operators [n]
  (let [add-operators
        (fn [ops]
          (vector (conj ops +)
                  (conj ops *)))]
    (loop [i 1 ops [[+] [*]]]
      (if (= n i)
        ops
        (recur (inc i)
               (mapcat add-operators ops))))))

(defn test-calibration [ops-fn s]
  (let [[tval ns] (string/split s #":")
        tval (parse-long tval)
        ns (vec (map parse-long
                     (-> ns string/trim (string/split #" "))))
        ops (-> ns count dec ops-fn)
        check-fn
        (fn [op-seq]
          (reduce
           (fn [r i]
             ((get op-seq i) r (get ns (inc i))))
           (first ns)
           (range (count op-seq))))]
    (if (empty?
         (filter (partial = tval) (map check-fn ops)))
      0 tval)))

(println "Total calibration result:"
         (reduce + (map (partial test-calibration operators) input)))


(defn || [a b]
  (parse-long (str a b)))

(defn operators2 [n]
  (let [add-operators
        (fn [ops]
          (vector (conj ops +)
                  (conj ops *)
                  (conj ops ||)))]
    (loop [i 1 ops [[+] [*] [||]]]
      (if (= n i)
        ops
        (recur (inc i)
               (mapcat add-operators ops))))))

(println "Total calibration result (part 2):"
         (reduce + (map (partial test-calibration operators2) input)))