(ns adventofcode2019.day08
    [:require [adventofcode2019.lib :refer :all]
              [clojure.core.match :refer [match]]])

(def combine-layers 
  "Binary operation on the pixels of two layers, the first above the second."
  #(match [%1 %2]
          [0 _] 0
          [1 _] 1
          [2 p] p))

(defn day08 []
  (let [input (mapv parse-int (get-list-from-file (input-file) #""))
        layer-size (* 25 6)
        count-num #(count (filter (hash-set %1) %2))
        layers (partition layer-size input)
        fewest-zeroes (apply (partial min-key (partial count-num 0)) 
                             layers)
        layered-image (reduce #(mapv combine-layers %1 %2) layers)
        to-ascii #(match % 0 \u0020 ; 0s are spaces, 1s are full-block
                           1 \u2588)] 
    (part1 (* (count-num 1 fewest-zeroes)
              (count-num 2 fewest-zeroes)))
    (part2 "see below")
    (run! println (partition 25 (map to-ascii layered-image)))))