(ns clojure-blackjack.core
  (:require [clojure.math.combinatorics :as combo]))

(defn get-deck []
  (let [suits ["H" "D" "C" "S"]
        faces [2 3 4 5 6 7 8 9 10 "J" "Q" "K" "A"]]
    (map clojure.string/join
         (combo/cartesian-product suits faces))))

(defn get-decks
  [num-decks]
  (flatten (repeat num-decks (get-deck))))

(defn shuffle-deck
  [deck]
  (shuffle (shuffle (shuffle deck))))

(defn suit
  [card]
  (str (first card)))

(defn face
  [card]
  (clojure.string/join (rest card)))

(defn value
  [card]
  (let [face (get-face card)]
    (cond
      (= face "A") [1 11]
      (or (= face "J")
          (= face "Q")
          (= face "K")) [10]
      :else [(read-string face)])))

(defn hand-value
  [cards]
  (let [values (map value cards)]
    (map #(reduce + %)
         (apply combo/cartesian-product values))))