game.phel

#########################################################################################
# This is a full version of the snake-cli-game, with the following elements:
# - A board
# - A snake with constant speed inside the board
# - The game ends when the snake touches the board
#########################################################################################
# Try it out: vendor/bin/phel run src/simple-version/game.phel
#########################################################################################
(ns phel-snake\simple-version\game
  (:require phel-cli-gui\terminal-gui :as gui))

(gui/add-output-formatter {:style-name "snake-head"
                           :foreground "black" :background "red" :options ["bold"]})
(gui/add-output-formatter {:style-name "snake-tail"
                           :foreground "black" :background "green" :options ["bold"]})

(defstruct board-struct [width height])
(defstruct snake-struct [direction speed head tail])

(def board (board-struct 40 20))

# Hexadecimal keys
(def directions
  {"1b5b44" :left
   "1b5b42" :down
   "1b5b43" :right
   "1b5b41" :up})

(defn move-snake [s next-direction]
  (if (nil? next-direction)
    (recur s (s :direction))
    (let [s2 (case next-direction
               :left (update-in s [:head :x] dec)
               :right (update-in s [:head :x] inc)
               :up (update-in s [:head :y] dec)
               :down (update-in s [:head :y] inc))
          new-tail (push (drop 1 (s2 :tail)) (s :head))
          s3 (put s2 :tail new-tail)]
      (put s3 :direction next-direction))))

(defn collision-with-board? [snake]
  (or
   (>= 1 (get-in snake [:head :x]))
   (>= 0 (get-in snake [:head :y]))
   (= (board :width) (get-in snake [:head :x]))
   (= (dec (board :height)) (get-in snake [:head :y]))))

(defn render-snake [snake]
  (for [t :in (snake :tail)]
    (gui/render (t :x) (t :y) " " "snake-tail"))
  (let [h (snake :head)]
    (gui/render (h :x) (h :y) " " "snake-head")))

(defn game-over [snake]
  (render-snake snake)
  (println "GAME OVER")
  (php/exit))

(defn render-board []
  (gui/clear-screen)
  (gui/render-board board {:horizontal "-" :vertical "|" :corner "+"}))

(def initial-snake (snake-struct :right 1 {:x 5 :y 5} [{:x 4 :y 5} {:x 3 :y 5}]))

(defn simple-game []
  (loop [snake initial-snake]
    (render-board)
    (println "Move your snake with the arrow-keys [UP, DOWN, LEFT, RIGHT]")

    (if (collision-with-board? snake)
      (game-over snake))

    (let [{:hex in} (gui/read-input 3)
          next-direction (directions in)
          new-snake (move-snake snake next-direction)]

      (render-snake new-snake)
      (php/usleep 50000)
      (recur new-snake))))