(ns mw-engine.world)

(defn make-cell 
  "Create a default cell at x, y"
  [x y]
  {:x x :y y :altitude 1 :state :pasture})

(defn make-world-row 
  "Make the (remaining) cells in a row at this height in a world of this width."
  [index width height]
  (cond (= index width) nil
    true (cons (make-cell index height)
               (make-world-row (+ index 1) width height))))

(defn make-world-rows [index width height]
  "Make the (remaining) rows in a world of this width and height, from this
   index."
  (cond (= index height) nil
    true (cons (apply vector (make-world-row 0 width index))
               (make-world-rows (+ index 1) width height))))

(defn make-world 
  "Make a world width cells from east to west, and height cells from north to
   south."
  [width height]
  (apply vector (make-world-rows 0 width height)))

(defn in-bounds   
  "True if x, y are in bounds for this world (i.e., there is a cell at x, y)
   else false."
  [world x y]
  (and (>= x 0)(>= y 0)(< y (count world))(< x (count (first world)))))

(defn get-cell 
  "Return the cell a x, y in this world, if any"
  [world x y]
  (cond (in-bounds world x y)
    (nth (nth world y) x)))

(defn get-neighbours 
  "Get the neighbours to distance depth of the cell at x, y in this world.
   NOTE: this implementation is broken, it gets the diagonal"
  [world x y depth]
  (map #(get-cell world %1 %2) (range (- x depth) (+ x depth)) (range (- y depth) (+ y depth))))