(defpackage game
  (:use :cl)
  (:export :new-game
		   :buy-item
		   :sell-item
		   :change-zone
		   :get-profit
		   :get-profit-in-zone))

(in-package :game)

(defclass game ()
  ((player :initarg :player
		   :accessor player)
   (zones  :initarg :zones
		   :accessor zones)
   (cur-zone :initarg :start-zone
			 :accessor cur-zone)))

(defun new-game (player start-zone zones)
  (make-instance 'game
				 :player player
				 :zones zones
				 :start-zone start-zone))

(defmethod buy-item ((g game) name amount)
  (with-slots (player cur-zone) g
	(let ((item (zone:get-commodity cur-zone name)))
	  (when item
		(player:buy-item player item amount)))))

(defmethod sell-item ((g game) name amount)
  (with-slots (player cur-zone) g
	(let ((item (zone:get-commodity cur-zone name)))
	  (when item
		(player:sell-item player item amount)))))

(defmethod change-zone ((g game) name)
  (with-slots (cur-zone zones) g
	(let ((z (find-if (lambda (z) (string= name
										   (zone:name z)))
					  zones)))
	  (when z
		(setq cur-zone z)))))

(defmethod get-profit-in-zone ((g game) name zone)
  (with-slots (player) g
	  (let ((player-item (car (player:find-item player name)))
			(zone-item (zone:get-commodity zone name)))
		(if (and player-item zone-item)
			(- (commodities:price zone-item)
			   (commodities:price player-item))
			0))))

(defmethod get-profit ((g game) name)
  (with-slots (cur-zone) g
	  (get-profit-in-zone g name cur-zone)))