;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; Maintain a chess game that is being played or viewed
;;

;;; Commentary:

;; A chess game is represented by a set of tags that describe the
;; game, and a list of plies representing the main variation.

(require 'chess-ply)
(require 'chess-pgn)

(defvar chess-game-inhibit-events nil)

(defconst chess-game-default-tags
  `(("Event"	   . "Computer chess game")
    ("Round"	   . "-")
    ("Site"	   . ,(system-name))
    ("White"	   . "?")
    ("Black"	   . "?")
    ("Result"	   . "*")
    ("TimeControl" . "-")))

(defsubst chess-game-hooks (game)
  "Return the tags alist associated with GAME."
  (assert game)
  (car game))

(defsubst chess-game-set-hooks (game hooks)
  "Return the tags alist associated with GAME."
  (assert game)
  (assert (or hooks (eq hooks nil)))
  (setcar game hooks))

(defun chess-game-add-hook (game function &optional data prepend)
  "Return the tags alist associated with GAME."
  (assert game)
  (assert function)
  (let ((hooks (chess-game-hooks game)))
    (if (null hooks)
	(chess-game-set-hooks game (list (cons function data)))
      (if prepend
	  (chess-game-set-hooks game (cons (cons function data) hooks))
	(nconc hooks (list (cons function data)))))))

(defun chess-game-remove-hook (game function &optional data)
  "Remove from GAME all event hooks that match FUNCTION.
If DATA is specified, only remove those hooks whose associated data
matches."
  (assert game)
  (assert function)
  (let* ((hooks (chess-game-hooks game))
	 (h hooks) last-hook)
    (while h
      (if (and (eq (caar h) function)
	       (or (null data)
		   (eq data (cdar h))))
	  (if last-hook
	      (setcdr last-hook (cdr h))
	    (setq hooks (cdr h)))
	(setq last-hook h))
      (setq h (cdr h)))
    (chess-game-set-hooks game hooks)))

(defsubst chess-game-run-hooks (game &rest args)
  "Return the tags alist associated with GAME."
  (assert game)
  (unless chess-game-inhibit-events
    (let (result)
      (dolist (hook (chess-game-hooks game) result)
	(setq result (apply (car hook) game (cdr hook) args))))))


(defsubst chess-game-tags (game)
  "Return the tags alist associated with GAME."
  (assert game)
  (cadr game))

(defsubst chess-game-set-tags (game tags)
  "Return the tags alist associated with GAME."
  (assert game)
  (assert (or tags (eq tags nil)))
  (setcar (cdr game) tags)
  (chess-game-run-hooks game 'set-tags))

(defsubst chess-game-tag (game tag)
  "Return the value for TAG in GAME."
  (assert game)
  (assert tag)
  (let ((tags (chess-game-tags game)))
    (and tags (cdr (assoc tag tags)))))

(defun chess-game-set-tag (game tag value)
  "Set a TAG for GAME to VALUE."
  (assert game)
  (assert tag)
  (assert value)
  (let ((tags (chess-game-tags game)))
    (if (null tags)
	(chess-game-set-tags game (list (cons tag value)))
      (let ((entry (assoc tag tags)))
	(if entry
	    (setcdr entry value)
	  (nconc tags (list (cons tag value)))))))
  (chess-game-run-hooks game 'set-tag tag))

(defsubst chess-game-del-tag (game tag)
  "Set a TAG for GAME to VALUE."
  (assert game)
  (assert tag)
  (chess-game-set-tags game (assq-delete-all tag (chess-game-tags game)))
  (chess-game-run-hooks game 'delete-tag tag))


(defsubst chess-game-data-alist (game)
  (assert game)
  (nth 2 game))

(defsubst chess-game-set-data-alist (game value)
  (assert game)
  (setcar (nthcdr 2 game) value))

(defun chess-game-set-data (game key value)
  (assert game)
  (assert (symbolp key))
  (let* ((alist (chess-game-data-alist game))
	 (cell (assq key alist)))
    (if cell
	(setcdr cell value)
      (if (null alist)
	  (setcar (nthcdr 2 game) (list (cons key value)))
	(push (cons key value) alist)
	(setcar (nthcdr 2 game) alist)))
    (chess-game-run-hooks game 'set-data key)
    value))

(defun chess-game-data (game key)
  (assert game)
  (assert (symbolp key))
  (let ((alist (chess-game-data-alist game)))
    (if alist
	(cdr (assq key alist)))))

(defun chess-game-del-data (game key)
  (assert game)
  (assert (symbolp key))
  (let ((alist (chess-game-data-alist game)))
    (if alist
	(assq-delete-all key alist))))


(defsubst chess-game-plies (game)
  "Return the tags alist associated with GAME."
  (assert game)
  (nth 3 game))

(defalias 'chess-game-main-var 'chess-game-plies)

(defsubst chess-game-set-plies (game plies)
  "Return the tags alist associated with GAME."
  (assert game)
  (setcdr (nthcdr 2 game) (if plies (list plies) nil))
  (chess-game-run-hooks game 'setup-game game))

(defsubst chess-game-set-start-position (game position)
  "Return the tags alist associated with GAME."
  (assert game)
  (assert (vectorp position))
  (chess-game-set-plies game (list (chess-ply-create* position))))

(defsubst chess-game-pos (game &optional index)
  "Return the position related to GAME's INDEX position."
  (assert game)
  (chess-ply-pos (chess-game-ply game index)))

(defun chess-game-status (game &optional index)
  "Return a symbol, such as :checkmate, :resign, etc.
This conveys the status of the game at the given index."
  (assert game)
  (or (chess-pos-status (chess-game-pos game index))
      (chess-ply-final-p (chess-game-ply game index))))

(defsubst chess-game-index (game)
  "Return the GAME's current position index."
  (assert game)
  (1- (length (chess-game-plies game))))

(defun chess-game-seq (game)
  "Return the current GAME sequence."
  (assert game)
  (let ((index (chess-game-index game)))
    (if (> index 1)
	(if (= (mod index 2) 0)
	    (/ index 2)
	  (1+ (/ index 2)))
      1)))

(defsubst chess-game-side-to-move (game &optional index)
  "Return the color whose move it is in GAME at INDEX (or at the last position
if INDEX is nil)."
  (assert game)
  (chess-pos-side-to-move (chess-game-pos game index)))

(defun chess-game-ply (game &optional index)
  "Return the position related to GAME's INDEX position."
  (assert game)
  (if index
      (nth index (chess-game-plies game))
    (car (last (chess-game-plies game)))))

(defun chess-game-add-ply (game ply)
  "Return the position related to GAME's INDEX position."
  (assert game)
  (assert (listp ply))
  (let ((plies (chess-game-plies game)))
    (if plies
	(nconc plies (list ply))
      (let ((chess-game-inhibit-events t))
	(chess-game-set-plies game (list ply))))))

(chess-message-catalog 'english
  '((undo-limit-reached . "Cannot undo further")
    (add-to-completed	. "Cannot add moves to a completed game")))

(defun chess-game-undo (game count)
  "Undo the last COUNT plies of GAME."
  (assert game)
  (assert (integerp count))
  (assert (> count 0))
  (if (> count (chess-game-index game))
      (chess-error 'undo-limit-reached))
  (let ((chess-game-inhibit-events t))
    (chess-game-set-plies game (nbutlast (chess-game-plies game) count)))
  (chess-game-run-hooks game 'post-undo count))


(defun chess-game-strip-annotations (game)
  "Strip all annotations from the given GAME."
  (assert game)
  (dotimes (i (chess-game-index game))
    (let ((position (chess-game-pos game i)))
      (chess-pos-set-annotations position nil))))


(defsubst chess-game-over-p (game)
  "Return the position related to GAME's INDEX position."
  (assert game)
  (let ((last-ply (car (last (nth 3 game) 2))))
    (and last-ply (chess-ply-final-p last-ply))))


(defsubst chess-game-to-string (game &optional indented)
  (assert game)
  (chess-game-to-pgn game indented t))

(defsubst chess-game-from-string (pgn)
  (assert (stringp pgn))
  (chess-pgn-to-game pgn))


(defsubst chess-game-copy-game (game new-game)
  (assert game)
  (assert new-game)
  (chess-game-set-tags game (chess-game-tags new-game))
  (chess-game-set-plies game (chess-game-plies new-game)))


(defun chess-game-create (&optional position tags)
  "Create a new chess game object.
Optionally use the given starting POSITION.
TAGS is the starting set of game tags (which can always be changed
later using the various tag-related methods)."
  (let ((game (list nil tags nil
		    (list (chess-ply-create* (or position
						 chess-starting-position))))))
    (dolist (tag (cons (cons "Date" (format-time-string "%Y.%m.%d"))
		       chess-game-default-tags))
      (unless (chess-game-tag game (car tag))
	(chess-game-set-tag game (car tag) (cdr tag))))
    game))

(defun chess-game-move (game ply)
  "Make a move in the current GAME, from FROM to TO.
This creates a new position and adds it to the main variation.
The 'changes' of the last ply reflect whether the game is currently in
progress (nil), if it is drawn, resigned, mate, etc."
  (assert game)
  (assert (listp ply))
  (let ((current-ply (chess-game-ply game))
	(position (chess-ply-pos ply))
	(changes (chess-ply-changes ply)))

    (assert current-ply)
    (assert (and position (eq position (chess-ply-pos current-ply))))
    (assert changes)

    (if (chess-ply-final-p current-ply)
	(chess-error 'add-to-completed))

    (chess-ply-set-changes current-ply changes)
    (unless (chess-ply-any-keyword ply :drawn :perpetual :repetition
				   :resign :aborted :flag-fell)
      (chess-game-add-ply game (chess-ply-create*
				(chess-ply-next-pos current-ply))))

    (let ((long (> (length changes) 2)))
      (cond
       ((and long (chess-ply-any-keyword ply :resign :checkmate))
	(let ((color (chess-game-side-to-move game)))
	  (if (chess-ply-any-keyword ply :resign :flag-fell)
	      (chess-game-set-tag game "Result" (if color "0-1" "1-0"))
	    (chess-game-set-tag game "Result" (if color "1-0" "0-1")))))
       ((and long (chess-ply-any-keyword ply :drawn :perpetual :repetition
					 :stalemate))
	(chess-game-set-tag game "Result" "1/2-1/2"))))

    (if (chess-ply-keyword ply :resign)
	(chess-game-run-hooks game 'resign)
      (chess-game-run-hooks game 'move current-ply)
      (chess-game-run-hooks game 'post-move))))

(defsubst chess-game-end (game keyword)
  "End the current game, by resignation, draw, etc."
  (chess-game-move game (list (chess-game-pos game) keyword)))

(provide 'chess-game)

;;; chess-game.el ends here