;;; inferior-scala-mode.el - Interaction with a Scala interpreter.
;;; $Id$

(require 'comint)

(defgroup inferior-scala
  nil
  "Mode to interact with a Scala interpreter."
  :group 'scala
  :tag "Inferior Scala")

(defcustom scala-default-interpreter "scalaint -emacs"
  "Name of the interpreter to use by default."
  :type 'string
  :group 'inferior-scala)

(defvar scala-interpreter scala-default-interpreter
  "The interpreter that `run-scala' should run.
If you want to change the defaut value, don't change that variable
but customize `scala-default-interpreter' instead.")

(defconst scala-inf-buffer-name "*inferior-scala*")

(define-derived-mode inferior-scala-mode comint-mode "Inferior Scala"
  "Major mode for interacting with a Scala interpreter.

\\{inferior-scala-mode-map\\}"
  (define-key inferior-scala-mode-map [(meta return)] 'comint-accumulate)

  ;; Comint configuration
  (make-local-variable 'comint-input-sender)
  (setq comint-input-sender 'scala-input-sender))

(defun scala-input-sender (proc string)
  (comint-send-string proc string)
  (comint-send-string proc "\nemacs:end\n"))

;;;###autoload
(defun scala-interpreter-running-p-1 ()
  ;; True iff a Scala interpreter is currently running in a buffer.
  (comint-check-proc scala-inf-buffer-name))

(defun scala-check-interpreter-running ()
  (unless (scala-interpreter-running-p-1)
    (error "Scala interpreter not running")))

;;;###autoload
(defun run-scala (cmd-line)
  "Run a Scala interpreter in an Emacs buffer"
  (interactive (list (if current-prefix-arg
			 (read-string "Scala interpreter: " scala-interpreter)
                       scala-interpreter)))
  (unless (scala-interpreter-running-p-1)
    (setq scala-interpreter cmd-line)
    (let ((cmd/args (split-string cmd-line)))
      (set-buffer
       (apply 'make-comint "inferior-scala" (car cmd/args) nil (cdr cmd/args))))
    (inferior-scala-mode)
    (pop-to-buffer scala-inf-buffer-name)))

(defun scala-send-string (str &rest args)
  ;; Send string to interpreter
  (comint-send-string scala-inf-buffer-name (apply 'format str args))
  (comint-send-string scala-inf-buffer-name "\nemacs:end\n"))

;;;###autoload
(defun scala-switch-to-interpreter ()
  "Switch to buffer containing the interpreter"
  (interactive)
  (scala-check-interpreter-running)
  (switch-to-buffer scala-inf-buffer-name))

(defvar scala-tmp-file nil)

;;;###autoload
(defun scala-eval-region (start end)
  "Send current region to Scala interpreter."
  (interactive "r")
  (scala-check-interpreter-running)
  (if scala-tmp-file
      (delete-file scala-tmp-file)
    (setq scala-tmp-file (make-temp-file "scala_tmp")))
  (write-region start end scala-tmp-file nil 'quiet)
  (scala-send-string ":use %s" scala-tmp-file))

;;;###autoload
(defun scala-eval-buffer ()
  "Send whole buffer to Scala interpreter."
  (interactive)
  (scala-eval-region (point-min) (point-max)))

(defvar scala-prev-l/c-dir/file nil
  "Caches the last (directory . file) pair.
Caches the last pair used in the last scala-load-file.
Used for determining the default in the next one.")

;;;###autoload
(defun scala-load-file (file-name)
  "Load a file in the Scala interpreter."
  (interactive (comint-get-source "Load Scala file: " scala-prev-l/c-dir/file
				  '(scala-mode) t))
  (scala-check-interpreter-running)
  (comint-check-source file-name)
  (setq scala-prev-l/c-dir/file (cons (file-name-directory file-name)
                                      (file-name-nondirectory file-name)))
  (scala-send-string ":load %s" file-name))

;;;###autoload
(defun scala-quit-interpreter ()
  "Quit Scala interpreter."
  (interactive)
  (scala-check-interpreter-running)
  (scala-send-string "\n:quit"))

(provide 'inferior-scala-mode)