#| -*-Scheme-*-

Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016,
    2017, 2018, 2019, 2020 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

MIT/GNU Scheme is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at
your option) any later version.

MIT/GNU Scheme is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with MIT/GNU Scheme; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301,
USA.

|#

;;;; Command Reader

(declare (usual-integrations))

(define *command-key*)		;Key read to find current command
(define *command*)		;The current command
(define *last-command*)		;The previous command, excluding arg commands
(define *command-argument*)	;Argument from last command
(define *next-argument*)	;Argument to next command
(define *command-message*)	;Message from last command
(define *next-message*)		;Message to next command
(define *non-undo-count*)	;# of self-inserts since last undo boundary
(define keyboard-keys-read)	;# of keys read from keyboard
(define command-history)
(define command-history-limit 30)
(define command-reader-override-queue)
(define *command-suffixes*)

(add-event-receiver! editor-initializations
  (lambda ()
    (set! keyboard-keys-read 0)
    (set! command-history (make-circular-list command-history-limit #f))
    (set! command-reader-override-queue (make-queue))
    (set! *command-suffixes* #f)
    unspecific))

(define (top-level-command-reader init)
  (with-keyboard-macro-disabled
   (lambda ()
     (bind-condition-handler (list condition-type:abort-current-command)
	 return-to-command-loop
       (lambda ()
	 (command-reader init))))))

(define (command-reader #!optional initialization)
  (fluid-let ((*last-command* #f)
	      (*command* #f)
	      (*command-argument*)
	      (*next-argument* #f)
	      (*command-message*)
	      (*next-message* #f)
	      (*non-undo-count* 0)
	      (*command-key* #f))
    (bind-condition-handler (list condition-type:editor-error)
	editor-error-handler
      (lambda ()
	(bind-condition-handler (list condition-type:abort-current-command)
	    (lambda (condition)
	      (if (not (condition/^G? condition))
		  (return-to-command-loop condition)))
	  (lambda ()
	    (if (and (not (default-object? initialization)) initialization)
		(bind-abort-editor-command
		 (lambda ()
		   (reset-command-state!)
		   (initialization))))
	    (do () (#f)
	      (bind-abort-editor-command
	       (lambda ()
		 (do () (#f)
		   (reset-command-state!)
		   (if (queue-empty? command-reader-override-queue)
		       (let ((input (get-next-keyboard-char)))
			 (if (input-event? input)
			     (begin
			       (apply-input-event input)
			       (if (not (eq? 'BUTTON (input-event/type input)))
				   (preserve-command-state!)))
			     (begin
			       (set! *command-key* input)
			       (clear-message)
			       (set-command-prompt!
				(if (not (command-argument))
				    (key-name input)
				    (string-append-separated
				     (command-argument-prompt)
				     (key-name input))))
			       (let ((window (current-window)))
				 (%dispatch-on-command
				  window
				  (local-comtab-entry (buffer-comtabs
						       (window-buffer window))
						      input
						      (window-point window))
				  #f)))))
		       ((dequeue! command-reader-override-queue)))))))))))))

(define (bind-abort-editor-command thunk)
  (call-with-current-continuation
   (lambda (k)
     (with-restart 'ABORT-EDITOR-COMMAND "Return to the editor command loop."
	 (lambda (#!optional input)
	   (keyboard-macro-disable)
	   (if (and (not (default-object? input)) (input-event? input))
	       (within-continuation k
		 (lambda ()
		   (reset-command-state!)
		   (apply-input-event input)))
	       (begin
		 (abort-keyboard-macro)
		 (k unspecific))))
	 values
       thunk))))

(define (return-to-command-loop condition)
  (let ((restart (find-restart 'ABORT-EDITOR-COMMAND)))
    (if (not restart) (error "Missing ABORT-EDITOR-COMMAND restart."))
    (invoke-restart restart
		    (and (condition/abort-current-command? condition)
			 (abort-current-command/input condition)))))

(define (get-next-keyboard-char)
  (if *executing-keyboard-macro?*
      (begin
	(set! keyboard-keys-read (+ keyboard-keys-read 1))
	(keyboard-macro-read-key))
      (with-editor-interrupts-disabled keyboard-read)))

(define (reset-command-state!)
  (unblock-thread-events)
  (set! *last-command* *command*)
  (set! *command* #f)
  (set! *command-argument* *next-argument*)
  (set! *next-argument* #f)
  (set! *command-message* *next-message*)
  (set! *next-message* #f)
  (if (command-argument)
      (set-command-prompt! (command-argument-prompt))
      (reset-command-prompt!))
  (if *defining-keyboard-macro?*
      (keyboard-macro-finalize-keys)))

(define (preserve-command-state!)
  (set! *next-argument* *command-argument*)
  (set! *next-message* *command-message*)
  (set! *command* *last-command*)
  unspecific)

(define (override-next-command! override)
  (enqueue! command-reader-override-queue override))

(define-integrable (current-command-key)
  *command-key*)

(define (last-command-key)
  (if (key? *command-key*)
      *command-key*
      (car (last-pair *command-key*))))

(define (set-current-command! command)
  (set! *command* command)
  unspecific)

(define-integrable (current-command)
  *command*)

(define-integrable (last-command)
  *last-command*)

(define (set-command-argument! argument mode)
  (set! *next-argument* (cons argument mode))
  ;; Preserve message and last command.
  (set! *next-message* *command-message*)
  (set! *command* *last-command*)
  unspecific)

(define-integrable (command-argument)
  (and *command-argument* (car *command-argument*)))

(define (auto-argument-mode?)
  (and *command-argument* (cdr *command-argument*)))

(define (set-command-message! tag . arguments)
  (set! *next-message* (cons tag arguments))
  unspecific)

(define (command-message-receive tag if-received if-not-received)
  (if (and *command-message*
	   (eq? (car *command-message*) tag))
      (apply if-received (cdr *command-message*))
      (if-not-received)))

(define (command-history-list)
  (let loop ((history command-history))
    (if (car history)
	(let loop ((history (cdr history)) (result (list (car history))))
	  (if (eq? history command-history)
	      result
	      (loop (cdr history) (cons (car history) result))))
	(let ((history (cdr history)))
	  (if (eq? history command-history)
	      '()
	      (loop history))))))

(define (add-command-suffix! procedure . arguments)
  (if *command-suffixes*
      (without-interrupts
       (lambda ()
	 (%add-command-suffix! procedure arguments)))
      (apply procedure arguments)))

(define (maybe-add-command-suffix! procedure . arguments)
  (if *command-suffixes*
      (without-interrupts
       (lambda ()
	 (let loop ((items (car *command-suffixes*)))
	   (cond ((not (pair? items))
		  (%add-command-suffix! procedure arguments))
		 ((not (and (eq? procedure (caar items))
			    (equal? arguments (cdar items))))
		  (loop (cdr items)))))))
      (apply procedure arguments)))

(define (%add-command-suffix! procedure arguments)
  (let ((next (cons (cons procedure arguments) '())))
    (if (pair? (cdr *command-suffixes*))
	(set-cdr! (cdr *command-suffixes*) next)
	(set-car! *command-suffixes* next))
    (set-cdr! *command-suffixes* next)))

(define (run-command-suffixes)
  (let loop ()
    (let ((item
	   (without-interrupts
	    (lambda ()
	      (let ((next (car *command-suffixes*)))
		(and (pair? next)
		     (begin
		       (if (pair? (cdr next))
			   (set-car! *command-suffixes* (cdr next))
			   (begin
			     (set-car! *command-suffixes* '())
			     (set-cdr! *command-suffixes* '())))
		       (car next))))))))
      (if item
	  (begin
	    (apply (car item) (cdr item))
	    (loop))))))

;;; The procedures for executing commands come in two flavors.  The
;;; difference is that the EXECUTE-foo procedures reset the command
;;; state first, while the DISPATCH-ON-foo procedures do not.  The
;;; latter should only be used by "prefix" commands such as C-X or
;;; C-4, since they want arguments, messages, etc. to be passed on.

(define-integrable (execute-key comtab key)
  (reset-command-state!)
  (dispatch-on-key comtab key))

(define-integrable (execute-command command)
  (reset-command-state!)
  (%dispatch-on-command (current-window) command #f))

(define (execute-button-command screen button x y)
  (clear-message)
  (reset-command-state!)
  (send (screen-root-window screen) ':button-event! button x y))

(define (read-and-dispatch-on-key)
  (dispatch-on-key (current-comtabs)
		   (with-editor-interrupts-disabled keyboard-read)))

(define (dispatch-on-key comtab key)
  (if (input-event? key)
      (apply-input-event key)
      (begin
	(set! *command-key* key)
	(set-command-prompt!
	 (string-append-separated (command-argument-prompt) (xkey->name key)))
	(%dispatch-on-command (current-window)
			      (comtab-entry comtab key)
			      #f))))

(define (dispatch-on-command command #!optional record?)
  (%dispatch-on-command (current-window)
			command
			(if (default-object? record?) #f record?)))

(define (%dispatch-on-command window command record?)
  (set! *command* command)
  (guarantee-command-loaded command)
  (define (char-image-string ch)
    (window-char->image window ch))
  (let ((point (window-point window))
	(point-x (window-point-x window))
	(procedure (command-procedure command)))
    (let ((normal
	   (lambda ()
	     (set! *non-undo-count* 0)
	     (if (not *command-argument*)
		 (undo-boundary! point))
	     (fluid-let ((*command-suffixes* (cons '() '())))
	       (let ((v
		      (apply procedure
			     (interactive-arguments command record?))))
		 (run-command-suffixes)
		 v)))))
      (cond ((or *executing-keyboard-macro?* *command-argument*)
	     (normal))
	    ((and (char? *command-key*)
		  (or (eq? command (ref-command-object self-insert-command))
		      (command-argument-self-insert? command)))
	     (let ((non-undo-count *non-undo-count*))
	       (if (or (fix:= non-undo-count 0)
		       (fix:>= non-undo-count 20))
		   (begin
		     (set! *non-undo-count* 1)
		     (undo-boundary! point))
		   (set! *non-undo-count* (fix:+ non-undo-count 1))))
	     (let ((key *command-key*))
	       (if (and (not (window-needs-redisplay? window))
			(let ((buffer (window-buffer window)))
			  (and (buffer-auto-save-modified? buffer)
			       (null? (cdr (buffer-windows buffer)))))
			(line-end? point)
			(not (char=? key #\newline))
			(not (char=? key #\tab))
			(let ((image (char-image-string key)))
			  (and (fix:= (string-length image) 1)
			       (char=? (string-ref image 0) key)))
			(fix:< point-x (fix:- (window-x-size window) 1)))
		   (if (self-insert key 1 #t)
		       (begin
			 (set! *non-undo-count* 0)
			 (undo-boundary! point))
		       (window-direct-output-insert-char! window key))
		   (normal))))
	    ((eq? command (ref-command-object forward-char))
	     (if (and (not (window-needs-redisplay? window))
		      (not (group-end? point))
		      (let ((char (mark-right-char point)))
			(and (not (char=? char #\newline))
			     (not (char=? char #\tab))
			     (fix:= (string-length (char-image-string char))
				    1)))
		      (fix:< point-x (fix:- (window-x-size window) 2)))
		 (window-direct-output-forward-char! window)
		 (normal)))
	    ((eq? command (ref-command-object backward-char))
	     (if (and (not (window-needs-redisplay? window))
		      (not (group-start? point))
		      (let ((char (mark-left-char point)))
			(and (not (char=? char #\newline))
			     (not (char=? char #\tab))
			     (fix:= (string-length (char-image-string char))
				    1)))
		      (fix:< 0 point-x)
		      (fix:< point-x (fix:- (window-x-size window) 1)))
		 (window-direct-output-backward-char! window)
		 (normal)))
	    (else
	     (normal))))))

(define (interactive-arguments command record?)
  (let ((specification (command-interactive-specification command))
	(record-command-arguments
	 (lambda (arguments)
	   (let ((history command-history))
	     (set-car! history (cons (command-name command) arguments))
	     (set! command-history (cdr history))))))
    (cond ((string? specification)
	   (call-with-values
	       (lambda ()
		 (let ((end (string-length specification)))
		   (let loop
		       ((index
			 (if (and (not (zero? end))
				  (char=? #\* (string-ref specification 0)))
			     (begin
			       (if (buffer-read-only? (current-buffer))
				   (barf-if-read-only))
			       1)
			     0)))
		     (if (< index end)
			 (let ((newline
				(substring-find-next-char specification
							  index
							  end
							  #\newline)))
			   (call-with-values
			       (lambda ()
				 (interactive-argument
				  (string-ref specification index)
				  (substring specification
					     (+ index 1)
					     (or newline end))))
			     (lambda (argument expression from-tty?)
			       (call-with-values
				   (lambda ()
				     (if newline
					 (loop (+ newline 1))
					 (values '() '() #f)))
				 (lambda (arguments expressions any-from-tty?)
				   (values (cons argument arguments)
					   (cons expression expressions)
					   (or from-tty? any-from-tty?)))))))
			 (values '() '() #f)))))
	     (lambda (arguments expressions any-from-tty?)
	       (if (or record?
		       (and any-from-tty?
			    (not (prefix-key-list? (current-comtabs)
						   (current-command-key)))))
		   (record-command-arguments expressions))
	       arguments)))
	  ((null? specification)
	   (if record? (record-command-arguments '()))
	   '())
	  (else
	   (let ((old-keys-read keyboard-keys-read))
	     (let ((arguments (specification)))
	       (if (or record? (not (= keyboard-keys-read old-keys-read)))
		   (record-command-arguments (map quotify-sexp arguments)))
	       arguments))))))

(define (execute-command-history-entry entry)
  (let ((history command-history))
    (if (not (equal? entry
		     (let loop ((entries (cdr history)) (tail history))
		       (if (eq? entries history)
			   (car tail)
			   (loop (cdr entries) entries)))))
	(begin
	  (set-car! history entry)
	  (set! command-history (cdr history)))))
  (apply (command-procedure (name->command (car entry)))
	 (map (let ((environment (->environment '(EDWIN))))
		(lambda (expression)
		  (eval-with-history expression environment)))
	      (cdr entry))))

(define (interactive-argument key prompt)
  (let ((prompting
	 (lambda (value)
	   (values value (quotify-sexp value) #t)))
	(prefix
	 (lambda (prefix)
	   (values prefix (quotify-sexp prefix) #f)))
	(varies
	 (lambda (value expression)
	   (values value expression #f))))
    (case key
      ((#\b)
       (prompting
	(buffer-name (prompt-for-existing-buffer prompt (current-buffer)))))
      ((#\B)
       (prompting (buffer-name (prompt-for-buffer prompt (current-buffer)))))
      ((#\c)
       (prompting (prompt-for-char prompt)))
      ((#\C)
       (prompting (command-name (prompt-for-command prompt))))
      ((#\d)
       (varies (current-point) '(CURRENT-POINT)))
      ((#\D)
       (prompting (prompt-for-directory prompt #f)))
      ((#\f)
       (prompting (prompt-for-existing-file prompt #f)))
      ((#\F)
       (prompting (prompt-for-file prompt #f)))
      ((#\k)
       (prompting (prompt-for-key prompt (current-comtabs))))
      ((#\m)
       (varies (current-mark) '(CURRENT-MARK)))
      ((#\n)
       (prompting (prompt-for-number prompt #f)))
      ((#\N)
       (prefix
	(or (command-argument-value (command-argument))
	    (prompt-for-number prompt #f))))
      ((#\p)
       (prefix (command-argument-numeric-value (command-argument))))
      ((#\P)
       (prefix (command-argument)))
      ((#\r)
       (varies (current-region) '(CURRENT-REGION)))
      ((#\s)
       (prompting
	(or (prompt-for-string prompt #f 'DEFAULT-TYPE 'NULL-DEFAULT)
	    "")))
      ((#\v)
       (prompting (variable-name (prompt-for-variable prompt))))
      ((#\x)
       (prompting (prompt-for-expression prompt)))
      ((#\X)
       (prompting (prompt-for-expression-value prompt)))
      (else
       (editor-error "Invalid control letter "
		     key
		     " in interactive calling string")))))

(define (quotify-sexp sexp)
  (if (or (boolean? sexp)
	  (number? sexp)
	  (string? sexp)
	  (char? sexp))
      sexp
      `(QUOTE ,sexp)))