#| -*-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,
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|#

;;;; Window System

(declare (usual-integrations))

;;;  Based on WINDOW-WIN, designed by RMS.
;;;  See WINOPS.TXT for more information.

;;; The convention of using method names like :FOO is somewhat
;;; arbitrary.  However, methods without the prefix ":" are intended
;;; to be internal (non-public) methods.

;;; Procedural covers are used as the ultimate outside interface to
;;; the window system, since that minimizes dependence on the
;;; syntactic details of the class/object system.

;;; It is assumed in several places that all windows keep the
;;; following instance variables updated: SUPERIOR, X-SIZE, and
;;; Y-SIZE.  Thus these are normally accessed using procedure calls or
;;; instance variable references, rather than the more cumbersome
;;; method invocation.  However, these instance variables are always
;;; set by a method defined on the window itself.

;;; It is assumed in several places that the methods to set a window's
;;; size are called with interrupts disabled.

;;;; Vanilla Window

(define-class vanilla-window ()
  (superior x-size y-size redisplay-flags inferiors))

(define (window-initialize! window window*)
  (%set-window-superior! window window*)
  (set-window-inferiors! window '())
  (%set-window-redisplay-flags!
   window
   (==> window* :inferior-redisplay-flags window)))

(define (window-kill! window)
  (for-each-inferior-window window (lambda (window) (==> window :kill!))))

(define-integrable (window-superior window)
  (with-instance-variables vanilla-window window () superior))

(define-integrable (%set-window-superior! window window*)
  (with-instance-variables vanilla-window window (window*)
    (set! superior window*)))

(define-integrable (window-x-size window)
  (with-instance-variables vanilla-window window () x-size))

(define-integrable (%set-window-x-size! window x)
  (with-instance-variables vanilla-window window (x) (set! x-size x)))

(define-integrable (window-y-size window)
  (with-instance-variables vanilla-window window () y-size))

(define-integrable (%set-window-y-size! window y)
  (with-instance-variables vanilla-window window (y) (set! y-size y)))

(define-integrable (window-redisplay-flags window)
  (with-instance-variables vanilla-window window () redisplay-flags))

(define-integrable (%set-window-redisplay-flags! window flags)
  (with-instance-variables vanilla-window window (flags)
    (set! redisplay-flags flags)))

(define-integrable (window-inferiors window)
  (with-instance-variables vanilla-window window () inferiors))

(define-integrable (set-window-inferiors! window inferiors*)
  (with-instance-variables vanilla-window window (inferiors*)
    (set! inferiors inferiors*)))

(define (window-root-window window)
  (if (window-superior window)
      (window-root-window (window-superior window))
      window))

(define (set-window-superior! window window*)
  (%set-window-superior! window window*)
  (let ((flags (==> window* :inferior-redisplay-flags window)))
    (%set-window-redisplay-flags! window flags)
    (setup-redisplay-flags! flags)
    (for-each-inferior window
      (lambda (inferior)
	(set-inferior-redisplay-flags! inferior (cons false flags))
	(==> (inferior-window inferior) :set-superior! window)))))

(define (window-size window receiver)
  (receiver (window-x-size window) (window-y-size window)))

(define (set-window-x-size! window x)
  (%set-window-x-size! window x)
  (window-needs-redisplay! window))

(define (set-window-y-size! window y)
  (%set-window-y-size! window y)
  (window-needs-redisplay! window))

(define (set-window-size! window x y)
  (%set-window-x-size! window x)
  (%set-window-y-size! window y)
  (window-needs-redisplay! window))

(define-integrable (window-needs-redisplay? window)
  (car (window-redisplay-flags window)))

(define-integrable (window-needs-redisplay! window)
  (if (not (car (window-redisplay-flags window)))
      (setup-redisplay-flags! (window-redisplay-flags window))))

(define-integrable (window-inferior? window window*)
  (find-inferior? (window-inferiors window) window*))

(define-integrable (window-inferior window window*)
  (find-inferior (window-inferiors window) window*))

(define-integrable (for-each-inferior window procedure)
  (let loop ((inferiors (window-inferiors window)))
    (if (not (null? inferiors))
	(begin
	  (procedure (car inferiors))
	  (loop (cdr inferiors))))))

(define-integrable (for-each-inferior-window window procedure)
  (for-each-inferior window
    (lambda (inferior)
      (procedure (inferior-window inferior)))))

(define (make-inferior window class)
  (let ((window* (make-object class)))
    (let ((inferior
	   (%make-inferior window*
			   false
			   false
			   (cons false (window-redisplay-flags window)))))
      (set-window-inferiors! window (cons inferior (window-inferiors window)))
      (==> window* :initialize! window)
      inferior)))

(define (add-inferior! window window*)
  (let ((inferior
	 (%make-inferior window*
			 false
			 false
			 (cons false (window-redisplay-flags window)))))
    (set-window-inferiors! window (cons inferior (window-inferiors window)))
    (==> window* :set-superior! window)
    inferior))

(define (delete-inferior! window window*)
  (set-window-inferiors! window
			 (let ((inferiors (window-inferiors window)))
			   (delq! (find-inferior inferiors window*)
				  inferiors))))

(define (replace-inferior! window old new)
  (set-inferior-window! (find-inferior (window-inferiors window) old) new)
  (==> new :set-superior! window))

;;; Returns #T if the redisplay finished, #F if aborted.
;;; Notice that the :UPDATE-DISPLAY! operation is assumed to return
;;; the same value.  This is used to control the setting of the
;;; redisplay flags.

(define (window-update-display! window screen x-start y-start xl xu yl yu
				display-style)
  (update-inferiors! (window-inferiors window) screen x-start y-start
		     xl xu yl yu display-style
    (lambda (window screen x-start y-start xl xu yl yu display-style)
      (and (or (display-style/ignore-input? display-style)
	       (not ((editor-halt-update? current-editor))))
	   (==> window :update-display! screen x-start y-start xl xu yl yu
		display-style)))))

(define (update-inferiors! inferiors screen x-start y-start xl xu yl yu
			   display-style updater)
  (let loop ((inferiors inferiors))
    (if (null? inferiors)
	true
	(and (update-inferior! (car inferiors) screen x-start y-start
			       xl xu yl yu display-style updater)
	     (loop (cdr inferiors))))))

(define (update-inferior! inferior screen x-start y-start xl xu yl yu
			  display-style updater)
  (or (not (or (display-style/ignore-redisplay-flags? display-style)
	       (inferior-needs-redisplay? inferior)))
      (let ((window (inferior-window inferior))
	    (xi (inferior-x-start inferior))
	    (yi (inferior-y-start inferior)))
	(and (or (not xi)
		 (clip-window-region-1 (fix:- xl xi)
				       (fix:- xu xi)
				       (window-x-size window)
		   (lambda (xl xu)
		     (clip-window-region-1 (fix:- yl yi)
					   (fix:- yu yi)
					   (window-y-size window)
		       (lambda (yl yu)
			 (updater window
				  screen (fix:+ x-start xi) (fix:+ y-start yi)
				  xl xu yl yu display-style))))))
	     (begin
	       (set-car! (inferior-redisplay-flags inferior) #f)
	       #t)))))

(declare (integrate-operator clip-window-region-1))
(define (clip-window-region-1 al au bs receiver)
  (declare (integrate al au bs))
  (if (fix:< 0 al)
      (if (fix:< au bs)
	  (if (fix:< al au) (receiver al au) true)
	  (if (fix:< al bs) (receiver al bs) true))
      (if (fix:< au bs)
	  (if (fix:< 0 au) (receiver 0 au) true)
	  (if (fix:< 0 bs) (receiver 0 bs) true))))

(define (salvage-inferiors! window)
  (for-each-inferior-window window (lambda (window) (==> window :salvage!))))

(define (display-style/discard-screen-contents? display-style)
  (if (pair? display-style)
      (memq 'DISCARD-SCREEN-CONTENTS display-style)
      (and display-style (not (null? display-style)))))

(define (display-style/no-screen-output? display-style)
  (and (pair? display-style)
       (memq 'NO-SCREEN-OUTPUT display-style)))

(define (display-style/ignore-redisplay-flags? display-style)
  (if (pair? display-style)
      (memq 'IGNORE-REDISPLAY-FLAGS display-style)
      (and display-style (not (null? display-style)))))

(define (display-style/ignore-input? display-style)
  (if (pair? display-style)
      (memq 'IGNORE-INPUT display-style)
      (and display-style (not (null? display-style)))))

;;;; Standard Methods
;;;  All windows support these operations

(define-method vanilla-window :initialize! window-initialize!)
(define-method vanilla-window :kill! window-kill!)
(define-method vanilla-window :superior window-superior)
(define-method vanilla-window :set-superior! set-window-superior!)
(define-method vanilla-window :x-size window-x-size)
(define-method vanilla-window :set-x-size! set-window-x-size!)
(define-method vanilla-window :y-size window-y-size)
(define-method vanilla-window :set-y-size! set-window-y-size!)
(define-method vanilla-window :size window-size)
(define-method vanilla-window :set-size! set-window-size!)

(define-method vanilla-window (:make-inferior window class)
  (inferior-window (make-inferior window class)))

(define-method vanilla-window :add-inferior! add-inferior!)
(define-method vanilla-window :delete-inferior! delete-inferior!)
(define-method vanilla-window :replace-inferior! replace-inferior!)
(define-method vanilla-window :update-display! window-update-display!)
(define-method vanilla-window :salvage! salvage-inferiors!)

;;;; Operations on Inferiors

(define-method vanilla-window (:inferior-redisplay-flags window window*)
  (inferior-redisplay-flags (find-inferior inferiors window*)))

(define-method vanilla-window (:inferior-needs-redisplay! window window*)
  (inferior-needs-redisplay! (find-inferior inferiors window*)))

(define-method vanilla-window (:inferior-position window window*)
  (inferior-position (find-inferior inferiors window*)))

(define-method vanilla-window (:set-inferior-position! window window* position)
  (set-inferior-position! (find-inferior inferiors window*) position))

(define-method vanilla-window (:inferior-x-start window window*)
  (inferior-x-start (find-inferior inferiors window*)))

(define-method vanilla-window (:set-inferior-x-start! window window* x-start)
  (set-inferior-x-start! (find-inferior inferiors window*) x-start))

(define-method vanilla-window (:inferior-x-end window window*)
  (inferior-x-end (find-inferior inferiors window*)))

(define-method vanilla-window (:set-inferior-x-end! window window* x-end)
  (set-inferior-x-end! (find-inferior inferiors window*) x-end))

(define-method vanilla-window (:inferior-y-start window window*)
  (inferior-y-start (find-inferior inferiors window*)))

(define-method vanilla-window (:set-inferior-y-start! window window* y-start)
  (set-inferior-y-start! (find-inferior inferiors window*) y-start))

(define-method vanilla-window (:inferior-y-end window window*)
  (inferior-y-end (find-inferior inferiors window*)))

(define-method vanilla-window (:set-inferior-y-end! window window* y-end)
  (set-inferior-y-end! (find-inferior inferiors window*) y-end))

(define-method vanilla-window (:inferior-start window window* receiver)
  (inferior-start (find-inferior inferiors window*) receiver))

(define-method vanilla-window (:set-inferior-start! window window* x y)
  (set-inferior-start! (find-inferior inferiors window*) x y))

;;;; Inferiors

(define %inferior-tag
  '|#[(edwin window) inferior]|)

(define (%inferior? object)
  (and (vector? object)
       (fix:= 5 (vector-length object))
       (eq? %inferior-tag (vector-ref object 0))))
(register-predicate! %inferior? 'inferior '<= vector?)

(define-integrable (%make-inferior window x-start y-start redisplay-flags)
  (vector %inferior-tag window x-start y-start redisplay-flags))

(define-integrable (inferior-window inferior)
  (vector-ref inferior 1))

(define-integrable (set-inferior-window! inferior window)
  (vector-set! inferior 1 window))

(define-integrable (inferior-x-start inferior)
  (vector-ref inferior 2))

(define-integrable (%set-inferior-x-start! inferior x-start)
  (vector-set! inferior 2 x-start))

(define-integrable (inferior-y-start inferior)
  (vector-ref inferior 3))

(define-integrable (%set-inferior-y-start! inferior y-start)
  (vector-set! inferior 3 y-start))

(define-integrable (inferior-redisplay-flags inferior)
  (vector-ref inferior 4))

(define-integrable (set-inferior-redisplay-flags! inferior redisplay-flags)
  (vector-set! inferior 4 redisplay-flags))

(define-print-method %inferior?
  (bracketed-print-method 'inferior
    (lambda (inferior port)
      (write-string " " port)
      (write (inferior-window inferior) port)
      (write-string " x,y=(" port)
      (write (inferior-x-start inferior) port)
      (write-string "," port)
      (write (inferior-y-start inferior) port)
      (write-string ")" port)
      (if (inferior-needs-redisplay? inferior)
	  (write-string " needs-redisplay" port)))))

(define (inferior-copy inferior)
  (%make-inferior (inferior-window inferior)
		  (inferior-x-start inferior)
		  (inferior-y-start inferior)
		  (inferior-redisplay-flags inferior)))

(define (inferior-start inferior receiver)
  (receiver (inferior-x-start inferior)
	    (inferior-y-start inferior)))

(define (%set-inferior-start! inferior x-start y-start)
  (%set-inferior-x-start! inferior x-start)
  (%set-inferior-y-start! inferior y-start))

(define (set-inferior-x-start! inferior x-start)
  (%set-inferior-x-start! inferior x-start)
  (inferior-needs-redisplay! inferior))

(define (set-inferior-y-start! inferior y-start)
  (%set-inferior-y-start! inferior y-start)
  (inferior-needs-redisplay! inferior))

(define (set-inferior-start! inferior x-start y-start)
  (%set-inferior-start! inferior x-start y-start)
  (inferior-needs-redisplay! inferior))

(define-integrable (%inferior-x-end inferior)
  (fix:+ (inferior-x-start inferior) (inferior-x-size inferior)))

(define-integrable (%inferior-y-end inferior)
  (fix:+ (inferior-y-start inferior) (inferior-y-size inferior)))

(define (inferior-x-end inferior)
  (and (inferior-x-start inferior)
       (%inferior-x-end inferior)))

(define (inferior-y-end inferior)
  (and (inferior-y-start inferior)
       (%inferior-y-end inferior)))

(define (set-inferior-x-end! inferior x-end)
  (set-inferior-x-start! inferior (fix:- x-end (inferior-x-size inferior))))

(define (set-inferior-y-end! inferior y-end)
  (set-inferior-y-start! inferior (fix:- y-end (inferior-y-size inferior))))

(define (inferior-position inferior)
  (and (inferior-x-start inferior)
       (cons (inferior-x-start inferior)
	     (inferior-y-start inferior))))

(define (set-inferior-position! inferior position)
  (if (not position)
      (set-inferior-start! inferior false false)
      (set-inferior-start! inferior (car position) (cdr position))))

(define-integrable (inferior-needs-redisplay? inferior)
  (car (inferior-redisplay-flags inferior)))

(define (inferior-needs-redisplay! inferior)
  (if (and (inferior-x-start inferior) (inferior-y-start inferior))
      (if (not (car (inferior-redisplay-flags inferior)))
	  (setup-redisplay-flags! (inferior-redisplay-flags inferior)))
      (set-car! (inferior-redisplay-flags inferior) false)))

(define (setup-redisplay-flags! flags)
  (let loop ((flags flags))
    (if (not (or (null? flags) (car flags)))
	(begin
	  (set-car! flags true)
	  (loop (cdr flags))))))

(define-integrable (inferior-x-size inferior)
  (window-x-size (inferior-window inferior)))

(define-integrable (%set-inferior-x-size! inferior x)
  (%set-window-x-size! (inferior-window inferior) x))

(define-integrable (set-inferior-x-size! inferior x)
  (==> (inferior-window inferior) :set-x-size! x))

(define-integrable (inferior-y-size inferior)
  (window-y-size (inferior-window inferior)))

(define-integrable (%set-inferior-y-size! inferior y)
  (%set-window-y-size! (inferior-window inferior) y))

(define-integrable (set-inferior-y-size! inferior y)
  (==> (inferior-window inferior) :set-y-size! y))

(define-integrable (inferior-size inferior receiver)
  (window-size (inferior-window inferior) receiver))

(define-integrable (set-inferior-size! inferior x y)
  (==> (inferior-window inferior) :set-size! x y))

(define (find-inferior? inferiors window)
  (let loop ((inferiors inferiors))
    (and (not (null? inferiors))
	 (if (eq? window (inferior-window (car inferiors)))
	     (car inferiors)
	     (loop (cdr inferiors))))))

(define (find-inferior inferiors window)
  (let ((inferior (find-inferior? inferiors window)))
    (if (not inferior)
	(error "window not in inferiors" window))
    inferior))

(define (inferior-containing-coordinates window x y stop-search?)
  (let search ((window window) (x x) (y y))
    (if (stop-search? window)
	(values window x y)
	(let loop ((inferiors (window-inferiors window)))
	  (if (null? inferiors)
	      (values false false false)
	      (let ((inferior (car inferiors)))
		(let ((x-start (inferior-x-start inferior))
		      (y-start (inferior-y-start inferior)))
		  (if (and x-start y-start)
		      (let ((x (fix:- x x-start))
			    (y (fix:- y y-start)))
			(if (and (fix:<= 0 x)
				 (fix:< x (inferior-x-size inferior))
				 (fix:<= 0 y)
				 (fix:< y (inferior-y-size inferior)))
			    (search (inferior-window inferior) x y)
			    (loop (cdr inferiors))))
		      (loop (cdr inferiors))))))))))