;; This file is part of Idest
;; Copyright (C) 2011 Sergey Poznyakoff
;;
;; Idest 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 3, or (at your option)
;; any later version.
;;
;; Idest 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 Idest.  If not, see <http://www.gnu.org/licenses/>.

(define-module (idest list-modules))

(use-modules (ice-9 getopt-long)
	     (srfi srfi-1))

(define (strip-suffix name)
  (call-with-current-continuation
   (lambda (return)
     (for-each
      (lambda (suf)
	(if (and (not (string-null? suf)) (string-suffix? suf name))
	    (return
	     (substring name 0 (- (string-length name) (string-length suf))))))
      %load-extensions)
     (return #f))))

(define-public (idest-list-modules type)
  (let ((progname (car (command-line)))
	(grammar `((which (single-char #\w))))
	(print-dir #f))
    (catch 'misc-error
	   (lambda ()
	     (for-each
	      (lambda (x)
		(case (car x)
		  ((which)
		   (set! print-dir #t))
		  (else
		   (set-program-arguments (cons progname (cdr x))))))
	      (getopt-long (command-line) grammar)))
	   (lambda (key . args)
	     (with-output-to-port
		 (current-error-port)
	       (lambda ()
		 (format #t "~A: " progname)
		 (apply format #t (list-ref args 1) (list-ref args 2))
		 (newline)
		 (exit 1)))))

    (let ((saved-load-hook %load-hook)
	  ;; Collect a list of possible modules.  List elements are conses:
	  ;;  (basename . dir)
	  ;; where basename is the module name and dir is the directory where
	  ;; it is found. Make sure only one entry for each basename exists.
	  ;; Sort the list alphabetically on basename.
	  (candidates
	   (sort
	    (fold
	     (lambda (elt prev)
	       (catch 'misc-error
		      (lambda ()
			(let ((dir (string-append elt "/idest/"
						  (symbol->string type))))
			  (if (and dir
				   (file-exists? dir)
				   (eq? (stat:type (stat dir)) 'directory))
			      (let ((d (opendir dir)))
				(let loop ((file (readdir d)))
				  (cond
				   ((not (eof-object? file))
				    (if (eq? (stat:type
					      (stat
					       (string-append dir "/" file)))
					     'regular)
					(let ((base (strip-suffix file)))
					  (if (and base
						   (not (assoc-ref prev base)))
					      (set! prev (cons (cons base dir)
							       prev)))))
				    (loop (readdir d)))))))))
		      (lambda (key . args)
			#f))
	       prev)
	     '()
	     %load-path)
	    (lambda (a b)
	      (string<? (car a) (car b))))))

      ;; Try out each candidate and print ist name, directory and description
      ;; if it happens to be a valid idest format module.
      ;; Take care not to bail out on errors.  Disable %load-hook as it migh
      ;; clobber the output.
      (set! %load-hook #f)
      (for-each
       (lambda (candidate)
	 (catch 'misc-error
		(lambda ()
		  (let ((mod (resolve-module
			      (list 'idest type
				    (string->symbol (car candidate))))))
		    ; Check if it defines idest-main
		    (module-ref mod 'idest-main)
		    ; Print module name
		    (display (car candidate))
		    ; Its directory, if required
		    (if print-dir
			(format #t " (~A)" (cdr candidate)))
		    ; A colon, and description (if any
		    (format #t ": ~A~%"
			    (catch #t
				   (lambda ()
				     (module-ref mod 'description))
				   (lambda (key . args)
				     "no description")))))
		(lambda (key . args)
		  #f)))
       candidates)
      (newline)
      (set! %load-hook saved-load-hook))))