;;;
;;; interactive/info.scm - online helper
;;;
;;;   Copyright (c) 2000-2014  Shiro Kawai  <shiro@acm.org>
;;;
;;;   Redistribution and use in source and binary forms, with or without
;;;   modification, are permitted provided that the following conditions
;;;   are met:
;;;
;;;   1. Redistributions of source code must retain the above copyright
;;;      notice, this list of conditions and the following disclaimer.
;;;
;;;   2. Redistributions in binary form must reproduce the above copyright
;;;      notice, this list of conditions and the following disclaimer in the
;;;      documentation and/or other materials provided with the distribution.
;;;
;;;   3. Neither the name of the authors nor the names of its contributors
;;;      may be used to endorse or promote products derived from this
;;;      software without specific prior written permission.
;;;
;;;   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
;;;   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
;;;   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
;;;   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
;;;   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
;;;   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
;;;   TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
;;;   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
;;;   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
;;;   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
;;;   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
;;;

(define-module gauche.interactive.info
  (use srfi-1)
  (use srfi-13)
  (use text.info)
  (use file.util)
  (use gauche.process)
  (use gauche.config)
  (export info)
  )
(select-module gauche.interactive.info)

(define *info-file* "gauche-refe.info")
(define *info* #f)
(define *info-index* (make-hash-table 'string=?))

(define *pager* (or (sys-getenv "PAGER")
                    (find-file-in-paths "less")
                    (find-file-in-paths "more")))

(define viewer
  (if (or (equal? (sys-getenv "TERM") "emacs")
          (equal? (sys-getenv "TERM") "dumb")
          (not (sys-isatty (current-output-port)))
          (not *pager*))
      display
      (lambda (s)
        (let1 p (run-process *pager* :input :pipe)
          ;; NB: ignore SIGPIPE, for the pager may be terminated prematurely.
          ;; This is not MT safe.
          (let1 h #f
            (with-signal-handlers
                ((SIGPIPE => #f))
              (lambda ()
                (guard (e (else #f))
                  (display s (process-input p)))
                (close-output-port (process-input p))
                (process-wait p))))))
      ))

(define (get-info-paths)
  (let* ((syspath (cond ((sys-getenv "INFOPATH") => (cut string-split <> #\:))
                        (else '())))
         (instpath (list (gauche-config "--infodir")))
         (in-place (list "../doc")))
    (append syspath instpath in-place)))

(define (find-info-file)
  (let ((paths (get-info-paths)))
    (or (find-file-in-paths *info-file*
                            :paths paths
                            :pred (lambda (p)
                                    (or (file-is-readable? p)
                                        (file-is-readable? #`",|p|.gz")
                                        (file-is-readable? #`",|p|.bz2"))))
        (errorf "couldn't find info file ~s in paths: ~s" *info-file* paths))
    ))

(define (info fn)
  (unless *info*
    (set! *info* (open-info-file (find-info-file)))
    (for-each (lambda (p)
                (hash-table-put! *info-index* (car p) (cdr p)))
              (info-parse-menu (info-get-node *info*
                                              "Function and Syntax Index"))))
  (let1 nodename (hash-table-get *info-index* (x->string fn) #f)
    (unless nodename (errorf "no info document for ~a" fn))
    (viewer (ref (info-get-node *info* nodename) 'content)))
  (values))


