;;; org-pdfview.el --- Support for links to documents in pdfview mode

;; Copyright (C) 2014 Markus Hauck

;; Author: Markus Hauck <markus1189@gmail.com>
;; Maintainer: Markus Hauck <markus1189@gmail.com>
;; Keywords: org, pdf-view, pdf-tools
;; Version: 0.1
;; Package-Requires: ((org "8.2.10") (pdf-tools "0.80"))

;; This program 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 of the License, or
;; (at your option) any later version.
;;
;; This program 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 this program. If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:
;; Add support for org links from pdfview buffers like docview.
;;
;; To enable this automatically, use:
;;     (eval-after-load 'org '(require 'org-pdfview))

;; If you want, you can also configure the org-mode default open PDF file function.
;; (add-to-list 'org-file-apps '("\\.pdf\\'" . (lambda (file link) (org-pdfview-open link))))

;;; Code:
(require 'org)
(require 'pdf-tools)
(require 'pdf-view)

(defun org-pdfview-open (link)
  "Open LINK in pdf-view-mode."
  (cond ((string-match "\\(.*\\)::\\([0-9]*\\)\\+\\+\\([[0-9]\\.*[0-9]*\\)"  link)
         (let* ((path (match-string 1 link))
                (page (string-to-number (match-string 2 link)))
                (height (string-to-number (match-string 3 link))))
           (org-open-file path 1)
           (pdf-view-goto-page page)
           (image-set-window-vscroll
            (round (/ (* height (cdr (pdf-view-image-size))) (frame-char-height))))))
        ((string-match "\\(.*\\)::\\([0-9]+\\)$"  link)
         (let* ((path (match-string 1 link))
                (page (string-to-number (match-string 2 link))))
           (org-open-file path 1)
           (pdf-view-goto-page page)))
        (t
         (org-open-file link 1))))

(defun org-pdfview-store-link ()
  "Store a link to a pdfview buffer."
  (when (eq major-mode 'pdf-view-mode)
    ;; This buffer is in pdf-view-mode
    (let* ((path buffer-file-name)
           (page (pdf-view-current-page))
           (link (concat "pdfview:" path "::" (number-to-string page))))
      (org-store-link-props
       :type "pdfview"
       :link link
       :description path))))

(defun org-pdfview-export (link description format)
  "Export the pdfview LINK with DESCRIPTION for FORMAT from Org files."
  (let* ((path (when (string-match "\\(.+\\)::.+" link)
                 (match-string 1 link)))
         (desc (or description link)))
    (when (stringp path)
      (setq path (org-link-escape (expand-file-name path)))
      (cond
       ((eq format 'html) (format "<a href=\"%s\">%s</a>" path desc))
       ((eq format 'latex) (format "\\href{%s}{%s}" path desc))
       ((eq format 'ascii) (format "%s (%s)" desc path))
       (t path)))))

(defun org-pdfview-complete-link (&optional arg)
  "Use the existing file name completion for file.
Links to get the file name, then ask the user for the page number
and append it."
  (concat (replace-regexp-in-string "^file:" "pdfview:"
                                    (org-file-complete-link arg))
	  "::"
	  (read-from-minibuffer "Page:" "1")))


(org-link-set-parameters "pdfview"
                         :follow #'org-pdfview-open
                         :complete #'org-pdfview-complete-link
                         :store #'org-pdfview-store-link)

(provide 'jao-org-pdfview)
;;; jao-org-pdfview.el ends here