;;; biblio-dissemin.el --- Lookup bibliographic information and open access records from Dissemin -*- lexical-binding: t -*-

;; Copyright (C) 2016  Clément Pit-Claudel

;; Author: Clément Pit-Claudel <clement.pitclaudel@live.com>
;; URL: https://github.com/cpitclaudel/biblio.el

;; 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 <https://www.gnu.org/licenses/>.

;;; Commentary:
;;
;; Lookup publication records on Dissemin by DOI using `dissemin-lookup'.
;;
;; This package also plugs into `biblio-selection-mode' by adding an entry to
;; the extended actions menu (`x') to quickly locate the Dissemin record of
;; e.g. a CrossRef entry.

;;; Code:

(require 'biblio-core)

(defun biblio-dissemin--format-author (author)
  "Format a Dissemin AUTHOR entry."
  (let-alist author
    (format "%s %s" .name.first .name.last)))

(defun biblio-dissemin--insert-button (url prefix)
  "Insert a button pointing to URL, prefixed by PREFIX."
  (unless (seq-empty-p url)
    (insert "\n" prefix)
    (insert (biblio-make-url-button url))))

(defun biblio-dissemin--insert-record (record)
  "Insert a Dissemin RECORD entry into the current buffer."
  (let-alist record
    (insert "\n\n")
    (biblio-with-fontification 'font-lock-preprocessor-face
      (biblio-insert-with-prefix ">> " .identifier))
    (biblio-dissemin--insert-button .pdf_url "   ")
    (unless (string= .pdf_url .splash_url)
      (biblio-dissemin--insert-button .splash_url "   "))
    (unless (seq-empty-p .abstract)
      (insert "\n")
      ;; (biblio-with-fontification 'font-lock-doc-face
      (biblio-insert-with-prefix "   " .abstract))))

(defun biblio-dissemin--translate-classification (classification)
  "Translate Dissemin's CLASSIFICATION for display."
  (pcase classification
    (`"OA" "Available from the publisher")
    (`"OK" "Some versions may be shared by the author")
    (`"UNK" "Sharing policy is unclear")
    (`"CLOSED" "Subject to a restrictive sharing policy")
    (_ classification)))

(defun biblio-dissemin--suggest-upload (doi)
  "Insert a link to Dissemin's upload page for DOI."
  (insert "\n\nDid you write this paper? ")
  (biblio-with-fontification '(:weight bold)
    (insert
     (biblio-make-url-button (format "https://dissem.in/%s" doi) "upload it")))
  (insert "!\n"))

(defun biblio-dissemin--pretty-print (paper doi)
  "Pretty-print a Dissemin PAPER entry (with DOI) to current buffer."
  (let-alist paper
    (biblio-insert-result
     (list (cons 'title .title)
           (cons 'authors (seq-map #'biblio-dissemin--format-author .authors))
           (cons 'open-access-status
                 (biblio-dissemin--translate-classification .classification)))
     t)
    (biblio-dissemin--insert-button .pdf_url "  ")
    (if (seq-empty-p .records)
        (progn (insert "\n\n(no records)")
               (when (member .classification '("OA" "OK"))
                 (biblio-dissemin--suggest-upload doi)))
      (seq-do #'biblio-dissemin--insert-record .records))
    (goto-char (point-min))))

(defun biblio-dissemin--print-results (paper doi)
  "Create a buffer for Dissemin, and print PAPER (with DOI) into it."
  (with-current-buffer (biblio-dissemin--make-buffer)
    (let ((inhibit-read-only t))
      (erase-buffer)
      (help-mode)
      (visual-line-mode)
      (biblio-dissemin--pretty-print paper doi))
    (setq buffer-read-only t)
    (pop-to-buffer (current-buffer))))

(defun biblio-dissemin--make-buffer ()
  "Create a buffer to display Dissemin results in."
  (get-buffer-create "*Dissemin search results*"))

(defun biblio-dissemin--parse-buffer ()
  "Extract search results from DBLP response."
  (biblio-decode-url-buffer 'utf-8)
  (let-alist (json-read)
    (unless (string= .status "ok")
      (display-warning 'biblio-dissemin "Dissemin query failed"))
    .paper))

(defun biblio-dissemin--url (doi)
  "Create a DBLP url to look up DOI."
  (format "https://dissem.in/api/%s" (url-encode-url doi)))

(defun biblio-dissemin--callback (doi)
  "Generate a callback to parse Dissemin results for DOI."
  (lambda () ;; no allowed errors, so no arguments
    (biblio-dissemin--print-results (biblio-dissemin--parse-buffer) doi)))

;;;###autoload
(defun biblio-dissemin-lookup (doi &optional cleanup)
  "Retrieve a record by DOI from Dissemin, and display it.
Interactively, or if CLEANUP is non-nil, pass DOI through
`biblio-cleanup-doi'."
  (interactive "MDOI: \nd")
  (when cleanup
    (setq doi (biblio-cleanup-doi doi)))
  (let ((buf (biblio-dissemin--make-buffer)))
    (biblio-url-retrieve (biblio-dissemin--url doi)
                         (biblio-generic-url-callback (biblio-dissemin--callback doi)))
    buf))

;;;###autoload
(defalias 'dissemin-lookup 'biblio-dissemin-lookup)

(defun biblio-dissemin--lookup-record (record)
  "Retrieve a RECORD from Dissemin, and display it.
RECORD is a formatted record as expected by `biblio-insert-result'."
  (let-alist record
    (if .doi (dissemin-lookup .doi)
      (user-error "Dissemin needs a DOI, but this record does not contain one"))))

;;;###autoload
(defun biblio-dissemin--register-action ()
  "Add Dissemin to list of `biblio-selection-mode' actions."
  (add-to-list 'biblio-selection-mode-actions-alist
               '("Dissemin (find open access copies of this article)" . biblio-dissemin--lookup-record)))

;;;###autoload
(add-hook 'biblio-selection-mode-hook #'biblio-dissemin--register-action)

(provide 'biblio-dissemin)
;;; biblio-dissemin.el ends here