Add (optional) ebib support to bibtex layer

CHANGELOG.develop

@@ -1517,6 +1517,7 @@ Other:
 - Key bindings:
   - Replaced =org-ref-helm-insert-cite-link= with =org-ref-insert-link=
     (thanks to Tianshu Wang)
+  - Add [[https://joostkremers.github.io/ebib/ebib-manual.html][ebib]] support (thanks to Daniel Nicolai)
 **** C-C++
 - Breaking changes:
   - Moved =cmake-ide= and cmake script support to separate =cmake= layer

layers/+lang/bibtex/README.org

@@ -9,6 +9,8 @@
   - [[#features][Features:]]
 - [[#install][Install]]
 - [[#configuration][Configuration]]
+  - [[#ebib-and-biblio][Ebib and biblio]]
+    - [[#comment][Comment]]
 - [[#key-bindings][Key bindings]]
 
 * Description
@@ -22,6 +24,7 @@ This layer adds support to manipulate BibTeX and BibLaTeX files in Spacemacs.
 - Syntax highlighting for BibTeX and BibLaTeX files.
 - Utilities for automatically adding entries from different data sources.
 - Support for inserting citations in various other modes.
+- Optionally install full fledged [[https://joostkremers.github.io/ebib/ebib-manual.html][ebib reference manager]]
 
 * Install
 To use this configuration layer, add it to your =~/.spacemacs=. You will need to
@@ -54,7 +57,39 @@ to use Zathura:
 #+END_SRC
 
 More configuration options are available and are detailed in the =org-ref=,
-=helm-bibtex= and =ivy-bibtex= package documentations.
+=helm-bibtex=, =ivy-bibtex= and [[https://github.com/cpitclaudel/biblio.el][biblio]]  package documentations.
+
+** Ebib and biblio
+   To enable installation of the [[https://joostkremers.github.io/ebib/ebib-manual.html][ebib reference manager]] set the variable
+   =bibtex-enable-ebib-support= as shown in the following code block:
+#+begin_src emacs-lisp :tangle yes
+         (bibtex :variables
+                 bibtex-enable-ebib-support t
+                 ebib-preload-bib-files '("path-to-bib-file.bib")
+                 ebib-file-search-dirs '("/path-to-documents-directory")
+                 ebib-import-directory "path-to-e.g.-download-directory")
+#+end_src   
+The code block also shows how to set some optional [[https://joostkremers.github.io/ebib/ebib-manual.html][ebib]] variables.
+
+With the installation of the =ebib= package, Spacemacs automatically loads the
+[[https://joostkremers.github.io/ebib/ebib-manual.html#integration-with-the-biblio-package][ebib-biblio]] package that uses the [[https://github.com/cpitclaudel/biblio.el][biblio]] package to provide an easy way of
+fetching citations from the web into the database (follow the links to the
+packages additional descriptions and usage instructions).
+
+*** Comment
+    If you prefer to use an additional external reference manager (e.g. for the
+    browser extension functionality), then note that [[https://www.jabref.org/][JabRef]] stores and manages
+    its database as .bib file, while [[https://www.zotero.org/][Zotero]] uses a sqlite database.
+    Additionally, JabRef does not require a running instance to use its
+    browser-extension. However, if you rely on the Zotero web-api, then you
+    might prefer to stay with Zotero and use the [[https://gitlab.com/fvdbeek/emacs-zotero][Emacs-zotero]] package.
+
+    To migrate from Zotero to =Ebib=, simply export your database including the
+    files. Then, to fix the file paths use the following *evil* replace regexp
+    pattern in the exported .bib file:
+   #+begin_src
+   :%s/^\t\(file = {\).*files\/\([0-9]+\/.+\.pdf\).*\(}\)/\1\2\3
+   #+end_src
 
 * Key bindings
 In a Bib(La)TeX file, the following key bindings are added:
@@ -82,3 +117,24 @@ key binding added:
 | Key binding | Description     |
 |-------------+-----------------|
 | ~SPC m i c~ | Insert citation |
+
+*EBIB*
+
+*Index buffer*
+| Key Binding     | Description                                           |
+|-----------------+-------------------------------------------------------|
+| ~J/K~           | scroll page down/up                                   |
+| ~SPC m j~       | jump to entry (searches only author and title fields) |
+| ~SPC u SPC m j~ | jump to entry (only) in current database              |
+| ~/~             | ebib-search (searches in all fields)                  |
+| ~n~             | ebib-search-next                                      |
+| ~e~             | switch to entry buffer                                |
+| ~SPC m k~       | delete current entry                                  |
+| ~SPC m b~       | fetch current entry bibtex from web                   |
+| ~q~             | quit ebib                                             |
+
+*Entry buffer*
+| ~q~ | quit entry buffer |
+
+*Biblio selection buffer*
+| ~e~ | import entry to current database |

layers/+lang/bibtex/packages.el

@@ -28,7 +28,9 @@
     (ivy-bibtex :requires ivy)
     markdown-mode
     org
-    org-ref))
+    org-ref
+    biblio
+    (ebib :toggle bibtex-enable-ebib-support)))
 
 (defun bibtex/post-init-auctex ()
   (spacemacs/set-leader-keys-for-major-mode 'latex-mode
@@ -110,3 +112,48 @@
         "ld" 'doi-utils-add-bibtex-entry-from-doi
         "li" 'isbn-to-bibtex
         "lp" 'pubmed-insert-bibtex-from-pmid))))
+
+(defun bibtex/init-ebib ()
+  (use-package ebib
+    :defer t
+    :init
+    (spacemacs/set-leader-keys "ate" 'ebib)
+    :config
+    (setq ebib-bibtex-dialect 'biblatex)
+
+    (evilified-state-evilify-map ebib-index-mode-map
+      :mode ebib-index-mode
+      :bindings
+      "j" 'ebib-next-entry
+      "k" 'ebib-prev-entry
+      "J" 'evil-scroll-page-down
+      "K" 'evil-scroll-page-up
+
+      "/" 'ebib-search
+      "n" 'ebib-search-next)
+
+    (spacemacs/set-leader-keys-for-major-mode 'ebib-index-mode
+      "j" 'ebib-jump-to-entry
+      "k" 'ebib-kill-entry
+      "b" 'biblio-lookup)
+
+    (evilified-state-evilify-map ebib-entry-mode-map
+      :mode ebib-entry-mode)
+
+    (evilified-state-evilify-map ebib-log-mode-map
+      :mode ebib-log-mode)
+
+    (use-package ebib-biblio
+      :after (ebib biblio)
+      :config
+      (evilified-state-evilify-map biblio-selection-mode-map
+        :mode biblio-selection-mode
+        :bindings
+        "e" 'ebib-biblio-selection-import
+        (kbd "C-j") 'biblio--selection-next
+        (kbd "C-k") 'biblio--selection-previous))
+))
+
+(defun bibtex/init-biblio()
+  (use-package biblio
+    :defer t))