From fe1374efae651f914636fd0575f877837136f0d5 Mon Sep 17 00:00:00 2001
From: Yuchen Pei <id@ypei.org>
Date: Sun, 9 Jul 2023 22:37:52 +1000
Subject: Browsing and navigating with various wiki engines

---
 wiki-engine.el | 49 ++++++++++++++++++++++++++++++++++---------------
 wiki-markup.el | 12 +++++++++---
 wiki-utils.el  | 23 +++++++++++++++++++++++
 3 files changed, 66 insertions(+), 18 deletions(-)

diff --git a/wiki-engine.el b/wiki-engine.el
index a9f65d5..f878c30 100644
--- a/wiki-engine.el
+++ b/wiki-engine.el
@@ -26,22 +26,41 @@
 
 ;;; Code:
 (require 'wiki-utils)
+(require 'wiki-markup)
 
-(defun wiki-make-wikilink-url (title))
-
-(defun wiki-engine-mediawiki-fetch (base-url title fetcher)
-  "Fetch a mediawiki entry describing TITLE."
-  (wiki-fetch-url
-   (format "%s%s?action=raw" base-url title)
-   (lambda ()
-     (wiki-mode)
-     (setq-local wiki-fetcher fetcher)
-     )))
-
-(defun wiki-wikipedia-fetch (title)
-  (interactive "sFetch wiki title: ")
-  (wiki-engine-mediawiki-fetch "https://en.wikipedia.org/wiki/" title
-                               'wiki-wikipedia-fetch))
+(defun wiki-engine-mediawiki-fetch (wiki-site title)
+  "Fetch a mediawiki entry describing TITLE.
+
+The site name is passed as a symbol WIKI-SITE."
+  (let ((wiki-site-info (alist-get wiki-site wiki-sites)))
+    (cl-assert (eq (plist-get wiki-site-info :engine) 'mediawiki))
+    (wiki-fetch-url
+     (format "%s%s?action=raw"
+             (plist-get wiki-site-info :base-url)
+             title)
+     (lambda ()
+       (wiki-mode)
+       (setq-local wiki-site wiki-site)
+       ))))
+
+(defun wiki-engine-fetcher (wiki-site-info)
+  (intern (format "wiki-engine-%s-fetch"
+                  (plist-get wiki-site-info :engine))))
+
+(defmacro defun-wiki-fetchers ()
+  (cons 'progn
+        (mapcar
+         (lambda (pair)
+           (pcase-let ((`(,id . ,info) pair))
+             `(defun ,(wiki-site-fetcher id) (title)
+                (interactive ,(format "sFetch title for %s: "
+                                      (plist-get info :display-name)))
+                (,(wiki-engine-fetcher info) ',id title))))
+         (seq-filter #'cdr
+                     wiki-sites)
+         )))
+
+(defun-wiki-fetchers)
 
 (provide 'wiki-engine)
 ;;; wiki-engine.el ends here
diff --git a/wiki-markup.el b/wiki-markup.el
index 23888d3..d9cc2c9 100644
--- a/wiki-markup.el
+++ b/wiki-markup.el
@@ -68,11 +68,11 @@
 
 (defvar wiki-outline-regexp "=+.*=+\ *$")
 
-(defvar-local wiki-fetcher nil
-  "Buffer-local function to fetch a wiki title")
+(defvar-local wiki-site nil
+  "The identifier of the wiki site")
 (defun wiki-follow-wikilink-action (data)
   "Button action to follow a wikilink"
-  (funcall wiki-fetcher (alist-get 'title data)))
+  (funcall (wiki-site-fetcher wiki-site) (alist-get 'title data)))
 
 (defun wiki-outline-level ()
   (when (looking-at "\\(=+\\).*[^=]\\(=+\\)\\ *$")
@@ -127,5 +127,11 @@
   (setq-local outline-level 'wiki-outline-level)
   )
 
+(defun set-wiki-site (wiki-site)
+  (interactive (list
+                (completing-read "Set wiki site: "
+                                 (mapcar 'car wiki-sites))))
+  (setq-local wiki-site (intern wiki-site)))
+
 (provide 'wiki-markup)
 ;;; wiki-markup.el ends here
diff --git a/wiki-utils.el b/wiki-utils.el
index 53b7bd0..26e25b7 100644
--- a/wiki-utils.el
+++ b/wiki-utils.el
@@ -64,5 +64,28 @@ Then calls CALLBACK which is a closure taking no argument."
     (car (url-path-and-query (url-generic-parse-url
                               (url-unhex-string url)))))))
 
+(defvar wiki-sites
+  '((local)
+    (wikipedia-en :base-url "https://en.wikipedia.org/wiki/"
+                  :engine mediawiki
+                  :display-name "Wikipedia EN")
+    (wiktionary-en :base-url "https://en.wiktionary.org/wiki/"
+                   :engine mediawiki
+                   :display-name "Wiktionary EN")
+    (emacswiki :base-url "https://www.emacswiki.org/emacs/"
+               :engine oddmuse
+               :display-name "EmacsWiki")
+    (debianwiki :base-url "https://wiki.debian.org/"
+                :engine moinmoin
+                :display-name "Debian Wiki"))
+  "Alist of wiki sites.
+
+Each item is in the form of (identifier . properties), where
+identifier is a symbol, and properties is a plist of the site.
+One of the sites is (local), meaning a local filesystem.")
+
+(defun wiki-site-fetcher (wiki-site)
+  (intern (format "wiki-%s-fetch" wiki-site)))
+
 (provide 'wiki-utils)
 ;;; wiki-utils.el ends here
-- 
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