feat:browser: Add browser configuration module

Introduce `browser-config.el` to handle browser selection and
configuration within Emacs. This module discovers available
browsers, allows user selection through `M-x cj/choose-browser`, and
persists the choice while supporting all link types.

1 files changed, 132 insertions, 0 deletions

diff --git a/modules/browser-config.el b/modules/browser-config.el
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+;;; browser-config.el --- Browser Configuration -*- lexical-binding: t; coding: utf-8; -*-
+;; author: Craig Jennings <c@cjennings.net>
+
+;;; Commentary:
+;; This module provides browser selection and configuration for Emacs.
+;; It automatically discovers available browsers on the system, allows the user
+;; to choose their preferred browser via completing-read, and persists the choice
+;; to a file. Works with all link types including org-mode links.
+;;
+;; Interactive Commands:
+;;   M-x cj/choose-browser - Select default browser from available options
+
+;;; Code:
+
+(require 'cl-lib)
+
+;; Persistence file for storing browser choice
+(defvar cj/browser-choice-file
+  (expand-file-name "browser-choice.el" user-emacs-directory)
+  "File to persist the user's browser choice.")
+
+;; Browser definitions: (executable-name browse-function display-name [program-var])
+;; Use nil for executable-name to indicate a built-in Emacs browser (always available)
+(defvar cj/browser-definitions
+  '((nil                    eww-browse-url        "EWW (Emacs Browser)" nil)
+    ("google-chrome"        browse-url-chrome     "Google Chrome"     browse-url-chrome-program)
+    ("google-chrome-stable" browse-url-chrome     "Google Chrome"     browse-url-chrome-program)
+    ("chrome"               browse-url-chrome     "Chrome"            browse-url-chrome-program)
+    ("chromium"             browse-url-chromium   "Chromium"          browse-url-chromium-program)
+    ("chromium-browser"     browse-url-chromium   "Chromium"          browse-url-chromium-program)
+    ("firefox"              browse-url-firefox    "Firefox"           browse-url-firefox-program)
+    ("brave"                browse-url-chrome     "Brave"             browse-url-chrome-program)
+    ("brave-browser"        browse-url-chrome     "Brave Browser"     browse-url-chrome-program)
+    ("microsoft-edge"       browse-url-chrome     "Microsoft Edge"    browse-url-chrome-program)
+    ("vivaldi"              browse-url-chrome     "Vivaldi"           browse-url-chrome-program)
+    ("opera"                browse-url-chrome     "Opera"             browse-url-chrome-program)
+    ("qutebrowser"          browse-url-generic    "qutebrowser"       browse-url-generic-program))
+  "List of browser definitions.
+Each entry is (EXECUTABLE BROWSE-FUNCTION DISPLAY-NAME [PROGRAM-VAR]).
+Use nil for EXECUTABLE to indicate a built-in Emacs browser (always available).")
+
+(defun cj/discover-browsers ()
+  "Discover available browsers on the system.
+Returns a list of plists with :executable, :function, :name, and :path.
+Includes built-in Emacs browsers (those with nil executable)."
+  (let ((found-browsers '())
+        (seen-names (make-hash-table :test 'equal)))
+    (dolist (def cj/browser-definitions)
+      (let* ((executable (nth 0 def))
+             (browse-fn (nth 1 def))
+             (display-name (nth 2 def))
+             (program-var (nth 3 def))
+             (path (when executable (executable-find executable)))
+             ;; Built-in browsers (nil executable) are always available
+             (available-p (or (null executable) path)))
+        (when (and available-p (not (gethash display-name seen-names)))
+          (puthash display-name t seen-names)
+          (push (list :executable executable
+                      :function browse-fn
+                      :name display-name
+                      :path path
+                      :program-var program-var)
+                found-browsers))))
+    (nreverse found-browsers)))
+
+(defun cj/save-browser-choice (browser-plist)
+  "Save BROWSER-PLIST to the persistence file."
+  (with-temp-file cj/browser-choice-file
+    (insert ";;; Browser choice - Auto-generated\n")
+    (insert (format "(setq cj/saved-browser-choice '%S)\n" browser-plist))))
+
+(defun cj/load-browser-choice ()
+  "Load browser choice from the persistence file.
+Returns the browser plist if found, nil otherwise."
+  (when (file-exists-p cj/browser-choice-file)
+    (condition-case nil
+        (progn
+          (load cj/browser-choice-file)
+          (when (boundp 'cj/saved-browser-choice)
+            cj/saved-browser-choice))
+      (error nil))))
+
+(defun cj/apply-browser-choice (browser-plist)
+  "Apply the browser settings from BROWSER-PLIST."
+  (when browser-plist
+    (let ((browse-fn (plist-get browser-plist :function))
+          (executable (plist-get browser-plist :executable))
+          (path (plist-get browser-plist :path))
+          (program-var (plist-get browser-plist :program-var)))
+      ;; Set the main browse-url function
+      (setq browse-url-browser-function browse-fn)
+      ;; Set the specific browser program variable if it exists
+      (when program-var
+        (set program-var (or path executable)))
+      (message "Default browser set to: %s" (plist-get browser-plist :name)))))
+
+(defun cj/choose-browser ()
+  "Interactively choose a browser from available options.
+Persists the choice for future sessions."
+  (interactive)
+  (let* ((browsers (cj/discover-browsers))
+         (choices (mapcar (lambda (b) (plist-get b :name)) browsers)))
+    (if (null browsers)
+        (message "No supported browsers found on system PATH")
+      (let* ((choice (completing-read "Choose default browser: " choices nil t))
+             (selected (cl-find-if (lambda (b)
+                                     (string= (plist-get b :name) choice))
+                                   browsers)))
+        (when selected
+          (cj/save-browser-choice selected)
+          (cj/apply-browser-choice selected))))))
+
+;; Initialize: Load saved choice or use first available browser
+(defun cj/initialize-browser ()
+  "Initialize browser configuration on startup."
+  (let ((saved-choice (cj/load-browser-choice)))
+    (if saved-choice
+        (cj/apply-browser-choice saved-choice)
+      ;; No saved choice - try to set first available browser silently
+      (let ((browsers (cj/discover-browsers)))
+        (when browsers
+          (cj/apply-browser-choice (car browsers))
+          (message "No browser configured. Using %s. Run M-x cj/choose-browser to change."
+                   (plist-get (car browsers) :name)))))))
+
+;; Run initialization
+(cj/initialize-browser)
+
+(keymap-global-set "C-; B" #'cj/choose-browser)
+
+(provide 'browser-config)
+;;; browser-config.el ends here