ELisp code to switch between controller, view and templates in an Elixir Phoenix project

vfex.el

(setq
 vfex--view-regex-old "^lib/\\(.+\\)/views/\\(.+\\)_view.ex"
 vfex--template-regex-old "^lib/\\(.+\\)/templates/\\(.+\\)/"
 vfex--view-regex-new "^lib/\\(.+\\)/controllers/\\(.+\\)_html.ex"
 vfex--template-regex-new "^lib/\\(.+\\)/controllers/\\(.+\\)_html/"
 vfex--controller-regex "^lib/\\(.+\\)/controllers/\\(.+\\)_controller.ex"
 vfex--liveview-regex "^lib/\\(.+\\)/live/\\(.+\\)_live.ex"
 vfex--liveview-template-regex "^lib/\\(.+\\)/live/\\(.+\\)_live.html.heex")

(defun vfex--dot-p (name)
  "Predicate to know if a name is dot file or not"
  (or (string-equal name ".") (string-equal name "..")))

(defun vfex--view-p (path)
  "Predicate to know if a path is view or not"
  (or
   (string-match vfex--view-regex-new path)
   (string-match vfex--view-regex-old path)))

(defun vfex--template-p (path)
  "Predicate to know if a path is template or not"
  (or
   (string-match vfex--template-regex-new path)
   (string-match vfex--template-regex-old path)))


(defun vfex--controller-p (path)
  "Predicate to know if a path is controller or not"
  (string-match vfex--controller-regex path))

(defun vfex--liveview-p (path)
  "Predicate to know if a path is liveview or not"
  (string-match vfex--liveview-regex path))

(defun vfex--liveview-template-p (path)
  "Predicate to know if a path is liveview template or not"
  (string-match vfex--liveview-template-regex path))

(defun vfex--switch-to-old-view-from-controller (filename-r)
  "Switch to old view of current controller"
  (let* ((controller-p (vfex--controller-p filename-r)))
    (when (and filename-r controller-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (view_path (concat "lib/" app "/views/" name "_view.ex"))
	     (view (file-relative-name view_path (file-name-parent-directory filename-r))))
	(if (file-exists-p view)
	    (find-file view)
	  (message "View %s not found" view))))))

(defun vfex--switch-to-view-from-controller (filename-r)
  "Switch to view of current controller"
  (let* ((controller-p (vfex--controller-p filename-r)))
    (when (and filename-r controller-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (view (concat name "_html.ex")))
	(if (file-exists-p view)
	    (find-file view)
	  (message "View %s not found" view))))))

(defun vfex--switch-to-old-view-from-template (filename-r)
  "Switch to old view of current template"
  (let* ((template-p (vfex--template-p filename-r)))
    (when (and filename-r template-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (view_path (concat "lib/" app "/views/" name "_view.ex"))
	     (view (file-relative-name view_path (file-name-parent-directory filename-r))))
	(if (file-exists-p view)
	    (find-file view)
	  (message "View %s not found" view))))))

(defun vfex--switch-to-view-from-template (filename-r)
  "Switch to view of current template"
  (let* ((controller-p (vfex--template-p filename-r)))
    (when (and filename-r controller-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (view (concat "../" name "_html.ex")))
	(if (file-exists-p view)
	    (find-file view)
	  (message "View %s not found" view))))))

(defun vfex-switch-to-view ()
  "Switch to view from controller or template"
  (interactive)
  (let* ((root (project-root (project-current)))
	 (filename (buffer-file-name))
	 (filename-r (file-relative-name filename root))
	 (controller-p (vfex--controller-p filename-r))
	 (template-p (vfex--template-p filename-r)))
    (when controller-p
      (vfex--switch-to-view-from-controller filename-r)
      (vfex--switch-to-old-view-from-controller filename-r))
    (when template-p
      (vfex--switch-to-view-from-template filename-r)
      (vfex--switch-to-old-view-from-template filename-r))))

(defun vfex--switch-to-controller-from-old-view (filename-r)
  "Switch to controller of current old view"
  (let* ((view-p (vfex--view-p filename-r)))
    (when (and filename-r view-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (controller_path (concat "lib/" app "/controllers/" name "_controller.ex"))
	     (controller (file-relative-name controller_path (file-name-parent-directory filename-r))))
	(if (file-exists-p controller)
	    (find-file controller)
	  (message "Controller %s not found" controller))))))

(defun vfex--switch-to-controller-from-view (filename-r)
  "Switch to controller of current view"
  (let* ((view-p (vfex--view-p filename-r)))
    (when (and filename-r view-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (controller (concat name "_controller.ex")))
	(if (file-exists-p controller)
	    (find-file controller)
	  (message "Controller %s not found" controller))))))

(defun vfex--switch-to-controller-from-old-template (filename-r)
  "Switch to controller of current old template"
  (let* ((template-p (vfex--template-p filename-r)))
    (when (and filename-r template-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (controller_path (concat "lib/" app "/controllers/" name "_controller.ex"))
	     (controller (file-relative-name controller_path (file-name-parent-directory filename-r))))
	(if (file-exists-p controller)
	    (find-file controller)
	  (message "Controller %s not found" controller))))))

(defun vfex--switch-to-controller-from-template (filename-r)
  "Switch to controller of current template"
  (let* ((template-p (vfex--template-p filename-r)))
    (when (and filename-r template-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (controller (concat "../" name "_controller.ex")))
	(if (file-exists-p controller)
	    (find-file controller)
	  (message "Controller %s not found" controller))))))

(defun vfex-switch-to-controller ()
  "Switch to controller from view or template"
  (interactive)
  (let* ((root (project-root (project-current)))
	 (filename (buffer-file-name))
	 (filename-r (file-relative-name filename root))
	 (view-p (vfex--view-p filename-r))
	 (template-p (vfex--template-p filename-r)))
    (when view-p
      (vfex--switch-to-controller-from-view filename-r)
      (vfex--switch-to-controller-from-old-view filename-r))
    (when template-p
      (vfex--switch-to-controller-from-template filename-r)
      (vfex--switch-to-controller-from-old-template filename-r))))

(defun vfex--select-template (path)
  "Provide a selection to switch to templates in dir"
  (let* ((files (directory-files path))
	 (templates (cl-remove-if #'vfex--dot-p files))
	 (template (completing-read "Select an template: " templates)))
    (when template (find-file (concat path template)))))

(defun vfex--switch-to-template-from-old-view (filename-r)
  "Switch to a template of current old view"
  (let* ((view-p (vfex--view-p filename-r)))
    (when (and filename-r view-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (path-a (concat "lib/" app "/templates/" name "/"))
	     (path (file-relative-name path-a (file-name-parent-directory filename-r))))
	(if (file-exists-p path)
	    (vfex--select-template path)
	  (message "Templates not found in %s" path))))))

(defun vfex--switch-to-template-from-view (filename-r)
  "Switch to a template of current view"
  (let* ((view-p (vfex--view-p filename-r)))
    (when (and filename-r view-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (path (concat name "_html/")))
	(if (file-exists-p path)
	    (vfex--select-template path)
	  (message "Templates not found in %s" path))))))

(defun vfex--switch-to-old-template-from-controller (filename-r)
  "Switch to an old template of current controller"
  (let* ((controller-p (vfex--controller-p filename-r)))
    (when (and filename-r controller-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (path-a (concat "lib/" app "/templates/" name "/"))
	     (path (file-relative-name path-a (file-name-parent-directory filename-r))))
	(if (file-exists-p path)
	    (vfex--select-template path)
	  (message "Templates not found in %s" path))))))

(defun vfex--switch-to-template-from-controller (filename-r)
  "Switch to a template of current controller"
  (let* ((controller-p (vfex--controller-p filename-r)))
    (when (and filename-r controller-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (path (concat name "_html/")))
	(if (file-exists-p path)
	    (vfex--select-template path)
	  (message "Templates not found in %s" path))))))

(defun vfex-switch-to-template ()
  "Switch to a template of view or controller"
  (interactive)
  (let* ((root (project-root (project-current)))
	 (filename (buffer-file-name))
	 (filename-r (file-relative-name filename root))
	 (controller-p (vfex--controller-p filename-r))
	 (view-p (vfex--view-p filename-r)))
    (when controller-p
      (vfex--switch-to-template-from-controller filename-r)
      (vfex--switch-to-old-template-from-controller filename-r))
    (when view-p
      (vfex--switch-to-template-from-view filename-r)
      (vfex--switch-to-template-from-old-view filename-r))))

(defun vfex--switch-to-template-from-liveview (filename-r)
  "Switch to template of current liveview"
  (let* ((liveview-p (vfex--liveview-p filename-r)))
    (when (and filename-r liveview-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (template (concat name "_live.html.heex")))
	(if (file-exists-p template)
	    (find-file template)
	  (message "Template not found in %s" path))))))

(defun vfex--switch-to-liveview-from-template (filename-r)
  "Switch to liveview of current template"
  (let* ((template-p (vfex--liveview-template-p filename-r)))
    (when (and filename-r template-p)
      (let* ((app (match-string 1 filename-r))
	     (name (match-string 2 filename-r))
	     (liveview (concat name "_live.ex")))
	(if (file-exists-p liveview)
	    (find-file liveview)
	  (message "LiveView not found in %s" path))))))

(defun vfex-switch-lv-template ()
  "Switch between a LiveView and its template"
  (interactive)
  (let* ((root (project-root (project-current)))
	 (filename (buffer-file-name))
	 (filename-r (file-relative-name filename root))
	 (liveview-p (vfex--liveview-p filename-r))
	 (template-p (vfex--liveview-template-p filename-r)))
    (when liveview-p (vfex--switch-to-template-from-liveview filename-r))
    (when template-p (vfex--switch-to-liveview-from-template filename-r))))

(global-set-key (kbd "C-c s c") 'vfex-switch-to-controller)
(global-set-key (kbd "C-c s v") 'vfex-switch-to-view)
(global-set-key (kbd "C-c s t") 'vfex-switch-to-template)
(global-set-key (kbd "C-c s l") 'vfex-switch-lv-template)