;;; fuel-autodoc.el -- doc snippets in the echo area -*- lexical-binding: t -*-

;; Copyright (C) 2008, 2009 Jose Antonio Ortega Ruiz
;; See https://factorcode.org/license.txt for BSD license.

;; Author: Jose Antonio Ortega Ruiz <jao@gnu.org>
;; Keywords: languages, fuel, factor
;; Start date: Sat Dec 20, 2008 00:50

;;; Comentary:

;; Utilities for displaying information automatically in the echo
;; area.

;;; Code:

(require 'fuel-eval)
(require 'fuel-base)
(require 'factor-mode)


;;; Customization:

;;;###autoload
(defgroup fuel-autodoc nil
  "Options controlling FUEL's autodoc system."
  :group 'fuel)

(defcustom fuel-autodoc-minibuffer-font-lock t
  "Whether to use font lock for info messages in the minibuffer."
  :group 'fuel-autodoc
  :type 'boolean)


;;; Eldoc function:

(defvar fuel-autodoc--timeout 200)

(defun fuel-autodoc--word-synopsis (&optional word)
  (let ((word (or word (factor-symbol-at-point)))
        (fuel-log--inhibit-p t))
    (when word
      (let ((cmd `(:fuel* (,word ,'fuel-word-synopsis)
                          ,(factor-current-vocab)
                          ,(factor-usings))))
        (let* ((ret (fuel-eval--send/wait cmd fuel-autodoc--timeout))
               (res (fuel-eval--retort-result ret)))
          (if (not res)
              (message "No synopsis for '%s'" word)
            (if fuel-autodoc-minibuffer-font-lock
                (factor-font-lock-string res)
              res)))))))

(defvar-local fuel-autodoc--fallback-function nil)

(defun fuel-autodoc--eldoc-function ()
  (or (and fuel-autodoc--fallback-function
           (funcall fuel-autodoc--fallback-function))
      (condition-case e
          (fuel-autodoc--word-synopsis)
        (error (format "Autodoc not available (%s)"
                       (error-message-string e))))))


;;; Autodoc mode:

(defvar-local fuel-autodoc-mode-string " A"
  "Modeline indicator for fuel-autodoc-mode")

;;;###autoload
(define-minor-mode fuel-autodoc-mode
  "Toggle Fuel's Autodoc mode.
With no argument, this command toggles the mode.
Non-null prefix argument turns on the mode.
Null prefix argument turns off the mode.

When Autodoc mode is enabled, a synopsis of the word at point is
displayed in the minibuffer."
  :init-value nil
  :lighter fuel-autodoc-mode-string
  :group 'fuel-autodoc

  (setq-local eldoc-documentation-function
       (when fuel-autodoc-mode 'fuel-autodoc--eldoc-function))
  (setq-local eldoc-minor-mode-string nil)
  (eldoc-mode fuel-autodoc-mode)
  (message "Fuel Autodoc %s" (if fuel-autodoc-mode "enabled" "disabled")))


(provide 'fuel-autodoc)

;;; fuel-autodoc.el ends here