;;; -*- lexical-binding: t -*-
;;
;; -----------------------------------------------------------------------------
;; https://dataswamp.org/~incal/emacs-init/ll/meta.el
;; -----------------------------------------------------------------------------

(require 'cl-lib)

(defun meta--count-list (l)
  (cl-loop
    with res
    with done
    for e in l do
    (unless (member e done)
      (push (list (cl-count e l :test #'equal) e) res)
      (push e done))
    finally return (cl-sort res #'>= :key #'car)))

(defun meta--result-list (l)
  (cl-loop
    with biggest = (length (number-to-string (caar l)))
    with num-len = (length (number-to-string (length l)))
    with longest = (apply #'max (cl-mapcar (lambda (e) (length (cadr e))) l))
    for (j lib) in l
    for i from 1
    for str = (concat str
                (format (concat (format "%%%dd. " num-len)
                                (format "%%-%ds " longest)
                                (format "%%%dd"   biggest)
                                "\n")
                        i lib j))
    finally (insert "\n" str)))

(defun meta--funs (&optional n pred label)
  (or n (setq n 20))
  (or pred (setq pred #'functionp))
  (or label (setq label (symbol-name pred)))
  (let ((num 0)
        (libs)
        (str)
        (dash)
        (par))
    (mapatoms (lambda (e) (when (funcall pred e)
                            (setq str  (symbol-name e))
                            (setq dash (string-match "-" str))
                            (setq par  (string-match "(" str))
                            (unless par
                              (cl-incf num)
                              (when dash
                                (push (substring str 0 dash) libs))))))
    (let ((buf (get-buffer-create "*emeta*")))
      (with-current-buffer buf
        (insert (format "%s%s: %d\n" (if (= (point-min) (point-max)) "" "\n") label num))
        (let* ((clst (meta--count-list libs))
               (len  (length clst)))
          (meta--result-list (cl-subseq clst 0 (min n (1- len)))))
        (pop-to-buffer buf)
        (if noninteractive
            (message (buffer-substring-no-properties (point-min) (point-max)) buf))))))

(defun meta-report (&optional n)
  (let ((n (or n 16)))
    (meta--funs n nil      "functions")
    (meta--funs n #'boundp "variables")
    (meta--funs n #'facep  "faces"))
  (pop-to-buffer "*emeta*"))

;; (meta-report)

(provide 'meta)