#-quicklisp
(let ((quicklisp-init (merge-pathnames "quicklisp/setup.lisp"
                                       (user-homedir-pathname))))
  (when (probe-file quicklisp-init)
    (load quicklisp-init)))
(ql:quickload :loop :silent t)
(in-package #:loop)
(defun find-duplicate-mids ()
  "Displays any duplicated message-ids across all group articles."
  (let ((mid-map (make-hash-table :test 'equal))
        (found-dupes nil))
    ;; collect all articles and group by message-id
    (loop for path in (in-groups (directory "**/*"))
          do (let* ((dir-list (pathname-directory path))
                    (g (when dir-list (str:trim (first (last dir-list)))))
                    (i (pathname-name path))
                    (i-str (when i (str:trim i))))
               ;; process numeric article files only
               (when (and g i-str (parse-integer i-str :junk-allowed t))
                 (let ((mid (ignore-errors (get-mid-from-path path))))
                   (when (and mid (> (length (str:trim mid)) 0))
                     ;; push the (group . article-number) pair into the hash map
                     (push (cons g i-str) (gethash mid mid-map)))))))
    ;; remove duplicates
    (maphash (lambda (mid locations)
               (when (> (length locations) 1)
                 (push (cons mid locations) found-dupes)))
             mid-map)
    ;; displays
    (when found-dupes
      (loop for (mid . locs) in found-dupes
            do (format t "message-id: ~a~%" mid)
            ;; sort by group
            (let ((sorted-locs (sort locs #'string-lessp :key #'car)))
              (loop for (g . i) in sorted-locs
                    do (format t "~a/~a~%" g i)))))))
(find-duplicate-mids)