;;; jao-recoll.el --- Utilities to use recoll        -*- lexical-binding: t; -*-

;; Copyright (C) 2025  Jose Antonio Ortega Ruiz

;; Author: Jose Antonio Ortega Ruiz <mail@jao.io>
;; Keywords: mail, text

;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; Notably, a half-backed backend for Gnus

;;; Code:

(require 'gnus-search)

(defclass gnus-search-recoll (gnus-search-indexed)
  ((separator :type string :initform ".")
   (program :initform "recoll")
   (raw-queries-p :initform t)))

(cl-defmethod gnus-search-indexed-extract ((_engine gnus-search-recoll))
  (prog1 (and (looking-at "^file://\\(.+\\)$") (list (match-string 1) 100))
    (forward-line 1)))

(cl-defmethod gnus-search-transform-expression ((_engine gnus-search-recoll)
                                                expr)
  expr)

(cl-defmethod gnus-search-indexed-search-command ((engine gnus-search-recoll)
                                                  (qstring string)
                                                  query
                                                  &optional groups)
  (let* ((subdir (slot-value engine 'remove-prefix))
         (sep (slot-value engine 'separator))
         (gdirs (mapcar (lambda (g)
                          (let ((g (gnus-group-short-name g)))
                            (replace-regexp-in-string "\\." sep g)))
                        (or groups
                            (and (not (string= "" subdir)) (list subdir)))))
         (dirsq (and gdirs
                     (concat "("
                             (mapconcat (lambda (d) (format "dir:%s" d))
                                        gdirs " OR ")
                             ")")))
         (qstring (if (string-prefix-p "id:" qstring)
                      (replace-regexp-in-string "<\\|>" "\"" qstring)
                    qstring))
         (qstring (if (cdr (assoc 'thread query))
                      (concat qstring " OR "
                              (replace-regexp-in-string "id:\"" "ref:\""
                                                        qstring))
                    qstring))
         (qstring (replace-regexp-in-string " or " " OR " qstring))
         (qstring (replace-regexp-in-string " and " " AND " qstring))
         (q (format "mime:message %s (%s)" dirsq qstring)))
    ;; (message "query is: %s -- %S" q query)
    `("-b" "-t" "-q" ,q)))

(defun jao-recoll-gnus-search-engine (dir)
  `(nnml "" (gnus-search-engine gnus-search-recoll (remove-prefix ,dir))))

(provide 'jao-recoll)
;;; jao-recoll.el ends here