;;; lsp-origami.el --- origami.el support for lsp-mode    -*- lexical-binding: t; -*-

;; Copyright (C) 2019-2020  Vibhav Pant <vibhavp@gmail.com>

;; Author: Vibhav Pant
;; Version: 1.0.0
;; Keywords: languages lsp-mode
;; Package-Requires: ((origami "1.0") (lsp-mode "6.1"))
;; URL: https://github.com/emacs-lsp/lsp-origami

;; 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:

;; lsp-origami provides support for origami.el using language server
;; protocol's "textDocument/foldingRange" functionality.  It can be enabled
;; with
;; (require 'lsp-origami)
;; (add-hook 'lsp-after-open-hook #'lsp-origami-try-enable)

;;; Code:

(require 'origami)
(require 'lsp-mode)

(defun lsp-origami--folding-range-to-fold (range create)
  "Using the components of RANGE as arguments, execute the CREATE callback."
  (funcall create
           (lsp--folding-range-beg range)
           (lsp--folding-range-end range)
           0
           (seq-map
            (lambda (range) (lsp-origami--folding-range-to-fold range create))
            (seq-remove (lambda (child-range)
                          (or (eq (lsp--folding-range-beg child-range)
                                  (lsp--folding-range-beg range))
                              (eq (lsp--folding-range-end child-range)
                                  (lsp--folding-range-end range))))
                        (lsp--folding-range-children range)))))


(defun lsp-origami--parser (create)
  "Get a list of Folding Ranges for the current buffer, with CREATE as the origami callback."
  (lambda (_content)
    (unless (lsp-feature? "foldingRangeProvider")
      (signal 'lsp-capability-not-supported (list "foldingRangeProvider")))
    (seq-map (lambda (range)
               (lsp-origami--folding-range-to-fold range create))
             (lsp--get-nested-folding-ranges))))

;;;###autoload
(defun lsp-origami-try-enable ()
  "Turn on `origami-mode' locally and try to enable `lsp-origami-mode'."
  (interactive)
  (origami-mode 1)
  (cond ((lsp-feature? "textDocument/foldingRange")
         (lsp-origami-mode 1))
        ((called-interactively-p 'any)
         (signal 'lsp-capability-not-supported (list "foldingRangeProvider")))
        (t
         (lsp-log "This server does not support foldingRangeProvider"))))

;;;###autoload
(define-minor-mode lsp-origami-mode
  "Toggle code folding support for origami."
  :group 'lsp-origami
  :global nil
  (cond
   (lsp-origami-mode
    (setq-local origami-fold-style 'lsp-mode)
    (setq-local origami-parser-alist
                (cons '(lsp-mode . lsp-origami--parser) origami-parser-alist)))
   (t
    (setq-local origami-fold-style nil))))

(provide 'lsp-origami)
;;; lsp-origami.el ends here