;;; lsp-bridge-inlay-hint.el --- Inlay hint protocol   -*- lexical-binding: t; no-byte-compile: t; -*-*-

;; Filename: lsp-bridge-inlay-hint.el
;; Description: Inlay hint protocol
;; Author: Andy Stewart <lazycat.manatee@gmail.com>
;; Maintainer: Andy Stewart <lazycat.manatee@gmail.com>
;; Copyright (C) 2023, Andy Stewart, all rights reserved.
;; Created: 2023-10-03 21:35:08
;; Version: 0.1
;; Last-Updated: 2023-10-03 21:35:08
;;           By: Andy Stewart
;; URL: https://www.github.org/manateelazycat/lsp-bridge-inlay-hint
;; Keywords:
;; Compatibility: GNU Emacs 30.0.50
;;
;; Features that might be required by this library:
;;
;;
;;

;;; This file is NOT part of GNU Emacs

;;; License
;;
;; 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, 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; see the file COPYING.  If not, write to
;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth
;; Floor, Boston, MA 02110-1301, USA.

;;; Commentary:
;;
;; Inlay hint protocol
;;

;;; Installation:
;;
;; Put lsp-bridge-inlay-hint.el to your load-path.
;; The load-path is usually ~/elisp/.
;; It's set in your ~/.emacs like this:
;; (add-to-list 'load-path (expand-file-name "~/elisp"))
;;
;; And the following to your ~/.emacs startup file.
;;
;; (require 'lsp-bridge-inlay-hint)
;;
;; No need more.

;;; Customize:
;;
;;
;;
;; All of the above can customize by:
;;      M-x customize-group RET lsp-bridge-inlay-hint RET
;;

;;; Change log:
;;
;; 2023/10/03
;;      * First released.
;;

;;; Acknowledgements:
;;
;;
;;

;;; TODO
;;
;;
;;

;;; Require


;;; Code:

(defface lsp-bridge-inlay-hint-face
  `((t :foreground "#aaaaaa"))
  "Face for inlay hint."
  :group 'lsp-bridge-inlay-hint)

(defun lsp-bridge-inlay-hint ()
  (lsp-bridge-call-file-api "inlay_hint"
                            (lsp-bridge--point-position (window-start))
                            ;; We need pass UPDATE argument to `window-end', to make sure it's value is update, not cache.
                            (lsp-bridge--point-position (window-end nil t))))

(defvar-local lsp-bridge-inlay-hint-overlays '())

(defun lsp-bridge-inlay-hint-hide-overlays ()
  (when lsp-bridge-inlay-hint-overlays
    (dolist (inlay-hint-overlay lsp-bridge-inlay-hint-overlays)
      (delete-overlay inlay-hint-overlay)))

  (setq-local lsp-bridge-inlay-hint-overlays nil))

(defun lsp-bridge-inlay-hint-padding-text (hint-padding is-left)
  (and hint-padding
       (not (eq hint-padding :json-false))
       (not (memq (if is-left
                      (char-before)
                    (char-after))
                  '(32 9)))
       " "))

(defun lsp-bridge-inlay-hint-label-text (label-info)
  (format "%s"
          (if (listp label-info)
              ;; We concat value of list if label is list.
              (mapconcat (lambda (label)
                           (plist-get label :value))
                         label-info
                         "") ; Separator for mapconcat
            ;; Otherwise label is string, just return itself.
            label-info))
  )

(defun lsp-bridge-inlay-hint--render (filepath filehost inlay-hints)
  (lsp-bridge--with-file-buffer
      filepath filehost
      ;; Hide previous overlays first.
      (lsp-bridge-inlay-hint-hide-overlays)

      ;; Render new overlays.
      (save-excursion
        (save-restriction
          (let ((hint-index 0))
            (dolist (hint inlay-hints)
              (goto-char (acm-backend-lsp-position-to-point (plist-get hint :position)))
              (let* ((hint-kind (plist-get hint :kind))
                     ;; InlayHintKind is 1 mean is an inlay hint that for a type annotation.
                     ;; 2 mean is an inlay hint that is for a parameter.
                     ;; type annotation is hint need render at end of line, we use `after-string' overlay to implement it.
                     (hint-render-use-after-string-p (eql hint-kind 1))
                     ;; Hint text need concat padding-left, label and padding-right.
                     (hint-text (concat
                                 (lsp-bridge-inlay-hint-padding-text (plist-get hint :paddingLeft) t)
                                 (lsp-bridge-inlay-hint-label-text (plist-get hint :label))
                                 (lsp-bridge-inlay-hint-padding-text (plist-get hint :paddingRight) nil)))
                     (overlay (if hint-render-use-after-string-p
                                  (make-overlay (point) (1+ (point)) nil t)
                                (make-overlay (1- (point)) (point) nil nil nil))))
                (when (and (equal hint-index 0)
                           hint-render-use-after-string-p)
                  (put-text-property 0 1 'cursor 1 hint-text))
                (overlay-put overlay
                             (if hint-render-use-after-string-p 'before-string 'after-string)
                             (propertize hint-text 'face 'lsp-bridge-inlay-hint-face))
                (overlay-put overlay 'evaporate t) ; NOTE, `evaporate' is import
                (push overlay lsp-bridge-inlay-hint-overlays)

                (setq hint-index (1+ hint-index))
                )))))))

(provide 'lsp-bridge-inlay-hint)

;;; lsp-bridge-inlay-hint.el ends here