;;; lsp-ui-peek.el --- Lsp-Ui-Peek  -*- lexical-binding: t -*-

;; Copyright (C) 2017 Sebastien Chapuis

;; Author: Sebastien Chapuis <sebastien@chapu.is>
;; URL: https://github.com/emacs-lsp/lsp-ui
;; Keywords: lsp, ui
;; Version: 0.0.1

;;; 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:
;;
;; Load this file and execute `lsp-ui-peek-find-references'
;; on a symbol to find its references
;; or `lsp-ui-peek-find-definitions'.
;; Type 'q' to close the window.
;;

;;; Code:

(require 'lsp-mode)
(require 'xref)
(require 'dash)

(defgroup lsp-ui-peek nil
  "Improve version of xref with peek feature."
  :group 'tools
  :group 'convenience
  :group 'lsp-ui
  :link '(custom-manual "(lsp-ui-peek) Top")
  :link '(info-link "(lsp-ui-peek) Customizing"))

(defcustom lsp-ui-peek-enable t
  "Whether or not to enable ‘lsp-ui-peek’."
  :type 'boolean
  :group 'lsp-ui)

(defcustom lsp-ui-peek-peek-height 20
  "Height of the peek code."
  :type 'integer
  :group 'lsp-ui-peek)

(defcustom lsp-ui-peek-list-width 50
  "Width of the right panel."
  :type 'integer
  :group 'lsp-ui-peek)

(defcustom lsp-ui-peek-fontify 'on-demand
  "Whether to fontify chunks of code (use semantics colors).
WARNING: 'always can heavily slow the processing when `lsp-ui-peek-expand-function'
expands more than 1 file.  It is recommended to keeps the default value of
`lsp-ui-peek-expand-function' when this variable is 'always."
  :type '(choice (const :tag "Never" never)
                 (const :tag "On demand" on-demand)
                 (const :tag "Always" always))
  :group 'lsp-ui-peek)

(defcustom lsp-ui-peek-always-show nil
  "Show the peek view even if there is only 1 cross reference.
By default, the peek view isn't shown if there is 1 xref."
  :type 'boolean
  :group 'lsp-ui-peek)

(defface lsp-ui-peek-peek
  '((((background light)) :background "light gray")
    (t :background "#031A25"))
  "Face used for the peek."
  :group 'lsp-ui-peek)

(defface lsp-ui-peek-list
  '((((background light)) :background "light gray")
    (t :background "#181818"))
  "Face used to list references."
  :group 'lsp-ui-peek)

(defface lsp-ui-peek-filename
  '((((background light)) :foreground "red")
    (t :foreground "dark orange"))
  "Face used for the filename's reference in the list."
  :group 'lsp-ui-peek)

(defface lsp-ui-peek-line-number
  '((t :foreground "grey25"))
  "Line number face."
  :group 'lsp-ui-peek)

(defface lsp-ui-peek-highlight
  '((((background light)) :background "dim gray"
     :foreground "white"
     :distant-foreground "black")
    (t :background "white"
       :foreground "black"
       :distant-foreground "white"
       :box (:line-width -1 :color "white")))
  "Face used to highlight the reference/definition.
Do not use box, underline or overline prop.  If you want to use
box, use a negative value for its width.  Those properties deform
the whole overlay."
  :group 'lsp-ui-peek)

(defface lsp-ui-peek-header
  '((((background light)) :background "grey30" :foreground "white")
    (t :background "white" :foreground "black"))
  "Face used for the headers."
  :group 'lsp-ui-peek)

(defface lsp-ui-peek-footer
  '((t :inherit lsp-ui-peek-header))
  "Face used for the footers.  Only the background of this face is used."
  :group 'lsp-ui-peek)

(defface lsp-ui-peek-selection
  '((((background light)) :background "grey30" :foreground "white")
    (t :background "white" :foreground "black"))
  "Face used for the current selection.
Do not use box, underline or overline prop.  If you want to use
box, use a negative value for its width.  Those properties
deform the whole overlay."
  :group 'lsp-ui-peek)

(defvar lsp-ui-peek-expand-function 'lsp-ui-peek--expand-buffer
  "A function used to determinate which file(s) to expand in the list of xrefs.
The function takes one parameter: a list of cons where the car is the
filename and the cdr is the number of references in that file.
It should returns a list of filenames to expand.
WARNING: If you change this variable and expand more than 1 file, it is
recommended to set `lsp-ui-peek-fontify' to 'never or 'on-demand, otherwise it
will cause performances issues.")

(defvar-local lsp-ui-peek--overlay nil)
(defvar-local lsp-ui-peek--list nil)
(defvar-local lsp-ui-peek--last-xref nil)
(defvar-local lsp-ui-peek--selection 0)
(defvar-local lsp-ui-peek--offset 0)
(defvar-local lsp-ui-peek--size-list 0)
(defvar-local lsp-ui-peek--win-start nil)
(defvar-local lsp-ui-peek--kind nil)
(defvar-local lsp-ui-peek--deactivate-keymap-fn nil)

(defvar lsp-ui-peek--jumps (make-hash-table)
  "Hashtable which stores all jumps on a per window basis.")

(defvar evil--jumps-window-jumps)  ; defined in evil-jumps.el

(defmacro lsp-ui-peek--with-evil-jumps (&rest body)
  "Make `evil-jumps.el' commands work on `lsp-ui-peek--jumps'."
  (declare (indent 1))
  `(let ((evil--jumps-window-jumps lsp-ui-peek--jumps))
     ,@body))

(with-eval-after-load 'evil-jumps
  ;; We need to jump through some hoops to prevent the byte-compiler from
  ;; compiling this code.  We can’t compile the code without requiring
  ;; ‘evil-macros’.
  (eval '(progn
          (evil-define-motion lsp-ui-peek-jump-backward (count)
            (lsp-ui-peek--with-evil-jumps
             (evil--jump-backward count)
             (run-hooks 'xref-after-return-hook)))
          (evil-define-motion lsp-ui-peek-jump-forward (count)
            (lsp-ui-peek--with-evil-jumps
             (evil--jump-forward count)
             (run-hooks 'xref-after-return-hook))))
        t))

(defmacro lsp-ui-peek--prop (prop &optional string)
  `(get-text-property 0 ,prop (or ,string (lsp-ui-peek--get-text-selection) "")))

(defmacro lsp-ui-peek--add-prop (prop &optional string)
  `(let ((obj (or ,string (lsp-ui-peek--get-text-selection))))
     (add-text-properties 0 (length obj) ,prop obj)
     obj))

(defun lsp-ui-peek--truncate (len s)
  (if (> (string-width s) len)
      (format "%s.." (substring s 0 (- len 2)))
    s))

(defun lsp-ui-peek--get-text-selection (&optional n)
  (nth (or n lsp-ui-peek--selection)
       (--remove (get-text-property 0 'lsp-ui-peek-hidden it) lsp-ui-peek--list)))

(defun lsp-ui-peek--get-selection ()
  (get-text-property 0 'lsp-ui-peek (or (lsp-ui-peek--get-text-selection) "")))

(defun lsp-ui-peek--visual-index ()
  (- lsp-ui-peek--selection lsp-ui-peek--offset))

(defun lsp-ui-peek--make-line (index src)
  (-let* (((s1 . s2) src)
          (len-s1 (length s1))
          (len-s2 (length s2))
          (on-selection (= (1+ (lsp-ui-peek--visual-index)) index))
          (face-left (if (= index 0) 'lsp-ui-peek-header 'lsp-ui-peek-peek))
          (face-right (cond (on-selection 'lsp-ui-peek-selection)
                            ((= index 0) 'lsp-ui-peek-header)
                            (t 'lsp-ui-peek-list))))
    (when on-selection
      (setq s2 (copy-sequence s2))
      (add-face-text-property 0 len-s2 face-right nil s2))
    (unless (get-text-property 0 'lsp-ui-peek-faced s2)
      (add-face-text-property 0 len-s2 face-right t s2)
      (add-text-properties 0 len-s2 '(lsp-ui-peek-faced t) s2)
      (add-face-text-property 0 len-s2 'default t s2))
    (add-face-text-property 0 len-s1 face-left t s1)
    (add-face-text-property 0 len-s1 'default t s1)
    (concat
     s1
     (propertize "_" 'face face-left 'display `(space :align-to (- right-fringe ,(1+ lsp-ui-peek-list-width))))
     " "
     s2
     (propertize "_" 'face face-right 'display `(space :align-to (- right-fringe 1)))
     (propertize "\n" 'face face-right))))

(defun lsp-ui-peek--adjust (width strings)
  (-let* (((s1 . s2) strings))
    (cons (lsp-ui-peek--truncate (- width (1+ lsp-ui-peek-list-width)) s1)
          (lsp-ui-peek--truncate (- lsp-ui-peek-list-width 2) s2))))

(defun lsp-ui-peek--make-footer ()
  ;; Character-only terminals don't support characters of different height
  (when (display-graphic-p)
    (list
     (concat
      (propertize " "
                  'face `(:background ,(face-background 'lsp-ui-peek-footer nil t) :height 1)
                  'display `(space :align-to (- right-fringe ,(1+ lsp-ui-peek-list-width))))
      (propertize " " 'face '(:height 1)
                  'display `(space :align-to (- right-fringe ,lsp-ui-peek-list-width)))
      (propertize " "
                  'face `(:background ,(face-background 'lsp-ui-peek-footer nil t) :height 1)
                  'display `(space :align-to (- right-fringe 0)))
      (propertize "\n" 'face '(:height 1))
      (propertize "\n" 'face '(:height 0.5))))))

(defun lsp-ui-peek--peek-new (src1 src2)
  (-let* ((win-width (window-text-width))
          (string (-some--> (-zip-fill "" src1 src2)
                            (--map (lsp-ui-peek--adjust win-width it) it)
                            (-map-indexed 'lsp-ui-peek--make-line it)
                            (-concat it (lsp-ui-peek--make-footer))))
          (next-line (line-beginning-position 2))
          (ov (or (when (overlayp lsp-ui-peek--overlay) lsp-ui-peek--overlay)
                  (make-overlay next-line next-line))))
    (setq lsp-ui-peek--overlay ov)
    (overlay-put ov 'after-string (mapconcat 'identity string ""))
    (overlay-put ov 'display-line-numbers-disable t)
    (overlay-put ov 'window (get-buffer-window))))

(defun lsp-ui-peek--expand-buffer (files)
  (if (--any? (equal (car it) buffer-file-name) files)
      (list buffer-file-name)
    (list (caar files))))

(defun lsp-ui-peek--expand (xrefs)
  (let* ((to-expand (->> (--map (cons (plist-get it :file) (plist-get it :count)) xrefs)
                         (funcall lsp-ui-peek-expand-function)))
         first)
    (while (nth lsp-ui-peek--selection lsp-ui-peek--list)
      (when (and (lsp-ui-peek--prop 'xrefs)
                 (member (lsp-ui-peek--prop 'file) to-expand))
        (unless first
          (setq first (1+ lsp-ui-peek--selection)))
        (lsp-ui-peek--toggle-file t))
      (setq lsp-ui-peek--selection (1+ lsp-ui-peek--selection)))
    (setq lsp-ui-peek--selection (or first 0))
    (lsp-ui-peek--recenter)))

(defun lsp-ui-peek--show (xrefs)
  "Create a window to list references/defintions.
XREFS is a list of references/definitions."
  (setq lsp-ui-peek--win-start (window-start)
        lsp-ui-peek--selection 0
        lsp-ui-peek--offset 0
        lsp-ui-peek--size-list 0
        lsp-ui-peek--list nil)
  (when (eq (logand lsp-ui-peek-peek-height 1) 1)
    (setq lsp-ui-peek-peek-height (1+ lsp-ui-peek-peek-height)))
  (when (< (- (line-number-at-pos (window-end)) (line-number-at-pos))
           (+ lsp-ui-peek-peek-height 3))
    (recenter 15))
  (setq xrefs (--sort (string< (plist-get it :file) (plist-get other :file)) xrefs))
  (--each xrefs
    (-let* (((&plist :file filename :xrefs xrefs :count count) it)
            (len-str (number-to-string count)))
      (setq lsp-ui-peek--size-list (+ lsp-ui-peek--size-list count))
      (push (concat (propertize (lsp-ui--workspace-path filename)
                                'face 'lsp-ui-peek-filename
                                'file filename
                                'xrefs xrefs)
                    (propertize " " 'display `(space :align-to (- right-fringe ,(1+ (length len-str)))))
                    (propertize len-str 'face 'lsp-ui-peek-filename))
            lsp-ui-peek--list)))
  (setq lsp-ui-peek--list (nreverse lsp-ui-peek--list))
  (lsp-ui-peek--expand xrefs)
  (lsp-ui-peek--peek))

(defun lsp-ui-peek--recenter ()
  (let ((half-height (/ lsp-ui-peek-peek-height 2)))
    (when (> lsp-ui-peek--selection half-height)
      (setq lsp-ui-peek--offset (- lsp-ui-peek--selection (1- half-height))))))

(defun lsp-ui-peek--fill (min-len list)
  (let ((len (length list)))
    (if (< len min-len)
        (append list (-repeat (- min-len len) ""))
      list)))

(defun lsp-ui-peek--render (major string)
  (with-temp-buffer
    (insert string)
    (delay-mode-hooks
      (let ((inhibit-message t))
        (funcall major))
      (ignore-errors
        (font-lock-ensure)))
    (buffer-string)))

(defun lsp-ui-peek--peek ()
  "Show reference's chunk of code."
  (-let* ((xref (lsp-ui-peek--get-selection))
          ((&plist :file file :chunk chunk) (or xref lsp-ui-peek--last-xref))
          (header (concat " " (lsp-ui--workspace-path file) "\n"))
          (header2 (format " %s %s" lsp-ui-peek--size-list (symbol-name lsp-ui-peek--kind)))
          (ref-view (--> chunk
                         (if (eq lsp-ui-peek-fontify 'on-demand)
                             (lsp-ui-peek--render major-mode it)
                           chunk)
                         (subst-char-in-string ?\t ?\s it)
                         (concat header it)
                         (split-string it "\n")))
          (list-refs (->> lsp-ui-peek--list
                          (--remove (lsp-ui-peek--prop 'lsp-ui-peek-hidden it))
                          (-drop lsp-ui-peek--offset)
                          (-take (1- lsp-ui-peek-peek-height))
                          (lsp-ui-peek--fill (1- lsp-ui-peek-peek-height))
                          (-concat (list header2)))))
    (setq lsp-ui-peek--last-xref (or xref lsp-ui-peek--last-xref))
    (lsp-ui-peek--peek-new ref-view list-refs)))

(defun lsp-ui-peek--toggle-text-prop (s)
  (let ((state (lsp-ui-peek--prop 'lsp-ui-peek-hidden s)))
    (lsp-ui-peek--add-prop `(lsp-ui-peek-hidden ,(not state)) s)))

(defun lsp-ui-peek--toggle-hidden (file)
  (setq lsp-ui-peek--list
        (--map-when (string= (plist-get (lsp-ui-peek--prop 'lsp-ui-peek it) :file) file)
                    (prog1 it (lsp-ui-peek--toggle-text-prop it))
                    lsp-ui-peek--list)))

(defun lsp-ui-peek--remove-hidden (file)
  (setq lsp-ui-peek--list
        (--map-when (string= (plist-get (lsp-ui-peek--prop 'lsp-ui-peek it) :file) file)
                    (prog1 it (lsp-ui-peek--add-prop '(lsp-ui-peek-hidden nil) it))
                    lsp-ui-peek--list)))

(defun lsp-ui-peek--make-ref-line (xref)
  (-let* (((&plist :summary summary :line line :file file) xref)
          (string (format "%-3s %s"
                          (propertize (number-to-string (1+ line))
                                      'face 'lsp-ui-peek-line-number)
                          (string-trim summary))))
    (lsp-ui-peek--add-prop `(lsp-ui-peek ,xref file ,file) string)))

(defun lsp-ui-peek--insert-xrefs (xrefs filename index)
  (setq lsp-ui-peek--list (--> (lsp-ui-peek--get-xrefs-in-file (cons filename xrefs))
                               (-map 'lsp-ui-peek--make-ref-line it)
                               (-insert-at (1+ index) it lsp-ui-peek--list)
                               (-flatten it)))
  (lsp-ui-peek--add-prop '(xrefs nil)))

(defun lsp-ui-peek--toggle-file (&optional no-update)
  (interactive)
  (-if-let* ((xrefs (lsp-ui-peek--prop 'xrefs))
             (filename (lsp-ui-peek--prop 'file))
             (index (--find-index (equal (lsp-ui-peek--prop 'file it) filename)
                                  lsp-ui-peek--list)))
      (lsp-ui-peek--insert-xrefs xrefs filename index)
    (let ((file (lsp-ui-peek--prop 'file)))
      (lsp-ui-peek--toggle-hidden file)
      (while (not (equal file (lsp-ui-peek--prop 'file)))
        (lsp-ui-peek--select-prev t))))
  (unless no-update
    (lsp-ui-peek--peek)))

(defun lsp-ui-peek--select (index)
  (setq lsp-ui-peek--selection (+ lsp-ui-peek--selection index)))

(defun lsp-ui-peek--select-next (&optional no-update)
  (interactive)
  (when (lsp-ui-peek--get-text-selection (1+ lsp-ui-peek--selection))
    (lsp-ui-peek--select 1)
    (while (> (lsp-ui-peek--visual-index) (- lsp-ui-peek-peek-height 2))
      (setq lsp-ui-peek--offset (1+ lsp-ui-peek--offset)))
    (unless no-update
      (lsp-ui-peek--peek))))

(defun lsp-ui-peek--select-prev (&optional no-update)
  (interactive)
  (when (> lsp-ui-peek--selection 0)
    (lsp-ui-peek--select -1)
    (while (< (lsp-ui-peek--visual-index) 0)
      (setq lsp-ui-peek--offset (1- lsp-ui-peek--offset))))
  (unless no-update
    (lsp-ui-peek--peek)))

(defun lsp-ui-peek--skip-refs (fn)
  (let ((last-file (lsp-ui-peek--prop 'file))
        last-selection)
    (when (lsp-ui-peek--get-selection)
      (while (and (equal (lsp-ui-peek--prop 'file) last-file)
                  (not (equal last-selection lsp-ui-peek--selection)))
        (setq last-selection lsp-ui-peek--selection)
        (funcall fn t)))))

(defun lsp-ui-peek--select-prev-file ()
  (interactive)
  (if (not (lsp-ui-peek--get-selection))
      (lsp-ui-peek--select-prev)
    (lsp-ui-peek--skip-refs 'lsp-ui-peek--select-prev)
    (when (lsp-ui-peek--get-selection)
      (lsp-ui-peek--skip-refs 'lsp-ui-peek--select-prev)
      (unless (= lsp-ui-peek--selection 0)
        (lsp-ui-peek--select-next t))))
  (if (lsp-ui-peek--prop 'xrefs)
      (lsp-ui-peek--toggle-file)
    (lsp-ui-peek--remove-hidden (lsp-ui-peek--prop 'file)))
  (lsp-ui-peek--select-next t)
  (lsp-ui-peek--recenter)
  (lsp-ui-peek--peek))

(defun lsp-ui-peek--select-next-file ()
  (interactive)
  (lsp-ui-peek--skip-refs 'lsp-ui-peek--select-next)
  (if (lsp-ui-peek--prop 'xrefs)
      (lsp-ui-peek--toggle-file)
    (lsp-ui-peek--remove-hidden (lsp-ui-peek--prop 'file)))
  (lsp-ui-peek--select-next t)
  (lsp-ui-peek--recenter)
  (lsp-ui-peek--peek))

(defun lsp-ui-peek--peek-hide ()
  "Hide the chunk of code and restore previous state."
  (when (overlayp lsp-ui-peek--overlay)
    (delete-overlay lsp-ui-peek--overlay))
  (setq lsp-ui-peek--overlay nil
        lsp-ui-peek--last-xref nil)
  (set-window-start (get-buffer-window) lsp-ui-peek--win-start))

(defun lsp-ui-peek--deactivate-keymap ()
  "Deactivate keymap."
  (-when-let (fn lsp-ui-peek--deactivate-keymap-fn)
    (setq lsp-ui-peek--deactivate-keymap-fn nil)
    (funcall fn)))

(defun lsp-ui-peek--goto-xref (&optional x other-window)
  "Go to a reference/definition."
  (interactive)
  (-if-let (xref (or x (lsp-ui-peek--get-selection)))
      (-let (((&plist :file file :line line :column column) xref)
             (buffer (current-buffer)))
        (if (not (file-readable-p file))
            (user-error "File not readable: %s" file)
          (setq lsp-ui-peek--win-start nil)
          (lsp-ui-peek--abort)
          (let ((marker (with-current-buffer
                            (or (get-file-buffer file)
                                (find-file-noselect file))
                          (save-restriction
                            (widen)
                            (save-excursion
                              ;; When we jump to a file with line/column unspecified,
                              ;; we do not want to move the point if the buffer exists.
                              ;; We interpret line=column=0 differently here.
                              (when (> (+ line column) 0)
                                (goto-char 1)
                                (forward-line line)
                                (forward-char column))
                              (point-marker)))))
                (current-workspace lsp--cur-workspace))
            (if other-window
                (pop-to-buffer (marker-buffer marker) t)
              (switch-to-buffer (marker-buffer marker)))
            (with-current-buffer buffer
              (lsp-ui-peek-mode -1))
            (unless lsp--cur-workspace
              (setq lsp--cur-workspace current-workspace))
            (unless lsp-mode
              (lsp-mode 1)
              (lsp-on-open))
            (goto-char marker)
            (run-hooks 'xref-after-jump-hook))))
    (lsp-ui-peek--toggle-file)))

(defun lsp-ui-peek--goto-xref-other-window ()
  (interactive)
  (lsp-ui-peek--goto-xref nil t))

(defvar lsp-ui-peek-mode-map nil
  "Keymap for ‘lsp-ui-peek-mode’.")
(unless lsp-ui-peek-mode-map
  (let ((map (make-sparse-keymap)))
    (suppress-keymap map t)
    (define-key map "\e\e\e" 'lsp-ui-peek--abort)
    (define-key map "\C-g" 'lsp-ui-peek--abort)
    (define-key map (kbd "M-n") 'lsp-ui-peek--select-next-file)
    (define-key map (kbd "<right>") 'lsp-ui-peek--select-next-file)
    (define-key map (kbd "M-p") 'lsp-ui-peek--select-prev-file)
    (define-key map (kbd "<left>") 'lsp-ui-peek--select-prev-file)
    (define-key map (kbd "C-n") 'lsp-ui-peek--select-next)
    (define-key map (kbd "n") 'lsp-ui-peek--select-next)
    (define-key map (kbd "<down>") 'lsp-ui-peek--select-next)
    (define-key map (kbd "C-p") 'lsp-ui-peek--select-prev)
    (define-key map (kbd "p") 'lsp-ui-peek--select-prev)
    (define-key map (kbd "<up>") 'lsp-ui-peek--select-prev)
    (define-key map (kbd "TAB") 'lsp-ui-peek--toggle-file)
    (define-key map (kbd "q") 'lsp-ui-peek--abort)
    (define-key map (kbd "RET") 'lsp-ui-peek--goto-xref)
    (define-key map (kbd "M-RET") 'lsp-ui-peek--goto-xref-other-window)
    (setq lsp-ui-peek-mode-map map)))

(defun lsp-ui-peek--disable ()
  "Do not call this function, call `lsp-ui-peek--abort' instead."
  (when (bound-and-true-p lsp-ui-peek-mode)
    (lsp-ui-peek-mode -1)
    (lsp-ui-peek--peek-hide)))

(defun lsp-ui-peek--abort ()
  (interactive)
  ;; The timer fixes https://github.com/emacs-lsp/lsp-ui/issues/33
  (run-with-idle-timer 0 nil 'lsp-ui-peek--disable))

(define-minor-mode lsp-ui-peek-mode
  "Mode for lsp-ui-peek."
  :init-value nil
  (if lsp-ui-peek-mode
      (setq lsp-ui-peek--deactivate-keymap-fn (set-transient-map lsp-ui-peek-mode-map t 'lsp-ui-peek--abort))
    (lsp-ui-peek--deactivate-keymap)
    (lsp-ui-peek--peek-hide)))

(defun lsp-ui-peek--find-xrefs (input kind &optional request param)
  "Find INPUT references.
KIND is ‘references’, ‘definitions’ or a custom kind."
  (setq lsp-ui-peek--kind kind)
  (let ((xrefs (lsp-ui-peek--get-references kind request param)))
    (unless xrefs
      (user-error "No %s found for: %s" (symbol-name kind) input))
    (xref-push-marker-stack)
    (when (featurep 'evil-jumps)
      (lsp-ui-peek--with-evil-jumps (evil-set-jump)))
    (if (and (not lsp-ui-peek-always-show)
             (not (cdr xrefs))
             (= (length (plist-get (car xrefs) :xrefs)) 1))
        (-let* ((xref (car (plist-get (car xrefs) :xrefs)))
                ((&hash "uri" file "range" range) xref)
                ((&hash "line" line "character" col) (gethash "start" range))
                (file (lsp--uri-to-path file)))
          (lsp-ui-peek--goto-xref `(:file ,file :line ,line :column ,col)))
      (lsp-ui-peek-mode)
      (lsp-ui-peek--show xrefs))))

(defun lsp-ui-peek-find-references ()
  "Find references to the IDENTIFIER at point."
  (interactive)
  (lsp-ui-peek--find-xrefs (symbol-at-point)
                           'references
                           "textDocument/references"
                           (lsp--make-reference-params)))

(defun lsp-ui-peek-find-definitions ()
  "Find definitions to the IDENTIFIER at point."
  (interactive)
  (lsp-ui-peek--find-xrefs (symbol-at-point)
                           'definitions
                           "textDocument/definition"))

(defun lsp-ui-peek-find-implementation ()
  "Find implementation locations of the symbol at point."
  (interactive)
  (lsp-ui-peek--find-xrefs (symbol-at-point)
                           'implementation
                           "textDocument/implementation"))

(defun lsp-ui-peek-find-workspace-symbol (pattern)
  "Find symbols in the worskpace.
The symbols are found matching PATTERN."
  (interactive (list (read-string "workspace/symbol: "
                                  nil 'xref--read-pattern-history)))
  (lsp-ui-peek--find-xrefs pattern
                           'symbols
                           "workspace/symbol"
                           (list :query pattern)))

(defun lsp-ui-peek-find-custom (kind request &optional param)
  "Find custom references.
KIND is a symbol to name the references (definition, reference, ..).
REQUEST is the method string to send the the language server.
PARAM is the method parameter.  If nil, it default to TextDocumentPositionParams."
  (lsp-ui-peek--find-xrefs (symbol-at-point) kind request param))

(defun lsp-ui-peek--extract-chunk-from-buffer (pos start end)
  "Return the chunk of code pointed to by POS (a Position object) in the current buffer.
START and END are delimiters."
  (let* ((point (lsp--position-to-point pos))
         (inhibit-field-text-motion t)
         (line-start (1+ (- 1 (/ lsp-ui-peek-peek-height 2))))
         (line-end (/ lsp-ui-peek-peek-height 2)))
    (save-excursion
      (goto-char point)
      (let* ((before (buffer-substring (line-beginning-position line-start) (line-beginning-position)))
             (line (buffer-substring (line-beginning-position) (line-end-position)))
             (after (buffer-substring (line-end-position) (line-end-position line-end)))
             (len (length line)))
        (add-face-text-property (max (min start len) 0)
                                (max (min end len) 0)
                                'lsp-ui-peek-highlight t line)
        `(,line . ,(concat before line after))))))

(defun lsp-ui-peek--xref-make-item (filename location)
  "Return an item from a LOCATION in FILENAME.
LOCATION can be either a LSP Location or SymbolInformation."
  ;; TODO: Read more informations from SymbolInformation.
  ;;       For now, only the location is used.
  (-let* ((location (or (gethash "location" location) location))
          (range (gethash "range" location))
          ((&hash "start" pos-start "end" pos-end) range)
          (start (gethash "character" pos-start))
          (end (gethash "character" pos-end))
          ((line . chunk) (lsp-ui-peek--extract-chunk-from-buffer pos-start start end)))
    (list :summary (or line filename)
          :chunk (or chunk filename)
          :file filename
          :line (gethash "line" pos-start)
          :column start
          :len (- end start))))

(defun lsp-ui-peek--fontify-buffer (filename)
  (when (eq lsp-ui-peek-fontify 'always)
    (unless buffer-file-name
      (make-local-variable 'delay-mode-hooks)
      (let ((buffer-file-name filename)
            (enable-local-variables nil)
            (inhibit-message t)
            (delay-mode-hooks t))
        (set-auto-mode)))
    (font-lock-ensure)))

(defun lsp-ui-peek--get-xrefs-in-file (file)
  "Return all references that contain a file.
FILE is a cons where its car is the filename and the cdr is a list of Locations
within the file.  We open and/or create the file/buffer only once for all
references.  The function returns a list of `ls-xref-item'."
  (let* ((filename (car file))
         (visiting (find-buffer-visiting filename))
         (fn (lambda (loc) (lsp-ui-peek--xref-make-item filename loc))))
    (cond
     (visiting
      (with-temp-buffer
        (insert-buffer-substring-no-properties visiting)
        (lsp-ui-peek--fontify-buffer filename)
        (mapcar fn (cdr file))))
     ((file-readable-p filename)
      (with-temp-buffer
        (insert-file-contents-literally filename)
        (lsp-ui-peek--fontify-buffer filename)
        (mapcar fn (cdr file))))
     (t (user-error "Cannot read %s" filename)))))

(defun lsp-ui-peek--get-xrefs-list (file)
  "Return a list of xrefs in FILE."
  (-let* (((filename . xrefs) file))
    `(:file ,filename :xrefs ,xrefs :count ,(length xrefs))))

(defun lsp-ui-peek--locations-to-xref-items (locations)
  "Return a list of list of item from LOCATIONS.
LOCATIONS is an array of Location objects:

interface Location {
	uri: DocumentUri;
	range: Range;
}"
  (-some--> (lambda (loc) (lsp--uri-to-path (gethash "uri" (or (gethash "location" loc) loc))))
            (seq-group-by it locations)
            (mapcar #'lsp-ui-peek--get-xrefs-list it)))

(defun lsp-ui-peek--to-sequence (maybe-sequence)
  "If maybe-sequence is not a sequence, wraps it into a single-element sequence."
  (if (sequencep maybe-sequence) maybe-sequence (list maybe-sequence)))

(defun lsp-ui-peek--get-references (_kind request &optional param)
  "Get all references/definitions for the symbol under point.
Returns item(s)."
  (-some->> (lsp--send-request (lsp--make-request
                                request
                                (or param (lsp--text-document-position-params))))
            ;; Language servers may return a single LOCATION instead of a sequence of them.
            (lsp-ui-peek--to-sequence)
            (lsp-ui-peek--locations-to-xref-items)
            (-filter 'identity)))

(defvar lsp-ui-mode-map)

(defun lsp-ui-peek-enable (_enable)
  (interactive)
  (unless (bound-and-true-p lsp-ui-mode-map)
    (user-error "Please load lsp-ui before trying to enable lsp-ui-peek")))

;; lsp-ui.el loads lsp-ui-peek.el, so we can’t ‘require’ lsp-ui.
;; FIXME: Remove this cyclic dependency.
(declare-function lsp-ui--workspace-path "lsp-ui" (path))

(declare-function evil-set-jump "evil-jumps.el" (&optional pos))

(provide 'lsp-ui-peek)
;;; lsp-ui-peek.el ends here