;;; lsp.el --- Language Server Protocol.             -*- lexical-binding: t; -*-

;;; Commentary:

;;; Code:

(require 'basics/package-management)
(require 'basics/global-variables)
(require 'programming/common)
(require 'text/common)

;; Client for Language Server Protocol servers.
(use-package lsp-mode
  :defines (lsp-clients-clangd-args)
  :diminish lsp-mode
  :custom ((lsp-prefer-flymake nil)     ; Disable flymake.
           (lsp-auto-guess-root t)      ; Don't ask for project root.
           (lsp-eldoc-render-all nil)
           (lsp-restart 'auto-restart)
           (lsp-enable-semantic-highlighting t) ; Needs clangd 11(?).
           (lsp-semantic-tokens-apply-modifiers t)
           (lsp-keymap-prefix "C-c l")
           (lsp-keep-workspace-alive nil)
           (lsp-headerline-breadcrumb-segments
            '(path-up-to-project file symbols))
           (lsp-bash-highlight-parsing-errors t))
  :custom-face
  ;; Semantic highlighting. TODO: Check later if better options are available.
  (lsp-face-semhl-variable ((t (:inherit font-lock-variable-name-face
                                         :italic t))))
  (lsp-face-semhl-parameter ((t (:inherit font-lock-variable-name-face
                                          :italic t :underline t))))
  (lsp-face-semhl-member ((t (:inherit default :weight semibold))))
  ;; (lsp-face-semhl-enum ((t (:inherit font-lock-type-face))))
  :config (progn
            (setq lsp-clients-clangd-args '("--compile-commands-dir=build"))
            (when (>= (my/clangd-version) 9.0)
              (add-to-list 'lsp-clients-clangd-args "--clang-tidy" t))
            ;; Ranking algorithm trained on snippets from a large C++ codebase.
            (when (>= (my/clangd-version) 12.0)
              (add-to-list 'lsp-clients-clangd-args
                           "--ranking-model=decision_forest" t))
            ;; Always enabled in >= 12.0
            (when (< (my/clangd-version) 12.0)
              (add-to-list 'lsp-clients-clangd-args "--recovery-ast" t)
              (add-to-list 'lsp-clients-clangd-args "--background-index" t))
            ;; Mark lsp-clients-clangd-args as safe to override.
            (put 'lsp-clients-clangd-args 'safe-local-variable #'consp)

            (defun my/rebind-other-file-maybe ()
              "Rebind C-: to LSP equivalent."
              (when (equal major-mode 'c++-mode)
                (bind-key "C-:" #'lsp-clangd-find-other-file 'c++-mode-map))))
  :bind ("C-c C-f" . lsp-execute-code-action)
  :hook ((c++-mode . lsp)
         (c-mode . lsp)
         (python-mode . lsp)
         (nxml-mode . lsp)
         (json-mode . lsp)
         (web-mode . lsp)
         (css-mode . lsp)
         (js-mode . lsp)
         (lsp-mode . lsp-enable-which-key-integration)
         (lsp-mode . my/rebind-other-file-maybe)))

;; Eye-candy and flycheck support for lsp-mode.
(use-package lsp-ui
  :after (lsp-mode flycheck whitespace)
  :functions (my/whitespace-mode-on my/whitespace-mode-off)
  :custom ((lsp-ui-sideline-enable nil) ; Documentation in buffer.
           (lsp-ui-doc-include-signature nil)
           (lsp-ui-doc-max-width 100)
           (lsp-ui-doc-max-height 20)
           (lsp-ui-doc-enable t))       ; Documentation popup.
  :config (defun my/lsp-ws-toggle ()
            "Works around the dots-in-wrong-color bug."
            (if lsp-ui-peek-mode
                (my/whitespace-mode-off)
              (my/whitespace-mode-on)))
  :bind (:map lsp-ui-mode-map
              ("M-." . lsp-ui-peek-find-definitions)
              ("C-M-." . lsp-ui-peek-find-references)
              ("C-M-," . lsp-ui-peek-find-implementation))
  :hook ((lsp-mode . lsp-ui-mode)
         (lsp-ui-peek-mode . my/lsp-ws-toggle)))

;; ivy interface to lsp-mode.
(use-package lsp-ivy
  :demand t
  :after (lsp-mode ivy))

;; Integration between lsp-mode and treemacs.
(use-package lsp-treemacs
  :after (treemacs lsp-ui)
  :bind (:map lsp-ui-mode-map
              ("<f7>" . lsp-treemacs-errors-list)))

(provide 'programming/lsp)
;;; lsp.el ends here