;;; c++.el --- C++ settings. -*- lexical-binding: t; -*-

;; Time-stamp: <2019-12-26T07:40:19+00:00>

;;; Commentary:

;;; Code:

(require 'basics/global-variables)
(require 'programming/common)

(unless slow-computer
  (use-package flycheck-clang-tidy
    :pin melpa
    :after (flycheck projectile lsp-ui)
    :if (executable-find "clang-tidy")
    :config
    (defun my/clang-tidy-off ()
      "Disable c/c++-clang-tidy."
      (when (or (eq major-mode 'c++-mode) (eq major-mode 'c-mode))
        (add-to-list 'flycheck-disabled-checkers 'c/c++-clang-tidy))
      )
    (defun my/clang-tidy-on ()
      "Enable c/c++-clang-tidy."
      (when (or (eq major-mode 'c++-mode) (eq major-mode 'c-mode))
        (setq-local flycheck-disabled-checkers
                    (remove 'c/c++-clang-tidy flycheck-disabled-checkers)))
      )

    (defun my/flycheck-clang-tidy-setup ()
      (flycheck-clang-tidy-setup)
      ;; Run clang-tidy after the lsp-ui checker.
      (when lsp-mode
        (unless (equal (flycheck-get-next-checker-for-buffer 'lsp-ui)
                       'c/c++-clang-tidy)
          (flycheck-add-next-checker 'lsp-ui '(warning . c/c++-clang-tidy)))))
    :hook
    (flycheck-mode . my/flycheck-clang-tidy-setup)
    (first-change . my/clang-tidy-off)  ; Disable when file is modified.
    (before-save . my/clang-tidy-on)    ; Enable if file is saved.
    )
  ) ; unless slow-computer.

;; Highlight Doxygen comments.
(use-package highlight-doxygen
  :custom-face
  (highlight-doxygen-comment ((t (:inherit font-lock-comment-face
                                           :foreground "#667788"))))
  (highlight-doxygen-code-block ((t (:inherit highlight-doxygen-comment-face))))

  :hook
  (prog-mode . highlight-doxygen-mode)
  )

;; Set coding style.
(use-package cc-mode
  :ensure nil                           ; Builtin.

  :config
  (c-add-style                          ; Construct own coding style definition.
   "tastytea"
   '("bsd"
     (c-basic-offset . 4)                        ; Indent with 4 spaces.
     (c-offsets-alist . ((innamespace . [0]))))) ; Don't indent in namespaces.
  (c-add-style
   "tastytea-legacy"                    ; For old code.
   '("bsd"
     (c-basic-offset . 4)))

  (defun my/get-builddir ()
    (if (member 'projectile-mode minor-mode-list)
        (concat (projectile-project-root) "build")
      nil))

  :custom
  (c-default-style "tastytea")
  )

(unless slow-computer
  ;; Client for Language Server Protocol servers.
  (use-package lsp-mode
    :if (executable-find "clangd")
    :after (whitespace)

    :custom
    (lsp-prefer-flymake nil)            ; Disable flymake.
    (lsp-auto-guess-root t)             ; Don't ask for project root.
    (lsp-clients-clangd-args '("-compile-commands-dir=build"))
    (lsp-eldoc-render-all t)            ; Display all eldoc information.

    :config
    (defun my/lsp-ws-toggle ()
      (if lsp-ui-peek-mode
          (my/whitespace-mode-off)
        (my/whitespace-mode-on)))

    :hook
    (c++-mode . lsp)
    (c-mode . lsp)
    (lsp-ui-peek-mode . my/lsp-ws-toggle) ; Dots in wrong color.
    )

  ;; Eye-candy and flycheck support for lsp-mode.
  (use-package lsp-ui
    :after (lsp-mode flycheck)

    :custom
    (lsp-ui-sideline-enable nil)        ; Do not insert doc into buffer.
    (lsp-ui-doc-include-signature t)    ; Include signature in doc popup.
    (lsp-ui-doc-enable nil)             ; Disable doc popup.

    :bind
    (:map lsp-ui-mode-map
          ("M-." . lsp-ui-peek-find-definitions)
          ("C-M-." . lsp-ui-peek-find-references)
          )

    :hook
    (lsp-mode . lsp-ui-mode)
    )

  ;; Completions with lsp-mode.
  (use-package company-lsp
    :after (lsp-mode company)

    :config
    (push 'company-lsp company-backends)
    )

  ;; ivy interface to lsp-mode.
  (use-package lsp-ivy
    :after (lsp-mode ivy)
    )
  ) ; unless slow-computer.

;; Highlighting and indentation for CMake.
(use-package cmake-mode
  ;; The CMake ebuild installs and activates the mode.
  :unless (string-match-p "gentoo" operating-system-release)

  :mode
  ("CMakeLists\\.txt$" . cmake-mode)
  ("\\.cmake$" . cmake-mode)
  )

;; CMake reference.
(use-package eldoc-cmake
  :after cmake-mode

  :hook
  (cmake-mode . eldoc-cmake-enable)
  )

;; GUI for gdb and other debuggers.
(use-package realgud
  :after (cc-mode)
  :functions (realgud:gdb)

  :config
  (defun my/launch-gdb ()
    "Load realgud and launch gdb."
    (interactive)
    (load-library "realgud")
    (realgud:gdb))

  :bind
  (:map c-mode-base-map
        ("C-c g" . my/launch-gdb)
        ("M-<down>" . nil)         ; Disabled, because I use them for scrolling.
        ("M-<up>" . nil))          ; ^ FIXME: Does not work. ^
  )

;; Extra highlighting.
(use-package modern-cpp-font-lock
  :hook
  (c++-mode . modern-c++-font-lock-mode)
  )

;; Add #include directives for missing symbols.
(use-package clang-include-fixer
  :ensure nil                           ; Installed by clang.
  :if (executable-find "clang-include-fixer")
  :functions (clang-include-fixer--start clang-include-fixer--add-header)

  :init
  (defvar my/llvm-path
    (concat (file-name-directory (executable-find "clang-include-fixer")) ".."))
  (add-to-list 'load-path (concat my/llvm-path "/share/clang"))

  :config
  (defun my/clang-find-all-symbols ()
    "Invokes run-find-all-symbols.py."
    (interactive)
    (shell-command (concat "cd " (my/get-builddir) " && "
                           my/llvm-path "/share/clang/run-find-all-symbols.py"
                           " -b " my/llvm-path "/bin/find-all-symbols")))

  (defun my/clang-include-fixer ()
    "Invoke clang-include-fixer with -p=build."
    (interactive)
    (message (concat "Calling the include fixer. "
                     "This might take some seconds. Please wait."))
    (clang-include-fixer--start #'clang-include-fixer--add-header
                                "-output-headers"
                                (concat "-p=" (my/get-builddir))))

  :bind
  ("C-x M-i" . my/clang-include-fixer)
  )

(provide 'programming/c++)
;;; c++.el ends here