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

;; Time-stamp: <2020-03-27T13:52:06+0100>

;;; Commentary:

;;; Code:

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

(unless slow-computer
  (when (and (executable-find "clang-tidy")
             ;; clang-tidy is built into clangd >= 9.
             (< (my/clangd-version) 9.0))
    (use-package flycheck-clang-tidy
      :after (flycheck projectile lsp-ui)
      :defines (lsp-mode)
      :config (progn
                (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
  :commands (cc-mode)

  :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")
  )

;; Highlighting, indentation and documentation for CMake.
;; The CMake ebuild installs and activates the mode.
(unless (string-match-p "gentoo" operating-system-release)
  (use-package cmake-mode
    :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
  :diminish modern-c++-font-lock-mode
  :hook
  (c++-mode . modern-c++-font-lock-mode)
  )

;; Add #include directives for missing symbols.
(use-package clang-include-fixer
  :straight 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)
  )

(use-package find-file
  :custom
  (cc-search-directories '("."         ; Set directories for ff-find-other-file.
                           "../src"
                           "../include"
                           "../../src"
                           "../../include"
                           "../src/*"
                           "../include/*"
                           "../../src/*"
                           "../../include/*"
                           "/usr/include"
                           "/usr/local/include/*"))
  )

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