Engineering notes
from operational systems.

"*****************************************************************************
"*****************************************************************************
" Vim-Plug bootstrap

"*****************************************************************************
let vimplug_exists=expand('~/.vim/autoload/plug.vim')
if !filereadable(vimplug_exists)
  echo "Installing Vim-Plug..."
  silent exec "!curl -fLo " . shellescape(vimplug_exists) . " --create-dirs https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim"
  autocmd VimEnter * PlugInstall --sync | source $MYVIMRC
endif
if !isdirectory(expand('~/.vim/undodir'))
  call mkdir(expand('~/.vim/undodir'), "p", 0700)
endif
call plug#begin(expand('~/.vim/plugged'))
"-----------------------------------------------------------------------------
" Plugins: work in both Vim and VSCode
" [Cursor side] VSCode Neovim extension handles these automatically.
"              No additional setup required unless noted.
"-----------------------------------------------------------------------------
" --- Core editing ---
Plug 'tpope/vim-commentary'               " gcc to comment/uncomment lines
Plug 'tpope/vim-dispatch'                 " async build and test dispatch
Plug 'tpope/vim-surround'                 " cs"' ysiw" ds" to manipulate surrounds
Plug 'tpope/vim-repeat'                   " repeat plugin actions with .
Plug 'junegunn/vim-easy-align'            " ga= to align by delimiter
Plug 'moll/vim-bbye'                      " :Bdelete without closing window
Plug 'AndrewRadev/splitjoin.vim'          " gS / gJ to split/join lines
Plug 'stephpy/vim-yaml'                   " improved YAML syntax
" --- Language syntax ---
" VSCode handles LSP and completion via extensions (noted per language).
" These plugins add syntax highlighting and indentation rules only.
Plug 'mattn/emmet-vim'                    " HTML/CSS abbreviation expansion (Ctrl+Y,)
                                          " [Cursor] No extra extension needed
Plug 'hail2u/vim-css3-syntax'             " CSS3 syntax improvements
Plug 'leafgarland/typescript-vim'         " TypeScript syntax
                                          " [Cursor] Install: ESLint (dbaeumer.vscode-eslint)
                                          "          Install: Prettier (esbenp.prettier-vscode)
Plug 'posva/vim-vue'                      " Vue.js single-file component syntax
                                          " [Cursor] Install: Volar (vue.volar)
Plug 'JuliaLang/julia-vim'               " Julia syntax and indentation
                                          " [Cursor] Install: julia-vscode (julialang.language-julia)
Plug 'guns/vim-clojure-static'            " Clojure syntax
Plug 'benknoble/vim-sexp'                 " S-expression structural editing
Plug 'tpope/vim-sexp-mappings-for-regular-people' " friendlier sexp keymaps
                                          " [Cursor] Install: Calva (betterthantomorrow.calva)
Plug 'udalov/kotlin-vim'                  " Kotlin syntax
                                          " [Cursor] Install: Kotlin (fwcd.kotlin)
Plug 'derekwyatt/vim-scala'               " Scala syntax
                                          " [Cursor] Install: Metals (scalameta.metals)
Plug 'zah/nim.vim'                        " Nim language syntax
                                          " [Cursor] Install: NimVSCode (nimsaem.nimvscode)
Plug 'vim-pandoc/vim-pandoc-syntax'       " Pandoc-flavored Markdown syntax
Plug 'quarto-dev/quarto-vim'              " Quarto document syntax
                                          " [Cursor] Install: Quarto (quarto.quarto)
Plug 'benknoble/vim-racket'               " Racket syntax
Plug 'elixir-editors/vim-elixir'          " Elixir syntax
                                          " [Cursor] Install: ElixirLS (jakebecker.elixir-ls)
Plug 'kaarmu/typst.vim'                   " Typst document syntax
                                          " [Cursor] Install: Typst LSP (nvarner.typst-lsp)
Plug 'plasticboy/vim-markdown'            " enhanced Markdown syntax
Plug 'rhysd/reply.vim'                    " REPL integration for various languages
Plug 'bakpakin/janet.vim'                 " Janet language syntax
Plug 'ocaml/vim-ocaml'                    " OCaml syntax, indentation, and ftplugin
                                          " [Cursor] Install: OCaml Platform
                                          "   (ocamllabs.ocaml-platform)
                                          "   Requires opam packages:
                                          "   opam install ocaml-lsp-server ocamlformat
" --- Colorschemes ---
Plug 'morhetz/gruvbox'
Plug 'wesQ3/wombat.vim'
"-----------------------------------------------------------------------------
" Plugins: Vim / Neovim terminal only
" Excluded in VSCode because VSCode provides equivalent built-in features.
" [Cursor side] Install the noted extension from the Extensions panel (Ctrl+Shift+X).
"-----------------------------------------------------------------------------
if !exists('g:vscode')
  " --- File management / UI ---
  Plug 'preservim/nerdtree'               " [Cursor] Built-in Explorer (Ctrl+Shift+E)
  Plug 'jistr/vim-nerdtree-tabs'          " [Cursor] Built-in Explorer
  Plug 'vim-airline/vim-airline'          " [Cursor] Built-in status bar
  Plug 'vim-airline/vim-airline-themes'   " [Cursor] Built-in status bar
  Plug 'airblade/vim-gitgutter'           " [Cursor] Install: GitLens (eamodio.gitlens)
  Plug 'nathanaelkane/vim-indent-guides'  " [Cursor] Settings: editor.guides.indentation: true
  Plug 'liuchengxu/vim-which-key'         " [Cursor] Command Palette (Ctrl+Shift+P)
  Plug 'junegunn/fzf', { 'do': { -> fzf#install() } } " [Cursor] Quick Open (Ctrl+P)
  Plug 'junegunn/fzf.vim'                 " [Cursor] Quick Open (Ctrl+P)
  Plug 'vifm/vifm.vim'                    " [Cursor] Built-in Explorer
  Plug 'junegunn/goyo.vim'                " [Cursor] No direct equivalent
  Plug 'junegunn/limelight.vim'           " [Cursor] No direct equivalent
  " --- LSP / Completion / Linting ---
  Plug 'davidhalter/jedi-vim'             " [Cursor] Install: Python (ms-python.python)
  Plug 'dense-analysis/ale'               " [Cursor] Install per language:
                                          "   Shell:      ShellCheck (timonwong.shellcheck)
                                          "   Python:     Ruff (charliermarsh.ruff)
                                          "   JS/TS:      ESLint (dbaeumer.vscode-eslint)
                                          "   Go:         bundled in golang.go extension
                                          "   Rust:       bundled in rust-analyzer
  Plug 'github/copilot.vim'               " [Cursor] Install: GitHub Copilot (github.copilot)
                                          "   Cursor Pro includes Copilot-equivalent built-in
  Plug 'SirVer/ultisnips'                 " [Cursor] Built-in snippet support
  Plug 'easymotion/vim-easymotion'        " [Cursor] Requires VSCode-specific fork:
                                          "   asvetliakov.vscode-easymotion
  " --- Language tooling ---
  Plug 'fatih/vim-go', { 'do': ':GoUpdateBinaries' }
                                          " [Cursor] Install: Go (golang.go)
                                          "   Run: Go: Install/Update Tools after install
  Plug 'rust-lang/rust.vim'               " [Cursor] Install: rust-analyzer (rust-lang.rust-analyzer)
  Plug 'racer-rust/vim-racer'             " [Cursor] Bundled in rust-analyzer
  Plug 'kdheepak/JuliaFormatter.vim'      " [Cursor] Bundled in julia-vscode extension
  Plug 'venantius/vim-cljfmt'             " [Cursor] Bundled in Calva extension
  " --- Document authoring ---
  Plug 'iamcco/markdown-preview.nvim', { 'do': { -> mkdp#util#install() }, 'for': ['markdown', 'vim-plug']}
                                          " [Cursor] Install: Markdown Preview Enhanced
                                          "   (shd101wyy.markdown-preview-enhanced)
  Plug 'dhruvasagar/vim-table-mode', { 'on': 'TableModeEnable' }
  Plug 'mattn/vim-maketable'
  Plug 'lervag/vimtex'                    " [Cursor] Install: LaTeX Workshop
                                          "   (james-yu.latex-workshop)
                                          "   Requires: TeX Live or MiKTeX installed
  Plug 'xuhdev/vim-latex-live-preview'    " [Cursor] Bundled in LaTeX Workshop
  Plug 'reedes/vim-pencil'
  Plug 'reedes/vim-lexical'
  Plug 'reedes/vim-wordy'
endif
call plug#end()

"*****************************************************************************
" General settings
"*****************************************************************************
" Encoding
set encoding=utf-8
set fileencoding=utf-8
set fileencodings=utf-8,ucs-bom,euc-jp,cp932
" Display
syntax on
set number relativenumber cursorline showcmd showmatch laststatus=2 wildmenu visualbell
" Indentation
set autoindent smartindent tabstop=4 shiftwidth=4 expandtab smarttab
" Search
set hlsearch incsearch ignorecase smartcase
" System
set nobackup noswapfile autoread hidden clipboard=unnamedplus undofile
set undodir=~/.vim/undodir
" Performance
set lazyredraw
" Folding
set foldmethod=indent
set foldlevelstart=99

"*****************************************************************************
" Colorscheme
"*****************************************************************************
set background=dark
let g:gruvbox_contrast_dark = 'medium'
try
  colorscheme gruvbox
catch /^Vim\%((\a\+)\)\=:E185/
  colorscheme default | set background=dark
endtry

"*****************************************************************************
" Key mappings: common (both Vim and VSCode)
"*****************************************************************************
let mapleader=','
" Redo with U
nnoremap U <C-r>
" Close buffer without closing window (bbye)
nnoremap <Leader>q :Bdelete<CR>
" Save / reload vimrc
nnoremap <leader>w  :w<CR>
cnoremap w!!        w !sudo tee % > /dev/null
nnoremap <leader>vS :source $MYVIMRC<CR>:echo 'vimrc reloaded'<CR>
" Clipboard
vnoremap <leader>y "+y
nnoremap <leader>Y "+Y
nnoremap <leader>p "+p
nnoremap <leader>P "+P
" Window resize
nnoremap <leader>> :vertical resize +5<CR>
nnoremap <leader>< :vertical resize -5<CR>
nnoremap <leader>+ :resize +5<CR>
nnoremap <leader>- :resize -5<CR>
" Tabs
nnoremap <leader>tn :tabnext<CR>
nnoremap <leader>tp :tabprevious<CR>
nnoremap <leader>tc :tabclose<CR>
nnoremap <leader>t  :tabnew<CR>
" Splits
nnoremap <leader>s :split<CR>
nnoremap <leader>v :vsplit<CR>
" Paste mode toggle
function! SafePasteToggle()
  if &paste
    set nopaste | echo "paste mode: OFF"
  else
    set paste   | echo "paste mode: ON"
  endif
endfunction
nnoremap <leader>pt :call SafePasteToggle()<CR>
nnoremap <leader>pp :call SafePasteToggle()<CR>
nnoremap <leader>ps :echo "paste mode: " . (&paste ? "ON" : "OFF")<CR>
set statusline+=%{&paste?'[PASTE]':''}
" EasyAlign: ga= to align by character
xmap ga <Plug>(EasyAlign)
nmap ga <Plug>(EasyAlign)

"*****************************************************************************
" VSCode Neovim specific settings
" These mappings call VSCode commands via VSCodeNotify.
" [Cursor side] No additional extensions required unless noted below.
"*****************************************************************************
if exists('g:vscode')
  " Pane navigation (replaces <C-w>hjkl)
  " [Cursor] Built-in pane navigation - no extension needed
  nnoremap <C-h> :call VSCodeNotify('workbench.action.navigateLeft')<CR>
  nnoremap <C-j> :call VSCodeNotify('workbench.action.navigateDown')<CR>
  nnoremap <C-k> :call VSCodeNotify('workbench.action.navigateUp')<CR>
  nnoremap <C-l> :call VSCodeNotify('workbench.action.navigateRight')<CR>
  " File search (replaces fzf)
  " [Cursor] Built-in Quick Open - no extension needed
  nnoremap <leader>ff :call VSCodeNotify('workbench.action.quickOpen')<CR>
  nnoremap <leader>fg :call VSCodeNotify('workbench.action.findInFiles')<CR>
  nnoremap <leader>f. :call VSCodeNotify('workbench.action.openRecent')<CR>
  " Explorer (replaces NERDTree)
  " [Cursor] Built-in Explorer - no extension needed
  nnoremap <leader>nt :call VSCodeNotify('workbench.view.explorer')<CR>
  " Command Palette (replaces which-key)
  " [Cursor] Built-in - no extension needed
  nnoremap <leader>p :call VSCodeNotify('workbench.action.showCommands')<CR>
  " Git panel (replaces vim-fugitive)
  " [Cursor] Install: GitLens (eamodio.gitlens) for enhanced git features
  nnoremap <leader>gs :call VSCodeNotify('workbench.view.scm')<CR>
  nnoremap <leader>gp :call VSCodeNotify('git.push')<CR>
  nnoremap <leader>gl :call VSCodeNotify('git.pull')<CR>
  " Copilot toggle (replaces copilot.vim)
  " [Cursor] Install: GitHub Copilot (github.copilot)
  nnoremap <leader>cs :call VSCodeNotify('github.copilot.toggleCopilot')<CR>
  " Buffer / editor management
  nnoremap <leader>bd :call VSCodeNotify('workbench.action.closeActiveEditor')<CR>
  nnoremap <leader>wq :call VSCodeNotify('workbench.action.files.saveAndCloseActiveEditor')<CR>
  " Comment (uses VSCode built-in; also works via vim-commentary above)
  xmap gc  <Plug>VSCodeCommentary
  nmap gc  <Plug>VSCodeCommentary
  omap gc  <Plug>VSCodeCommentary
  nmap gcc <Plug>VSCodeCommentaryLine

"*****************************************************************************
" Vim / Neovim terminal specific settings
"*****************************************************************************
else
  " Window navigation
  nnoremap <C-h> <C-w>h
  nnoremap <C-j> <C-w>j
  nnoremap <C-k> <C-w>k
  nnoremap <C-l> <C-w>l
  nnoremap <leader>wq :wq<CR>
  nnoremap <leader>bd :bd<CR>
  " NERDTree
  nnoremap <leader>nt :NERDTreeToggle<CR>
  let g:NERDTreeChDirMode=2
  let g:NERDTreeWinSize = 50
  " fzf
  nnoremap <leader>ff :Files<CR>
  nnoremap <leader>f. :Files %:p:h<CR>
  " vifm
  nnoremap <leader>vf :Vifm<CR>
  nnoremap <leader>vv :Vifm %:p:h<CR>
  nnoremap <leader>v/ :VsplitVifm<CR>
  nnoremap <leader>v\ :SplitVifm<CR>
  nnoremap <leader>vt :TabVifm<CR>
  nnoremap <leader>vc :EditVifm .<CR>
  " EasyMotion
  nnoremap <leader><leader> <Plug>(easymotion-prefix)
  " Markdown
  nnoremap <leader>mp :MarkdownPreviewToggle<CR>
  nnoremap <leader>mt :TableModeEnable<CR>
  " LaTeX
  nnoremap <leader>ll :VimtexCompile<CR>
  nnoremap <leader>lv :VimtexView<CR>
  nnoremap <leader>le :VimtexErrors<CR>
  " Writing / distraction-free
  nnoremap <leader>goyo :Goyo<CR>
  nnoremap <leader>li   :Limelight!!<CR>
  nnoremap <leader>sp   :SoftPencil<CR>
  nnoremap <leader>hp   :HardPencil<CR>
  "--- Airline ---
  let g:airline#extensions#tabline#enabled = 1
  let g:airline_powerline_fonts = 1
  let g:airline#extensions#tabline#formatter = 'default'
  let g:airline#extensions#tabline#show_buffers = 1
  " --- which-key ---
  nnoremap <silent> <leader> :<C-u>WhichKey ','<CR>
  vnoremap <silent> <leader> :<C-u>WhichKeyVisual ','<CR>
  let g:which_key_timeout = 300
  let g:which_key_use_floating_win = 1
  let g:which_key_map = {}
  let g:which_key_map.f = { 'name': '+find',
    \ 'f': [':Files',       'files (cwd)'],
    \ '.': [':Files %:p:h', 'files (this dir)'] }
  let g:which_key_map.n = { 'name': '+nerdtree',
    \ 't': [':NERDTreeToggle', 'toggle'] }
  let g:which_key_map.g = { 'name': '+go',
    \ 'r': [':GoRun',            'run'],
    \ 'b': [':GoBuild',          'build'],
    \ 't': [':GoTest',           'test'],
    \ 'c': [':GoCoverageToggle', 'coverage'],
    \ 'f': [':GoFmt',            'fmt'],
    \ 'i': [':GoImports',        'imports'],
    \ 'd': [':GoDecls',          'decls'],
    \ 'D': [':GoDeclsDir',       'decls (dir)'],
    \ 'o': [':GoDoc',            'doc'],
    \ 'v': [':GoVet',            'vet'],
    \ 'l': [':GoLint',           'lint'],
    \ 'k': [':GoKeyify',         'keyify'] }
  let g:which_key_map.r = { 'name': '+rust',
    \ 'r': [':!cargo run',            'run'],
    \ 'b': [':!cargo build',          'build'],
    \ 't': [':!cargo test',           'test'],
    \ 'c': [':!cargo check',          'check'],
    \ 'f': [':RustFmt',               'fmt'],
    \ 'd': [':RacerGoToDefinition',   'goto def'],
    \ 's': [':RacerShowDocumentation','doc'] }
  let g:which_key_map.p = { 'name': '+paste',
    \ 't': [':call SafePasteToggle()',             'toggle'],
    \ 's': [':echo "paste:".(&paste?"ON":"OFF")',  'status'] }
  autocmd VimEnter * call which_key#register(',', 'g:which_key_map')
  " --- Copilot ---
  let g:copilot_no_tab_map = v:true
  let g:copilot_assume_mapped = v:true
  augroup copilot_setup
    autocmd!
    autocmd VimEnter * call SetupCopilotKeys()
  augroup END
  function! SetupCopilotKeys()
    if exists('g:loaded_copilot')
      imap <silent><script><expr> <C-J> copilot#Accept("")
      imap <C-K> <Plug>(copilot-dismiss)
      imap <C-L> <Plug>(copilot-next)
      imap <C-H> <Plug>(copilot-previous)
      imap <C-Right> <Plug>(copilot-accept-word)
      imap <C-Down>  <Plug>(copilot-accept-line)
      nnoremap <leader>cs :Copilot status<CR>
      nnoremap <leader>ce :Copilot enable<CR>
      nnoremap <leader>cd :Copilot disable<CR>
    endif
  endfunction
  " --- Python (jedi) ---
  let g:jedi#auto_initialization = 1
  let g:jedi#completions_enabled = 1
  let g:jedi#popup_on_dot = 1
  let g:jedi#completions_command = "<C-Space>"
  let g:jedi#goto_command = "<leader>d"
  let g:jedi#documentation_command = "K"
  let g:jedi#usages_command = "<leader>n"
  let g:jedi#rename_command = "<leader>r"
  let g:jedi#use_splits_not_buffers = "right"
  let g:jedi#show_call_signatures = "2"
  let g:jedi#case_insensitive_completion = 1
  " --- Go ---
  let g:go_fmt_command = "goimports"
  let g:go_fmt_autosave = 1
  let g:go_imports_autosave = 1
  let g:go_mod_fmt_autosave = 1
  let g:go_highlight_types = 1
  let g:go_highlight_fields = 1
  let g:go_highlight_functions = 1
  let g:go_highlight_function_calls = 1
  let g:go_highlight_extra_types = 1
  let g:go_highlight_generate_tags = 1
  let g:go_highlight_operators = 1
  let g:go_highlight_build_constraints = 1
  let g:go_auto_type_info = 1
  let g:go_auto_sameids = 1
  let g:go_metalinter_autosave = 1
  let g:go_metalinter_autosave_enabled = ['vet', 'golint']
  let g:go_list_type = "quickfix"
  let g:go_addtags_transform = "snakecase"
  let g:go_def_mode = 'guru'
  let g:go_decls_includes = "func,type"
  nnoremap <leader>gr :GoRun<CR>
  nnoremap <leader>gb :GoBuild<CR>
  nnoremap <leader>gt :GoTest<CR>
  nnoremap <leader>gc :GoCoverageToggle<CR>
  nnoremap <leader>gf :GoFmt<CR>
  nnoremap <leader>gi :GoImports<CR>
  nnoremap <leader>gd :GoDecls<CR>
  nnoremap <leader>gD :GoDeclsDir<CR>
  nnoremap <leader>go :GoDoc<CR>
  nnoremap <leader>gv :GoVet<CR>
  nnoremap <leader>gl :GoLint<CR>
  nnoremap <leader>gk :GoKeyify<CR>
  " --- Rust ---
  let g:rustfmt_autosave = 1
  let g:rustfmt_emit_files = 1
  let g:rustfmt_fail_silently = 0
  let g:rust_clip_command = 'xclip -selection clipboard'
  nnoremap <leader>rr :!cargo run<CR>
  nnoremap <leader>rb :!cargo build<CR>
  nnoremap <leader>rt :!cargo test<CR>
  nnoremap <leader>rc :!cargo check<CR>
  nnoremap <leader>rf :RustFmt<CR>
  nnoremap <leader>rd :RacerGoToDefinition<CR>
  nnoremap <leader>rs :RacerShowDocumentation<CR>
  " --- Julia ---
  nnoremap <leader>jr :!julia %<CR>
  nnoremap <leader>jf :JuliaFormatterFormat<CR>
  " --- Clojure ---
  nnoremap <leader>ce  :Eval<CR>
  vnoremap <leader>ce  :Eval<CR>
  nnoremap <leader>cf  :Eval (load-file "%")<CR>
  nnoremap <leader>cn  :Eval (in-ns 'user)<CR>
  nnoremap <leader>cr  :Require<CR>
  nnoremap <leader>cR  :Require!<CR>
  nnoremap <leader>ct  :RunTests<CR>
  nnoremap <leader>cF  :Fmt<CR>
  " --- Kotlin ---
  nnoremap <leader>kr :!kotlinc % -include-runtime -d %:r.jar && java -jar %:r.jar<CR>
  nnoremap <leader>kc :!kotlinc %<CR>
  nnoremap <leader>kt :!gradle test<CR>
  nnoremap <leader>kb :!gradle build<CR>
  " --- Scala ---
  nnoremap <leader>sr :!scala %<CR>
  nnoremap <leader>sc :!scalac %<CR>
  " --- ALE ---
  let g:ale_enabled = 1
  let g:ale_completion_enabled = 0
  let g:ale_fix_on_save = 1
  let g:ale_lint_on_save = 1
  let g:ale_lint_on_text_changed = 'never'
  let g:ale_lint_on_insert_leave = 0
  let g:ale_linters = {
    \ 'sh':         ['shellcheck'],
    \ 'python':     ['flake8', 'pylint'],
    \ 'go':         ['gofmt', 'golint', 'govet'],
    \ 'rust':       ['rust-analyzer'],
    \ 'ocaml':      ['ocamllsp'],
    \ 'julia':      ['languageserver'],
    \ 'javascript': ['eslint'],
    \ 'typescript': ['eslint'],
    \ 'vim':        ['vint'],
    \ 'clojure':    [],
    \ 'kotlin':     ['kotlinc', 'ktlint'],
    \ 'scala':      [],
    \ 'nim':        ['nimcheck'],
    \ }
  let g:ale_fixers = {
    \ '*':          ['remove_trailing_lines', 'trim_whitespace'],
    \ 'sh':         ['shfmt'],
    \ 'python':     ['autopep8', 'black'],
    \ 'go':         ['gofmt', 'goimports'],
    \ 'rust':       ['rustfmt'],
    \ 'ocaml':      ['ocamlformat'],
    \ 'javascript': ['prettier', 'eslint'],
    \ 'typescript': ['prettier', 'eslint'],
    \ 'json':       ['prettier'],
    \ 'markdown':   ['prettier'],
    \ 'clojure':    ['cljfmt'],
    \ 'kotlin':     ['ktlint'],
    \ 'nim':        ['nimpretty'],
    \ }
  let g:ale_python_flake8_options = '--max-line-length=120 --ignore=E501,E302,E303,W391,W293'
  let g:ale_python_pylint_options = '--max-line-length=120 --disable=C0301,C0303,C0304,C0305'
  " --- Limelight / Goyo ---
  let g:limelight_conceal_ctermfg = 240
  let g:limelight_conceal_guifg   = '#777777'
  let g:limelight_conceal_code    = 1
  let g:limelight_default_coefficient = 0.7
  let g:limelight_paragraph_span  = 1
  let g:limelight_bop = '^\s'
  let g:limelight_eop = '\ze\n^\s'
  let g:limelight_priority = -1
  augroup goyo_limelight
    autocmd!
    autocmd User GoyoEnter Limelight
    autocmd User GoyoLeave Limelight!
  augroup END
  " --- Markdown Preview ---
  let g:mkdp_auto_start = 0
  let g:mkdp_auto_close = 1
  let g:mkdp_refresh_slow = 0
  let g:mkdp_theme = 'dark'
  let g:mkdp_preview_options = {
    \ 'mkit': {}, 'katex': {}, 'uml': {}, 'maid': {},
    \ 'disable_sync_scroll': 0, 'sync_scroll_type': 'middle',
    \ 'hide_yaml_meta': 1, 'disable_filename': 0
    \ }
  " --- vimtex ---
  let g:vimtex_view_method = 'zathura'
  " --- vim-indent-guides ---
  let g:indent_guides_enable_on_vim_startup = 1
  " --- Table mode ---
  let g:table_mode_corner_char = '+'
  let g:table_mode_header_fillchar = '-'
endif

"*****************************************************************************
" Plugin settings: common (both Vim and VSCode)
"*****************************************************************************
" Markdown
let g:vim_markdown_folding_disabled = 1
" Clojure / S-expressions
let g:clojure_align_multiline_strings = 1
let g:clojure_maxlines = 100
let g:sexp_enable_insert_mode_mappings = 0
let g:sexp_filetypes = 'clojure,scheme,lisp,timl'
" Julia
let g:julia_syntax_highlight_deprecated = 0
let g:julia_indent_align_brackets = 1
let g:julia_indent_align_funcargs = 1
" Kotlin / Scala
let g:kotlin_auto_detect_file_type = 1
let g:scala_scaladoc_indent = 1

"*****************************************************************************
" Filetype settings
"*****************************************************************************
filetype plugin indent on
augroup go_filetype
  autocmd!
  autocmd BufRead,BufNewFile *.go setfiletype go
  autocmd FileType go setlocal tabstop=4 shiftwidth=4 softtabstop=4 noexpandtab
  autocmd FileType go setlocal listchars=tab:\ \ ,trail:·,extends:>,precedes:< | setlocal list
augroup END
augroup rust_filetype
  autocmd!
  autocmd BufRead,BufNewFile *.rs setfiletype rust
  autocmd FileType rust setlocal tabstop=4 shiftwidth=4 softtabstop=4 expandtab textwidth=100
augroup END
augroup ocaml_filetype
  autocmd!
  autocmd BufRead,BufNewFile *.ml,*.mli setfiletype ocaml
  autocmd FileType ocaml setlocal tabstop=2 shiftwidth=2 softtabstop=2 expandtab textwidth=80
  autocmd FileType ocaml setlocal commentstring=(*\ %s\ *)
augroup END
augroup julia_settings
  autocmd!
  autocmd BufRead,BufNewFile *.jl setfiletype julia
  autocmd FileType julia setlocal tabstop=4 shiftwidth=4 softtabstop=4 expandtab textwidth=92
  autocmd FileType julia setlocal commentstring=#\ %s
augroup END
augroup clojure_settings
  autocmd!
  autocmd BufRead,BufNewFile *.clj,*.cljs,*.cljc setfiletype clojure
  autocmd FileType clojure setlocal tabstop=2 shiftwidth=2 softtabstop=2 expandtab lisp
augroup END
augroup kotlin_settings
  autocmd!
  autocmd BufRead,BufNewFile *.kt setfiletype kotlin
  autocmd FileType kotlin setlocal tabstop=4 shiftwidth=4 softtabstop=4 expandtab textwidth=120
augroup END
augroup scala_settings
  autocmd!
  autocmd BufRead,BufNewFile *.scala,*.sbt setfiletype scala
  autocmd FileType scala setlocal tabstop=2 shiftwidth=2 softtabstop=2 expandtab textwidth=120
  autocmd FileType scala setlocal commentstring=//\ %s
augroup END
augroup nim_filetype
  autocmd!
  autocmd BufRead,BufNewFile *.nim setfiletype nim
augroup END
augroup markdown_settings
  autocmd!
  autocmd FileType markdown setlocal tabstop=2 shiftwidth=2 softtabstop=2
  if !exists('g:vscode')
    autocmd FileType markdown call pencil#init({'wrap': 'soft'})
  endif
augroup END
augroup pencil_settings
  autocmd!
  autocmd User PencilEnter setlocal wrap linebreak nolist
  autocmd User PencilLeave setlocal nowrap nolinebreak list!
augroup END
" Do not create undo files for temporary / generated files
augroup undo_ignore
  autocmd!
  autocmd BufWritePre /tmp/*,*.log,*.csv,*.dat,*.npz setlocal noundofile
augroup END
" end of file

################################################################################
# The level scale
#
# L0 — Out-of-box defaults. NOFILE=1024, CUBIC, stock irqbalance.
#      Fresh install; adequate for low-traffic services.
# L1 — Basic production. NOFILE ~64k, somaxconn raised, noatime mount.
#      Most small-to-mid SaaS backends.
# L2 — Well-tuned high-load server. file-max=1M, 128 MiB TCP buffers,       <-- Part 1
#      BBR+fq, systemd limits raised, I/O scheduler per device, THP managed.
# L3 — Low-latency oriented. isolcpus + nohz_full + rcu_nocbs,               <-- Part 1 + Part 2
#      manual IRQ pinning, performance governor, per-socket SO_BUSY_POLL,
#      slew-only time sync, hardware timestamping where available.
# L4 — Microsecond HFT. Kernel bypass (DPDK / AF_XDP / OpenOnload),
#      user-space TCP, PREEMPT_RT, hugetlbfs, SMT off, exchange co-location.
# L5 — Nanosecond league. FPGA TCP/UDP offload, L1 switches, microwave WAN,
#      tick-to-trade entirely in silicon.
#
# --- Next-stage hints (toward Level 4) ---------------------------------------
#   Hardware ........... Solarflare / Xilinx (ef_vi, OpenOnload), ConnectX-6+
#   Kernel bypass ...... DPDK (full user-space) or AF_XDP (lighter)
#   User-space TCP ..... Seastar, mTCP, F-Stack, TCPDirect
#   Real-time kernel ... Ubuntu Pro PREEMPT_RT
#   Huge pages ......... hugetlbfs with pre-allocated pages (replacing THP)
#   SMT off ............ nosmt at boot + NUMA-aware allocator
#   Physical placement . exchange co-location, same rack when possible
#   Measurement ........ cyclictest, perf sched, HW timestamp diffs, TSC cal
#
# Every Level-4 change is a hypothesis to be measured, not a best practice
# to be applied. Best practices are not a substitute for measurement.
################################################################################

# /etc/sysctl.d/99-ubuntu-general.conf
# Apply: sudo sysctl --system

# === File descriptors ===
# System-wide open file limit. Prevents EMFILE/ENFILE under high concurrency.
fs.file-max = 1048576

# === mmap / VM ===
# Per-process mmap region count. Required by QuestDB, Elasticsearch, etc.
vm.max_map_count = 1048576

# Minimize swapping without disabling it. 10 is the general-server sweet spot.
# Setting 0 makes the OOM killer fire sooner than expected.
vm.swappiness = 10

# === Dirty writeback ===
vm.dirty_background_ratio = 5
vm.dirty_ratio = 20
vm.dirty_expire_centisecs = 3000
vm.dirty_writeback_centisecs = 500

# === Network backlog ===
# accept() queue depth for listen sockets; absorbs SYN bursts.
net.core.somaxconn = 65535
# NIC -> kernel packet queue; absorbs traffic bursts.
net.core.netdev_max_backlog = 262144
# NAPI polling budget. Default 300 drops packets under heavy bursts.
net.core.netdev_budget = 600
net.core.netdev_budget_usecs = 8000

# === TCP buffers ===
# Raise ceiling for high bandwidth-delay products (128 MiB).
net.core.rmem_max = 134217728
net.core.wmem_max = 134217728
net.ipv4.tcp_rmem = 4096 87380 134217728
net.ipv4.tcp_wmem = 4096 65536 134217728

# === TCP tuning ===
net.ipv4.tcp_fin_timeout = 15
# TIME-WAIT reuse is CLIENT-side only; does not affect server sockets.
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_max_syn_backlog = 16384
net.ipv4.tcp_fastopen = 3
net.ipv4.tcp_mtu_probing = 1

# === Ports ===
net.ipv4.ip_local_port_range = 10240 65535

# === inotify ===
fs.inotify.max_user_instances = 8192
fs.inotify.max_user_watches = 524288

# === Security baseline ===
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
kernel.kptr_restrict = 1
kernel.dmesg_restrict = 1

# Intentionally NOT included here (Part 2 territory):
#   vm.overcommit_memory = 1    (Redis-specific; early OOM elsewhere)
#   kernel.numa_balancing = 0   (only sensible when pinning)
#   kernel.shmmax / shmall      (workload-specific)
#   net.core.busy_poll          (prefer per-socket SO_BUSY_POLL)

# --- /etc/sysctl.d/10-bbr.conf -----------------------------------------------
# fq qdisc enables pacing, which BBR requires.
# In a data center (RTT < 1ms) BBR and CUBIC are near-tied; the benefit
# shows on WAN paths, high-RTT links, and lossy networks.
net.core.default_qdisc = fq
net.ipv4.tcp_congestion_control = bbr

# --- /etc/systemd/system.conf ------------------------------------------------
# systemd limits are hit BEFORE sysctl limits.
# These apply to every systemd-managed service.
[Manager]
DefaultLimitNOFILE=1048576
DefaultLimitNPROC=500000
DefaultTasksMax=infinity

# Apply:  sudo systemctl daemon-reexec
# Existing services pick up the new defaults only after restart.

# --- /etc/security/limits.d/99-highload.conf ---------------------------------
# PAM-based limits apply to LOGIN SESSIONS ONLY.
# systemd services ignore this file — see system.conf above.
# Both mechanisms are required for full coverage.
*       soft    nofile      1048576
*       hard    nofile      1048576
*       soft    nproc       unlimited
*       hard    nproc       unlimited
*       soft    memlock     unlimited
*       hard    memlock     unlimited

# Ubuntu already loads pam_limits.so in /etc/pam.d/common-session.
# Confirm with:
#   grep pam_limits /etc/pam.d/common-session*

# --- /etc/udev/rules.d/60-ioschedulers.rules ---------------------------------
# NVMe: none (no block-layer reordering; measurably faster).
ACTION=="add|change", KERNEL=="nvme[0-9]n[0-9]", ATTR{queue/scheduler}="none"
# SATA/SAS SSD
ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="mq-deadline"
# HDD
ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="1", ATTR{queue/scheduler}="bfq"

# Reload:
#   sudo udevadm control --reload
#   sudo udevadm trigger --type=devices --action=change

# --- /etc/fstab (data volumes) -----------------------------------------------
# noatime kills per-access timestamp writes; visibly reduces write I/O.
# Example:
#   UUID=xxxx-xxxx  /var/lib/data  ext4  defaults,noatime,nodiratime  0  2

# --- /etc/systemd/system/thp.service (general-purpose: madvise) -------------
# DB-dedicated hosts use 'never' — see Part 2.
[Unit]
Description=Set Transparent Huge Pages to madvise
DefaultDependencies=no
After=sysinit.target local-fs.target
Before=basic.target

[Service]
Type=oneshot
ExecStart=/bin/sh -c 'echo madvise > /sys/kernel/mm/transparent_hugepage/enabled'
ExecStart=/bin/sh -c 'echo madvise > /sys/kernel/mm/transparent_hugepage/defrag'
RemainAfterExit=yes

[Install]
WantedBy=basic.target

# Enable:
#   sudo systemctl enable --now thp.service

# --- IRQ balancing (general-purpose: ENABLED) --------------------------------
# sudo apt-get install -y irqbalance
# sudo systemctl enable --now irqbalance
# Trading workloads disable this and pin IRQs manually — see Part 2.

# Observe for 24-72 hours after applying Part 1.
# No metric should show abnormal growth.

# File descriptor usage vs. limit
cat /proc/sys/fs/file-nr

# TCP state summary
ss -s

# Disk I/O wait
iostat -x 1 5

# Dirty / writeback memory pressure
grep -E 'Dirty|Writeback' /proc/meminfo

# Interrupt distribution across cores
cat /proc/interrupts | awk 'NR==1 || /eth|nvme/'

# Confirm sysctl application
sudo sysctl --system 2>&1 | grep -iE 'applying|error'

# BBR active?
sysctl net.ipv4.tcp_congestion_control
lsmod | grep bbr
tc qdisc show dev eth0

# I/O scheduler per device
cat /sys/block/nvme0n1/queue/scheduler

# /etc/sysctl.d/99-trading.conf
# Layered ON TOP of the general-purpose profile.
# Same key in multiple files: last-loaded wins. Keep number <= 99.

# Avoid fork-time COW failure for Redis / QuestDB / memory-locked workloads.
# Side effect: allocations that would normally be refused may succeed
# and trigger OOM later. Use ONLY on dedicated DB / trading hosts.
vm.overcommit_memory = 1
vm.overcommit_ratio = 90

# Minimize swap interference. Complements memlock for strict in-memory behavior.
vm.swappiness = 1

# Disable NUMA balancing.
# REQUIRES explicit pinning via taskset / numactl / systemd CPUAffinity.
# Without pinning this setting is a net negative.
kernel.numa_balancing = 0

# Large shared memory segments (PostgreSQL, some QuestDB modes).
# Values assume a 64 GiB host; scale to physical RAM.
kernel.shmmni = 8192
kernel.shmmax = 68719476736
kernel.shmall = 16777216

# SysV semaphores (PostgreSQL requirement)
kernel.sem = 250 64000 100 4096

# conntrack scaling — ONLY when the host also acts as NAT / stateful firewall.
# A standalone trading server does not need this block.
# net.netfilter.nf_conntrack_max = 1048576
# net.netfilter.nf_conntrack_tcp_timeout_established = 600

# --- /etc/default/grub -------------------------------------------------------
# 8C/16T example: housekeeping=0-7, trading-isolated=8-15.
#
# Verify SMT sibling layout FIRST (AMD and Intel differ):
#   lscpu -e
# Rows with the same CORE value are SMT siblings.
#
# Ubuntu/Debian variable. RHEL-family uses GRUB_CMDLINE_LINUX.

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash \
  isolcpus=managed_irq,domain,8-15 \
  nohz_full=8-15 \
  rcu_nocbs=8-15 \
  rcu_nocb_poll \
  irqaffinity=0-7 \
  processor.max_cstate=1 \
  intel_idle.max_cstate=0 \
  idle=poll \
  mitigations=off"

# isolcpus .................... remove CPUs from the normal scheduler
# nohz_full ................... stop 1000 Hz tick on single-task CPUs
# rcu_nocbs + rcu_nocb_poll ... offload RCU callbacks from isolated CPUs
# irqaffinity ................. default IRQ affinity mask at boot
# processor.max_cstate=1 ...... forbid deep idle states (wake latency)
# idle=poll ................... spin instead of sleeping; latency=0, power up
# mitigations=off ............. disable Spectre/Meltdown mitigations
#                               ONLY on trusted, dedicated hosts

# Apply:
#   sudo update-grub
#   sudo reboot
# Verify:
#   cat /proc/cmdline
#   cat /sys/devices/system/cpu/isolated
#   cat /sys/devices/system/cpu/nohz_full

# --- Disable irqbalance; pin NIC IRQs manually -------------------------------
sudo systemctl disable --now irqbalance

# Find NIC IRQ numbers
grep -E 'eth0|ens' /proc/interrupts

# Pin every eth0 IRQ to housekeeping cores 0-7
for irq in $(awk '/eth0/ {gsub(":",""); print $1}' /proc/interrupts); do
    echo "0-7" | sudo tee /proc/irq/$irq/smp_affinity_list
done

# Multi-queue RSS (raise to hardware maximum)
ethtool -l eth0
sudo ethtool -L eth0 combined 8

# Ring buffers (drop prevention under bursts)
ethtool -g eth0
sudo ethtool -G eth0 rx 4096 tx 4096

# --- /etc/systemd/system/trading-engine.service.d/cpu.conf -------------------
# Pin the trading process to isolated cores 12-15.
# isolcpus reserves cores; this places the process onto them.
[Service]
CPUAffinity=12 13 14 15
Nice=-20
IOSchedulingClass=realtime
IOSchedulingPriority=0

# Apply:
#   sudo systemctl daemon-reload
#   sudo systemctl restart trading-engine
# Verify:
#   taskset -cp $(pgrep trading-engine)

# Multi-socket hosts: pin memory to the same NUMA node
#   numactl --cpunodebind=0 --membind=0 ./trading-engine

# --- THP disabled entirely (dedicated DB / trading hosts) -------------------
# Replace thp.service ExecStart lines with:
#   echo never > /sys/kernel/mm/transparent_hugepage/enabled
#   echo never > /sys/kernel/mm/transparent_hugepage/defrag
# Matches the official Redis and MongoDB recommendations.
#   sudo systemctl daemon-reload
#   sudo systemctl restart thp.service
#   cat /sys/kernel/mm/transparent_hugepage/enabled     # expect [never]

# --- CPU governor: performance (eliminate clock-ramp latency) ---------------
sudo apt-get install -y cpufrequtils
echo 'GOVERNOR="performance"' | sudo tee /etc/default/cpufrequtils
sudo systemctl restart cpufrequtils
cpupower frequency-info
cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor | sort -u

# --- /etc/chrony/chrony.conf (slew-only, never step) ------------------------
# Monotonic timestamps matter more than exact offset.
# A clock step breaks the ordering of trade logs.

# AWS EC2: link-local NTP, one hop away
server 169.254.169.123 prefer iburst minpoll 4 maxpoll 4
# Regional low-latency NTP
pool ntp.nict.jp iburst

# Never step the clock. makestep -1 disables stepping entirely.
# Even a large boot-time offset is corrected by slewing.
makestep 1.0 -1

lock_all
driftfile /var/lib/chrony/chrony.drift
rtcsync
logdir /var/log/chrony

# Verify:  chronyc sources -v ;  chronyc tracking
# Offset within +/- 100 us is healthy.

# Hardware timestamping (PHC-capable NIC):
#   ethtool -T eth0
#   hardware-receive / hardware-transmit / hardware-raw-clock must be YES.

// --- Go: per-socket busy-poll + Nagle off ---------------------------------
// Per-socket SO_BUSY_POLL is preferred over the global sysctl.
conn.Control(func(fd uintptr) {
    // syscall.SO_BUSY_POLL = 46
    syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, 46, 50) // 50 us busy poll
})
tcpConn.SetNoDelay(true)

// Pin this goroutine to its current OS thread.
// Combined with external taskset, the goroutine becomes effectively pinned.
runtime.LockOSThread()

// --- QuestDB: ILP over HTTP (port 9000) ------------------------------------
// UDP ILP was deprecated in QuestDB 6.5.2; do not use it.
import qdb "github.com/questdb/go-questdb-client/v3"

sender, _ := qdb.LineSenderFromConf(ctx, "http::addr=localhost:9000;")
defer sender.Close(ctx)

sender.Table("trades").
    Symbol("symbol", "BTCUSDT").
    Float64Column("price", 95000.5).
    StringColumn("side", "buy").
    At(ctx, time.Now())
sender.Flush(ctx)

// --- Python: per-socket busy-poll + kernel timestamps ----------------------
// import socket, struct, os
//
// sock.setsockopt(socket.SOL_SOCKET, 46, 50)                      # SO_BUSY_POLL
// sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
// sock.setsockopt(socket.SOL_SOCKET, socket.SO_TIMESTAMPNS, 1)    # Python 3.9+
//
// # Unpack timespec. On 64-bit Linux: two int64 fields.
// # Using "qq" makes the width explicit; avoid "LL" (C long is platform-sized).
// sec, nsec = struct.unpack("qq", cmsg_data)
//
// # Pin this process to CPUs 12-14 (isolated set).
// os.sched_setaffinity(0, {12, 13, 14})

// --- QuestDB from Python ---------------------------------------------------
// from questdb.ingress import Sender, TimestampNanos
// with Sender.from_conf("http::addr=localhost:9000;") as sender:
//     sender.row(
//         "trades",
//         symbols={"symbol": "BTCUSDT", "side": "buy"},
//         columns={"price": 95000.5, "amount": 0.01},
//         at=TimestampNanos.now(),
//     )
//     sender.flush()

// --- Runtime tuning (Go) ---------------------------------------------------
// export GOMAXPROCS=4     # match the isolated core count
// export GOGC=200         # lower GC frequency (memory-permitting)
// taskset -c 12-15 ./trading-engine

# --- Part 2 verification -----------------------------------------------------
# Isolated cores should show near-zero %usr for anything other than the app.
mpstat -P ALL 1 5

# Interrupt counts on isolated cores should NOT grow.
cat /proc/interrupts | awk '/eth0/ {print}'

# Context-switch frequency on the trading process — should be minimal.
pidstat -w -p $(pgrep trading-engine) 1

# Time-sync jitter
chronyc tracking | grep -E 'Last offset|RMS offset|System time'

# CPU frequency pinned at the performance ceiling
cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_cur_freq | sort -u

# Latency distribution — the final arbiter
sudo apt-get install -y rt-tests
sudo cyclictest -p 99 -t1 -a 12 -n -m -D 60
# Max latency under 50 us indicates a healthy Level-3 setup.

# --- Application order -------------------------------------------------------
# 1. Apply Part 1 in full. Most requires no reboot. Observe 24-72h.
# 2. Add /etc/sysctl.d/99-trading.conf alone. Observe.
# 3. THP = never (on dedicated DB hosts). Observe.
# 4. Governor = performance. Watch power.
# 5. Stop irqbalance + pin IRQs. Watch for drops.
# 6. GRUB parameters. REQUIRES REBOOT. Back up current cmdline first.
# 7. CPUAffinity + SO_BUSY_POLL last.
# At each step, cyclictest Max should decrease. If not, investigate.

# --- Rollback (each change is isolated to a single file) --------------------
# sysctl:   sudo rm /etc/sysctl.d/99-*.conf && sudo sysctl --system
# systemd:  revert /etc/systemd/system.conf ; sudo systemctl daemon-reexec
# THP:      sudo systemctl disable --now thp.service
# GRUB:     restore /etc/default/grub cmdline ; sudo update-grub ; reboot
# IRQs:     sudo systemctl enable --now irqbalance
#
# This document gets a public-internet trading system to a well-engineered
# state. It does NOT turn it into an HFT system. Preserve that distinction.