{ pkgs, ... }: {
  environment.variables = { EDITOR = "vim"; };

  environment.systemPackages = with pkgs;
    [
      (neovim.override {
        vimAlias = true;
        configure = {
          packages.myPlugins = with pkgs.vimPlugins; {
            start = [
              airline # Lean & mean status/tabline for vim that's light as air
              dracula-vim # Dracula theme for vim
              formatter-nvim # A format runner for neovim
              fugitive # Vim Git wrapper
              fzf-vim # Full path fuzzy file, buffer, mru, tag, finder for Vim
              haskell-vim # Syntax Highlighting and Indentation for Haskell
              indentLine # Display thin vertical lines at each indentation level
              neocomplete-vim # Keyword completion system
              nerdcommenter # Comment functions so powerful—no comment necessary
              nerdtree # File system explorer
              nerdtree-git-plugin # Plugin for nerdtree showing git status
              #statix                # Lints and suggestions for the nix programming language
              supertab # Allows you to use <Tab> for all your insert completion
              syntastic # Syntax checking hacks
              vim-addon-nix # Scripts assisting writing .nix files
              vim-cue # Cue filetype plugin for Vim
              vim-lastplace
              vim-markdown-toc # Generate table of contents for Markdown files
              vim-nix # Support for writing Nix expressions in vim
              vim-numbertoggle # Toggle between relative / absolute line numbers automatically
              vim-one
            ];
            opt = [ ];
          };
          customRC = ''
            " Preferred global default settings:
            set nocompatible
            set backspace=indent,eol,start
            set number relativenumber     " Enable relative line numbers by default
            set cursorline                " Highlight the current line number
            set smartindent               " Automatically insert extra level of indentation
            set tabstop=4                 " Default tabstop
            set shiftwidth=4              " Default indent spacing
            set expandtab                 " Expand [TABS] to spaces
            packadd! dracula-vim
            syntax on                     " Enable syntax highlighting
            set t_Co=256                  " Use 265 colors in vim
            set background=dark           " Set the default background scheme
            colorscheme dracula           " Set the default colour scheme
            "let g:one_allow_italics = 1   " I love italic for comments
            set spell spelllang=en_au     " Defaul spell checking language
            set spellfile=~/.vim-spell.en.utf-8.add    " Add the spellfile
            hi clear SpellBad             " Clear any unwanted default settings
            hi SpellBad cterm=underline   " Set the spell checking highlight style
            hi SpellBad ctermbg=NONE      " Set the spell checking highlight background
            match ErrorMsg '\s\+$'        "

            nnoremap <silent> <C-p> :Files<CR>
            nnoremap <silent> <Leader>f :Rg<CR>
            set grepprg=rg\ --vimgrep\ --smart-case\ --follow

            let g:airline_powerline_fonts = 1   " Use powerline fonts
            let g:airline_theme='dracula'       " Set the airline theme

            "call togglebg#map("<F10>")   " Toggle background colour between dark|light

            set laststatus=2   " Set up the status line so it's coloured and always on

            " Removes trailing spaces:
            function! TrimWhiteSpace()
                %s/\s\+$//e
            endfunction

            " Trigger for numbertoggle to switch modes
            nnoremap <silent> <C-n> :set relativenumber!<CR>

            " Tab settings
            let g:SuperTabDefaultCompletionType = 'context'
            let g:SuperTabContextTextOmniPrecedence = ['&omnifunc','&completefunc']
            let g:SuperTabRetainCompletionType=2

            inoremap <expr><Enter>  pumvisible() ? "\<C-Y>" : "\<Enter>"
            inoremap <expr><TAB>  pumvisible() ? "\<C-n>" : "\<TAB>"

            nnoremap <silent> <Leader>RemoveTrailingWhiteSpace :call TrimWhiteSpace()<CR>
            autocmd FileWritePre    * :call TrimWhiteSpace()
            autocmd FileAppendPre   * :call TrimWhiteSpace()
            autocmd FilterWritePre  * :call TrimWhiteSpace()
            autocmd BufWritePre     * :call TrimWhiteSpace()

            augroup FormatAutogroup
              autocmd!
              autocmd BufWritePost * silent! FormatWrite
            augroup END

            " FIXME: Currently always set to dark due to issues with Termonad Solarized theme
            " Light during the day, dark during the night
            let hour = strftime("%H")
            if 7 <= hour && hour < 17
              "set background=dark
              "hi Normal ctermbg=none              " Set a transparent background
              "let g:airline_solarized_bg='dark'   " Set the airline background
            else
              "set background=dark
              "hi Normal ctermbg=none              " Set a transparent background
              "let g:airline_solarized_bg='dark'   " Set the airline background
            endif

            " Transparent editing of gpg encrypted files.
            " By Wouter Hanegraaff <wouter@blub.net>
            augroup encrypted
                au!

                " First make sure nothing is written to ~/.viminfo while editing an encrypted file.
                autocmd BufReadPre,FileReadPre      *.gpg set viminfo=
                " We don't want a swap file, as it writes unencrypted data to disk
                autocmd BufReadPre,FileReadPre      *.gpg set noswapfile
                " Switch to binary mode to read the encrypted file
                autocmd BufReadPre,FileReadPre      *.gpg set bin
                autocmd BufReadPre,FileReadPre      *.gpg let ch_save = &ch|set ch=2
                autocmd BufReadPost,FileReadPost    *.gpg '[,']!gpg --decrypt 2> /dev/null
                " Switch to normal mode for editing
                autocmd BufReadPost,FileReadPost    *.gpg set nobin
                autocmd BufReadPost,FileReadPost    *.gpg let &ch = ch_save|unlet ch_save
                autocmd BufReadPost,FileReadPost    *.gpg execute ":doautocmd BufReadPost " . expand("%:r")

                " Convert all text to encrypted text before writing
                autocmd BufWritePre,FileWritePre    *.gpg   '[,']!gpg --default-key=7E66C3B5CDE94A4A --default-recipient-self -ae 2>/dev/null
                " Undo the encryption so we are back in the normal text, directly
                " after the file has been written.
                autocmd BufWritePost,FileWritePost    *.gpg   u
            augroup END

            " Manage ISO files
            augroup iso
                au!

                " First make sure nothing is written to ~/.viminfo while editing an encrypted file.
                autocmd BufReadPre,FileReadPre      *.iso set viminfo=
                " We don't want a swap file, as it writes unencrypted data to disk
                autocmd BufReadPre,FileReadPre      *.iso set noswapfile
                " Switch to binary mode to read the encrypted file
                autocmd BufReadPre,FileReadPre      *.iso set bin
                autocmd BufReadPre,FileReadPre      *.iso let ch_save = &ch|set ch=2
                autocmd BufReadPost,FileReadPost    *.iso '[,']!gpg --decrypt 2> /dev/null
                " Switch to normal mode for editing
                autocmd BufReadPost,FileReadPost    *.iso set nobin
                autocmd BufReadPost,FileReadPost    *.iso let &ch = ch_save|unlet ch_save
                autocmd BufReadPost,FileReadPost    *.iso execute ":doautocmd BufReadPost " . expand("%:r")

                " Convert all text to encrypted text before writing
                autocmd BufWritePre,FileWritePre    *.iso   '[,']!gpg --default-key=A4122FF3971B6865 --default-recipient-self -ae 2>/dev/null
                " Undo the encryption so we are back in the normal text, directly
                " after the file has been written.
                autocmd BufWritePost,FileWritePost    *.iso   u
            augroup END

            " Use persistent history.
            if !isdirectory("/tmp/.vim-undo-dir")
                call mkdir("/tmp/.vim-undo-dir", "", 0700)
            endif
            set undodir=/tmp/.vim-undo-dir
            set undofile

            " My Markdown environment
            function! MarkdownSettings()
                set textwidth=79
                set spell spelllang=en_au
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.mdwn :call MarkdownSettings()
            autocmd BufNewFile,BufFilePre,BufRead *.md :call MarkdownSettings()

            " My ReStructured Text environment
            function! ReStructuredSettings()
                set textwidth=79
                set spell spelllang=en_au
                hi clear SpellBad             " Clear any unwanted default settings
                hi SpellBad cterm=underline   " Set the spell checking highlight style
                hi SpellBad ctermbg=NONE      " Set the spell checking highlight background
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.rst :call ReStructuredSettings()
            autocmd BufNewFile,BufFilePre,BufRead *.txt :call ReStructuredSettings()

            " My LaTeX environment:
            function! LaTeXSettings()
                set textwidth=79
                set spell spelllang=en_au
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.tex :call LaTeXSettings()

            " Settings for my Haskell environment:
            function! HaskellSettings()
                set tabstop=2
                set shiftwidth=2
                set expandtab
                set textwidth=79
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.hs :call HaskellSettings()

            " Settings for my Nix environment:
            function! NixSettings()
                set tabstop=2
                set shiftwidth=2
                set expandtab
                set textwidth=79
                set filetype=nix
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.nix :call NixSettings()

            " Settings for my Cue environment:
            function! CueSettings()
                set noexpandtab
                set tabstop=2
                set shiftwidth=2
                set textwidth=79
                let g:cue_fmt_on_save = 1
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.cue :call CueSettings()

            " Settings for my Rust environment:
            function! RustSettings()
                set tabstop=4
                set shiftwidth=4
                set expandtab
                set textwidth=79
                let g:rustfmt_autosave = 1
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.rs :call RustSettings()

            " Settings for my Crystal environment:
            function! CrystalSettings()
                set tabstop=2
                set shiftwidth=2
                set expandtab
                set textwidth=79
                set filetype=crystal
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.cr :call CrystalSettings()

            " Settings for my Golang environment:
            function! GoSettings()
                set tabstop=7
                set shiftwidth=7
                set noexpandtab
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.go :call GoSettings()

            " Settings for my Python environment:
            function! PythonSettings()
                set tabstop=4
                set shiftwidth=4
                set expandtab
                set textwidth=79
                set spell!
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.py :call PythonSettings()

            " My Mutt environment
            function! MuttSettings()
                set textwidth=79
                set spell spelllang=en_au
                hi clear SpellBad             " Clear any unwanted default settings
                hi SpellBad cterm=underline   " Set the spell checking highlight style
                hi SpellBad ctermbg=NONE      " Set the spell checking highlight background
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead mutt-* :call MuttSettings()
            autocmd BufNewFile,BufFilePre,BufRead neomutt-* :call MuttSettings()

            " Settings for my C environment:
            function! CSettings()
                set tabstop=2
                set shiftwidth=2
                set expandtab
                set textwidth=79
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.c :call CSettings()

            " Settings for my YAML environment:
            function! YAMLSettings()
                set tabstop=2
                set shiftwidth=2
                set expandtab
                set textwidth=79
                set spell spelllang=en_au
                hi clear SpellBad             " Clear any unwanted default settings
                hi SpellBad cterm=underline   " Set the spell checking highlight style
                hi SpellBad ctermbg=NONE      " Set the spell checking highlight background
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.yaml :call YAMLSettings()
            autocmd BufNewFile,BufFilePre,BufRead *.yml :call YAMLSettings()

            " Settings for my Bash environment:
            function! BashSettings()
                set tabstop=4
                set shiftwidth=4
                set expandtab
                set textwidth=79
                set spell!
            endfunction
            autocmd BufNewFile,BufFilePre,BufRead *.sh :call BashSettings()

            lua <<EOF
              local treefmt = {
                function()
                  return {
                    exe = "treefmt",
                    args = {"--stdin", vim.fn.fnameescape(vim.api.nvim_buf_get_name(0))},
                    stdin = true,
                  }
                end
              }
              require("formatter").setup({
                filetype = {
                  crystal = treefmt,
                  cue = treefmt,
                  go = treefmt,
                  javascript = treefmt,
                  lua = treefmt,
                  mint = treefmt,
                  nix = treefmt,
                  rego = treefmt,
                  ruby = treefmt,
                  rust = treefmt,
                  vim = treefmt,
                }
              })
            EOF
          '';
        };
      })
    ];
}