" Plugins
" ==============================================================================
call plug#begin(stdpath('config') . '/plugged')
    " nerdtree provides a file tree explorer
    " vim-dispatch allows running async jobs in vim (i.e. builds in the background)
    Plug 'https://github.com/scrooloose/nerdtree', { 'on': 'NERDTreeToggle' }
    Plug 'https://github.com/tpope/vim-dispatch'
    Plug 'https://github.com/tpope/vim-fugitive'

    " TODO: 2022-06-19 Treesitter is too slow on large C++ files
    " Plug 'https://github.com/nvim-treesitter/nvim-treesitter', {'do': ':TSUpdate'}
    Plug 'https://github.com/bfrg/vim-cpp-modern'

    " Telescope file picker, sorter and previewer
    Plug 'https://github.com/nvim-lua/plenary.nvim'
    Plug 'https://github.com/nvim-telescope/telescope.nvim'
    Plug 'nvim-telescope/telescope-fzf-native.nvim', { 'do': 'cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release && cmake --build build --config Release && cmake --install build --prefix build' }

    " nvim-lspconfig sets up sane defaults for LSP servers (i.e. clangd)
    " nvim-cmp is a more powerful autocomplete engine
    " LuaSnip allow writing snippets into the buffer, we can power the snippets from LSP
    " cmp-nvim-lsp preset capability flags to request more powerful autocomplete from LSP server
    " cmp_luasnip a LuaSnip addon that provides a completion source to nvim-cmp
    " cmp-buffer provides a buffer completion source to nvim-cmp
    " cmp-path provides a path completion source to nvim-cmp
    Plug 'https://github.com/neovim/nvim-lspconfig'
    Plug 'https://github.com/hrsh7th/nvim-cmp'
    Plug 'https://github.com/L3MON4D3/LuaSnip'
    Plug 'https://github.com/hrsh7th/cmp-nvim-lsp'
    Plug 'https://github.com/saadparwaiz1/cmp_luasnip'
    Plug 'https://github.com/hrsh7th/cmp-buffer'
    Plug 'https://github.com/hrsh7th/cmp-path'

    " odin for syntax highlighting
    Plug 'https://github.com/Tetralux/odin.vim'
    Plug 'https://github.com/sainnhe/gruvbox-material'

    " Lua cache to speed up load times
    Plug 'https://github.com/lewis6991/impatient.nvim'
call plug#end()

" Lua Setup
" ==============================================================================
lua <<EOF
  require('impatient')
  require('telescope').load_extension('fzf')
  require('telescope').setup {
    defaults = {
      layout_config = {
        horizontal = { width = 0.95 }
      },
      mappings = {
        i = {
          ["<C-j>"] = require('telescope.actions').move_selection_next,
          ["<C-k>"] = require('telescope.actions').move_selection_previous,
        },
        n = {
          ["<C-j>"] = require('telescope.actions').move_selection_next,
          ["<C-k>"] = require('telescope.actions').move_selection_previous,
        },
      },
    },
    pickers = {
      find_files = {
        find_command = { "fd", "--unrestricted", "--strip-cwd-prefix" }
      },
    }
  }

  -- Vim Options
  -- ===========================================================================
  vim.opt.autowrite=true        -- Automatically save before cmds like :next and :prev
  vim.opt.colorcolumn={80, 100} -- Set a 80 and 100 char column ruler
  vim.opt.completeopt={'menu', 'menuone', 'noselect'}
  vim.opt.cpoptions:append('$') -- $ as end marker for the change operator
  vim.opt.cursorline=true       -- Highlight current line
  vim.opt.expandtab=true        -- Replace tabs with spaces
  vim.opt.guifont={'JetBrains_Mono:h9',
                   'Consolas:h9',
                   'InputMonoCondensed:h9'}
  vim.opt.hlsearch=false        -- Highlight just the first match on search
  vim.opt.ignorecase=true       -- Search is not case sensitive
  vim.opt.linebreak=true        -- On wrapped lines, break on the wrapping word intelligently
  vim.opt.list=true             -- Show the 'listchar' characters on trailing spaces, tabs e.t.c
  vim.opt.listchars:append('tab:>-,trail:■,extends:»,precedes:«')
  vim.opt.number=true           -- Show line numbers
  vim.opt.relativenumber=true   -- Show relative line numbers
  vim.opt.shiftwidth=4          -- Number of spaces for each autoindent step
  vim.opt.splitright=true       -- Open new splits to the right of the current one
  vim.opt.swapfile=false        -- Disable swapfile (stores the things changed in a file)
  vim.opt.textwidth=80          -- On format, format to 80 char long lines
  vim.opt.visualbell=true       -- Flash the screen on error
  vim.opt.wrap=false            -- Don't wrap lines of text automatically

  vim.diagnostic.config({
    -- Turn off the diagnostics signs on the line number. In LSP mode, editing
    -- a C++ buffer constantly toggles the sign column on and off as you change
    -- modes which is very visually distracting.
    signs = false,
  })

  -- Check if there were args (i.e. opened file), non-empty buffer, or started in insert mode
  if vim.fn.argc() == 0 or vim.fn.line2byte("$") ~= -1 and not opt.insertmode then
    local ascii = {
        "",
        "  Useful Bindings (Normal Mode)",
        "  --------------------------------------------------",
        "  <ctrl+n>  to open the file tree explorer",
        "  <ctrl+i>  clang format selected lines",
        "  <ctrl+j>  jump to next compilation error",
        "  <ctrl+k>  jump to prev compilation error",
        "  <cd>      change working directory to current file",
        "  <\\s>      split buffer vertically",
        "  ",
        "  Telescope Bindings (Normal Mode)",
        "  --------------------------------------------------",
        "  <\\te>     open telescope menu",
        "  <\\ta>     search for symbol via tags",
        "  <\\f>      search for file",
        "  <\\g>      search for text",
        "  <\\b>      search for buffer",
        "  <\\h>      search VIM help menu",
        "  ",
        "  LSP Bindings (Normal Mode)",
        "  --------------------------------------------------",
        "  <gD>      on (applicable) symbol, jump to declaration",
        "  <gd>      on (applicable) symbol, jump to definition",
        "  <gt>      on (applicable) symbol, jump to type definition",
        "  <gr>      on (applicable) symbol, show caller references",
        "  <gf>      on (applicable) symbol, search available symbols",
        "  <ga>      on (applicable) symbol, show code-actions prompt",
        "  <gR>      on (applicable) symbol, code-aware symbol rename",
        "  <gs>      on (applicable) symbol, show signature help",
        "  <shift+k> on (applicable) symbol, show documentation",
        "  <space+e> on red underlined symbol error, show error message",
        "  <alt+n>   jump to next LSP error",
        "  <alt+n>   jump to prev LSP error",
    }

    local height = vim.api.nvim_get_option("lines")
    local width = vim.api.nvim_get_option("columns")
    local ascii_rows = #ascii
    local ascii_cols = #ascii[1]
    local win = vim.api.nvim_get_current_win()
    local buf = vim.api.nvim_create_buf(true, true)

    local function reset_start_screen()
        vim.cmd("enew")
        local buf = vim.api.nvim_get_current_buf()
        local win = vim.api.nvim_get_current_win()
        vim.api.nvim_buf_set_option(buf, "modifiable", true)
        vim.api.nvim_buf_set_option(buf, "buflisted", true)
        vim.api.nvim_buf_set_option(buf, "buflisted", true)
        vim.api.nvim_win_set_option(win, "colorcolumn", "80,100")
        vim.api.nvim_win_set_option(win, "relativenumber", true)
        vim.api.nvim_win_set_option(win, "number", true)
        vim.api.nvim_win_set_option(win, "list", true)
    end

    -- Only display if there is enough space
    if height >= ascii_rows and width >= ascii_cols then
      vim.api.nvim_buf_set_lines(buf, 0, -1, false, ascii)
      vim.api.nvim_buf_set_option(buf, "modified", false)
      vim.api.nvim_buf_set_option(buf, "buflisted", false)
      vim.api.nvim_buf_set_option(buf, "bufhidden", "wipe")
      vim.api.nvim_buf_set_option(buf, "buftype", "nofile")
      vim.api.nvim_buf_set_option(buf, "swapfile", false)
      vim.api.nvim_win_set_option(win, "colorcolumn", "")
      vim.api.nvim_win_set_option(win, "relativenumber", false)
      vim.api.nvim_win_set_option(win, "number", false)
      vim.api.nvim_win_set_option(win, "list", false)
      vim.api.nvim_set_current_buf(buf)

      vim.api.nvim_create_autocmd("InsertEnter,WinEnter", {
          pattern = "<buffer>",
          callback = reset_start_screen,
      })
    end
  end

  -- LSP Setup
  -- ===========================================================================
  -- Load the additional capabilities supported by nvim-cmp
  local custom_capabilities = require('cmp_nvim_lsp').update_capabilities(vim.lsp.protocol.make_client_capabilities())

  -- Use an on_attach function to only map the following keys
  -- after the language server attaches to the current buffer
  local custom_on_attach = function(client, bufnr)
    -- Enable completion triggered by <c-x><c-o>
    vim.api.nvim_buf_set_option(bufnr, 'omnifunc', 'v:lua.vim.lsp.omnifunc')

    -- See `:help vim.diagnostic.*` for documentation on any of the below functions
    local opts = { noremap=true, silent=true }
    vim.keymap.set('n', '<space>e', vim.diagnostic.open_float, opts)
    vim.keymap.set('n', '<A-n>',    vim.diagnostic.goto_next,  opts)
    vim.keymap.set('n', '<A-p>',    vim.diagnostic.goto_prev,  opts)

    -- See `:help vim.lsp.*` for documentation on any of the below functions
    local bufopts = { noremap=true, silent=true, buffer=bufnr }
    vim.keymap.set('n',  'K', vim.lsp.buf.hover,           bufopts)
    vim.keymap.set('n', 'gD', vim.lsp.buf.declaration,     bufopts)
    vim.keymap.set('n', 'gs', vim.lsp.buf.signature_help,  bufopts)
    vim.keymap.set('n', 'ga', vim.lsp.buf.code_action,     bufopts)
    vim.keymap.set('n', 'gR', vim.lsp.buf.rename,          bufopts)
  end

  -- Request additional completion capabilities from the LSP server(s)
  local lspconfig = require('lspconfig')

  -- Clangd LSP Setup
  -- ===========================================================================
  lspconfig.clangd.setup {
    on_attach           = custom_on_attach,
    capabilities        = custom_capabilities,
    single_file_support = false, --- Don't launch LSP if the directory does not have LSP metadata
  }

  lspconfig.cmake.setup {
    on_attach    = custom_on_attach,
    capabilities = custom_capabilities,
  }

  -- Autocomplete Setup
  -- ===========================================================================
  local luasnip = require 'luasnip'
  local cmp     = require 'cmp'

  local has_words_before = function()
    local line, col = unpack(vim.api.nvim_win_get_cursor(0))
    return col ~= 0 and vim.api.nvim_buf_get_lines(0, line - 1, line, true)[1]:sub(col, col):match("%s") == nil
  end

  cmp.setup {
    snippet = {
      expand = function(args) luasnip.lsp_expand(args.body) end,
    },
    window = {
        completion = cmp.config.window.bordered(),
        documentation = cmp.config.window.bordered(),
    },
    completion = { autocomplete = false },
    mapping = cmp.mapping.preset.insert({
      ['<C-d>'] = cmp.mapping.scroll_docs(4),
      ['<C-u>'] = cmp.mapping.scroll_docs(-4),
      ['<C-k>'] = cmp.mapping.scroll_docs(-1),   -- Scroll the docs up   by 1 line
      ['<C-j>'] = cmp.mapping.scroll_docs(1),    -- Scroll the docs down by 1 line
      ['<CR>']  = cmp.mapping.confirm { behavior = cmp.ConfirmBehavior.Replace, select = true, },
      ['<Tab>'] = cmp.mapping(function(fallback) -- Move down the autocomplete list
        if cmp.visible() then
          cmp.select_next_item()
        elseif luasnip.expand_or_jumpable() then
          luasnip.expand_or_jump()
        elseif has_words_before() then
          cmp.complete()
        else
          fallback()
        end
      end, { 'i', 's' }),
      ['<S-Tab>'] = cmp.mapping(function(fallback) -- Move up the autocomplete list
        if cmp.visible() then
          cmp.select_prev_item()
        elseif luasnip.jumpable(-1) then
          luasnip.jump(-1)
        else
          fallback()
        end
      end, { 'i', 's' }),
    }),
    sources = {
      { name = 'nvim_lsp' },
      { name = 'luasnip' },
      { name = 'buffer' },
    },
  }

  -- TODO: 2022-06-19 Treesitter is too slow on large C++ files
  -- require('nvim-treesitter.configs').setup {
  --   ensure_installed = { "c", "cpp" }, -- A list of parser names, or "all"
  --   sync_install     = false,          -- Install parsers synchronously (only applied to `ensure_installed`)
  --   ignore_install   = { },            -- List of parsers to ignore installing (for "all")

  --   highlight = {
  --     enable = false, -- `false` will disable the whole extension

  --     -- NOTE: these are the names of the parsers and not the filetype. (for example if you want to
  --     -- disable highlighting for the `tex` filetype, you need to include `latex` in this list as this is
  --     -- the name of the parser)
  --     -- list of language that will be disabled
  --     disable = { },

  --     -- Setting this to true will run `:h syntax` and tree-sitter at the same time.
  --     -- Set this to `true` if you depend on 'syntax' being enabled (like for indentation).
  --     -- Using this option may slow down your editor, and you may see some duplicate highlights.
  --     -- Instead of true it can also be a list of languages
  --     additional_vim_regex_highlighting = false,
  --   },
  -- }
EOF

" Theme
" ==============================================================================
let g:gruvbox_material_background='hard'
let g:gruvbox_material_foreground='mix'
let g:gruvbox_material_disable_italic_comment=1
let g:gruvbox_material_enable_italic=0
let g:gruvbox_material_enable_bold=0
let g:gruvbox_material_diagnostic_virtual_text='colored'
let g:gruvbox_material_better_performance=1
colorscheme gruvbox-material

" Vim-cpp-modern customisation
" Disable function highlighting (affects both C and C++ files)
let g:cpp_function_highlight = 1

" Enable highlighting of C++11 attributes
let g:cpp_attributes_highlight = 1

" Highlight struct/class member variables (affects both C and C++ files)
let g:cpp_member_highlight = 0

" Put all standard C and C++ keywords under Vim's highlight group 'Statement'
" (affects both C and C++ files)
let g:cpp_simple_highlight = 1

" Options
" ==============================================================================
" Show EOL type and last modified timestamp, right after the filename
set statusline=%<%F%h%m%r\ [%{&ff}]\ (%{strftime(\"%H:%M\ %d/%m/%Y\",getftime(expand(\"%:p\")))})%=%l,%c%V\ %P

" Resize splits when the window is resized
au VimResized * :wincmd =

" File patterns to ignore in command line auto complete
set wildignore+=*.class,*.o
set wildignore+=*\\tmp\\*,*.swp,*.zip,*.exe,*.obj,*.vcxproj,*.pdb,*.idb

" Setup undo file
set undofile
let &undodir=stdpath('config') . '/undo'

" Setup backup directory
let &backupdir=stdpath('config') . '/backup'

" Enable mouse support
if has('mouse')
    set mouse=a
endif

" Functions
" ==============================================================================
" Increase font size using (Ctrl+Up Arrow) or (Ctrl+Down Arrow) if we are using
" gvim Otherwise font size is determined in terminal
nnoremap <C-Up> :silent! let &guifont = substitute(
 \ &guifont,
 \ ':h\zs\d\+',
 \ '\=eval(submatch(0)+1)',
 \ 'g')<CR>
nnoremap <C-Down> :silent! let &guifont = substitute(
 \ &guifont,
 \ ':h\zs\d\+',
 \ '\=eval(submatch(0)-1)',
 \ 'g')<CR>

" Formatting options (see :h fo-table)
augroup persistent_settings
  au!
  au bufenter * :set formatoptions=q1j
augroup end

" General Key Bindings
" ==============================================================================
" Telescope Bindings
nnoremap <leader>f  <cmd>Telescope find_files<cr>
nnoremap <leader>g  <cmd>Telescope live_grep<cr>
nnoremap <leader>ta <cmd>Telescope tags<cr>
nnoremap <leader>te <cmd>Telescope<cr>
nnoremap <leader>b  <cmd>Telescope buffers<cr>
nnoremap <leader>h  <cmd>Telescope help_tags<cr>

nnoremap gf <cmd>Telescope lsp_dynamic_workspace_symbols<cr>
nnoremap gd <cmd>Telescope lsp_definitions<cr>
nnoremap gt <cmd>Telescope lsp_type_definitions<cr>
nnoremap gr <cmd>Telescope lsp_references<cr>

" Map Ctrl+HJKL to navigate buffer window
nmap <silent> <C-h> :wincmd h<CR>
nmap <silent> <C-j> :wincmd j<CR>
nmap <silent> <C-k> :wincmd k<CR>
nmap <silent> <C-l> :wincmd l<CR>

" Move by wrapped lines instead of line numbers
nnoremap j gj
nnoremap k gk
nnoremap gj j
nnoremap gk k

" Map NERDTree to Ctrl-N
map <C-n> :NERDTreeToggle<CR>

" Change to current buffer's directory
nmap cd :cd <C-R>=expand("%:p:h")<CR><CR>

" Buffer Splitting
nnoremap <leader>s :vs<CR>

" Go to next error
" Go to previous error
nnoremap <A-j> :cn<CR>
nnoremap <A-k> :cp<CR>

" FZF
" ==============================================================================
" Empty value to disable preview window altogether
let g:fzf_preview_window = []

" Prefix all commands with Fzf for discoverability
let g:fzf_command_prefix = 'Fzf'

" - down / up / left / right
let g:fzf_layout = { 'down': '40%' }

" Clang Format
" ==============================================================================
map <C-I> :py3file ~/clang-format.py<CR>

" Compiler Error Formats
" ==============================================================================
" Error message formats thanks to
" https://forums.handmadehero.org/index.php/forum?view=topic&catid=4&id=704#3982
set errorformat+=\\\ %#%f(%l\\\,%c):\ %m                       " MSVC: MSBuild
set errorformat+=\\\ %#%f(%l)\ :\ %#%t%[A-z]%#\ %m             " MSVC: cl.exe
set errorformat+=\\\ %#%t%nxx:\ %m                             " MSVC: cl.exe, fatal errors is crudely implemented
set errorformat+=\\\ %#LINK\ :\ %m                             " MSVC: link.exe, can't find link library badly implemented
set errorformat+=\\\ %#%s\ :\ error\ %m                        " MSVC: link.exe, errors is badly implemented
set errorformat+=\\\ %#%s\ :\ fatal\ error\ %m                 " MSVC: link.exe, fatal errors is badly implemented
set errorformat+=\\\ %#%f(%l\\\,%c-%*[0-9]):\ %#%t%[A-z]%#\ %m " MSVC: HLSL fxc.exe
set errorformat+=%\\%%(CTIME%\\)%\\@=%m                        " ctime.exe -stats

" Vim Dispatch
" ==============================================================================
let s:running_windows = has("win16") || has("win32") || has("win64")
if s:running_windows
    set makeprg=build
    nnoremap <f5> :Make ./build.bat<cr>
else
    " Set vim terminal to enter normal mode using escape like normal vim behaviour
    tnoremap <Esc> <C-\><C-n>
    nnoremap <f5> :Make ./build.sh<cr>
    set makeprg=./build.sh
endif