09_completion.lua

-- Set up nvim-cmp.
local cmp = require('cmp')
local cmp_autopairs = require('nvim-autopairs.completion.cmp')
local lspkind = require('lspkind')

require("lsp_signature").setup({})

-- Add parentheses after selecting function or method item
cmp.event:on('confirm_done', cmp_autopairs.on_confirm_done())

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({
  formatting = {
    format = lspkind.cmp_format({
      mode = 'symbol_text', -- show only symbol annotations
      maxwidth = 50, -- prevent the popup from showing more than provided characters (e.g 50 will not show more than 50 characters)
                     -- can also be a function to dynamically calculate max width such as
                     -- maxwidth = function() return math.floor(0.45 * vim.o.columns) end,
      ellipsis_char = '...', -- when popup menu exceed maxwidth, the truncated part would show ellipsis_char instead (must define maxwidth first)
      show_labelDetails = true, -- show labelDetails in menu. Disabled by default

      -- The function below will be called before any actual modifications from lspkind
      -- so that you can provide more controls on popup customization. (See [#30](https://github.com/onsails/lspkind-nvim/pull/30))
      -- before = function (entry, vim_item)
      --   -- ...
      --   return vim_item
      -- end
    })
  },
  view = {
    entries = { name = 'custom', selection_order = 'near_cursor' }
  },
  experimental = {
    ghost_text = false,
  },
  sources = cmp.config.sources({
    { name = 'snippets' },
    { name = 'nvim_lsp' },
    {
      name = 'buffer',
      option = {
        get_bufnrs = function()
          return vim.api.nvim_list_bufs()
        end
      }
    },
    -- { name = 'tags' },
    -- { name = "rg" },
  }),
  snippet = {
    expand = function(args) vim.snippet.expand(args.body) end,
  },
  -- window = {
  --   completion = cmp.config.window.bordered(),
  --   documentation = cmp.config.window.bordered(),
  -- },
  mapping = cmp.mapping.preset.insert({
    ['<C-b>'] = cmp.mapping.scroll_docs(-4),
    ['<C-f>'] = cmp.mapping.scroll_docs(4),
    -- select completion item
    ['<CR>']  = cmp.mapping.confirm { behavior = cmp.ConfirmBehavior.Insert, select = true },
    -- next completion item with
    ['<Tab>'] = function(fallback)
      if not cmp.select_next_item() then
        if vim.bo.buftype ~= 'prompt' and has_words_before() then
          cmp.complete()
        else
          fallback()
        end
      end
    end,
    -- prev completion item with
    ['<S-Tab>'] = function(fallback)
      if not cmp.select_prev_item() then
        if vim.bo.buftype ~= 'prompt' and has_words_before() then
          cmp.complete()
        else
          fallback()
        end
      end
    end,
  }),

})

-- Use buffer source for `/` and `?` (if you enabled `native_menu`, this won't work anymore).
cmp.setup.cmdline({ '/', '?' }, {
  mapping = cmp.mapping.preset.cmdline(),
  sources = {
    { name = 'buffer' },
    -- { name = 'nvim_lsp_document_symbol' },
  }
})

-- Use cmdline & path source for ':' (if you enabled `native_menu`, this won't work anymore).
cmp.setup.cmdline(':', {
  mapping = cmp.mapping.preset.cmdline(),
  sources = cmp.config.sources({
    { name = 'cmdline' },
    { name = 'async_path' },
  })
})

-- TODO:

-- Set up lspconfig.
-- local capabilities = require('cmp_nvim_lsp').default_capabilities()

-- require('lspconfig').solargraph.setup {
--   capabilities = capabilities
-- }