-- completeopt is used to manage code suggestions
-- menuone: show popup even when there is only one suggestion
-- noinsert: Only insert text when selection is confirmed
-- noselect: force us to select one from the suggestions
vim.opt.completeopt = { 'menuone', 'noselect', 'noinsert', 'preview' }
-- shortmess is used to avoid excessive messages
vim.opt.shortmess = vim.opt.shortmess + { c = true }

local cmp = require('cmp')
local lspkind = require('lspkind')
cmp.setup({
  enabled = true,
  preselect = cmp.PreselectMode.None,
  snippet = {
    expand = function(args)
      require('luasnip').lsp_expand(args.body) -- For `luasnip` users.
    end,
  },
  formatting = {
    format = lspkind.cmp_format({
      mode = 'symbol', -- 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
    })
  },
  mapping = {
    -- Shift+TAB to go to the Previous Suggested item
    ['<Up>'] = cmp.mapping.select_prev_item(),
    ['<S-Tab>'] = cmp.mapping.select_prev_item(),
    -- Tab to go to the next suggestion
    ['<Down>'] = cmp.mapping.select_next_item(),
    ['<Tab>'] = cmp.mapping.select_next_item(),
    -- CTRL+SHIFT+f to scroll backwards in description
    ['<C-S-f>'] = cmp.mapping.scroll_docs(-4),
    -- CTRL+F to scroll forwards in the description
    ['<C-f>'] = cmp.mapping.scroll_docs(4),
    -- CTRL+SPACE to bring up completion at current Cursor location
    ['<C-Space>'] = cmp.mapping.complete(),
    -- CTRL+e to exit suggestion and close it
    ['<C-e>'] = cmp.mapping.close(),
    -- CR (enter or return) to CONFIRM the currently selection suggestion
    -- We set the ConfirmBehavior to insert the Selected suggestion
    ['<CR>'] = cmp.mapping.confirm({
      behavior = cmp.ConfirmBehavior.Insert,
      select = false, -- This prevents the selection of a suggestion by default
    })
  },

  -- sources are the installed sources that can be used for code suggestions
  sources = {
    { name = 'path' },
    { name = 'nvim_lsp',               keyword_length = 3 },
    { name = 'nvim_lsp_signature_help' },
    { name = 'nvim_lua',               keyword_length = 2 },
    { name = 'buffer',                 keyword_length = 2 },
    { name = 'vsnip',                  keyword_length = 2 },
  }
})