nvim/lua/config/plugins/cmp.lua

local M = {
	'hrsh7th/nvim-cmp',
	lazy = false,
	dependencies = {
		'hrsh7th/cmp-nvim-lsp',
		'hrsh7th/cmp-buffer',
		'hrsh7th/cmp-cmdline',
		'hrsh7th/cmp-path',
	},
}

function M.config()
	local cmp = require 'cmp'
	local snippy = require 'snippy'

	local ELLIPSIS_CHAR = '…'
	local MAX_LABEL_WIDTH = 20

	--[[ local winhighlight = 'NormalFloat:Pmenu,NormalFloat:Pmenu,CursorLine:PmenuSel,Search:None' ]]

	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 {
		view = {
			entries = {
				name = 'custom', -- can be "custom", "wildmenu" or "native"
				-- separator = ' | ',
			},
		},
		completion = {
			autocomplete = false,
		},
		snippet = {
			expand = function(args)
				require('snippy').expand_snippet(args.body)
			end,
		},
		window = {
			--[[ completion = {
				border = 'rounded',
				winhighlight = winhighlight,
			},
			documentation = {
				border = 'rounded',
				winhighlight = winhighlight,
			}, ]]
			completion = cmp.config.window.bordered(),
			documentation = cmp.config.window.bordered(),
		},
		experimental = {
			ghost_text = true,
		},
		formatting = {
			fields = { 'menu', 'abbr', 'kind' },
			format = function(entry, item)
				local menu_icon = {
					nvim_lsp = 'λ',
					snippy = '⋗',
					buffer = 'Ω',
					path = '🖫',
				}

				item.menu = menu_icon[entry.source.name]
				local label = item.abbr
				local truncated_label = vim.fn.strcharpart(label, 0, MAX_LABEL_WIDTH)
				if truncated_label ~= label then
					item.abbr = truncated_label .. ELLIPSIS_CHAR
				end
				return item
			end,
		},
		mapping = {
			['<C-k>'] = cmp.mapping.select_prev_item(),
			['<C-j>'] = cmp.mapping.select_next_item(),
			['<C-b>'] = cmp.mapping(cmp.mapping.scroll_docs(-4), { 'i', 'c' }),
			['<C-f>'] = cmp.mapping(cmp.mapping.scroll_docs(4), { 'i', 'c' }),
			['<C-Space>'] = cmp.mapping(cmp.mapping.complete(), { 'i', 'c' }),
			['<C-e>'] = cmp.mapping {
				i = cmp.mapping.abort(),
				c = cmp.mapping.close(),
			},
			['<CR>'] = cmp.mapping.confirm { select = true },
			['<Tab>'] = cmp.mapping(function(fallback)
				if cmp.visible() then
					cmp.select_next_item { behavior = cmp.SelectBehavior.Insert }
				elseif snippy.can_expand_or_advance() then
					snippy.expand_or_advance()
				elseif has_words_before() then
					cmp.complete()
				else
					fallback()
				end
			end, { 'i', 'c', 's' }),

			['<S-Tab>'] = cmp.mapping(function(fallback)
				if cmp.visible() then
					cmp.select_prev_item { behavior = cmp.SelectBehavior.Insert }
				elseif snippy.can_jump(-1) then
					snippy.previous()
				else
					fallback()
				end
			end, { 'i', 's', 'c' }),
		},
		sources = cmp.config.sources {
			{ name = 'nvim_lsp' },
			{ name = 'snippy' },
			{ name = 'buffer' },
			{ name = 'path' },
		},
	}

	cmp.setup.cmdline(':', {
		completion = { autocomplete = true },
		mapping = {
			['<TAB>'] = cmp.mapping(function(fallback)
				if cmp.visible() then
					cmp.select_next_item { behavior = cmp.SelectBehavior.Insert }
				else
					cmp.complete()
					cmp.select_next_item { behavior = cmp.SelectBehavior.Insert }
				end
			end, { 'i', 's', 'c' }),
			['<S-TAB>'] = cmp.mapping(function(fallback)
				if cmp.visible() then
					cmp.select_prev_item { behavior = cmp.SelectBehavior.Insert }
				else
					cmp.complete()
				end
			end, { 'i', 's', 'c' }),
			['<CR>'] = cmp.mapping { i = cmp.mapping.confirm { select = true } },
		},
		sources = {
			{ name = 'cmdline' },
			{ name = 'path' },
		},
		view = {
			entries = { name = 'wildmenu', separator = ' · ' },
		},
	})

	cmp.setup.cmdline('/', {
		completion = { autocomplete = true },
		sources = {
			{
				name = 'buffer',
			},
		},
		view = {
			entries = { name = 'wildmenu', separator = ' · ' },
		},
	})

	local config = {
		virtual_text = true,
		signs = false,
		underline = true,
		update_in_insert = true,
		severity_sort = true,
		float = {
			focusable = true,
			style = 'minimal',
			border = 'rounded',
			source = 'always',
			header = '',
			prefix = '',
		},
	}
	vim.diagnostic.config(config)

	vim.lsp.handlers['textDocument/hover'] = vim.lsp.with(vim.lsp.handlers.hover, {
		border = 'rounded',
	})

	vim.lsp.handlers['textDocument/signatureHelp'] = vim.lsp.with(vim.lsp.handlers.signature_help, {
		border = 'rounded',
	})

	--[[ local on_references = vim.lsp.handlers['textDocument/references'] ]]
	--[[ vim.lsp.handlers['textDocument/references'] = vim.lsp.with(on_references, { ]]
	--[[ 	-- Use location list instead of quickfix list ]]
	--[[ 	loclist = true, ]]
	--[[ }) ]]
end

return M