nvim/nvim/lua/plugins/lsp/cmp.lua

return {
	-- competion
	"hrsh7th/nvim-cmp",
	event = "InsertEnter",
	dependencies = {
        { "hrsh7th/cmp-buffer" }, -- source for text in buffer
        { "hrsh7th/cmp-path" }, -- source for file system paths
        { "L3MON4D3/LuaSnip" }, -- snippet engine
        { "saadparwaiz1/cmp_luasnip" }, -- for autocompletion
        { "rafamadriz/friendly-snippets" }, -- useful snippets
        { "onsails/lspkind.nvim" }, -- icons for cmp
        { "hrsh7th/cmp-nvim-lsp-signature-help" }, -- signature help
	},

	config = function()
		local cmp = require("cmp")
		local lspkind = require("lspkind")
		local luasnip = require("luasnip")

		-- loads vscode style snippets from installed plugins (e.g. friendly-snippets)
		require("luasnip.loaders.from_vscode").lazy_load()
		require("luasnip.loaders.from_vscode").load({paths = { "~/.config/nvim/snippets" }})
        luasnip.setup({
            region_check_events = { "CursorMoved" },
            delete_check_events = { "TextChanged" },
        })

        -- luasnip.filetype_extend("htmldjango", { "html" })

		cmp.setup({
			completion = {
				completeopt = "menu,menuone,preview,noselect",
			},

			window = {
				documentation = cmp.config.window.bordered(),
				completion = cmp.config.window.bordered({
					winhighlight = "Normal:CmpPmenu,CursorLine:PmenuSel,Search:None",
				}),
			},

			snippet = { -- configure how nvim-cmp interacts with snippet engine
				expand = function(args)
					luasnip.lsp_expand(args.body)
				end,
			},

			mapping = cmp.mapping.preset.insert({
				["<C-j>"] = cmp.mapping.select_next_item({ behavior = cmp.ConfirmBehavior.Select }), -- next suggestion
				["<C-k>"] = cmp.mapping.select_prev_item({ behavior = cmp.ConfirmBehavior.Select }), -- prev suggestion
				["<C-S-J>"] = cmp.mapping.scroll_docs(4, { behavior = cmp.ConfirmBehavior.Select }), -- docs forward
				["<C-S-K>"] = cmp.mapping.scroll_docs(-4, { behavior = cmp.ConfirmBehavior.Select }), -- docs back
				["<C-Space>"] = cmp.mapping.complete(), -- show completion suggestions
				["<C-q>"] = cmp.mapping.abort(), -- close completion window
				["<CR>"] = cmp.mapping.confirm({ select = false }), -- autocomplete if selected
                -- Mapping for Tab key
                ["<Tab>"] = cmp.mapping(function(fallback)
                    if cmp.visible() then
                        cmp.confirm({ behavior = cmp.ConfirmBehavior.Insert, select = true })
                    elseif require("luasnip").expandable() then
                        -- Expands snippet if possible
                        require("luasnip").expand()
                    else
                        -- Otherwise, fallback (insert a tab character)
                        fallback()
                    end
                end, { "i", "s" }),

                -- Mapping for jumping in snippets
                ["<C-p>"] = cmp.mapping(function(fallback)
                    if require("luasnip").jumpable() then
                        -- Jump backwards if inside a snippet
                        require("luasnip").jump()
                    else
                        -- Otherwise, fallback (insert a tab character)
                        fallback()
                    end
                end, { "i", "s" }),

                -- Mapping for jumping backwards in snippets
                ["<C-S-p>"] = cmp.mapping(function(fallback)
                    if require("luasnip").jumpable() then
                        -- Jump backwards if inside a snippet
                        require("luasnip").jump()
                    else
                        -- Otherwise, fallback (insert a tab character)
                        fallback()
                    end
                end, { "i", "s" })
			}),

			-- sources for autocompletion
			sources = cmp.config.sources({
				{ name = "nvim_lsp" }, -- lsp
				{ name = "luasnip" }, -- snippets
				{ name = "buffer" }, -- text within current buffer
				{ name = "path" }, -- file system paths
                { name = 'nvim_lsp_signature_help' }, -- signature help
			}),

			formatting = {
				fields = { "kind", "abbr", "menu" },
				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,
				}),
			},
		})

		local opts = { silent = true }
		opts.desc = "next snippet placeholder"
		vim.keymap.set({ "i", "s" }, "<C-w>", function()
			luasnip.jump(1)
		end, opts)

		opts.desc = "previous snippet placeholder"
		vim.keymap.set({ "i", "s" }, "<C-b>", function()
			luasnip.jump(-1)
		end, opts)
	end,
}