--
-- config for nvim-cmp
--

local cmp = require("cmp")
local mapping = cmp.mapping
local luasnip = require("luasnip")

local M = {}

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

local feedkey = function(key, mode)
	vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes(key, true, true, true), mode, true)
end

M.config = {
	snippet = {
		expand = function(args)
			vim.fn["vsnip#anonymous"](args.body)
			luasnip.lsp_expand(args.body)
		end,
	},
	mapping = mapping.preset.insert({
		["<Tab>"] = cmp.mapping(function(fallback)
			if cmp.visible() then
				cmp.select_next_item()
			elseif luasnip.expand_or_jumpable() then
				luasnip.expand_or_jump()
			elseif vim.fn["vsnip#available"](1) == 1 then
				feedkey("<Plug>(vsnip-expand-or-jump)", "")
			elseif has_words_before() then
				cmp.complete()
			else
				fallback()
			end
		end, { "i", "s" }),
		["<S-Tab>"] = cmp.mapping(function(fallback)
			if cmp.visible() then
				cmp.select_prev_item()
			elseif luasnip.jumpable(-1) then
				luasnip.jump(-1)
			elseif vim.fn["vsnip#available"](-1) == 1 then
				feedkey("<Plug>(vsnip-jump-prev)", "")
			else
				fallback()
			end
		end, { "i", "s" }),
	}),
	sources = cmp.config.sources({
		{ name = "nvim_lsp" },
		{ name = "luasnip" },
		{ name = "vsnip" },
		{ name = "buffer" },
		{ name = "path" },
	}),
}

local capabilities = require("cmp_nvim_lsp").default_capabilities()
capabilities.textDocument.completion.completionItem.snippetSupport = true

M.capabilities = capabilities

M.on_attach = function(_, bufnr)
	vim.api.nvim_buf_set_option(bufnr, "omnifunc", "v:lua.vim.lsp.omnifunc")
end

return M