local function prequire(...)
	local status, lib = pcall(require, ...)
	if status then
		return lib
	end
	return nil
end

local luasnip = prequire("luasnip")
local cmp = prequire("cmp")

local ls = require("luasnip")
require("luasnip.loaders.from_lua").load({ paths = "~/.config/nvim/luasnip" })

local t = function(str)
	return vim.api.nvim_replace_termcodes(str, true, true, true)
end

local check_back_space = function()
	local col = vim.fn.col(".") - 1
	if col == 0 or vim.fn.getline("."):sub(col, col):match("%s") then
		return true
	else
		return false
	end
end

_G.tab_complete = function()
	if cmp and cmp.visible() then
		cmp.select_next_item()
	elseif luasnip and luasnip.expand_or_jumpable() then
		return t("<Plug>luasnip-expand-or-jump")
	elseif check_back_space() then
		return t("<Tab>")
	else
		cmp.complete()
	end
	return ""
end
_G.s_tab_complete = function()
	if cmp and cmp.visible() then
		cmp.select_prev_item()
	elseif luasnip and luasnip.jumpable(-1) then
		return t("<Plug>luasnip-jump-prev")
	else
		return t("<S-Tab>")
	end
	return ""
end

vim.api.nvim_set_keymap("i", "<Tab>", "v:lua.tab_complete()", { expr = true })
vim.api.nvim_set_keymap("s", "<Tab>", "v:lua.tab_complete()", { expr = true })

vim.api.nvim_set_keymap("i", "<S-Tab>", "v:lua.s_tab_complete()", { expr = true })
vim.api.nvim_set_keymap("s", "<S-Tab>", "v:lua.s_tab_complete()", { expr = true })

vim.api.nvim_set_keymap("i", "<C-E>", "<Plug>luasnip-next-choice", {})
vim.api.nvim_set_keymap("s", "<C-E>", "<Plug>luasnip-next-choice", {})

ls.setup({})