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 luasnip = require 'luasnip'
local cmp = require 'cmp'
local lspkind = require 'lspkind'

-- Set completeopt to have a better completion experience
vim.o.completeopt = 'menuone,longest,preview'

cmp.setup({
    experimental = {
        ghost_text = true,
    },
    formatting = {
        format = lspkind.cmp_format {
            mode = 'symbol',
            menu = {
                nvim_lsp = '[LSP]',
                nvim_lua = '[Lua]',
                buffer = '[BUF]',
            },
        },
    },
    snippet = {
        expand = function(args)
            require('luasnip').lsp_expand(args.body)
        end,
    },
    mapping = {
        ['<C-p>'] = cmp.mapping.select_prev_item(),
        ['<C-n>'] = cmp.mapping.select_next_item(),
        ['<C-d>'] = cmp.mapping.scroll_docs(-4),
        ['<C-r>'] = cmp.mapping.scroll_docs(4),
        ['<C-Space>'] = cmp.mapping.complete(),
        ['<C-e>'] = cmp.mapping.close(),
        ['<CR>'] = cmp.mapping.confirm {
            behavior = cmp.ConfirmBehavior.replace,
            select = false,
        },
        ['<Tab>'] = cmp.mapping(function(fallback)
            if luasnip.expand_or_jumpable() then
                luasnip.expand_or_jump()
            elseif cmp.visible() then
                cmp.select_next_item()
            elseif has_words_before() then
                cmp.complete()
            else
                fallback()
            end
        end, { 'i', 's' }),
        ['<S-Tab>'] = cmp.mapping(function(fallback)
            if luasnip.jumpable(-1) then
                luasnip.jump(-1)
            elseif cmp.visible() then
                cmp.select_prev_item()
            else
                fallback()
            end

        end, { 'i', 's' }),
    },
    sources = {
        { name = 'nvim_lsp' },
        { name = 'nvim_lsp_signature_help' },
        { name = 'nvim_lua' },
        { name = 'luasnip' },
        { name = 'path' },
        { name = 'buffer' },
    },
})