require('compe').setup {
    enabled = true,
    autocomplete = true,
    debug = false,
    min_length = 1,
    preselect = 'always',
    source = {
        path = true,
        buffer = true,
        calc = false,
        nvim_lsp = true,
        nvim_lua = false,
        vsnip = false,
        luasnip = true,
        utilsnips = false,
        tags = false,
        spell = true
    }
}

-- Use (S-)Tab in completion menu
-- See https://github.com/neovim/nvim-lspconfig/wiki/Snippets
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 vim.fn.pumvisible() == 1 then
        return t '<C-n>'
    elseif require('luasnip').expand_or_jumpable() then
        return t '<Plug>luasnip-expand-or-jump'
    elseif check_back_space() then
        return t '<Tab>'
    else
        return vim.fn['compe#complete']()
    end
end
_G.s_tab_complete = function()
    if vim.fn.pumvisible() == 1 then
        return t '<C-p>'
    elseif require('luasnip').jumpable(-1) then
        return t '<Plug>luasnip-jump-prev'
    else
        return t '<S-Tab>'
    end
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-Space>', 'compe#complete()', {expr = true})
vim.api.nvim_set_keymap('i', '<C-e>', 'compe#close(\'<C-e>\')', {expr = true})