local fn = vim.fn
local install_path = fn.stdpath('data')..'/site/pack/packer/start/packer.nvim'
if fn.empty(fn.glob(install_path)) > 0 then
    packer_bootstrap = fn.system({'git', 'clone', '--depth', '1', 'https://github.com/wbthomason/packer.nvim', install_path})
    vim.cmd [[packadd packer.nvim]]
end

packer = require('packer')
packer.init()

packer.use 'https://github.com/wbthomason/packer.nvim'

-- common dependencies which require setup
packer.use {
    'https://github.com/nvim-treesitter/nvim-treesitter',
    run = function()
        require('nvim-treesitter.install').update({ with_sync = true })
    end
}

-- source file, install new plugins and compile when config file is written
vim.api.nvim_create_augroup('packer_user_config', { clear = true })
vim.api.nvim_create_autocmd(
    { 'User' },
    {
        group = 'packer_user_config',
        pattern = 'PackerComplete',
        command = 'PackerCompile'
    }
)
vim.api.nvim_create_autocmd(
    { 'BufWritePost' },
    {
        group = 'packer_user_config',
        pattern = { '*/nvim/lua/*.lua', '*/nvim/init.lua' },
        callback = function()
            -- exclude plugins.lua, because that would re-init packer
            if (not vim.api.nvim_buf_get_name(0):match('plugins.lua$')) then
                vim.cmd([[
                    echo 'reloading config file…'
                    source <afile>
                    PackerInstall
                    redraw
                ]])
            end
        end
    }
)