let s:matches = system('systemd --dump-configuration --no-pager | grep -o -P "(^\w+[=])|([\[]\w+[\]])"')
let s:matches = split(s:matches, "\n")
let s:allkeys = system('systemd --dump-configuration --no-pager | grep -o -P "(^[\[]\w+[\]])" | sed -e "s/[]]//g"')
let s:allkeys = split(s:allkeys, "\n")
"let g:AutoPairs = {'(':')', '{':'}',"'":"'",'"':'"', '`':'`'}
"let g:asyncomplete_triggers = {'*': ['.', '>', ':', '['] }

function s:get_key()
	let l:line = search('[\w*\]', "bnW")
	if l:line == 0
		return 0
	endif
	let l:key = getbufline(bufnr("%"), l:line)[0]
	return l:key
endfunction

function s:get_matches()
	let l:key = s:get_key()
	if l:key == 0
		let l:from = index(s:matches, l:key) + 1
		let l:until = match(s:matches, '\[\w\+\]', l:from)
		let l:until = l:until - 1
		return s:matches[l:from:l:until]
	endif
	return s:allkeys
endfunction

function! s:systemd_completor(opt, ctx) abort
    let l:col = a:ctx['col']
    let l:typed = a:ctx['typed']
	if match(l:typed, '[') != -1
		let l:matches = s:allkeys
	else
		let l:matches = s:get_matches()
	endif
	echom l:typed
    let l:kw = matchstr(l:typed, '\v\S+$')
    let l:kwlen = len(l:kw)
    let l:startcol = l:col - l:kwlen
	let l:startcol = 1
    call asyncomplete#complete(a:opt['name'], a:ctx, l:startcol, l:matches)
	echo 'done'
endfunction

au User asyncomplete_setup call asyncomplete#register_source({
    \ 'name': 'systemd',
    \ 'allowlist': ['systemd'],
    \ 'completor': function('s:systemd_completor'),
    \ })