package diary

// helpOnly reports whether args, a binary's command line without the
// program name, only ask for help: before "--" they hold --help or a
// single-dash cluster that reaches h. It is a tolerant pre-scan of the raw
// arguments, made before plugins boot, and reads them the way
// bonfire.PeekGlobals does: it stops at "--", skips the value of --env and
// reads a single-dash cluster letter by letter, stopping at the first
// letter that is not a global shorthand (v, q, n, h). It never fails and
// cannot tell a passthrough command (whose --help reaches its Run) from
// another, so "<passthrough> --help" counts; the root's OnGlobals hook
// (ApplyGlobals) restores the console levels before that command runs.
func helpOnly(args []string) bool {
	for i := 0; i < len(args); i++ {
		a := args[i]
		switch {
		case a == "--":
			return false
		case a == "--env":
			i++
		case a == "--help":
			return true
		case len(a) >= 2 && a[0] == '-' && a[1] != '-':
			if clusterHasHelp(a[1:]) {
				return true
			}
		}
	}
	return false
}

// clusterHasHelp reports whether a shorthand cluster (the letters after the
// dash) reaches h before a letter that is not a global shorthand.
func clusterHasHelp(cluster string) bool {
	for i := 0; i < len(cluster); i++ {
		switch cluster[i] {
		case 'h':
			return true
		case 'v', 'q', 'n':
		default:
			return false
		}
	}
	return false
}

// bootQuiet applies the help-only rule of Bootstrap and Setup: with Args
// set, no -v and arguments that only ask for help, the setup is installed
// with Quiet, which raises only the console channels to warn.
func bootQuiet(opts Options) Options {
	if opts.Args != nil && opts.Verbosity == 0 && helpOnly(opts.Args) {
		opts.Quiet = true
	}
	return opts
}