package checker

import "strings"

// ProbeMode selects how strictly we validate after MTProxy init.
type ProbeMode int

const (
	// ProbeFast: handshake + init, then short wait like Telethon TcpMTProxy (#1134): OK if proxy does not close immediately.
	ProbeFast ProbeMode = iota
	// ProbeDeep: MTProto req_pq then any valid unencrypted MTProto reply from DC (tunnel carries DC traffic; not only resPQ).
	ProbeDeep
	// ProbeDeepStrict: req_pq and response must be resPQ#05162463 (legacy strict check).
	ProbeDeepStrict
)

// Options configures Check. Nil or zero value uses ProbeFast.
type Options struct {
	Probe ProbeMode
}

// ParseProbe maps env/flag strings: "", "fast" -> ProbeFast; "deep" -> ProbeDeep; "deep-strict" -> ProbeDeepStrict.
func ParseProbe(s string) ProbeMode {
	switch strings.ToLower(strings.TrimSpace(s)) {
	case "deep-strict", "strict-deep", "respq-strict":
		return ProbeDeepStrict
	case "deep", "respq", "dc":
		return ProbeDeep
	default:
		return ProbeFast
	}
}

func effectiveOpts(opts *Options) *Options {
	if opts == nil {
		return &Options{Probe: ProbeFast}
	}
	return opts
}