package udp

import "testing"

// A Decode does not carry the mode's NAME. It carries the one-character marker
// from the decode line — "~" for FT8, "+" for FT4 — and that character used to
// be passed on as if it were a mode. Everything downstream compared it against
// the modes in the log, matched nothing, and reported every station on an
// already-worked band as a NEW MODE.
func TestDecodeModeNameResolvesTheMarker(t *testing.T) {
	for raw, want := range map[string]string{
		"~": "FT8",
		"+": "FT4",
		"#": "JT65",
		"@": "JT9",
	} {
		if got := DecodeModeName(raw, "FT8"); got != want {
			t.Errorf("DecodeModeName(%q) = %q, want %q", raw, got, want)
		}
	}
}

// A sender that puts the real name in the field is believed as-is — several do,
// and the marker table must not get in their way.
func TestDecodeModeNameKeepsARealName(t *testing.T) {
	for _, raw := range []string{"FT8", "ft4", "JS8", "Q65"} {
		if got := DecodeModeName(raw, ""); got == "" || got != upper(raw) {
			t.Errorf("DecodeModeName(%q) = %q, want the name itself", raw, got)
		}
	}
}

// The safety net: an unknown marker falls back to the mode from the sender's
// last Status, which always carries the real name. This is what keeps a future
// or unlisted marker degrading to correct rather than to nonsense.
func TestDecodeModeNameFallsBackToStatus(t *testing.T) {
	if got := DecodeModeName("%", "FT4"); got != "FT4" {
		t.Errorf("unknown marker resolved to %q, want the Status mode FT4", got)
	}
	if got := DecodeModeName("", "FT8"); got != "FT8" {
		t.Errorf("empty mode resolved to %q, want the Status mode FT8", got)
	}
	// Nothing known at all is empty rather than a guess: an empty mode makes the
	// status resolver answer "worked", which is the safe side — a wrong mode
	// would invent a new-mode flag exactly as the marker did.
	if got := DecodeModeName("%", ""); got != "" {
		t.Errorf("with no Status mode the result was %q, want empty", got)
	}
}

func upper(s string) string {
	out := []rune(s)
	for i, r := range out {
		if r >= 'a' && r <= 'z' {
			out[i] = r - 32
		}
	}
	return string(out)
}