package preset

import "testing"

func TestParsePrefix(t *testing.T) {
	ok := []struct {
		in   string
		want int
	}{
		{"24", 24},
		{"/24", 24},
		{" /24 ", 24},
		{"255.255.255.0", 24},
		{"255.255.255.255", 32},
		{"0.0.0.0", 0},
		{"255.255.254.0", 23},
		{"128.0.0.0", 1},
		{"32", 32},
		{"0", 0},
	}
	for _, tc := range ok {
		got, err := ParsePrefix(tc.in)
		if err != nil {
			t.Errorf("ParsePrefix(%q) returned error: %v", tc.in, err)
			continue
		}
		if got != tc.want {
			t.Errorf("ParsePrefix(%q) = %d, want %d", tc.in, got, tc.want)
		}
	}

	bad := []string{"", "33", "-1", "255.255.0.255", "1.2.3", "abc", "255.0.255.0", "/", "24.5"}
	for _, in := range bad {
		if got, err := ParsePrefix(in); err == nil {
			t.Errorf("ParsePrefix(%q) = %d, want error", in, got)
		}
	}
}

func TestMaskStringRoundTrip(t *testing.T) {
	for p := 0; p <= 32; p++ {
		got, err := ParsePrefix(MaskString(p))
		if err != nil {
			t.Fatalf("ParsePrefix(MaskString(%d)) errored: %v", p, err)
		}
		if got != p {
			t.Errorf("round trip of /%d gave /%d (mask %s)", p, got, MaskString(p))
		}
	}
}

func TestMaskStringKnown(t *testing.T) {
	cases := map[int]string{
		0:  "0.0.0.0",
		8:  "255.0.0.0",
		16: "255.255.0.0",
		24: "255.255.255.0",
		30: "255.255.255.252",
		32: "255.255.255.255",
	}
	for prefix, want := range cases {
		if got := MaskString(prefix); got != want {
			t.Errorf("MaskString(%d) = %s, want %s", prefix, got, want)
		}
	}
}