package blob

import (
	"encoding/json"
	"testing"
)

func TestParseDigest(t *testing.T) {
	cases := []struct {
		in    string
		valid bool
	}{
		{"sha256-0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef", true},
		{"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef", true},

		// too short
		{"sha256-0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcde", false},
		{"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcde", false},

		// too long
		{"sha256-0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0", false},
		{"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0", false},

		// invalid prefix
		{"sha255-0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef", false},
		{"sha255:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef", false},
		{"sha256!0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef", false},

		// invalid hex
		{"sha256-XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX", false},
		{"sha256:XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX", false},
	}

	for _, tt := range cases {
		got, err := ParseDigest(tt.in)
		if tt.valid && err != nil {
			t.Errorf("ParseDigest(%q) = %v, %v; want valid", tt.in, got, err)
		}
		want := "sha256:" + tt.in[7:]
		if tt.valid && got.String() != want {
			t.Errorf("ParseDigest(%q).String() = %q, want %q", tt.in, got.String(), want)
		}
	}
}

func TestDigestMarshalText(t *testing.T) {
	const s = `"sha256-0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"`
	var d Digest
	if err := json.Unmarshal([]byte(s), &d); err != nil {
		t.Errorf("json.Unmarshal: %v", err)
	}
	out, err := json.Marshal(d)
	if err != nil {
		t.Errorf("json.Marshal: %v", err)
	}
	want := `"sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"`
	if string(out) != want {
		t.Errorf("json.Marshal: got %s, want %s", out, want)
	}
	if err := json.Unmarshal([]byte(`"invalid"`), &Digest{}); err == nil {
		t.Errorf("json.Unmarshal: expected error")
	}
}