package auth

import (
	"testing"
	"time"
)

func testKey() [32]byte {
	var k [32]byte
	copy(k[:], "test-key-32-bytes-exactly-padded")
	return k
}

func TestSessionRoundTrip(t *testing.T) {
	key := testKey()
	sess := Session{
		Subject:  "jeanmi@example.com",
		Groups:   []string{"hsa-users", "admins"},
		IssuedAt: time.Now().UTC().Truncate(time.Second),
	}

	encoded, err := EncodeSession(sess, key)
	if err != nil {
		t.Fatalf("encode: %v", err)
	}

	got, err := DecodeSession(encoded, key)
	if err != nil {
		t.Fatalf("decode: %v", err)
	}

	if got.Subject != sess.Subject {
		t.Errorf("subject: got %q want %q", got.Subject, sess.Subject)
	}
	if len(got.Groups) != len(sess.Groups) || got.Groups[0] != sess.Groups[0] {
		t.Errorf("groups: got %v want %v", got.Groups, sess.Groups)
	}
	if !got.IssuedAt.Equal(sess.IssuedAt) {
		t.Errorf("issuedAt: got %v want %v", got.IssuedAt, sess.IssuedAt)
	}
}

func TestSessionTamperedRejected(t *testing.T) {
	key := testKey()
	sess := Session{Subject: "someone", Groups: []string{"hsa-users"}, IssuedAt: time.Now()}

	encoded, err := EncodeSession(sess, key)
	if err != nil {
		t.Fatal(err)
	}

	// Flip a byte near the end of the ciphertext.
	b := []byte(encoded)
	b[len(b)-4] ^= 0xFF
	tampered := string(b)

	if _, err := DecodeSession(tampered, key); err == nil {
		t.Error("expected error for tampered cookie, got nil")
	}
}

func TestSessionWrongKeyRejected(t *testing.T) {
	key := testKey()
	sess := Session{Subject: "someone", Groups: []string{"hsa-users"}, IssuedAt: time.Now()}

	encoded, err := EncodeSession(sess, key)
	if err != nil {
		t.Fatal(err)
	}

	var otherKey [32]byte
	copy(otherKey[:], "different-key-32-bytes-padded!!!")

	if _, err := DecodeSession(encoded, otherKey); err == nil {
		t.Error("expected error for wrong key, got nil")
	}
}