package derive_test

import (
	"bytes"
	"strings"
	"testing"

	"git.eeqj.de/sneak/keyfunc/internal/derive"
	"github.com/stretchr/testify/require"
)

// application is the number the SSH key type uses.
const application = 838372

// example returns the mnemonic every BIP-39 document uses to show its
// test vectors: eleven abandons and about.
func example() string {
	return strings.Repeat("abandon ", 11) + "about"
}

func TestPathIsTheOneTheSpecificationGives(t *testing.T) {
	t.Parallel()

	require.Equal(t, "m/83696968'/838372'/3'", derive.Path(application, 3))
}

func TestEveryIndexGivesItsOwnBytes(t *testing.T) {
	t.Parallel()

	first, err := derive.Bytes(example(), application, 0)
	require.NoError(t, err)
	require.Len(t, first, derive.Size)

	second, err := derive.Bytes(example(), application, 1)
	require.NoError(t, err)
	require.Len(t, second, derive.Size)

	require.False(t, bytes.Equal(first, second))
}

func TestAnIndexWithNoHardenedChildIsRefused(t *testing.T) {
	t.Parallel()

	_, err := derive.Bytes(example(), application, derive.MaxIndex+1)
	require.ErrorIs(t, err, derive.ErrIndexTooLarge)

	_, err = derive.Bytes(example(), application, derive.MaxIndex)
	require.NoError(t, err)
}

func TestTheSameInputAlwaysGivesTheSameBytes(t *testing.T) {
	t.Parallel()

	once, err := derive.Bytes(example(), application, 7)
	require.NoError(t, err)

	again, err := derive.Bytes(example(), application, 7)
	require.NoError(t, err)

	require.Equal(t, once, again)
}