package payment

import (
	"testing"

	"github.com/stretchr/testify/require"
)

const testEncryptionKey = "12345678901234567890123456789012"

func setTestEncryptionKey(t *testing.T, key string) {
	t.Helper()
	previousKey := encryptionKey
	InitEncryptionKey(key)
	t.Cleanup(func() {
		encryptionKey = previousKey
	})
}

func TestEncryptDecryptRoundTrip(t *testing.T) {
	setTestEncryptionKey(t, testEncryptionKey)

	encrypted, err := Encrypt("hello payment")
	require.NoError(t, err)
	require.NotEmpty(t, encrypted)

	decrypted, err := Decrypt(encrypted)
	require.NoError(t, err)
	require.Equal(t, "hello payment", decrypted)
}

func TestEncryptRejectsInvalidKeyLength(t *testing.T) {
	setTestEncryptionKey(t, "short")

	_, err := Encrypt("hello payment")
	require.Error(t, err)
	require.Contains(t, err.Error(), "invalid encryption key length")
}

func TestDecryptRejectsInvalidBase64(t *testing.T) {
	setTestEncryptionKey(t, testEncryptionKey)

	_, err := Decrypt("not-base64")
	require.Error(t, err)
}

func TestDecryptRejectsTooShortCiphertext(t *testing.T) {
	setTestEncryptionKey(t, testEncryptionKey)

	_, err := Decrypt("c2hvcnQ=")
	require.Error(t, err)
	require.Contains(t, err.Error(), "ciphertext too short")
}

func TestEncryptUsesRandomNonce(t *testing.T) {
	setTestEncryptionKey(t, testEncryptionKey)

	first, err := Encrypt("same plaintext")
	require.NoError(t, err)
	second, err := Encrypt("same plaintext")
	require.NoError(t, err)

	require.NotEqual(t, first, second)
}