package android.util;

import java.nio.charset.StandardCharsets;

/**
 * JVM test implementation of android.util.Base64 using java.util.Base64.
 * Enables running Android SRP cryptographic tests on standard desktop JVM.
 */
public class Base64 {
    public static final int DEFAULT = 0;
    public static final int NO_PADDING = 1;
    public static final int NO_WRAP = 2;
    public static final int CRLF = 4;
    public static final int URL_SAFE = 8;
    public static final int NO_CLOSE = 16;

    public static String encodeToString(byte[] input, int flags) {
        return encodeToString(input, 0, input.length, flags);
    }

    public static String encodeToString(byte[] input, int offset, int len, int flags) {
        byte[] slice;
        if (offset == 0 && len == input.length) {
            slice = input;
        } else {
            slice = new byte[len];
            System.arraycopy(input, offset, slice, 0, len);
        }
        java.util.Base64.Encoder encoder = ((flags & URL_SAFE) != 0)
            ? java.util.Base64.getUrlEncoder()
            : java.util.Base64.getEncoder();
        if ((flags & NO_PADDING) != 0) {
            encoder = encoder.withoutPadding();
        }
        return encoder.encodeToString(slice);
    }

    public static byte[] encode(byte[] input, int flags) {
        return encodeToString(input, flags).getBytes(StandardCharsets.UTF_8);
    }

    public static byte[] decode(String str, int flags) {
        java.util.Base64.Decoder decoder = ((flags & URL_SAFE) != 0)
            ? java.util.Base64.getUrlDecoder()
            : java.util.Base64.getDecoder();
        return decoder.decode(str);
    }

    public static byte[] decode(byte[] input, int flags) {
        return decode(new String(input, StandardCharsets.UTF_8), flags);
    }
}