/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.onosproject.xran.codecs.ber.types;

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonValue;
import org.onosproject.xran.codecs.ber.BerByteArrayOutputStream;
import org.onosproject.xran.codecs.ber.BerLength;
import org.onosproject.xran.codecs.ber.BerTag;
import org.onosproject.xran.codecs.ber.internal.Util;

import java.io.IOException;
import java.io.InputStream;
import java.io.Serializable;
import java.math.BigInteger;

public class BerInteger implements Serializable {

    public final static BerTag tag = new BerTag(BerTag.UNIVERSAL_CLASS, BerTag.PRIMITIVE, BerTag.INTEGER_TAG);
    private static final long serialVersionUID = 1L;
    @JsonIgnore
    public byte[] code = null;

    public BigInteger value;

    public BerInteger() {
    }

    public BerInteger(byte[] code) {
        this.code = code;
    }

    public BerInteger(BigInteger val) {
        this.value = val;
    }

    public BerInteger(long val) {
        this.value = BigInteger.valueOf(val);
    }

    public int encode(BerByteArrayOutputStream os) throws IOException {
        return encode(os, true);
    }

    public int encode(BerByteArrayOutputStream os, boolean withTag) throws IOException {

        if (code != null) {
            for (int i = code.length - 1; i >= 0; i--) {
                os.write(code[i]);
            }
            if (withTag) {
                return tag.encode(os) + code.length;
            }
            return code.length;
        }

        byte[] encoded = value.toByteArray();
        int codeLength = encoded.length;
        os.write(encoded);

        codeLength += BerLength.encodeLength(os, codeLength);

        if (withTag) {
            codeLength += tag.encode(os);
        }

        return codeLength;
    }

    public int decode(InputStream is) throws IOException {
        return decode(is, true);
    }

    public int decode(InputStream is, boolean withTag) throws IOException {

        int codeLength = 0;

        if (withTag) {
            codeLength += tag.decodeAndCheck(is);
        }

        BerLength length = new BerLength();
        codeLength += length.decode(is);

        if (length.val < 1) {
            throw new IOException("Decoded length of BerInteger is not correct");
        }

        byte[] byteCode = new byte[length.val];
        Util.readFully(is, byteCode);

        codeLength += length.val;

        value = new BigInteger(byteCode);

        return codeLength;
    }

    public void encodeAndSave(int encodingSizeGuess) throws IOException {
        BerByteArrayOutputStream os = new BerByteArrayOutputStream(encodingSizeGuess);
        encode(os, false);
        code = os.getArray();
    }

    @JsonValue
    @Override
    public String toString() {
        return "" + value;
    }

    public byte byteValue() {
        return value.byteValue();
    }

    public short shortValue() {
        return value.shortValue();
    }

    public int intValue() {
        return value.intValue();
    }

    public long longValue() {
        return value.longValue();
    }

}