package sega.a7;

import javacard.framework.JCSystem;
import javacard.framework.Util;
import javacard.security.MessageDigest;

public class Command {
    protected short m_ee_cmd;
    protected short m_ee_recvPacketSize;
    protected short m_ee_sendPacketSize;
    protected short[] m_ramD_setSendPacketSize;
    protected short m_ee_tag;
    protected MakePacket m_ee_packet;
    protected AppData m_ee_data;
    protected MessageDigest m_ee_sha1;

    private static final short ERROR_PACKET_SIZE = 26;
    protected static final short SET_SEND_PACKET_SIZE_ARRAY_SIZE = 1;

    protected byte[] m_ramD_outData;
    protected short[] m_ramD_outDataInfo;

    public Command(short cmd, short recvPacketSize, short sendPacketSize, AppData data, MakePacket packet,
            MessageDigest sha1) {
        this.m_ee_cmd = (short) cmd;
        this.m_ee_data = data;
        this.m_ee_packet = packet;
        this.m_ee_recvPacketSize = (short) recvPacketSize;
        this.m_ee_sendPacketSize = (short) sendPacketSize;
        this.m_ee_tag = AppConfig.A7_TAG_RQU_COMMAND;
        this.m_ee_sha1 = sha1;
        this.m_ramD_setSendPacketSize = JCSystem.makeTransientShortArray((short) 1, (byte) 1);
        this.m_ramD_setSendPacketSize[0] = this.m_ee_sendPacketSize;
        this.m_ramD_outData = data.getSendOutBuffer_ramD();
        this.m_ramD_outDataInfo = data.getSendOutInfo_ramD();
    }

    public boolean select() {
        this.m_ramD_setSendPacketSize[0] = this.m_ee_sendPacketSize;
        return true;
    }

    public short core(byte[] data, short dataOffset, short dataLength) {
        return AppConfig.A7_SUCCESS;
    }

    public short execute(byte[] data, short dataOffset, short dataLength, byte[] dst, short dstOffset,
            short dstLength) {
        short ramD_error = checkHeader(data, dataOffset, dataLength);
        if (ramD_error != AppConfig.A7_SUCCESS)
            return makeErrorPacket(ramD_error, dst, dstOffset, dstLength);

        ramD_error = checkFooter(data, dataOffset, dataLength);
        if (ramD_error != AppConfig.A7_SUCCESS)
            return makeErrorPacket(ramD_error, dst, dstOffset, dstLength);

        this.m_ramD_outDataInfo[0] = 0;
        this.m_ramD_outDataInfo[1] = 0;
        ramD_error = core(data, dataOffset, dataLength);

        if (ramD_error != AppConfig.A7_SUCCESS)
            return makeErrorPacket(ramD_error, dst, dstOffset, dstLength);

        return makeSendPacket(AppConfig.A7_TAG_RSP_COMMAND, this.m_ramD_setSendPacketSize[0], ramD_error,
                this.m_ramD_outData, this.m_ramD_outDataInfo[0], this.m_ramD_outDataInfo[1],
                dst, dstOffset, dstLength);
    }

    public short getCmd_ee() {
        return this.m_ee_cmd;
    }

    protected short setSendPacketSize_ramD(short sendSize) {
        this.m_ramD_setSendPacketSize[0] = sendSize;
        return this.m_ramD_setSendPacketSize[0];
    }

    /**
     * Validate packet header.
     * The header is 6 bytes.
     * 2 bytes: tag
     * 2 bytes: paramsize
     * 2 bytes: command
     */
    protected short checkHeader(byte[] data, short dataOfset, short dataLength) {
        short ramD_paramsize = Util.getShort(data, (short) (dataOfset + AppConfig.A7_PARAMSIZE_OFFSET));
        if (dataLength != ramD_paramsize)
            return AppConfig.A7_BAD_DATASIZE;

        short ramD_tag = Util.getShort(data, (short) (dataOfset + AppConfig.A7_TAG_OFFSET));

        if (ramD_tag != this.m_ee_tag)
            return AppConfig.A7_BAD_TAG;
        if (this.m_ee_recvPacketSize != 0 && dataLength != this.m_ee_recvPacketSize)
            return AppConfig.A7_BAD_DATASIZE;
        return AppConfig.A7_SUCCESS;
    }

    /**
     * Validate an unauthenticated packet footer.
     * The footer is a 20 byte SHA1 sum of the packet.
     */
    protected short checkFooter(byte[] data, short dataOffset, short dataLength) {
        short ramD_paramsize = (short) (dataOffset + dataLength - AppConfig.A7_CHECKSUM_SIZE);
        byte[] ramD_buffer = this.m_ee_data.getFooterBuffer_ramD();
        this.m_ee_sha1.reset();
        this.m_ee_sha1.doFinal(data, dataOffset, (short) (dataLength - AppConfig.A7_CHECKSUM_SIZE), ramD_buffer,
                (short) 0);
        if (Util.arrayCompare(data, ramD_paramsize, ramD_buffer, (short) 0, (short) AppConfig.A7_CHECKSUM_SIZE) != 0)
            return AppConfig.A7_SUMFAIL;
        return AppConfig.A7_SUCCESS;
    }

    protected short makeSendPacket(short tag, short paramSize, short result,
            byte[] data, short dataOffset, short dataSize, byte[] sendPacket, short packetOffset,
            short packetLength) {
        if (!this.m_ee_packet.setData(null, (short) 0, (short) 0, tag, paramSize, result, this.m_ee_cmd, data,
                dataOffset,
                dataSize, null, (short) 0, (short) 0, null, (short) 0, (short) 0, sendPacket, packetOffset,
                packetLength,
                this.m_ee_sha1, null)) {
            return makeErrorPacket(AppConfig.A7_FAIL, sendPacket, packetOffset, packetLength);
        }
        return paramSize;
    }

    protected short makeErrorPacket(short error, byte[] sendPacket, short packetOffset, short packetLength) {
        this.m_ee_data.setLastError_ramD(error);
        this.m_ee_packet.setData(null, (short) 0, (short) 0, AppConfig.A7_TAG_RSP_COMMAND, ERROR_PACKET_SIZE,
                error, this.m_ee_cmd, null, (short) 0, (short) 0, null, (short) 0, (short) 0,
                null, (short) 0, (short) 0, sendPacket, packetOffset, packetLength,
                this.m_ee_sha1, null);
        return ERROR_PACKET_SIZE;
    }
}