/*
 * Copyright (C) 2017 Schürmann & Breitmoser GbR
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.sufficientlysecure.keychain.securitytoken.usb.tpdu;


import org.sufficientlysecure.keychain.securitytoken.usb.UsbTransportException;


class T1TpduBlockFactory {
    private BlockChecksumAlgorithm checksumType;

    T1TpduBlockFactory(BlockChecksumAlgorithm checksumType) {
        this.checksumType = checksumType;
    }

    Block fromBytes(byte[] data) throws UsbTransportException {
        byte pcbByte = data[Block.OFFSET_PCB];

        if ((pcbByte & IBlock.MASK_IBLOCK) == IBlock.MASK_VALUE_IBLOCK) {
            return new IBlock(checksumType, data);
        } else if ((pcbByte & SBlock.MASK_SBLOCK) == SBlock.MASK_VALUE_SBLOCK) {
            return new SBlock(checksumType, data);
        } else if ((pcbByte & RBlock.MASK_RBLOCK) == RBlock.MASK_VALUE_RBLOCK) {
            return new RBlock(checksumType, data);
        }

        throw new UsbTransportException("TPDU Unknown block type");
    }

    IBlock newIBlock(byte sequence, boolean chaining, byte[] apdu, int offset, int length)
            throws UsbTransportException {
        return new IBlock(checksumType, (byte) 0, sequence, chaining, apdu, offset, length);
    }

    RBlock createAckRBlock(byte receivedSeqNum) throws UsbTransportException {
        return new RBlock(checksumType, (byte) 0, (byte) (receivedSeqNum + 1));
    }
}