/*
 * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */
package org.opendaylight.protocol.pcep.parser.object;

import static com.google.common.base.Preconditions.checkArgument;
import static org.opendaylight.protocol.util.ByteBufWriteUtil.writeFloat32;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import org.opendaylight.protocol.pcep.spi.CommonObjectParser;
import org.opendaylight.protocol.pcep.spi.ObjectSerializer;
import org.opendaylight.protocol.pcep.spi.ObjectUtil;
import org.opendaylight.protocol.pcep.spi.PCEPDeserializerException;
import org.opendaylight.protocol.util.BitArray;
import org.opendaylight.protocol.util.ByteArray;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.ieee754.rev130819.Float32;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.Object;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.ObjectHeader;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.metric.object.Metric;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.pcep.types.rev181109.metric.object.MetricBuilder;
import org.opendaylight.yangtools.yang.common.netty.ByteBufUtils;

/**
 * Parser for {@link Metric}.
 */
public final class PCEPMetricObjectParser extends CommonObjectParser implements ObjectSerializer {
    private static final int CLASS = 6;
    private static final int TYPE = 1;

    /*
     * lengths of fields in bytes
     */
    private static final int FLAGS_SIZE = 8;
    private static final int METRIC_VALUE_F_LENGTH = 4;
    /*
     * offsets of fields in bytes
     */
    private static final int RESERVED = 2;
    /*
     * flags offsets inside flags field in bits
     */
    private static final int C_FLAG_OFFSET = 6;
    private static final int B_FLAG_OFFSET = 7;

    private static final int SIZE = METRIC_VALUE_F_LENGTH + METRIC_VALUE_F_LENGTH;

    public PCEPMetricObjectParser() {
        super(CLASS, TYPE);
    }

    @Override
    public Metric parseObject(final ObjectHeader header, final ByteBuf bytes) throws PCEPDeserializerException {
        checkArgument(bytes != null && bytes.isReadable(), "Array of bytes is mandatory. Cannot be null or empty.");
        if (bytes.readableBytes() != SIZE) {
            throw new PCEPDeserializerException("Wrong length of array of bytes. Passed: " + bytes.readableBytes()
                + "; Expected: " + SIZE + ".");
        }
        bytes.skipBytes(RESERVED);
        final BitArray flags = BitArray.valueOf(bytes.readByte());
        return new MetricBuilder()
                .setIgnore(header.getIgnore())
                .setProcessingRule(header.getProcessingRule())
                .setBound(flags.get(B_FLAG_OFFSET))
                .setComputed(flags.get(C_FLAG_OFFSET))
                .setMetricType(ByteBufUtils.readUint8(bytes))
                .setValue(new Float32(ByteArray.readBytes(bytes, METRIC_VALUE_F_LENGTH)))
                .build();
    }

    @Override
    public void serializeObject(final Object object, final ByteBuf buffer) {
        checkArgument(object instanceof Metric, "Wrong instance of PCEPObject. Passed %s. Needed MetricObject.",
            object.getClass());
        final Metric mObj = (Metric) object;
        final ByteBuf body = Unpooled.buffer(SIZE);
        body.writeZero(RESERVED);
        final BitArray flags = new BitArray(FLAGS_SIZE);
        flags.set(C_FLAG_OFFSET, mObj.getComputed());
        flags.set(B_FLAG_OFFSET, mObj.getBound());
        flags.toByteBuf(body);
        ByteBufUtils.writeMandatory(body, mObj.getMetricType(), "MetricType");
        writeFloat32(mObj.getValue(), body);
        ObjectUtil.formatSubobject(TYPE, CLASS, object.getProcessingRule(), object.getIgnore(), body, buffer);
    }
}