/**
 * Copyright (c) 2014 Digi International Inc.,
 * All rights not expressly granted are reserved.
 *
 * 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/.
 *
 * Digi International Inc. 11001 Bren Road East, Minnetonka, MN 55343
 * =======================================================================
 */
package com.digi.xbee.api.packet.raw;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.LinkedHashMap;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.digi.xbee.api.models.XBee16BitAddress;
import com.digi.xbee.api.packet.XBeeAPIPacket;
import com.digi.xbee.api.packet.APIFrameType;
import com.digi.xbee.api.utils.ByteUtils;
import com.digi.xbee.api.utils.HexUtils;

/**
 * This class represents an RX (Receive) 16 Request packet. Packet is built 
 * using the parameters of the constructor or providing a valid API payload.
 * 
 * <p>When the module receives an RF packet, it is sent out the UART using this 
 * message type</p>
 * 
 * <p>This packet is the response to TX (transmit) 16 Request packets.</p>
 * 
 * @see TX16Packet
 * @see com.digi.xbee.api.packet.XBeeAPIPacket
 *
 */
public class RX16Packet extends XBeeAPIPacket {

        // Constants.
        private static final int MIN_API_PAYLOAD_LENGTH = 5; // 1 (Frame type) + 2 (16-bit address) + 1 (signal strength) + 1 (receive options)
        
        // Variables.
        private final XBee16BitAddress sourceAddress16;
        
        private final int rssi;
        private final int receiveOptions;
        
        private byte[] rfData;
        
        private Logger logger;
        
        /**
         * Creates a new {@code RX16Packet} object from the given payload.
         * 
         * @param payload The API frame payload. It must start with the frame type 
         *                corresponding to a RX16 packet ({@code 0x81}).
         *                The byte array must be in {@code OperatingMode.API} mode.
         * 
         * @return Parsed RX 16 packet.
         * 
         * @throws IllegalArgumentException if {@code payload[0] != APIFrameType.RX_16.getValue()} or
         *                                  if {@code payload.length < }{@value #MIN_API_PAYLOAD_LENGTH} or
         *                                  if {@code rssi < 0} or
         *                                  if {@code rssi > 100} or
         *                                  if {@code receiveOptions < 0} or
         *                                  if {@code receiveOptions > 255}.
         * @throws NullPointerException if {@code payload == null}.
         */
        public static RX16Packet createPacket(byte[] payload) {
                if (payload == null)
                        throw new NullPointerException("RX16 packet payload cannot be null.");
                
                // 1 (Frame type) + 2 (16-bit address) + 1 (signal strength) + 1 (receive options)
                if (payload.length < MIN_API_PAYLOAD_LENGTH)
                        throw new IllegalArgumentException("Incomplete RX16 packet.");
                
                if ((payload[0] & 0xFF) != APIFrameType.RX_16.getValue())
                        throw new IllegalArgumentException("Payload is not a RX16 packet.");
                
                // payload[0] is the frame type.
                int index = 1;
                
                // 2 bytes of 16-bit address.
                XBee16BitAddress sourceAddress16 = new XBee16BitAddress(payload[index] & 0xFF, payload[index + 1] & 0xFF);
                index = index + 2;
                
                // Signal strength byte.
                int signalStrength = payload[index] & 0xFF;
                index = index + 1;
                
                // Receive options byte.
                int receiveOptions = payload[index] & 0xFF;
                index = index + 1;
                
                // Get data.
                byte[] data = null;
                if (index < payload.length)
                        data = Arrays.copyOfRange(payload, index, payload.length);
                
                return new RX16Packet(sourceAddress16, signalStrength, receiveOptions, data);
        }
        
        /**
         * Class constructor. Instantiates a new {@code RX16Packet} object with
         * the given parameters.
         * 
         * @param sourceAddress16 16-bit address of the sender.
         * @param rssi Received signal strength indicator.
         * @param receiveOptions Bitfield indicating the receive options.
         * @param rfData Received RF data.
         * 
         * @throws IllegalArgumentException if {@code rssi < 0} or
         *                                  if {@code rssi > 100} or
         *                                  if {@code receiveOptions < 0} or
         *                                  if {@code receiveOptions > 255}.
         * @throws NullPointerException if {@code sourceAddress16 == null}.
         * 
         * @see com.digi.xbee.api.models.XBeeReceiveOptions
         * @see com.digi.xbee.api.models.XBee16BitAddress
         */
        public RX16Packet(XBee16BitAddress sourceAddress16, int rssi, int receiveOptions, byte[] rfData) {
                super(APIFrameType.RX_16);
                
                if (sourceAddress16 == null)
                        throw new NullPointerException("16-bit source address cannot be null.");
                if (rssi < 0 || rssi > 100)
                        throw new IllegalArgumentException("RSSI value must be between 0 and 100.");
                if (receiveOptions < 0 || receiveOptions > 255)
                        throw new IllegalArgumentException("Receive options value must be between 0 and 255.");
                
                this.sourceAddress16 = sourceAddress16;
                this.rssi = rssi;
                this.receiveOptions = receiveOptions;
                this.rfData = rfData;
                this.logger = LoggerFactory.getLogger(RX16Packet.class);
        }
        
        /*
         * (non-Javadoc)
         * @see com.digi.xbee.api.packet.XBeeAPIPacket#getAPIPacketSpecificData()
         */
        @Override
        protected byte[] getAPIPacketSpecificData() {
                ByteArrayOutputStream os = new ByteArrayOutputStream();
                try {
                        os.write(sourceAddress16.getValue());
                        os.write(rssi);
                        os.write(receiveOptions);
                        if (rfData != null)
                                os.write(rfData);
                } catch (IOException e) {
                        logger.error(e.getMessage(), e);
                }
                return os.toByteArray();
        }
        
        /*
         * (non-Javadoc)
         * @see com.digi.xbee.api.packet.XBeeAPIPacket#needsAPIFrameID()
         */
        @Override
        public boolean needsAPIFrameID() {
                return false;
        }
        
        /*
         * (non-Javadoc)
         * @see com.digi.xbee.api.packet.XBeeAPIPacket#isBroadcast()
         */
        @Override
        public boolean isBroadcast() {
                return ByteUtils.isBitEnabled(getReceiveOptions(), 1)
                                || ByteUtils.isBitEnabled(getReceiveOptions(), 2);
        }
        
        /**
         * Returns the 16-bit sender/source address. 
         * 
         * @return The 16-bit sender/source address.
         * 
         * @see com.digi.xbee.api.models.XBee16BitAddress
         */
        public XBee16BitAddress get16bitSourceAddress() {
                return sourceAddress16;
        }
        
        /**
         * Returns the Received Signal Strength Indicator (RSSI).
         * 
         * @return The Received Signal Strength Indicator (RSSI).
         */
        public int getRSSI() {
                return rssi;
        }
        
        /**
         * Returns the receive options bitfield.
         * 
         * @return Receive options bitfield.
         * 
         * @see com.digi.xbee.api.models.XBeeReceiveOptions
         */
        public int getReceiveOptions() {
                return receiveOptions;
        }
        
        /**
         * Sets the received RF data.
         * 
         * @param rfData Received RF data.
         */
        public void setRFData(byte[] rfData) {
                this.rfData = rfData;
        }
        
        /**
         * Returns the received RF data.
         * 
         * @return Received RF data.
         */
        public byte[] getRFData() {
                return rfData;
        }
        
        /*
         * (non-Javadoc)
         * @see com.digi.xbee.api.packet.XBeeAPIPacket#getAPIPacketParameters()
         */
        @Override
        public LinkedHashMap<String, String> getAPIPacketParameters() {
                LinkedHashMap<String, String> parameters = new LinkedHashMap<String, String>();
                parameters.put("16-bit source address", HexUtils.prettyHexString(sourceAddress16.toString()));
                parameters.put("RSSI", HexUtils.prettyHexString(HexUtils.integerToHexString(rssi, 1)));
                parameters.put("Options", HexUtils.prettyHexString(HexUtils.integerToHexString(receiveOptions, 1)));
                if (rfData != null)
                        parameters.put("RF data", HexUtils.prettyHexString(HexUtils.byteArrayToHexString(rfData)));
                return parameters;
        }
}