/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.cellbroadcastservice;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Objects;

/**
 * SMS user data header, as specified in TS 23.040 9.2.3.24.
 */
public class SmsHeader {

    // TODO(cleanup): this data structure is generally referred to as
    // the 'user data header' or UDH, and so the class name should
    // change to reflect this...

    /**
     * SMS user data header information element identifiers.
     * (see TS 23.040 9.2.3.24)
     */
    public static final int ELT_ID_CONCATENATED_8_BIT_REFERENCE = 0x00;
    public static final int ELT_ID_SPECIAL_SMS_MESSAGE_INDICATION = 0x01;
    public static final int ELT_ID_APPLICATION_PORT_ADDRESSING_8_BIT = 0x04;
    public static final int ELT_ID_APPLICATION_PORT_ADDRESSING_16_BIT = 0x05;
    public static final int ELT_ID_SMSC_CONTROL_PARAMS = 0x06;
    public static final int ELT_ID_UDH_SOURCE_INDICATION = 0x07;
    public static final int ELT_ID_CONCATENATED_16_BIT_REFERENCE = 0x08;
    public static final int ELT_ID_WIRELESS_CTRL_MSG_PROTOCOL = 0x09;
    public static final int ELT_ID_TEXT_FORMATTING = 0x0A;
    public static final int ELT_ID_PREDEFINED_SOUND = 0x0B;
    public static final int ELT_ID_USER_DEFINED_SOUND = 0x0C;
    public static final int ELT_ID_PREDEFINED_ANIMATION = 0x0D;
    public static final int ELT_ID_LARGE_ANIMATION = 0x0E;
    public static final int ELT_ID_SMALL_ANIMATION = 0x0F;
    public static final int ELT_ID_LARGE_PICTURE = 0x10;
    public static final int ELT_ID_SMALL_PICTURE = 0x11;
    public static final int ELT_ID_VARIABLE_PICTURE = 0x12;
    public static final int ELT_ID_USER_PROMPT_INDICATOR = 0x13;
    public static final int ELT_ID_EXTENDED_OBJECT = 0x14;
    public static final int ELT_ID_REUSED_EXTENDED_OBJECT = 0x15;
    public static final int ELT_ID_COMPRESSION_CONTROL = 0x16;
    public static final int ELT_ID_OBJECT_DISTR_INDICATOR = 0x17;
    public static final int ELT_ID_STANDARD_WVG_OBJECT = 0x18;
    public static final int ELT_ID_CHARACTER_SIZE_WVG_OBJECT = 0x19;
    public static final int ELT_ID_EXTENDED_OBJECT_DATA_REQUEST_CMD = 0x1A;
    public static final int ELT_ID_RFC_822_EMAIL_HEADER = 0x20;
    public static final int ELT_ID_HYPERLINK_FORMAT_ELEMENT = 0x21;
    public static final int ELT_ID_REPLY_ADDRESS_ELEMENT = 0x22;
    public static final int ELT_ID_ENHANCED_VOICE_MAIL_INFORMATION = 0x23;
    public static final int ELT_ID_NATIONAL_LANGUAGE_SINGLE_SHIFT = 0x24;
    public static final int ELT_ID_NATIONAL_LANGUAGE_LOCKING_SHIFT = 0x25;

    public static final int PORT_WAP_PUSH = 2948;
    public static final int PORT_WAP_WSP = 9200;

    /** The maximum number of payload bytes per message */
    public static final int MAX_USER_DATA_BYTES = 140;

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        SmsHeader smsHeader = (SmsHeader) o;
        return languageTable == smsHeader.languageTable
                && languageShiftTable == smsHeader.languageShiftTable
                && Objects.equals(portAddrs, smsHeader.portAddrs)
                && Objects.equals(concatRef, smsHeader.concatRef)
                && Objects.equals(specialSmsMsgList, smsHeader.specialSmsMsgList)
                && Objects.equals(miscEltList, smsHeader.miscEltList);
    }

    @Override
    public int hashCode() {
        return Objects.hash(portAddrs, concatRef, specialSmsMsgList, miscEltList, languageTable,
                languageShiftTable);
    }

    /**
     * Port addresses used in creating and parsing SmsHeader.
     */
    public static class PortAddrs {
        public PortAddrs() {
        }

        public int destPort;
        public int origPort;
        public boolean areEightBits;

        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;
            PortAddrs portAddrs = (PortAddrs) o;
            return destPort == portAddrs.destPort
                    && origPort == portAddrs.origPort
                    && areEightBits == portAddrs.areEightBits;
        }

        @Override
        public int hashCode() {
            return Objects.hash(destPort, origPort, areEightBits);
        }
    }

    /**
     * Concatenated reference used in creating and parsing SmsHeader.
     */
    public static class ConcatRef {
        public ConcatRef() {
        }

        public int refNumber;
        public int seqNumber;
        public int msgCount;
        public boolean isEightBits;

        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;
            ConcatRef concatRef = (ConcatRef) o;
            return refNumber == concatRef.refNumber
                    && seqNumber == concatRef.seqNumber
                    && msgCount == concatRef.msgCount
                    && isEightBits == concatRef.isEightBits;
        }

        @Override
        public int hashCode() {
            return Objects.hash(refNumber, seqNumber, msgCount, isEightBits);
        }
    }

    /**
     * Special SMS message indicator, used in creating and parsing SmsHeader.
     */
    public static class SpecialSmsMsg {
        public int msgIndType;
        public int msgCount;

        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;
            SpecialSmsMsg that = (SpecialSmsMsg) o;
            return msgIndType == that.msgIndType
                    && msgCount == that.msgCount;
        }

        @Override
        public int hashCode() {
            return Objects.hash(msgIndType, msgCount);
        }
    }

    /**
     * A header element that is not explicitly parsed, meaning not
     * PortAddrs or ConcatRef or SpecialSmsMsg.
     */
    public static class MiscElt {
        public int id;
        public byte[] data;

        @Override
        public boolean equals(Object o) {
            if (this == o) return true;
            if (o == null || getClass() != o.getClass()) return false;
            MiscElt miscElt = (MiscElt) o;
            return id == miscElt.id
                    && Arrays.equals(data, miscElt.data);
        }

        @Override
        public int hashCode() {
            int result = Objects.hash(id);
            result = 31 * result + Arrays.hashCode(data);
            return result;
        }
    }

    public PortAddrs portAddrs;
    public ConcatRef concatRef;
    public ArrayList<SpecialSmsMsg> specialSmsMsgList = new ArrayList<SpecialSmsMsg>();
    public ArrayList<MiscElt> miscEltList = new ArrayList<MiscElt>();

    /** 7 bit national language locking shift table, or 0 for GSM default 7 bit alphabet. */
    public int languageTable;

    /** 7 bit national language single shift table, or 0 for GSM default 7 bit extension table. */
    public int languageShiftTable;

    public SmsHeader() {
    }

    /**
     * Create structured SmsHeader object from serialized byte array representation.
     * (see TS 23.040 9.2.3.24)
     *
     * @param data is user data header bytes
     * @return SmsHeader object
     */
    public static SmsHeader fromByteArray(byte[] data) {
        ByteArrayInputStream inStream = new ByteArrayInputStream(data);
        SmsHeader smsHeader = new SmsHeader();
        while (inStream.available() > 0) {
            /**
             * NOTE: as defined in the spec, ConcatRef and PortAddr
             * fields should not reoccur, but if they do the last
             * occurrence is to be used.  Also, for ConcatRef
             * elements, if the count is zero, sequence is zero, or
             * sequence is larger than count, the entire element is to
             * be ignored.
             */
            int id = inStream.read();
            int length = inStream.read();
            ConcatRef concatRef;
            PortAddrs portAddrs;
            switch (id) {
                case ELT_ID_CONCATENATED_8_BIT_REFERENCE:
                    concatRef = new ConcatRef();
                    concatRef.refNumber = inStream.read();
                    concatRef.msgCount = inStream.read();
                    concatRef.seqNumber = inStream.read();
                    concatRef.isEightBits = true;
                    if (concatRef.msgCount != 0 && concatRef.seqNumber != 0
                            && concatRef.seqNumber <= concatRef.msgCount) {
                        smsHeader.concatRef = concatRef;
                    }
                    break;
                case ELT_ID_CONCATENATED_16_BIT_REFERENCE:
                    concatRef = new ConcatRef();
                    concatRef.refNumber = (inStream.read() << 8) | inStream.read();
                    concatRef.msgCount = inStream.read();
                    concatRef.seqNumber = inStream.read();
                    concatRef.isEightBits = false;
                    if (concatRef.msgCount != 0 && concatRef.seqNumber != 0
                            && concatRef.seqNumber <= concatRef.msgCount) {
                        smsHeader.concatRef = concatRef;
                    }
                    break;
                case ELT_ID_APPLICATION_PORT_ADDRESSING_8_BIT:
                    portAddrs = new PortAddrs();
                    portAddrs.destPort = inStream.read();
                    portAddrs.origPort = inStream.read();
                    portAddrs.areEightBits = true;
                    smsHeader.portAddrs = portAddrs;
                    break;
                case ELT_ID_APPLICATION_PORT_ADDRESSING_16_BIT:
                    portAddrs = new PortAddrs();
                    portAddrs.destPort = (inStream.read() << 8) | inStream.read();
                    portAddrs.origPort = (inStream.read() << 8) | inStream.read();
                    portAddrs.areEightBits = false;
                    smsHeader.portAddrs = portAddrs;
                    break;
                case ELT_ID_NATIONAL_LANGUAGE_SINGLE_SHIFT:
                    smsHeader.languageShiftTable = inStream.read();
                    break;
                case ELT_ID_NATIONAL_LANGUAGE_LOCKING_SHIFT:
                    smsHeader.languageTable = inStream.read();
                    break;
                case ELT_ID_SPECIAL_SMS_MESSAGE_INDICATION:
                    SpecialSmsMsg specialSmsMsg = new SpecialSmsMsg();
                    specialSmsMsg.msgIndType = inStream.read();
                    specialSmsMsg.msgCount = inStream.read();
                    smsHeader.specialSmsMsgList.add(specialSmsMsg);
                    break;
                default:
                    MiscElt miscElt = new MiscElt();
                    miscElt.id = id;
                    miscElt.data = new byte[length];
                    inStream.read(miscElt.data, 0, length);
                    smsHeader.miscEltList.add(miscElt);
            }
        }
        return smsHeader;
    }

    /**
     * Create serialized byte array representation from structured SmsHeader object.
     * (see TS 23.040 9.2.3.24)
     *
     * @return Byte array representing the SmsHeader
     */
    public static byte[] toByteArray(SmsHeader smsHeader) {
        if ((smsHeader.portAddrs == null) && (smsHeader.concatRef == null)
                && (smsHeader.specialSmsMsgList.isEmpty()) && (smsHeader.miscEltList.isEmpty()) && (
                smsHeader.languageShiftTable == 0) && (smsHeader.languageTable == 0)) {
            return null;
        }

        ByteArrayOutputStream outStream =
                new ByteArrayOutputStream(MAX_USER_DATA_BYTES);
        ConcatRef concatRef = smsHeader.concatRef;
        if (concatRef != null) {
            if (concatRef.isEightBits) {
                outStream.write(ELT_ID_CONCATENATED_8_BIT_REFERENCE);
                outStream.write(3);
                outStream.write(concatRef.refNumber);
            } else {
                outStream.write(ELT_ID_CONCATENATED_16_BIT_REFERENCE);
                outStream.write(4);
                outStream.write(concatRef.refNumber >>> 8);
                outStream.write(concatRef.refNumber & 0x00FF);
            }
            outStream.write(concatRef.msgCount);
            outStream.write(concatRef.seqNumber);
        }
        PortAddrs portAddrs = smsHeader.portAddrs;
        if (portAddrs != null) {
            if (portAddrs.areEightBits) {
                outStream.write(ELT_ID_APPLICATION_PORT_ADDRESSING_8_BIT);
                outStream.write(2);
                outStream.write(portAddrs.destPort);
                outStream.write(portAddrs.origPort);
            } else {
                outStream.write(ELT_ID_APPLICATION_PORT_ADDRESSING_16_BIT);
                outStream.write(4);
                outStream.write(portAddrs.destPort >>> 8);
                outStream.write(portAddrs.destPort & 0x00FF);
                outStream.write(portAddrs.origPort >>> 8);
                outStream.write(portAddrs.origPort & 0x00FF);
            }
        }
        if (smsHeader.languageShiftTable != 0) {
            outStream.write(ELT_ID_NATIONAL_LANGUAGE_SINGLE_SHIFT);
            outStream.write(1);
            outStream.write(smsHeader.languageShiftTable);
        }
        if (smsHeader.languageTable != 0) {
            outStream.write(ELT_ID_NATIONAL_LANGUAGE_LOCKING_SHIFT);
            outStream.write(1);
            outStream.write(smsHeader.languageTable);
        }
        for (SpecialSmsMsg specialSmsMsg : smsHeader.specialSmsMsgList) {
            outStream.write(ELT_ID_SPECIAL_SMS_MESSAGE_INDICATION);
            outStream.write(2);
            outStream.write(specialSmsMsg.msgIndType & 0xFF);
            outStream.write(specialSmsMsg.msgCount & 0xFF);
        }
        for (MiscElt miscElt : smsHeader.miscEltList) {
            outStream.write(miscElt.id);
            outStream.write(miscElt.data.length);
            outStream.write(miscElt.data, 0, miscElt.data.length);
        }
        return outStream.toByteArray();
    }
}