/*
 * Copyright (C) 2013 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.internal.telephony.cdma;

import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.res.Resources;
import android.os.Message;
import android.os.SystemProperties;
import android.preference.PreferenceManager;
import android.provider.Telephony.Sms.Intents;
import android.telephony.SmsCbMessage;

import com.android.internal.telephony.CellBroadcastHandler;
import com.android.internal.telephony.CommandsInterface;
import com.android.internal.telephony.InboundSmsHandler;
import com.android.internal.telephony.InboundSmsTracker;
import com.android.internal.telephony.PhoneBase;
import com.android.internal.telephony.SmsConstants;
import com.android.internal.telephony.SmsMessageBase;
import com.android.internal.telephony.SmsStorageMonitor;
import com.android.internal.telephony.TelephonyProperties;
import com.android.internal.telephony.WspTypeDecoder;
import com.android.internal.telephony.cdma.sms.SmsEnvelope;

import java.util.Arrays;

/**
 * Subclass of {@link InboundSmsHandler} for 3GPP2 type messages.
 */
public class CdmaInboundSmsHandler extends InboundSmsHandler {

    private final CdmaSMSDispatcher mSmsDispatcher;
    private final CdmaServiceCategoryProgramHandler mServiceCategoryProgramHandler;

    private byte[] mLastDispatchedSmsFingerprint;
    private byte[] mLastAcknowledgedSmsFingerprint;

    private final boolean mCheckForDuplicatePortsInOmadmWapPush = Resources.getSystem().getBoolean(
            com.android.internal.R.bool.config_duplicate_port_omadm_wappush);

    /**
     * Create a new inbound SMS handler for CDMA.
     */
    private CdmaInboundSmsHandler(Context context, SmsStorageMonitor storageMonitor,
            PhoneBase phone, CdmaSMSDispatcher smsDispatcher) {
        super("CdmaInboundSmsHandler", context, storageMonitor, phone,
                CellBroadcastHandler.makeCellBroadcastHandler(context));
        mSmsDispatcher = smsDispatcher;
        mServiceCategoryProgramHandler = CdmaServiceCategoryProgramHandler.makeScpHandler(context,
                phone.mCi);
        phone.mCi.setOnNewCdmaSms(getHandler(), EVENT_NEW_SMS, null);
    }

    /**
     * Unregister for CDMA SMS.
     */
    @Override
    protected void onQuitting() {
        mPhone.mCi.unSetOnNewCdmaSms(getHandler());
        mCellBroadcastHandler.dispose();

        if (DBG) log("unregistered for 3GPP2 SMS");
        super.onQuitting();
    }

    /**
     * Wait for state machine to enter startup state. We can't send any messages until then.
     */
    public static CdmaInboundSmsHandler makeInboundSmsHandler(Context context,
            SmsStorageMonitor storageMonitor, PhoneBase phone, CdmaSMSDispatcher smsDispatcher) {
        CdmaInboundSmsHandler handler = new CdmaInboundSmsHandler(context, storageMonitor,
                phone, smsDispatcher);
        handler.start();
        return handler;
    }

    /**
     * Return whether the device is in Emergency Call Mode (only for 3GPP2).
     * @return true if the device is in ECM; false otherwise
     */
    private static boolean isInEmergencyCallMode() {
        String inEcm = SystemProperties.get(TelephonyProperties.PROPERTY_INECM_MODE, "false");
        return "true".equals(inEcm);
    }

    /**
     * Return true if this handler is for 3GPP2 messages; false for 3GPP format.
     * @return true (3GPP2)
     */
    @Override
    protected boolean is3gpp2() {
        return true;
    }

    /**
     * Process Cell Broadcast, Voicemail Notification, and other 3GPP/3GPP2-specific messages.
     * @param smsb the SmsMessageBase object from the RIL
     * @return true if the message was handled here; false to continue processing
     */
    @Override
    protected int dispatchMessageRadioSpecific(SmsMessageBase smsb) {
        if (isInEmergencyCallMode()) {
            return Activity.RESULT_OK;
        }

        SmsMessage sms = (SmsMessage) smsb;
        boolean isBroadcastType = (SmsEnvelope.MESSAGE_TYPE_BROADCAST == sms.getMessageType());

        // Handle CMAS emergency broadcast messages.
        if (isBroadcastType) {
            log("Broadcast type message");
            SmsCbMessage cbMessage = sms.parseBroadcastSms();
            if (cbMessage != null) {
                mCellBroadcastHandler.dispatchSmsMessage(cbMessage);
            } else {
                loge("error trying to parse broadcast SMS");
            }
            return Intents.RESULT_SMS_HANDLED;
        }

        // Initialize fingerprint field, and see if we have a network duplicate SMS.
        mLastDispatchedSmsFingerprint = sms.getIncomingSmsFingerprint();
        if (mLastAcknowledgedSmsFingerprint != null &&
                Arrays.equals(mLastDispatchedSmsFingerprint, mLastAcknowledgedSmsFingerprint)) {
            return Intents.RESULT_SMS_HANDLED;
        }

        // Decode BD stream and set sms variables.
        sms.parseSms();
        int teleService = sms.getTeleService();

        switch (teleService) {
            case SmsEnvelope.TELESERVICE_VMN:
            case SmsEnvelope.TELESERVICE_MWI:
                // handle voicemail indication
                handleVoicemailTeleservice(sms);
                return Intents.RESULT_SMS_HANDLED;

            case SmsEnvelope.TELESERVICE_WMT:
            case SmsEnvelope.TELESERVICE_WEMT:
                if (sms.isStatusReportMessage()) {
                    mSmsDispatcher.sendStatusReportMessage(sms);
                    return Intents.RESULT_SMS_HANDLED;
                }
                break;

            case SmsEnvelope.TELESERVICE_SCPT:
                mServiceCategoryProgramHandler.dispatchSmsMessage(sms);
                return Intents.RESULT_SMS_HANDLED;

            case SmsEnvelope.TELESERVICE_WAP:
                // handled below, after storage check
                break;

            default:
                loge("unsupported teleservice 0x" + Integer.toHexString(teleService));
                return Intents.RESULT_SMS_UNSUPPORTED;
        }

        if (!mStorageMonitor.isStorageAvailable() &&
                sms.getMessageClass() != SmsConstants.MessageClass.CLASS_0) {
            // It's a storable message and there's no storage available.  Bail.
            // (See C.S0015-B v2.0 for a description of "Immediate Display"
            // messages, which we represent as CLASS_0.)
            return Intents.RESULT_SMS_OUT_OF_MEMORY;
        }

        if (SmsEnvelope.TELESERVICE_WAP == teleService) {
            return processCdmaWapPdu(sms.getUserData(), sms.mMessageRef,
                    sms.getOriginatingAddress(), sms.getTimestampMillis());
        }

        return dispatchNormalMessage(smsb);
    }

    /**
     * Send an acknowledge message.
     * @param success indicates that last message was successfully received.
     * @param result result code indicating any error
     * @param response callback message sent when operation completes.
     */
    @Override
    protected void acknowledgeLastIncomingSms(boolean success, int result, Message response) {
        if (isInEmergencyCallMode()) {
            return;
        }

        int causeCode = resultToCause(result);
        mPhone.mCi.acknowledgeLastIncomingCdmaSms(success, causeCode, response);

        if (causeCode == 0) {
            mLastAcknowledgedSmsFingerprint = mLastDispatchedSmsFingerprint;
        }
        mLastDispatchedSmsFingerprint = null;
    }

    /**
     * Called when the phone changes the default method updates mPhone
     * mStorageMonitor and mCellBroadcastHandler.updatePhoneObject.
     * Override if different or other behavior is desired.
     *
     * @param phone
     */
    @Override
    protected void onUpdatePhoneObject(PhoneBase phone) {
        super.onUpdatePhoneObject(phone);
        mCellBroadcastHandler.updatePhoneObject(phone);
    }

    /**
     * Convert Android result code to CDMA SMS failure cause.
     * @param rc the Android SMS intent result value
     * @return 0 for success, or a CDMA SMS failure cause value
     */
    private static int resultToCause(int rc) {
        switch (rc) {
        case Activity.RESULT_OK:
        case Intents.RESULT_SMS_HANDLED:
            // Cause code is ignored on success.
            return 0;
        case Intents.RESULT_SMS_OUT_OF_MEMORY:
            return CommandsInterface.CDMA_SMS_FAIL_CAUSE_RESOURCE_SHORTAGE;
        case Intents.RESULT_SMS_UNSUPPORTED:
            return CommandsInterface.CDMA_SMS_FAIL_CAUSE_INVALID_TELESERVICE_ID;
        case Intents.RESULT_SMS_GENERIC_ERROR:
        default:
            return CommandsInterface.CDMA_SMS_FAIL_CAUSE_ENCODING_PROBLEM;
        }
    }

    /**
     * Handle {@link SmsEnvelope#TELESERVICE_VMN} and {@link SmsEnvelope#TELESERVICE_MWI}.
     * @param sms the message to process
     */
    private void handleVoicemailTeleservice(SmsMessage sms) {
        int voicemailCount = sms.getNumOfVoicemails();
        if (DBG) log("Voicemail count=" + voicemailCount);

        // Store the voicemail count in preferences.
        SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(mContext);
        SharedPreferences.Editor editor = sp.edit();
        editor.putInt(CDMAPhone.VM_COUNT_CDMA, voicemailCount);
        editor.apply();
        mPhone.setVoiceMessageWaiting(1, voicemailCount);
    }

    /**
     * Processes inbound messages that are in the WAP-WDP PDU format. See
     * wap-259-wdp-20010614-a section 6.5 for details on the WAP-WDP PDU format.
     * WDP segments are gathered until a datagram completes and gets dispatched.
     *
     * @param pdu The WAP-WDP PDU segment
     * @return a result code from {@link android.provider.Telephony.Sms.Intents}, or
     *         {@link Activity#RESULT_OK} if the message has been broadcast
     *         to applications
     */
    private int processCdmaWapPdu(byte[] pdu, int referenceNumber, String address,
            long timestamp) {
        int index = 0;

        int msgType = (0xFF & pdu[index++]);
        if (msgType != 0) {
            log("Received a WAP SMS which is not WDP. Discard.");
            return Intents.RESULT_SMS_HANDLED;
        }
        int totalSegments = (0xFF & pdu[index++]);   // >= 1
        int segment = (0xFF & pdu[index++]);         // >= 0

        if (segment >= totalSegments) {
            loge("WDP bad segment #" + segment + " expecting 0-" + (totalSegments - 1));
            return Intents.RESULT_SMS_HANDLED;
        }

        // Only the first segment contains sourcePort and destination Port
        int sourcePort = 0;
        int destinationPort = 0;
        if (segment == 0) {
            //process WDP segment
            sourcePort = (0xFF & pdu[index++]) << 8;
            sourcePort |= 0xFF & pdu[index++];
            destinationPort = (0xFF & pdu[index++]) << 8;
            destinationPort |= 0xFF & pdu[index++];
            // Some carriers incorrectly send duplicate port fields in omadm wap pushes.
            // If configured, check for that here
            if (mCheckForDuplicatePortsInOmadmWapPush) {
                if (checkDuplicatePortOmadmWapPush(pdu, index)) {
                    index = index + 4; // skip duplicate port fields
                }
            }
        }

        // Lookup all other related parts
        log("Received WAP PDU. Type = " + msgType + ", originator = " + address
                + ", src-port = " + sourcePort + ", dst-port = " + destinationPort
                + ", ID = " + referenceNumber + ", segment# = " + segment + '/' + totalSegments);

        // pass the user data portion of the PDU to the shared handler in SMSDispatcher
        byte[] userData = new byte[pdu.length - index];
        System.arraycopy(pdu, index, userData, 0, pdu.length - index);

        InboundSmsTracker tracker = new InboundSmsTracker(userData, timestamp, destinationPort,
                true, address, referenceNumber, segment, totalSegments, true);

        return addTrackerToRawTableAndSendMessage(tracker);
    }

    /**
     * Optional check to see if the received WapPush is an OMADM notification with erroneous
     * extra port fields.
     * - Some carriers make this mistake.
     * ex: MSGTYPE-TotalSegments-CurrentSegment
     *       -SourcePortDestPort-SourcePortDestPort-OMADM PDU
     * @param origPdu The WAP-WDP PDU segment
     * @param index Current Index while parsing the PDU.
     * @return True if OrigPdu is OmaDM Push Message which has duplicate ports.
     *         False if OrigPdu is NOT OmaDM Push Message which has duplicate ports.
     */
    private static boolean checkDuplicatePortOmadmWapPush(byte[] origPdu, int index) {
        index += 4;
        byte[] omaPdu = new byte[origPdu.length - index];
        System.arraycopy(origPdu, index, omaPdu, 0, omaPdu.length);

        WspTypeDecoder pduDecoder = new WspTypeDecoder(omaPdu);
        int wspIndex = 2;

        // Process header length field
        if (!pduDecoder.decodeUintvarInteger(wspIndex)) {
            return false;
        }

        wspIndex += pduDecoder.getDecodedDataLength();  // advance to next field

        // Process content type field
        if (!pduDecoder.decodeContentType(wspIndex)) {
            return false;
        }

        String mimeType = pduDecoder.getValueString();
        return (WspTypeDecoder.CONTENT_TYPE_B_PUSH_SYNCML_NOTI.equals(mimeType));
    }
}
