/*
 * Copyright 2014 Google Inc. All rights reserved.
 *
 * 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.
 */

// THIS IS MODIFIED COPY OF THE "L" PLATFORM CLASS. BE CAREFUL ABOUT EDITS.
// THIS CODE SHOULD FOLLOW ANDROID STYLE.
//
// Changes:
//   Replace ArrayMap (new in Android L) with HashMap

package hu.uszeged.bluetooth;

import android.os.ParcelUuid;
import android.util.SparseArray;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.UUID;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;

/**
 * Represents a scan record from Bluetooth LE scan.
 */
public final class ScanRecord {

    // The following data type values are assigned by Bluetooth SIG.
    // For more details refer to Bluetooth 4.1 specification, Volume 3, Part C, Section 18.
    private static final int DATA_TYPE_FLAGS = 0x01;
    private static final int DATA_TYPE_SERVICE_UUIDS_16_BIT_PARTIAL = 0x02;
    private static final int DATA_TYPE_SERVICE_UUIDS_16_BIT_COMPLETE = 0x03;
    private static final int DATA_TYPE_SERVICE_UUIDS_32_BIT_PARTIAL = 0x04;
    private static final int DATA_TYPE_SERVICE_UUIDS_32_BIT_COMPLETE = 0x05;
    private static final int DATA_TYPE_SERVICE_UUIDS_128_BIT_PARTIAL = 0x06;
    private static final int DATA_TYPE_SERVICE_UUIDS_128_BIT_COMPLETE = 0x07;
    private static final int DATA_TYPE_LOCAL_NAME_SHORT = 0x08;
    private static final int DATA_TYPE_LOCAL_NAME_COMPLETE = 0x09;
    private static final int DATA_TYPE_TX_POWER_LEVEL = 0x0A;
    private static final int DATA_TYPE_SERVICE_DATA = 0x16;
    private static final int DATA_TYPE_MANUFACTURER_SPECIFIC_DATA = 0xFF;

    /** Length of bytes for 16 bit UUID */
    private static final int UUID_BYTES_16_BIT = 2;
    /** Length of bytes for 32 bit UUID */
    private static final int UUID_BYTES_32_BIT = 4;
    /** Length of bytes for 128 bit UUID */
    private static final int UUID_BYTES_128_BIT = 16;

    public static final ParcelUuid BASE_UUID =
        ParcelUuid.fromString("00000000-0000-1000-8000-00805F9B34FB");

    // Flags of the advertising data.
    private final int mAdvertiseFlags;

    private final List<ParcelUuid> mServiceUuids;

    private final SparseArray<byte[]> mManufacturerSpecificData;

    private final Map<ParcelUuid, byte[]> mServiceData;

    // Transmission power level(in dB).
    private final int mTxPowerLevel;

    // Local name of the Bluetooth LE device.
    private final String mDeviceName;

    // Raw bytes of scan record.
    private final byte[] mBytes;

    /**
     * Returns the advertising flags indicating the discoverable mode and capability of the device.
     * Returns -1 if the flag field is not set.
     */
    public int getAdvertiseFlags() {
        return mAdvertiseFlags;
    }

    /**
     * Returns a list of service UUIDs within the advertisement that are used to identify the
     * bluetooth GATT services.
     */
    public List<ParcelUuid> getServiceUuids() {
        return mServiceUuids;
    }

    /**
     * Returns a sparse array of manufacturer identifier and its corresponding manufacturer specific
     * data.
     */
    public SparseArray<byte[]> getManufacturerSpecificData() {
        return mManufacturerSpecificData;
    }

    public int[] getManufacturerDataKeys() {
        int size = getManufacturerDataKeysSize();
        if (size == 0) {
            return null;
        }
        int[] keys = new int[size];
        for (int i = 0; i < size; i++) {
            keys[i] = mManufacturerSpecificData.keyAt(i);
        }
        return keys;
    }

    public int getManufacturerDataKeysSize() {
        return mManufacturerSpecificData.size();
    }

    /**
     * Returns the manufacturer specific data associated with the manufacturer id. Returns
     * {@code null} if the {@code manufacturerId} is not found.
     */
    public byte[] getManufacturerSpecificData(int manufacturerId) {
        return mManufacturerSpecificData.get(manufacturerId);
    }

    public int[] getManufacturerDataValues(int key) {
        byte[] values = getManufacturerSpecificData(key);
        if (values == null)
            return null;

        int[] intArray = new int[values.length];
        for(int i = 0; i < values.length; i++) {
            intArray[i] = values[i] & (0xff);
        }
        return intArray;
    }

    public int getManufacturerDataValuesSize(int key) {
        return getManufacturerSpecificData(key).length;
    }

    /**
     * Returns a map of service UUID and its corresponding service data.
     */
    public Map<ParcelUuid, byte[]> getServiceData() {
        return mServiceData;
    }

    public Set<String> getServiceDataKeys() {
        Set<String> uuids = new HashSet();
        for (ParcelUuid uuid : mServiceData.keySet()) {
            uuids.add(uuid.getUuid().toString());
        }
        return uuids;
    }

    public int getServiceDataKeysSize() {
        return mServiceData.size();
    }

    /**
     * Returns the service data byte array associated with the {@code serviceUuid}. Returns
     * {@code null} if the {@code serviceDataUuid} is not found.
     */
    public byte[] getServiceData(ParcelUuid serviceDataUuid) {
        if (serviceDataUuid == null) {
            return null;
        }
        return mServiceData.get(serviceDataUuid);
    }

    public byte[] getServiceData(String serviceDataUuid) {
        return getServiceData(ParcelUuid.fromString(serviceDataUuid));
    }

    public int getServiceDataSize(String serviceDataUuid) {
        return getServiceData(serviceDataUuid).length;
    }

    public int[] getServiceDataValues(String key) {
        byte[] values = getServiceData(key);
        if (values == null)
            return null;

        int[] intArray = new int[values.length];
        for(int i = 0; i < values.length; i++) {
            intArray[i] = values[i] & (0xff);
        }
        return intArray;
    }

    public int getServiceDataValuesSize(String key) {
        return getServiceData(key).length;
    }

    /**
     * Returns the transmission power level of the packet in dBm. Returns {@link Integer#MIN_VALUE}
     * if the field is not set. This value can be used to calculate the path loss of a received
     * packet using the following equation:
     * <p>
     * <code>pathloss = txPowerLevel - rssi</code>
     */
    public int getTxPowerLevel() {
        return mTxPowerLevel;
    }

    /**
     * Returns the local name of the BLE device. The is a UTF-8 encoded string.
     */
    public String getDeviceName() {
        return mDeviceName;
    }

    /**
     * Returns raw bytes of scan record.
     */
    public byte[] getBytes() {
        return mBytes;
    }

    private ScanRecord(List<ParcelUuid> serviceUuids,
            SparseArray<byte[]> manufacturerData,
            Map<ParcelUuid, byte[]> serviceData,
            int advertiseFlags, int txPowerLevel,
            String localName, byte[] bytes) {
        mServiceUuids = serviceUuids;
        mManufacturerSpecificData = manufacturerData;
        mServiceData = serviceData;
        mDeviceName = localName;
        mAdvertiseFlags = advertiseFlags;
        mTxPowerLevel = txPowerLevel;
        mBytes = bytes;
    }

    /**
     * Parse scan record bytes to {@link ScanRecord}.
     * <p>
     * The format is defined in Bluetooth 4.1 specification, Volume 3, Part C, Section 11 and 18.
     * <p>
     * All numerical multi-byte entities and values shall use little-endian <strong>byte</strong>
     * order.
     *
     * @param scanRecord The scan record of Bluetooth LE advertisement and/or scan response.
     * @hide
     */
    public static ScanRecord parseFromBytes(byte[] scanRecord) {
        if (scanRecord == null) {
            return null;
        }

        int currentPos = 0;
        int advertiseFlag = -1;
        List<ParcelUuid> serviceUuids = new ArrayList<ParcelUuid>();
        String localName = null;
        int txPowerLevel = Integer.MIN_VALUE;

        SparseArray<byte[]> manufacturerData = new SparseArray<byte[]>();
        Map<ParcelUuid, byte[]> serviceData = new HashMap<ParcelUuid, byte[]>();

        try {
            while (currentPos < scanRecord.length) {
                // length is unsigned int.
                int length = scanRecord[currentPos++] & 0xFF;
                if (length == 0) {
                    break;
                }
                // Note the length includes the length of the field type itself.
                int dataLength = length - 1;
                // fieldType is unsigned int.
                int fieldType = scanRecord[currentPos++] & 0xFF;
                switch (fieldType) {
                    case DATA_TYPE_FLAGS:
                        advertiseFlag = scanRecord[currentPos] & 0xFF;
                        break;
                    case DATA_TYPE_SERVICE_UUIDS_16_BIT_PARTIAL:
                    case DATA_TYPE_SERVICE_UUIDS_16_BIT_COMPLETE:
                        parseServiceUuid(scanRecord, currentPos,
                                dataLength, UUID_BYTES_16_BIT, serviceUuids);
                        break;
                    case DATA_TYPE_SERVICE_UUIDS_32_BIT_PARTIAL:
                    case DATA_TYPE_SERVICE_UUIDS_32_BIT_COMPLETE:
                        parseServiceUuid(scanRecord, currentPos, dataLength,
                                UUID_BYTES_32_BIT, serviceUuids);
                        break;
                    case DATA_TYPE_SERVICE_UUIDS_128_BIT_PARTIAL:
                    case DATA_TYPE_SERVICE_UUIDS_128_BIT_COMPLETE:
                        parseServiceUuid(scanRecord, currentPos, dataLength,
                                UUID_BYTES_128_BIT, serviceUuids);
                        break;
                    case DATA_TYPE_LOCAL_NAME_SHORT:
                    case DATA_TYPE_LOCAL_NAME_COMPLETE:
                        localName = new String(
                                extractBytes(scanRecord, currentPos, dataLength));
                        break;
                    case DATA_TYPE_TX_POWER_LEVEL:
                        txPowerLevel = scanRecord[currentPos];
                        break;
                    case DATA_TYPE_SERVICE_DATA:
                        // The first two bytes of the service data are service data UUID in little
                        // endian. The rest bytes are service data.
                        int serviceUuidLength = UUID_BYTES_16_BIT;
                        byte[] serviceDataUuidBytes = extractBytes(scanRecord, currentPos,
                                serviceUuidLength);
                        ParcelUuid serviceDataUuid = parseUuidFrom(
                                serviceDataUuidBytes);
                        byte[] serviceDataArray = extractBytes(scanRecord,
                                currentPos + serviceUuidLength, dataLength - serviceUuidLength);
                        serviceData.put(serviceDataUuid, serviceDataArray);
                        break;
                    case DATA_TYPE_MANUFACTURER_SPECIFIC_DATA:
                        // The first two bytes of the manufacturer specific data are
                        // manufacturer ids in little endian.
                        int manufacturerId = ((scanRecord[currentPos + 1] & 0xFF) << 8)
                                + (scanRecord[currentPos] & 0xFF);
                        byte[] manufacturerDataBytes = extractBytes(scanRecord, currentPos + 2,
                                dataLength - 2);
                        manufacturerData.put(manufacturerId, manufacturerDataBytes);
                        break;
                    default:
                        // Just ignore, we don't handle such data type.
                        break;
                }
                currentPos += dataLength;
            }

            if (serviceUuids.isEmpty()) {
                serviceUuids = null;
            }
            return new ScanRecord(serviceUuids, manufacturerData, serviceData,
                    advertiseFlag, txPowerLevel, localName, scanRecord);
        } catch (Exception e) {
            // As the record is invalid, ignore all the parsed results for this packet
            // and return an empty record with raw scanRecord bytes in results
            return new ScanRecord(null, null, null, -1, Integer.MIN_VALUE, null, scanRecord);
        }
    }

    // Parse service UUIDs.
    private static int parseServiceUuid(byte[] scanRecord, int currentPos, int dataLength,
            int uuidLength, List<ParcelUuid> serviceUuids) {
        while (dataLength > 0) {
            byte[] uuidBytes = extractBytes(scanRecord, currentPos,
                    uuidLength);
            serviceUuids.add(parseUuidFrom(uuidBytes));
            dataLength -= uuidLength;
            currentPos += uuidLength;
        }
        return currentPos;
    }

    // Helper method to extract bytes from byte array.
    private static byte[] extractBytes(byte[] scanRecord, int start, int length) {
        byte[] bytes = new byte[length];
        System.arraycopy(scanRecord, start, bytes, 0, length);
        return bytes;
    }

    /**
     * Parse UUID from bytes. The {@code uuidBytes} can represent a 16-bit, 32-bit or 128-bit UUID,
     * but the returned UUID is always in 128-bit format. Note UUID is little endian in Bluetooth.
     *
     * @param uuidBytes Byte representation of uuid.
     * @return {@link ParcelUuid} parsed from bytes.
     * @throws IllegalArgumentException If the {@code uuidBytes} cannot be parsed.
     */
    public static ParcelUuid parseUuidFrom(byte[] uuidBytes) {
        if (uuidBytes == null) {
            throw new IllegalArgumentException("uuidBytes cannot be null");
        }
        int length = uuidBytes.length;
        if (length != UUID_BYTES_16_BIT && length != UUID_BYTES_32_BIT &&
                length != UUID_BYTES_128_BIT) {
            throw new IllegalArgumentException("uuidBytes length invalid - " + length);
        }
        // Construct a 128 bit UUID.
        if (length == UUID_BYTES_128_BIT) {
            ByteBuffer buf = ByteBuffer.wrap(uuidBytes).order(ByteOrder.LITTLE_ENDIAN);
            long msb = buf.getLong(8);
            long lsb = buf.getLong(0);
            return new ParcelUuid(new UUID(msb, lsb));
        }
        // For 16 bit and 32 bit UUID we need to convert them to 128 bit value.
        // 128_bit_value = uuid * 2^96 + BASE_UUID
        long shortUuid;
        if (length == UUID_BYTES_16_BIT) {
            shortUuid = uuidBytes[0] & 0xFF;
            shortUuid += (uuidBytes[1] & 0xFF) << 8;
        } else {
            shortUuid = uuidBytes[0] & 0xFF;
            shortUuid += (uuidBytes[1] & 0xFF) << 8;
            shortUuid += (uuidBytes[2] & 0xFF) << 16;
            shortUuid += (uuidBytes[3] & 0xFF) << 24;
        }
        long msb = BASE_UUID.getUuid().getMostSignificantBits() + (shortUuid << 32);
        long lsb = BASE_UUID.getUuid().getLeastSignificantBits();
        return new ParcelUuid(new UUID(msb, lsb));
    }
}