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/* mbed Microcontroller Library
 * Copyright (c) 2006-2013 ARM Limited
 *
 * 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.
 */

#ifndef SERVICES_URIBEACONCONFIGSERVICE_H_
#define SERVICES_URIBEACONCONFIGSERVICE_H_

#include "BLEDevice.h"
#include "GattCharacteristic.h"
#include "mbed.h"

#define UUID_URI_BEACON(FIRST, SECOND) { \
        0xee, 0x0c, FIRST, SECOND, 0x87, 0x86, 0x40, 0xba,       \
        0xab, 0x96, 0x99, 0xb9, 0x1a, 0xc9, 0x81, 0xd8,          \
}

static const uint8_t UUID_URI_BEACON_SERVICE[]    = UUID_URI_BEACON(0x20, 0x80);
static const uint8_t UUID_LOCK_STATE_CHAR[]       = UUID_URI_BEACON(0x20, 0x81);
static const uint8_t UUID_LOCK_CHAR[]             = UUID_URI_BEACON(0x20, 0x82);
static const uint8_t UUID_UNLOCK_CHAR[]           = UUID_URI_BEACON(0x20, 0x83);
static const uint8_t UUID_URI_DATA_CHAR[]         = UUID_URI_BEACON(0x20, 0x84);
static const uint8_t UUID_FLAGS_CHAR[]            = UUID_URI_BEACON(0x20, 0x85);
static const uint8_t UUID_ADV_POWER_LEVELS_CHAR[] = UUID_URI_BEACON(0x20, 0x86);
static const uint8_t UUID_TX_POWER_MODE_CHAR[]    = UUID_URI_BEACON(0x20, 0x87);
static const uint8_t UUID_BEACON_PERIOD_CHAR[]    = UUID_URI_BEACON(0x20, 0x88);
static const uint8_t UUID_RESET_CHAR[]            = UUID_URI_BEACON(0x20, 0x89);
static const uint8_t BEACON_UUID[] = {0xD8, 0xFE};

/**
* @class URIBeaconConfigService
* @brief UriBeacon Configuration Service. Can be used to set URL, adjust power levels, and set flags.
* See http://uribeacon.org
*
*/
class URIBeaconConfigService {
  public:
    /**
     * @brief Transmission Power Modes for UriBeacon
     */
    static const uint8_t TX_POWER_MODE_LOWEST = 0; /*!< Lowest TX power mode */
    static const uint8_t TX_POWER_MODE_LOW    = 1; /*!< Low TX power mode */
    static const uint8_t TX_POWER_MODE_MEDIUM = 2; /*!< Medium TX power mode */
    static const uint8_t TX_POWER_MODE_HIGH   = 3; /*!< High TX power mode */
    static const unisgned int NUM_POWER_MODES = 4; /*!< Number of Power Modes defined */


    typedef uint8_t Lock_t[16];               /* 128 bits */
    typedef int8_t PowerLevels_t[NUM_POWER_MODES];

    static const int URI_DATA_MAX = 18;
    typedef uint8_t UriData_t[URI_DATA_MAX];

    struct Params_t {
        Lock_t              lock;
        uint8_t             uriDataLength;
        UriData_t           uriData;
        uint8_t             flags;
        // Current value of AdvertisedPowerLevels
        PowerLevels_t       advPowerLevels;
        // Firmware power levels used with setTxPower()
        uint8_t             txPowerMode;
        uint16_t            beaconPeriod;
    };


    /**
     * @param[ref] ble
     *                 BLEDevice object for the underlying controller.
     * @param[in]  uridata
     *                 URI as a null-terminated string.
     * @param[in]  flagsIn
     *                 UriBeacon Flags.
     * @param[in]  powerLevels[]
     *                 Table of UriBeacon Tx Power Levels in dBm.
     * @param[in]  powerMode
     *                 Currently effective power mode.
     * @param[in]  beaconPeriodIn
     *                 The period in milliseconds that a UriBeacon packet is
     *                 transmitted. A value of zero disables UriBeacon
     *                 transmissions.
     */
    URIBeaconConfigService(BLEDevice      &bleIn,
                           Params_t       &paramsIn,
                           bool           resetToDefaultsFlag,
                           UriData_t      &defaultUriDataIn,
                           int            defaultUriDataLengthIn,
                           PowerLevels_t  &defaultAdvPowerLevelsIn) :
        ble(bleIn),
        params(paramsIn),
        defaultUriDataLength(defaultUriDataLengthIn),
        defaultUriData(defaultUriDataIn),
        defaultAdvPowerLevels(defaultAdvPowerLevelsIn),
        initSucceeded(false),
        lockedStateChar(UUID_LOCK_STATE_CHAR, &lockedState),
        lockChar(UUID_LOCK_CHAR, &params.lock),
        uriDataChar(UUID_URI_DATA_CHAR, params.uriData, URI_DATA_MAX, params.uriDataLength,
                    GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE),
        unlockChar(UUID_UNLOCK_CHAR, &params.lock),
        flagsChar(UUID_FLAGS_CHAR, &params.flags),
        advPowerLevelsChar(UUID_ADV_POWER_LEVELS_CHAR, &params.advPowerLevels),
        txPowerModeChar(UUID_TX_POWER_MODE_CHAR, &params.txPowerMode),
        beaconPeriodChar(UUID_BEACON_PERIOD_CHAR, &params.beaconPeriod),
        resetChar(UUID_RESET_CHAR, &resetFlag) {
        if (defaultUriDataLengthIn > URI_DATA_MAX) {
            return;
        }

        if (params.uriDataLength > URI_DATA_MAX) {
            resetToDefaultsFlag = true;
        }

        lockedState = isLocked();

        if (resetToDefaultsFlag) {
            resetToDefaults();
        } else {
            updateCharacteristicValues();
        }

        lockChar.setWriteAuthorizationCallback(this, &URIBeaconConfigService::lockAuthorizationCallback);
        unlockChar.setWriteAuthorizationCallback(this, &URIBeaconConfigService::unlockAuthorizationCallback);
        uriDataChar.setWriteAuthorizationCallback(this, &URIBeaconConfigService::uriDataWriteAuthorizationCallback);
        flagsChar.setWriteAuthorizationCallback(this, &URIBeaconConfigService::flagsAuthorizationCallback);
        advPowerLevelsChar.setWriteAuthorizationCallback(this, &URIBeaconConfigService::denyGATTWritesIfLocked);
        txPowerModeChar.setWriteAuthorizationCallback(this, &URIBeaconConfigService::denyGATTWritesIfLocked);
        beaconPeriodChar.setWriteAuthorizationCallback(this, &URIBeaconConfigService::denyGATTWritesIfLocked);
        resetChar.setWriteAuthorizationCallback(this, &URIBeaconConfigService::denyGATTWritesIfLocked);

        static GattCharacteristic *charTable[] = {
            &lockedStateChar, &lockChar, &unlockChar, &uriDataChar,
            &flagsChar, &advPowerLevelsChar, &txPowerModeChar, &beaconPeriodChar, &resetChar
        };

        GattService configService(UUID_URI_BEACON_SERVICE, charTable, sizeof(charTable) / sizeof(GattCharacteristic *));

        ble.addService(configService);
        ble.onDataWritten(this, &URIBeaconConfigService::onDataWrittenCallback);

        initSucceeded = true;
    }

    bool configuredSuccessfully(void) const {
        return initSucceeded;
    }


  private:
    bool isLocked() {
        Lock_t testLock;
        memset(testLock, 0, sizeof(Lock_t));
        return memcmp(params.lock, testLock, sizeof(Lock_t));
    }

    /*
     * This callback is invoked when a GATT client attempts to modify any of the
     * characteristics of this service. Attempts to do so are also applied to
     * the internal state of this service object.
     */
    void onDataWrittenCallback(const GattCharacteristicWriteCBParams *writeParams) {
        uint16_t handle = writeParams->charHandle;

        if (handle == lockChar.getValueHandle()) {
            // Validated earlier
            memcpy(params.lock, writeParams->data, sizeof(Lock_t));
            lockedState = true;
        } else if (handle == unlockChar.getValueHandle()) {
            // Validated earlier
            memset(params.lock, 0, sizeof(Lock_t));
            lockedState = false;
        } else if (handle == uriDataChar.getValueHandle()) {
            params.uriDataLength = writeParams->len;
            memcpy(params.uriData, writeParams->data, params.uriDataLength);
        } else if (handle == flagsChar.getValueHandle()) {
            params.flags = *(writeParams->data);
        } else if (handle == advPowerLevelsChar.getValueHandle()) {
            memcpy(params.advPowerLevels, writeParams->data, sizeof(PowerLevels_t));
        } else if (handle == txPowerModeChar.getValueHandle()) {
            params.txPowerMode = *(writeParams->data);
        } else if (handle == beaconPeriodChar.getValueHandle()) {
            params.beaconPeriod = *((uint16_t *)(writeParams->data));
        } else if (handle == resetChar.getValueHandle()) {
            resetToDefaults();
        }
    }

    /*
     * Reset the default values.
     */
    void resetToDefaults(void) {
        lockedState      = false;
        memset(params.lock, 0, sizeof(Lock_t));
        memcpy(params.uriData, defaultUriData, URI_DATA_MAX);
        params.uriDataLength    = defaultUriDataLength;
        params.flags            = 0;
        memcpy(params.advPowerLevels, defaultAdvPowerLevels, sizeof(PowerLevels_t));
        params.txPowerMode      = TX_POWER_MODE_LOW;
        params.beaconPeriod     = 1000;
        updateCharacteristicValues();
    }

    /*
     * Internal helper function used to update the GATT database following any
     * change to the internal state of the service object.
     */
    void updateCharacteristicValues(void) {
        ble.updateCharacteristicValue(lockedStateChar.getValueHandle(), &lockedState, 1);
        ble.updateCharacteristicValue(uriDataChar.getValueHandle(), params.uriData, params.uriDataLength);
        ble.updateCharacteristicValue(flagsChar.getValueHandle(), &params.flags, 1);
        ble.updateCharacteristicValue(beaconPeriodChar.getValueHandle(),
                                      reinterpret_cast<uint8_t *>(&params.beaconPeriod), sizeof(uint16_t));
        ble.updateCharacteristicValue(txPowerModeChar.getValueHandle(), &params.txPowerMode, 1);
        ble.updateCharacteristicValue(advPowerLevelsChar.getValueHandle(),
                                      reinterpret_cast<uint8_t *>(params.advPowerLevels), sizeof(PowerLevels_t));
    }

  private:
    void lockAuthorizationCallback(GattCharacteristicWriteAuthCBParams *authParams) {
        authParams->authorizationReply = (authParams->len == sizeof(Lock_t)) && !lockedState;
    }


    void unlockAuthorizationCallback(GattCharacteristicWriteAuthCBParams *authParams) {
        if (!lockedState || (authParams->len == sizeof(Lock_t) && (memcmp(authParams->data, params.lock, sizeof(Lock_t)) == 0))) {
            authParams->authorizationReply = true;
        } else {
            authParams->authorizationReply = false;
        }
    }

    void uriDataWriteAuthorizationCallback(GattCharacteristicWriteAuthCBParams *authParams) {
        if (lockedState || (authParams->offset != 0) || (authParams->len > URI_DATA_MAX)) {
            authParams->authorizationReply = false;
        }
    }

    void flagsAuthorizationCallback(GattCharacteristicWriteAuthCBParams *authParams) {
        if (lockedState || authParams->len != 1) {
            authParams->authorizationReply = false;
        }
    }

    void denyGATTWritesIfLocked(GattCharacteristicWriteAuthCBParams *authParams) {
        if (lockedState) {
            authParams->authorizationReply = false;
        }
    }

    BLEDevice          &ble;
    Params_t           &params;
    // Default value that is restored on reset
    uint16_t            defaultUriDataLength;
    UriData_t           &defaultUriData;
    // Default value that is restored on reset
    PowerLevels_t       &defaultAdvPowerLevels;
    uint8_t             lockedState;
    bool                initSucceeded;
    uint8_t             resetFlag;


    ReadOnlyGattCharacteristic<uint8_t> lockedStateChar;
    WriteOnlyGattCharacteristic<Lock_t> lockChar;
    GattCharacteristic uriDataChar;
    WriteOnlyGattCharacteristic<Lock_t> unlockChar;
    ReadWriteGattCharacteristic<uint8_t>  flagsChar;
    ReadWriteGattCharacteristic<PowerLevels_t> advPowerLevelsChar;
    ReadWriteGattCharacteristic<uint8_t> txPowerModeChar;
    ReadWriteGattCharacteristic<uint16_t> beaconPeriodChar;
    WriteOnlyGattCharacteristic<uint8_t> resetChar;
};

#endif  // SERVICES_URIBEACONCONFIGSERVICE_H_