/****************************************************************************
 *   Aug 11 17:13:51 2020
 *   Copyright  2020  Dirk Brosswick
 *   Email: dirk.brosswick@googlemail.com
 ****************************************************************************/
 
/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*
 *  inspire by https://github.com/bburky/t-watch-2020-project
 *
 */
#include "config.h"
#include "Arduino.h"

#include <BLEDevice.h>
#include <BLEServer.h>
#include <BLEUtils.h>
#include <BLE2902.h>

#include "blectl.h"
#include "json_psram_allocator.h"

#include "gui/statusbar.h"

EventGroupHandle_t blectl_status = NULL;
portMUX_TYPE blectlMux = portMUX_INITIALIZER_UNLOCKED;

blectl_config_t blectl_config;

blectl_event_t *blectl_event_cb_table = NULL;
uint32_t blectl_event_cb_entrys = 0;
void blectl_send_event_cb( EventBits_t event, char *msg );

BLEServer *pServer = NULL;
BLECharacteristic *pTxCharacteristic;
uint8_t txValue = 0;

char *gadgetbridge_msg = NULL;
uint32_t gadgetbridge_msg_size = 0;

/*
 *
 */
class BleCtlServerCallbacks: public BLEServerCallbacks {
    void onConnect(BLEServer* pServer) {
        blectl_set_event( BLECTL_CONNECT );
        blectl_clear_event( BLECTL_DISCONNECT );
        blectl_send_event_cb( BLECTL_CONNECT, (char*)"connected" );
        log_i("BLE connected");
    };

    void onDisconnect(BLEServer* pServer) {
        blectl_set_event( BLECTL_DISCONNECT );
        blectl_clear_event( BLECTL_CONNECT );
        blectl_send_event_cb( BLECTL_DISCONNECT, (char*)"disconnected" );
        log_i("BLE disconnected");
        delay(500);
        if ( blectl_get_advertising() ) {
            pServer->getAdvertising()->start();
            log_i("BLE advertising...");
        }
    }
};

/*
 *
 */
class BtlCtlSecurity : public BLESecurityCallbacks {

    uint32_t onPassKeyRequest(){
        return 123456;
    }
    void onPassKeyNotify(uint32_t pass_key){
        char pin[16]="";
        snprintf( pin, sizeof( pin ), "%06d", pass_key );
        blectl_set_event( BLECTL_PIN_AUTH );
        blectl_send_event_cb( BLECTL_PIN_AUTH, pin );
        log_i("Bluetooth Pairing Request\r\nPIN: %s", pin );
    }
    bool onConfirmPIN(uint32_t pass_key){
        return false;
    }
    bool onSecurityRequest(){
        return true;
    }

    void onAuthenticationComplete( esp_ble_auth_cmpl_t cmpl ){
        log_i("Bluetooth pairing %s", cmpl.success ? "successful" : "unsuccessful");

        if( cmpl.success ){
            if ( blectl_get_event( BLECTL_PIN_AUTH ) ) {
                blectl_send_event_cb( BLECTL_PAIRING_SUCCESS, (char*)"success" );
            }
        }
        else {
            if ( blectl_get_event( BLECTL_PIN_AUTH ) ) {
                blectl_send_event_cb( BLECTL_PAIRING_ABORT, (char*)"abort" );
            }
            pServer->startAdvertising();
        }

        if ( blectl_get_event( BLECTL_PIN_AUTH ) ) {
            blectl_clear_event( BLECTL_PIN_AUTH );
        }
    }
};

void blectl_add_char_to_gadgetbridge_msg( char msg_char ) {
    gadgetbridge_msg_size++;

    if ( gadgetbridge_msg == NULL ) {
        gadgetbridge_msg = (char *)ps_calloc( gadgetbridge_msg_size + 1, 1 );
        if ( gadgetbridge_msg == NULL ) {
            log_e("gadgetbridge_msg alloc fail");
            while(true);
        }
    }
    else {
        char *new_gadgetbridge_msg = NULL;
        new_gadgetbridge_msg = (char *)ps_realloc( gadgetbridge_msg, gadgetbridge_msg_size + 1 );
        if ( new_gadgetbridge_msg == NULL ) {
            log_e("gadgetbridge_msg realloc fail");
            while(true);            
        }
        gadgetbridge_msg = new_gadgetbridge_msg;
    }
    gadgetbridge_msg[ gadgetbridge_msg_size - 1 ] = msg_char;
    gadgetbridge_msg[ gadgetbridge_msg_size ] = '\0';
}

void blectl_delete_gadgetbridge_msg ( void ) {
    gadgetbridge_msg_size = 0;

    if ( gadgetbridge_msg == NULL ) {
        gadgetbridge_msg = (char *)ps_calloc( gadgetbridge_msg_size + 1, 1 );
        if ( gadgetbridge_msg == NULL ) {
            log_e("gadgetbridge_msg alloc fail");
            while(true);
        }
    }
    else {
        char *new_gadgetbridge_msg = NULL;
        new_gadgetbridge_msg = (char *)ps_realloc( gadgetbridge_msg, gadgetbridge_msg_size + 1 );
        if ( new_gadgetbridge_msg == NULL ) {
            log_e("gadgetbridge_msg realloc fail");
            while(true);            
        }
        gadgetbridge_msg = new_gadgetbridge_msg;
    }
    gadgetbridge_msg[ gadgetbridge_msg_size ] = '\0';
}

class BleCtlCallbacks : public BLECharacteristicCallbacks
{
    void onWrite(BLECharacteristic *pCharacteristic)
    {
        char *msg = (char *)ps_calloc( pCharacteristic->getValue().length() + 1, 1 );
        if ( msg == NULL ) {
            Serial.printf("ps_calloc fail\r\n");
            return;
        }
        else {
            strlcpy( msg, pCharacteristic->getValue().c_str(), pCharacteristic->getValue().length() + 1 );
            for ( int i = 0 ; i < pCharacteristic->getValue().length(); i++ ) {
                switch( msg[ i ] ) {
                    case EndofText:         blectl_delete_gadgetbridge_msg();
                                            log_i("attention, new link establish");
                                            break;
                    case DataLinkEscape:    blectl_delete_gadgetbridge_msg();
                                            log_i("attention, new message");
                                            break;
                    case LineFeed:          log_i("message complete, fire BLTCTL_MSG callback");
                                            if( gadgetbridge_msg[ 0 ] == 'G' && gadgetbridge_msg[ 1 ] == 'B' ) {
                                                log_i("gadgetbridge message identified, cut down to json");
                                                gadgetbridge_msg[ gadgetbridge_msg_size - 1 ] = '\0';
                                                log_i("msg: %s", &gadgetbridge_msg[ 3 ] );
                                                blectl_send_event_cb( BLECTL_MSG, &gadgetbridge_msg[ 3 ] );
                                            }
                                            else {
                                                log_i("msg: %s", gadgetbridge_msg );
                                                blectl_send_event_cb( BLECTL_MSG, gadgetbridge_msg );
                                            }
                                            break;
                    default:                blectl_add_char_to_gadgetbridge_msg( msg[ i ] );
                }
            }
            free(msg);
        }
    }
};

/*
 *
 */
void blectl_setup( void ) {

    blectl_status = xEventGroupCreate();

    esp_bt_controller_enable( ESP_BT_MODE_BLE );
    esp_bt_controller_mem_release( ESP_BT_MODE_CLASSIC_BT );
    esp_bt_mem_release( ESP_BT_MODE_CLASSIC_BT );
    esp_bt_controller_mem_release( ESP_BT_MODE_IDLE );
    esp_bt_mem_release( ESP_BT_MODE_IDLE );

    // Create the BLE Device
    // Name needs to match filter in Gadgetbridge's banglejs getSupportedType() function.
    // This is too long I think:
    // BLEDevice::init("Espruino Gadgetbridge Compatible Device");
    BLEDevice::init("Espruino (T-Watch2020)");
    // The minimum power level (-12dbm) ESP_PWR_LVL_N12 was too low
    BLEDevice::setPower( ESP_PWR_LVL_N9 );

    // Enable encryption
    BLEServer* pServer = BLEDevice::createServer();
    BLEDevice::setEncryptionLevel( ESP_BLE_SEC_ENCRYPT_NO_MITM );
    BLEDevice::setSecurityCallbacks( new BtlCtlSecurity() );

    // Enable authentication
    BLESecurity *pSecurity = new BLESecurity();
    pSecurity->setAuthenticationMode(ESP_LE_AUTH_REQ_SC_BOND);
    pSecurity->setCapability(ESP_IO_CAP_OUT);
    pSecurity->setInitEncryptionKey(ESP_BLE_ENC_KEY_MASK | ESP_BLE_ID_KEY_MASK);
    pSecurity->setRespEncryptionKey(ESP_BLE_ENC_KEY_MASK | ESP_BLE_ID_KEY_MASK);

    // Create the BLE Server
    pServer = BLEDevice::createServer();
    pServer->setCallbacks( new BleCtlServerCallbacks() );

    // Create the BLE Service
    BLEService *pService = pServer->createService(SERVICE_UUID);

    // Create a BLE Characteristic
    pTxCharacteristic = pService->createCharacteristic( CHARACTERISTIC_UUID_TX, BLECharacteristic::PROPERTY_NOTIFY );
    pTxCharacteristic->setAccessPermissions(ESP_GATT_PERM_READ_ENCRYPTED | ESP_GATT_PERM_WRITE_ENCRYPTED);
    pTxCharacteristic->addDescriptor( new BLE2902() );

    BLECharacteristic *pRxCharacteristic = pService->createCharacteristic( CHARACTERISTIC_UUID_RX, BLECharacteristic::PROPERTY_WRITE );
    pRxCharacteristic->setAccessPermissions(ESP_GATT_PERM_READ_ENCRYPTED | ESP_GATT_PERM_WRITE_ENCRYPTED);
    pRxCharacteristic->setCallbacks( new BleCtlCallbacks() );

    // Start the service
    pService->start();

    // Start advertising
    pServer->getAdvertising()->addServiceUUID( pService->getUUID() );
    // Slow advertising interval for battery life
    // The maximum 0x4000 interval of ~16 sec was too slow, I could not reliably connect
    pServer->getAdvertising()->setMinInterval( 100 );
    pServer->getAdvertising()->setMaxInterval( 200 );

    if ( blectl_get_advertising() ) {
        pServer->getAdvertising()->start();
        log_i("BLE advertising...");
    }
}

/*
 *
 */
void blectl_set_event( EventBits_t bits ) {
    portENTER_CRITICAL(&blectlMux);
    xEventGroupSetBits( blectl_status, bits );
    portEXIT_CRITICAL(&blectlMux);
}

/*
 *
 */
void blectl_clear_event( EventBits_t bits ) {
    portENTER_CRITICAL(&blectlMux);
    xEventGroupClearBits( blectl_status, bits );
    portEXIT_CRITICAL(&blectlMux);
}

/*
 *
 */
bool blectl_get_event( EventBits_t bits ) {
    portENTER_CRITICAL(&blectlMux);
    EventBits_t temp = xEventGroupGetBits( blectl_status ) & bits;
    portEXIT_CRITICAL(&blectlMux);
    if ( temp )
        return( true );

    return( false );
}

void blectl_register_cb( EventBits_t event, BLECTL_CALLBACK_FUNC blectl_event_cb ) {
    blectl_event_cb_entrys++;

    if ( blectl_event_cb_table == NULL ) {
        blectl_event_cb_table = ( blectl_event_t * )ps_malloc( sizeof( blectl_event_t ) * blectl_event_cb_entrys );
        if ( blectl_event_cb_table == NULL ) {
            log_e("blectl_event_cb_table malloc faild");
            while(true);
        }
    }
    else {
        blectl_event_t *new_blectl_event_cb_table = NULL;

        new_blectl_event_cb_table = ( blectl_event_t * )ps_realloc( blectl_event_cb_table, sizeof( blectl_event_t ) * blectl_event_cb_entrys );
        if ( new_blectl_event_cb_table == NULL ) {
            log_e("blectl_event_cb_table realloc faild");
            while(true);
        }
        blectl_event_cb_table = new_blectl_event_cb_table;
    }

    blectl_event_cb_table[ blectl_event_cb_entrys - 1 ].event = event;
    blectl_event_cb_table[ blectl_event_cb_entrys - 1 ].event_cb = blectl_event_cb;
    log_i("register event_cb success");
}
/*
 *
 */
void blectl_send_event_cb( EventBits_t event, char *msg ) {
    for ( int entry = 0 ; entry < blectl_event_cb_entrys ; entry++ ){
        if ( event & blectl_event_cb_table[ entry ].event ) {
            log_i("call event_cb");
            blectl_event_cb_table[ entry ].event_cb( event, msg );
        }
    }
}

void blectl_standby( void ) {
/*
*/
}

void blectl_wakeup( void ) {
/*
*/
}

void blectl_set_enable_on_standby( bool enable_on_standby ) {        
    blectl_config.enable_on_standby = enable_on_standby;
    blectl_save_config();
}

void blectl_set_advertising( bool advertising ) {
    blectl_config.advertising = advertising;
    blectl_save_config();
    if ( blectl_get_event( BLECTL_CONNECT ) )
        return;

    if ( advertising ) {
        pServer->getAdvertising()->start();
    }
    else {
        pServer->getAdvertising()->stop();
    }
}

bool blectl_get_enable_on_standby( void ) {
    return( blectl_config.enable_on_standby );
}

bool blectl_get_advertising( void ) {
    return( blectl_config.enable_on_standby );
}
/*
 *
 */
void blectl_save_config( void ) {
    fs::File file = SPIFFS.open( BLECTL_JSON_COFIG_FILE, FILE_WRITE );

    if (!file) {
        log_e("Can't open file: %s!", BLECTL_JSON_COFIG_FILE );
    }
    else {
        SpiRamJsonDocument doc( 1000 );

        doc["advertising"] = blectl_config.advertising;
        doc["enable_on_standby"] = blectl_config.enable_on_standby;

        if ( serializeJsonPretty( doc, file ) == 0) {
            log_e("Failed to write config file");
        }
        doc.clear();
    }
    file.close();
}

/*
 *
 */
void blectl_read_config( void ) {
    if ( SPIFFS.exists( BLECTL_JSON_COFIG_FILE ) ) {        
        fs::File file = SPIFFS.open( BLECTL_JSON_COFIG_FILE, FILE_READ );
        if (!file) {
            log_e("Can't open file: %s!", BLECTL_JSON_COFIG_FILE );
        }
        else {
            int filesize = file.size();
            SpiRamJsonDocument doc( filesize * 2 );

            DeserializationError error = deserializeJson( doc, file );
            if ( error ) {
                log_e("blectl deserializeJson() failed: %s", error.c_str() );
            }
            else {                
                blectl_config.advertising = doc["advertising"].as<bool>();
                blectl_config.enable_on_standby = doc["enable_on_standby"].as<bool>();
            }        
            doc.clear();
        }
        file.close();
    }
}