#include "mbed.h"
#include "main.h"
#include "sx1276-hal.h"
#include "debug.h"

/* Set this flag to '1' to display debug messages on the console */
#define DEBUG_MESSAGE   0

/* Set this flag to '1' to use the LoRa modulation or to '0' to use FSK modulation */
#define USE_MODEM_LORA  1
#define USE_MODEM_FSK   !USE_MODEM_LORA

#define RF_FREQUENCY                                    915000000 // Hz
#define TX_OUTPUT_POWER                                 14        // 14 dBm

#if USE_MODEM_LORA == 1

    #define LORA_BANDWIDTH                              1         // [0: 125 kHz,
                                                                  //  1: 250 kHz,
                                                                  //  2: 500 kHz,
                                                                  //  3: Reserved]
    #define LORA_SPREADING_FACTOR                       10         // [SF7..SF12]
    #define LORA_CODINGRATE                             1         // [1: 4/5,
                                                                  //  2: 4/6,
                                                                  //  3: 4/7,
                                                                  //  4: 4/8]
    #define LORA_PREAMBLE_LENGTH                        8         // Same for Tx and Rx
    #define LORA_SYMBOL_TIMEOUT                         5         // Symbols
    #define LORA_FIX_LENGTH_PAYLOAD_ON                  false
    #define LORA_FHSS_ENABLED                           true  
    #define LORA_NB_SYMB_HOP                            4     
    #define LORA_IQ_INVERSION_ON                        false
    #define LORA_CRC_ENABLED                            true

#elif USE_MODEM_FSK == 1

    #define FSK_FDEV                                    25000     // Hz
    #define FSK_DATARATE                                19200     // bps
    #define FSK_BANDWIDTH                               50000     // Hz
    #define FSK_AFC_BANDWIDTH                           83333     // Hz
    #define FSK_PREAMBLE_LENGTH                         5         // Same for Tx and Rx
    #define FSK_FIX_LENGTH_PAYLOAD_ON                   false
    #define FSK_CRC_ENABLED                             true

#else
    #error "Please define a modem in the compiler options."
#endif

#define RX_TIMEOUT_VALUE                                3500      // in ms
#define BUFFER_SIZE                                     32        // Define the payload size here

#if( defined ( TARGET_KL25Z ) || defined ( TARGET_LPC11U6X ) )
DigitalOut led( LED2 );
#else
DigitalOut led( LED1 );
#endif

/*
 *  Global variables declarations
 */
typedef enum
{
    LOWPOWER = 0,
    IDLE,

    RX,
    RX_TIMEOUT,
    RX_ERROR,

    TX,
    TX_TIMEOUT,

    CAD,
    CAD_DONE
}AppStates_t;

volatile AppStates_t State = LOWPOWER;

/*!
 * Radio events function pointer
 */
static RadioEvents_t RadioEvents;

/*
 *  Global variables declarations
 */
SX1276MB1xAS Radio( NULL );

const uint8_t PingMsg[] = "PING";
const uint8_t PongMsg[] = "PONG";

uint16_t BufferSize = BUFFER_SIZE;
uint8_t Buffer[BUFFER_SIZE];

int16_t RssiValue = 0.0;
int8_t SnrValue = 0.0;

int main( void ) 
{
    uint8_t i;
    bool isMaster = true;

    debug( "\n\n\r     SX1276 Ping Pong Demo Application \n\n\r" );

    // Initialize Radio driver
    RadioEvents.TxDone = OnTxDone;
    RadioEvents.RxDone = OnRxDone;
    RadioEvents.RxError = OnRxError;
    RadioEvents.TxTimeout = OnTxTimeout;
    RadioEvents.RxTimeout = OnRxTimeout;
    RadioEvents.FhssChangeChannel = OnFhssChangeChannel;
    Radio.Init( &RadioEvents );

    // verify the connection with the board
    while( Radio.Read( REG_VERSION ) == 0x00  )
    {
        debug( "Radio could not be detected!\n\r", NULL );
        wait( 1 );
    }

    debug_if( ( DEBUG_MESSAGE & ( Radio.DetectBoardType( ) == SX1276MB1LAS ) ), "\n\r > Board Type: SX1276MB1LAS < \n\r" );
    debug_if( ( DEBUG_MESSAGE & ( Radio.DetectBoardType( ) == SX1276MB1MAS ) ), "\n\r > Board Type: SX1276MB1MAS < \n\r" );

    Radio.SetChannel( HoppingFrequencies[0] ); 

#if USE_MODEM_LORA == 1

    debug_if( LORA_FHSS_ENABLED, "\n\n\r             > LORA FHSS Mode < \n\n\r" );
    debug_if( !LORA_FHSS_ENABLED, "\n\n\r             > LORA Mode < \n\n\r" );

    Radio.SetTxConfig( MODEM_LORA, TX_OUTPUT_POWER, 0, LORA_BANDWIDTH,
                         LORA_SPREADING_FACTOR, LORA_CODINGRATE,
                         LORA_PREAMBLE_LENGTH, LORA_FIX_LENGTH_PAYLOAD_ON,
                         LORA_CRC_ENABLED, LORA_FHSS_ENABLED, LORA_NB_SYMB_HOP,
                         LORA_IQ_INVERSION_ON, 4000 );

    Radio.SetRxConfig( MODEM_LORA, LORA_BANDWIDTH, LORA_SPREADING_FACTOR,
                         LORA_CODINGRATE, 0, LORA_PREAMBLE_LENGTH,
                         LORA_SYMBOL_TIMEOUT, LORA_FIX_LENGTH_PAYLOAD_ON, 0,
                         LORA_CRC_ENABLED, LORA_FHSS_ENABLED, LORA_NB_SYMB_HOP,
                         LORA_IQ_INVERSION_ON, true );

#elif USE_MODEM_FSK == 1

    debug("\n\n\r              > FSK Mode < \n\n\r" );
    Radio.SetTxConfig( MODEM_FSK, TX_OUTPUT_POWER, FSK_FDEV, 0,
                         FSK_DATARATE, 0,
                         FSK_PREAMBLE_LENGTH, FSK_FIX_LENGTH_PAYLOAD_ON,
                         FSK_CRC_ENABLED, 0, 0, 0, 3000 );

    Radio.SetRxConfig( MODEM_FSK, FSK_BANDWIDTH, FSK_DATARATE,
                         0, FSK_AFC_BANDWIDTH, FSK_PREAMBLE_LENGTH,
                         0, FSK_FIX_LENGTH_PAYLOAD_ON, 0, FSK_CRC_ENABLED,
                         0, 0, false, true );

#else

#error "Please define a modem in the compiler options."

#endif

    debug_if( DEBUG_MESSAGE, "Starting Ping-Pong loop\r\n" );

    led = 0;

    Radio.Rx( RX_TIMEOUT_VALUE );

    while( 1 )
    {
        switch( State )
        {
        case RX:
            if( isMaster == true )
            {
                if( BufferSize > 0 )
                {
                    if( strncmp( ( const char* )Buffer, ( const char* )PongMsg, 4 ) == 0 )
                    {
                        led = !led;
                        debug( "...Pong\r\n" );
                        // Send the next PING frame
                        strcpy( ( char* )Buffer, ( char* )PingMsg );
                        // We fill the buffer with numbers for the payload
                        for( i = 4; i < BufferSize; i++ )
                        {
                            Buffer[i] = i - 4;
                        }
                        wait_ms( 10 );
                        Radio.Send( Buffer, BufferSize );
                    }
                    else if( strncmp( ( const char* )Buffer, ( const char* )PingMsg, 4 ) == 0 )
                    { // A master already exists then become a slave
                        debug( "...Ping\r\n" );
                        led = !led;
                        isMaster = false;
                        // Send the next PONG frame
                        strcpy( ( char* )Buffer, ( char* )PongMsg );
                        // We fill the buffer with numbers for the payload
                        for( i = 4; i < BufferSize; i++ )
                        {
                            Buffer[i] = i - 4;
                        }
                        wait_ms( 10 );
                        Radio.Send( Buffer, BufferSize );
                    }
                    else // valid reception but neither a PING or a PONG message
                    {    // Set device as master ans start again
                        isMaster = true;
                        Radio.Rx( RX_TIMEOUT_VALUE );
                    }
                }
            }
            else
            {
                if( BufferSize > 0 )
                {
                    if( strncmp( ( const char* )Buffer, ( const char* )PingMsg, 4 ) == 0 )
                    {
                        led = !led;
                        debug( "...Ping\r\n" );
                        // Send the reply to the PING string
                        strcpy( ( char* )Buffer, ( char* )PongMsg );
                        // We fill the buffer with numbers for the payload
                        for( i = 4; i < BufferSize; i++ )
                        {
                            Buffer[i] = i - 4;
                        }
                        wait_ms( 10 );
                        Radio.Send( Buffer, BufferSize );
                    }
                    else // valid reception but not a PING as expected
                    {    // Set device as master and start again
                        isMaster = true;
                        Radio.Rx( RX_TIMEOUT_VALUE );
                    }
                }
            }
            State = LOWPOWER;
            break;
        case TX:
            led = !led;
            if( isMaster == true )  
            {
                debug( "Ping...\r\n" );
            }
            else
            {
                debug( "Pong...\r\n" );
            }
            Radio.Rx( RX_TIMEOUT_VALUE );
            State = LOWPOWER;
            break;
        case RX_TIMEOUT:
            if( isMaster == true )
            {
                // Send the next PING frame
                strcpy( ( char* )Buffer, ( char* )PingMsg );
                for( i = 4; i < BufferSize; i++ )
                {
                    Buffer[i] = i - 4;
                }
                wait_ms( 10 );
                Radio.Send( Buffer, BufferSize );
            }
            else
            {
                Radio.Rx( RX_TIMEOUT_VALUE );
            }
            State = LOWPOWER;
            break;
        case RX_ERROR:
            // We have received a Packet with a CRC error, send reply as if packet was correct
            if( isMaster == true )
            {
                // Send the next PING frame
                strcpy( ( char* )Buffer, ( char* )PingMsg );
                for( i = 4; i < BufferSize; i++ )
                {
                    Buffer[i] = i - 4;
                }
                wait_ms( 10 );
                Radio.Send( Buffer, BufferSize );
            }
            else
            {
                // Send the next PONG frame
                strcpy( ( char* )Buffer, ( char* )PongMsg );
                for( i = 4; i < BufferSize; i++ )
                {
                    Buffer[i] = i - 4;
                }
                wait_ms( 10 );
                Radio.Send( Buffer, BufferSize );
            }
            State = LOWPOWER;
            break;
        case TX_TIMEOUT:
            Radio.Rx( RX_TIMEOUT_VALUE );
            State = LOWPOWER;
            break;
        case LOWPOWER:
            break;
        default:
            State = LOWPOWER;
            break;
        }
    }
}

void OnTxDone( void )
{
    Radio.SetChannel( HoppingFrequencies[0] );
    Radio.Sleep( );
    State = TX;
    debug_if( DEBUG_MESSAGE, "> OnTxDone\n\r" );
}

void OnRxDone( uint8_t *payload, uint16_t size, int16_t rssi, int8_t snr )
{
    Radio.SetChannel( HoppingFrequencies[0] );
    Radio.Sleep( );
    BufferSize = size;
    memcpy( Buffer, payload, BufferSize );
    RssiValue = rssi;
    SnrValue = snr;
    State = RX;
    debug_if( DEBUG_MESSAGE, "> OnRxDone\n\r" );
}

void OnTxTimeout( void )
{
    Radio.SetChannel( HoppingFrequencies[0] );
    Radio.Sleep( );
    State = TX_TIMEOUT;
    debug_if( DEBUG_MESSAGE, "> OnTxTimeout\n\r" );
}

void OnRxTimeout( void )
{
    Radio.SetChannel( HoppingFrequencies[0] );
    Radio.Sleep( );
    Buffer[BufferSize] = 0;
    State = RX_TIMEOUT;
    debug_if( DEBUG_MESSAGE, "> OnRxTimeout\n\r" );
}

void OnRxError( void )
{
    Radio.SetChannel( HoppingFrequencies[0] );
    Radio.Sleep( );
    State = RX_ERROR;
    debug_if( DEBUG_MESSAGE, "> OnRxError\n\r" );
}

void OnFhssChangeChannel( uint8_t channelIndex )
{
    Radio.SetChannel( HoppingFrequencies[channelIndex] );
    debug_if( DEBUG_MESSAGE, "F%d-", channelIndex );
}