/*
TMRh20 2014 - Updated to work with optimized RF24 Arduino library
*/


/**
 * Example for efficient call-response using ack-payloads
 *
 * This example continues to make use of all the normal functionality of the radios including
 * the auto-ack and auto-retry features, but allows ack-payloads to be written optionlly as well.
 * This allows very fast call-response communication, with the responding radio never having to
 * switch out of Primary Receiver mode to send back a payload, but having the option to switch to
 * primary transmitter if wanting to initiate communication instead of respond to a commmunication.
 */

#include <cstdlib>
#include <iostream>
#include <sstream>
#include <string>
#include <unistd.h>
#include <RF24/RF24.h>

using namespace std;

//
// Hardware configuration
// Configure the appropriate pins for your connections

/****************** Linux ***********************/
// Radio CE Pin, CSN Pin, SPI Speed
// CE Pin uses GPIO number with BCM and SPIDEV drivers, other platforms use their own pin numbering
// CS Pin addresses the SPI bus number at /dev/spidev<a>.<b>
// ie: RF24 radio(<ce_pin>, <a>*10+<b>); spidev1.0 is 10, spidev1.1 is 11 etc..

// Generic:
RF24 radio(22,0);

/****************** Linux (BBB,x86,etc) ***********************/
// See http://tmrh20.github.io/RF24/pages.html for more information on usage
// See http://iotdk.intel.com/docs/master/mraa/ for more information on MRAA
// See https://www.kernel.org/doc/Documentation/spi/spidev for more information on SPIDEV

/********** User Config *********/
// Assign a unique identifier for this node, 0 or 1. Arduino example uses radioNumber 0 by default.
bool radioNumber = 1;

/********************************/


// Radio pipe addresses for the 2 nodes to communicate.
const uint8_t addresses[][6] = {"1Node", "2Node"};

bool role_ping_out = 1, role_pong_back = 0, role = 0;
uint8_t counter = 1;                                                          // A single byte to keep track of the data being sent back and forth


int main(int argc, char** argv)
{

    cout << "RPi/RF24/examples/gettingstarted_call_response\n";
    radio.begin();
    radio.enableAckPayload();               // Allow optional ack payloads
    radio.enableDynamicPayloads();
    radio.printDetails();                   // Dump the configuration of the rf unit for debugging


    /********* Role chooser ***********/

    printf("\n ************ Role Setup ***********\n");
    string input = "";
    char myChar = {0};
    cout << "Choose a role: Enter 0 for pong_back, 1 for ping_out (CTRL+C to exit)\n>";
    getline(cin, input);

    if (input.length() == 1) {
        myChar = input[0];
        if (myChar == '0') {
            cout << "Role: Pong Back, awaiting transmission " << endl << endl;
        } else {
            cout << "Role: Ping Out, starting transmission " << endl << endl;
            role = role_ping_out;
        }
    }
    /***********************************/
    // This opens two pipes for these two nodes to communicate
    // back and forth.
    if (!radioNumber) {
        radio.openWritingPipe(addresses[0]);
        radio.openReadingPipe(1, addresses[1]);
    } else {
        radio.openWritingPipe(addresses[1]);
        radio.openReadingPipe(1, addresses[0]);
    }
    radio.startListening();
    radio.writeAckPayload(1, &counter, 1);

    // forever loop
    while (1) {


        /****************** Ping Out Role ***************************/

        if (role == role_ping_out) {                               // Radio is in ping mode

            uint8_t gotByte;                                        // Initialize a variable for the incoming response

            radio.stopListening();                                  // First, stop listening so we can talk.
            printf("Now sending %d as payload. ", counter);          // Use a simple byte counter as payload
            unsigned long time = millis();                          // Record the current microsecond count

            if (radio.write(&counter, 1)) {                         // Send the counter variable to the other radio
                if (!radio.available()) {                             // If nothing in the buffer, we got an ack but it is blank
                    printf("Got blank response. round-trip delay: %lu ms\n\r", millis() - time);
                } else {
                    while (radio.available()) {                      // If an ack with payload was received
                        radio.read(&gotByte, 1);                  // Read it, and display the response time
                        printf("Got response %d, round-trip delay: %lu ms\n\r", gotByte, millis() - time);
                        counter++;                                  // Increment the counter variable
                    }
                }

            } else {
                printf("Sending failed.\n\r");
            }          // If no ack response, sending failed

            sleep(1);  // Try again later
        }

        /****************** Pong Back Role ***************************/

        if (role == role_pong_back) {
            uint8_t pipeNo, gotByte;                        // Declare variables for the pipe and the byte received
            if (radio.available(&pipeNo)) {                // Read all available payloads
                radio.read(&gotByte, 1);
                // Since this is a call-response. Respond directly with an ack payload.
                gotByte += 1;                                // Ack payloads are much more efficient than switching to transmit mode to respond to a call
                radio.writeAckPayload(pipeNo, &gotByte, 1);   // This can be commented out to send empty payloads.
                printf("Loaded next response %d \n\r", gotByte);
                delay(900); //Delay after a response to minimize CPU usage on RPi
                //Expects a payload every second
            }
        }

    } //while 1
} //main