/*
 * Decoder for traffic light with three or two leds on ARDUINO NANO
 * 
 * by default the red leds are switched on
 * pin 2 receives DCC interrupts
 * 
 * TRAFFIC LIGHT WITH THREE leds (GREEN, RED, YELLOW)
 * 5 decoders of traffic lights with three leds on Arduino NANO/UNO
 * the leds are controlled by pins 3 to A3 by triplet
 * traffic light 1 : 3,4,5
 * traffic light 2 : 6,7,8
 * traffic light 3 : 9,10,11
 * traffic light 4 : 12,13,A0
 * traffic light 5 : A1,A2,A3
 * two addresses by traffic light
 * even addresses for green and red lights
 * odd addresses for yellow light
 * 
 * TRAFFIC LIGHT WITH TWO leds (GREEN, RED)
 * 8 decoders of traffic lights with two leds on Arduino NANO/UNO
 * the leds are controlled by pins 3 to A4 by pair
 * traffic light 1 : 3,4
 * traffic light 2 : 5,6
 * traffic light 3 : 7,8
 * traffic light 4 : 9,10
 * traffic light 5 : 11,12
 * traffic light 6 : 13,A0
 * traffic light 7 : A1,A2
 * traffic light 8 : A3,A4
 * one address by traffic light
 * 
 * CONFIGURATION
 * MODE : determined by the common of the led, LOW if common = HIGH, HIGH if common = LOW
 * FIRST_ID_DCC : DCC address of the first traffic light
 * NB_TRAFFIC_LIGHT : determined by the kind of traffic light, BICOLOR for two leds, TRICOLOR for three leds
 * 
 */

/***************************************************************************************           
 *            CONFIGURATION SETTING
 *            
 ****************************************************************************************/
 
#define CONSOLE                             // output console, delete this after checking the configuration
#define MODE   LOW                          // LOW or HIGH
#define FIRST_ID_DCC   90                   // first DCC address, DCC_CODE
#define NB_TRAFFIC_LIGHT  TRICOLOR           //  TRICOLOR or BICOLOR 

/**********************************************************************************  
 *   DON'T CHANGE THE FOLLOWING
 *********************************************************************************/
 
/******************************************************************************
 *    INTERNAL PARAMETERS
 *    
 ********************************************************************************/
 
//  DCC

#include <DCC_Decoder.h>                 // Minabay library
#define kDCC_INTERRUPT    0             // pin 2 receives DCC interrupts
int previous_address = 0;               // avoids multiple DCC addresses
int previous_position = 2;              // avoids multiple DCC orders
volatile boolean update_light;          // set if an update should be processed after DCC control

// traffic light

#define BICOLOR  8                     // 8 traffic lights with two leds
#define TRICOLOR 5                     // 5 traffic lights with three leds
#define FIRST_PIN         3             // pin of the first traffic light
#define GREEN             0             // address DCC/0
#define RED               1             // address DCC/1 
#define YELLOW            2             // address DCC+1/0

// traffic light definition

struct light {
  int address;                    // its DCC address
  int current_position;           // green / red / yellow
  int green;                      // pin of the green led
  int red;                        // pin of the red led
  int yellow;                     // pin of the yellow led
  boolean activation_request;     // request of activation
};
light traffic_light[NB_TRAFFIC_LIGHT];    // the set of traffic light

/********************************************************************
 * method called if a request is made by the DCC
 * 
 *******************************************************************/
 
void activation_traffic_light() {
  for (int i = 0; i < NB_TRAFFIC_LIGHT; i++)                 // for all traffic lights
  {
    if (traffic_light[i].activation_request == true)  // if the traffic_light is waiting for activation
    {
      switch(traffic_light[i].current_position)            // we look the current position
      { 
        case GREEN :{                                                     // if green led
                      digitalWrite(traffic_light[i].green,MODE);         // switch on green
                      digitalWrite(traffic_light[i].red,!MODE);          // switch off red
                      if ( NB_TRAFFIC_LIGHT == TRICOLOR){digitalWrite(traffic_light[i].yellow,!MODE);} // switch off yellow
                      #ifdef CONSOLE
                        Serial.print("activation -> traffic light");Serial.print(i);Serial.println(" : green led");
                      #endif
                      break;}
        case RED : {                                                  // if red led
                      digitalWrite(traffic_light[i].green,!MODE);      // switch off green
                      digitalWrite(traffic_light[i].red,MODE);         // switch on red
                      if ( NB_TRAFFIC_LIGHT == TRICOLOR){digitalWrite(traffic_light[i].yellow,!MODE);} // switch off yellow
                      #ifdef CONSOLE
                        Serial.print("activation -> traffic light");Serial.print(i);Serial.println(" : red led");
                      #endif
                     break;}
         case YELLOW : {                                                  // if yellow led
                      digitalWrite(traffic_light[i].green,!MODE);         // switch off green 
                      digitalWrite(traffic_light[i].red,!MODE);           // switch off red
                      digitalWrite(traffic_light[i].yellow,MODE);         // switch on yellow
                      #ifdef CONSOLE
                        Serial.print("activation -> traffic light");Serial.print(i);Serial.println(" : yellow led");
                      #endif
                     break;}
         }
           }
       traffic_light[i].activation_request = false;            // the traffic light is updated
      }
  update_light = false;                                        // all updates are made
}

/************************************************************************************* 
 *  DCC method
 *  
 ***********************************************************************************/

void BasicAccDecoderPacket_Handler(int address, boolean activate, byte data)
{  
  
  address -= 1; address *= 4; address += 1; address += (data & 0x06) >> 1;    // DCC address decoding
  int led = (data & 0x01) ? GREEN : RED;                                      // DCC/0 or DCC/1
  int traffic_light_index = address;                                          // index of a traffic light   
  int color = led;                                                            // the color of the led
  boolean activation = false;
  if ((address != previous_address) || ((led != previous_position)&&(address == previous_address))){ // if we change the address or the led
        switch (NB_TRAFFIC_LIGHT) {
          case BICOLOR : {      // if the address is in our range for traffic light with two leds
                    if ((address >= FIRST_ID_DCC) && (address < FIRST_ID_DCC + NB_TRAFFIC_LIGHT)){ 
                      traffic_light_index = address - FIRST_ID_DCC;                                  // index of the traffic light
                      activation = true;}
                        break;}
          case TRICOLOR : {     // if the address is in our range for traffic light with three leds
                    if ((address >= FIRST_ID_DCC) && (address < FIRST_ID_DCC + (2*NB_TRAFFIC_LIGHT))){ 
                      if (address%2 != 0) {  traffic_light_index = address - 1; color = YELLOW;}         // if odd address => yellow led
                        traffic_light_index = (traffic_light_index - FIRST_ID_DCC)/2;                    // index of the traffic light
                        activation = true;}
                        break;}
        }
     traffic_light[traffic_light_index].activation_request =  activation;    // activation is requested
     traffic_light[traffic_light_index].current_position = color;            // state is requested (color of the led)
     update_light = activation;                                              // traffic light update is requested
    }
   previous_address = address; previous_position = led;                    // the current activation is saved
  }
/**********************************************************************************************
 *  setup
 * 
 ******************************************************************************************/

void setup() {
  int pin_jump = 0;                                                     // a jump for traffic light pins
  int traffic_light_jump = 0;                                           // a jump for traffic light number
  for (int i=0; i<NB_TRAFFIC_LIGHT; i++){                               // for all the traffic lights
    traffic_light[i].activation_request = false;                        // no activation request
    traffic_light[i].green = pin_jump + FIRST_PIN;                      // pin number of the green led
    pinMode(traffic_light[i].green, OUTPUT);                            // green led in output(ID DCC/0)                                                                                                                                                                                                                                                                   
    digitalWrite(traffic_light[i].green, !MODE);                       // green led switch off
    traffic_light[i].red = 1+ pin_jump + FIRST_PIN;                    // pin number of the red led
    pinMode(traffic_light[i].red, OUTPUT);                             // red led in output  (ID DCC/1)
    digitalWrite(traffic_light[i].red, MODE);                          // red led switch on
    if (NB_TRAFFIC_LIGHT == TRICOLOR) {                                // if three leds
      traffic_light[i].address = traffic_light_jump + FIRST_ID_DCC + i;   // its DCC ID
      traffic_light[i].yellow = 2+ pin_jump + FIRST_PIN;               // pin number of the yellow led
      pinMode(traffic_light[i].yellow, OUTPUT);                        // yellow led in output  (ID DCC+1/0)
      digitalWrite(traffic_light[i].yellow, !MODE);                    // yellow led switch off
      traffic_light_jump++;                                             // the following traffic light 
      pin_jump+=3;                                                     // the following pin for three leds
          }
    else {                                                             // if two leds
         traffic_light[i].address = FIRST_ID_DCC + i;                  // its DCC ID
        pin_jump+=2;                                                   // the following pin for two leds
        }
 
  }
  
  DCC.SetBasicAccessoryDecoderPacketHandler(BasicAccDecoderPacket_Handler, true);   // instanciate the DCC
  DCC.SetupDecoder( 0x00, 0x00, kDCC_INTERRUPT );                                   // its IT
  update_light = false;                                                             // no update
  
  #ifdef CONSOLE
   Serial.begin(115200);
   for (int i=0; i<NB_TRAFFIC_LIGHT; i++){
    Serial.print("traffic light");Serial.println(i);
    Serial.print("\t green led on pin : ");Serial.print(traffic_light[i].green);Serial.print(" , DCC address : ");Serial.print(traffic_light[i].address);Serial.println("/0"); 
    Serial.print("\t red led on pin : ");Serial.print(traffic_light[i].red);Serial.print(" , DCC address : ");Serial.print(traffic_light[i].address);Serial.println("/1");
    if (NB_TRAFFIC_LIGHT == TRICOLOR) {
      Serial.print("\t yellow led on pin : ");Serial.print(traffic_light[i].yellow);Serial.print(" , DCC address : ");Serial.print(traffic_light[i].address+1);Serial.println("/0");
      }
   }
  #endif
}

/*************************************************************************
 * loop
 * 
 ******************************************************************/
 
void loop() {
  DCC.loop();                                              // Is there a DCC command ?
  if (update_light) {activation_traffic_light();}          // if yes, activation of traffic lights
}