#include <Adafruit_NeoPixel.h>

// Define parameters for the LED strip
int ledPin = 13;
int ledCount = 42;

// Define trig and echo pins for the ultrasonic sensors
const int column1_trigPin = 2;
const int column1_echoPin = 3;
const int column2_trigPin = 4;
const int column2_echoPin = 5;
const int column3_trigPin = 6;
const int column3_echoPin = 7;
const int column4_trigPin = 8;
const int column4_echoPin = 9;
const int column5_trigPin = 10;
const int column5_echoPin = 11;
const int column6_trigPin = A0;
const int column6_echoPin = A1;
const int column7_trigPin = A2;
const int column7_echoPin = A3;

// Initialise variables for detecting tokens
long duration; // makes a long variable named duration
int distance; // makes an integer variable named distance

// Variable for identifying LED ids
int LedIds[][6][2] = {{{36, 0}, {37, 0}, {38, 0}, {39, 0}, {40, 0}, {41, 0}}, // {{bottom -> top}}
{{35, 0}, {34, 0}, {33, 0}, {32, 0}, {31, 0}, {30, 0}}, // {id, on/off (0/1)}
{{24, 0}, {25, 0}, {26, 0}, {27, 0}, {28, 0}, {29, 0}},
{{23, 0}, {22, 0}, {21, 0}, {20, 0}, {19, 0}, {18, 0}},
{{12, 0}, {13, 0}, {14, 0}, {15, 0}, {16, 0}, {17, 0}},
{{11, 0}, {10, 0}, {9, 0}, {8, 0}, {7, 0}, {6, 0}},
{{0, 0}, {1, 0}, {2, 0}, {3, 0}, {4, 0}, {5, 0}}};

Adafruit_NeoPixel strip(ledCount, ledPin, NEO_GRB + NEO_KHZ800);

int turn = 1; // Keeping track of player turns

const int columnPins[][2] = {{2, 3}, {4, 5}, {6, 7}, {8, 9}, {10, 11}, {A0, A1}, {A2, A3}}; // {TRIG, ECHO}

void setup() {
  // Set ultrasonic sensor pins for input/output
  for (int x = 0; x < 7; x++) {
    pinMode(columnPins[x][0], OUTPUT);
    pinMode(columnPins[x][1], INPUT); 
  }

  // Initialise LED strip
  strip.begin();
  strip.show();

  Serial.begin(9600); // Starts the serial communication on baud rate 9600
}

void loop() {

  // Detect tokens through each of the ultrasonic sensors
  for (int x = 0; x < 7; x++) {
    digitalWrite(columnPins[x][0], LOW); // Resets the trigPin
    delayMicroseconds(2); // Waits 2 microsenconds
    digitalWrite(columnPins[x][0], HIGH); // Sets the trigPin state to HIGH
    delayMicroseconds(10); // Waits 10 microseconds
    digitalWrite(columnPins[x][0], LOW); // Sets the trigPin state to LOW
    duration = pulseIn(columnPins[x][1], HIGH); // Reads the echoPin and assign it to the variable duration
    distance= duration*0.034/2; // Calculation of the distance

    if (distance < 3){ // 3cm
      AddToken(x); // Add token to the corresponding column
      delay(1000);
    }
  }
  delay(100); // Detect every 0.1 seconds
}

// Function for inserting a token into a column
int AddToken(int columnIndex){
  int bottomTokenIndex = 0;
  for (int x = 0; x <= 5; x++) { // Iterate to identify the lowest free slot
    if (LedIds[columnIndex][x][1] == 1){ // If slot is not empty
      bottomTokenIndex += 1; 
    }
  }

  if (bottomTokenIndex < 6){ // If column is not full
    if (turn == 1){
      for (int x = 5; x >= bottomTokenIndex; x--) { // Toggle each empty slot in order to create dropping animation
        strip.setPixelColor(LedIds[columnIndex][x][0], 255, 0, 0);
        strip.show();
        delay(100);
        strip.setPixelColor(LedIds[columnIndex][x][0], 0, 0, 0);
        strip.show();
      }
      strip.setPixelColor(LedIds[columnIndex][bottomTokenIndex][0], 255, 0, 0);
      strip.show();
      LedIds[columnIndex][bottomTokenIndex][1] = 1; // Rewrite array to set slot as filled
    }
    else{
      for (int x = 5; x >= bottomTokenIndex; x--) {
        strip.setPixelColor(LedIds[columnIndex][x][0], 255, 255, 0);
        strip.show();
        delay(100);
        strip.setPixelColor(LedIds[columnIndex][x][0], 0, 0, 0);
        strip.show();
      }
      strip.setPixelColor(LedIds[columnIndex][bottomTokenIndex][0], 255, 255, 0);
      strip.show();
      LedIds[columnIndex][bottomTokenIndex][1] = 1;
    }
  }

  // Switch turns
  if (turn == 1){
    return turn = 2;
  }
  else{
    return turn = 1;
  }
}