/*
   Project: Four digit 7 segment stopwatch
   Description: Basic stopwatch sketch
   Creation date: 10/12/22
   Author: AnonEngineering

   https://wokwi.com/projects/343741010016207442
   https://wokwi.com/projects/345369455239365203

   License: Beerware
*/

const int NUM_DIGITS  = 4;
const int DP_POS      = 1; // where to place decimal point, -1 for none
//const bool COM_ANODE = true; // common anode = true, common cathode = false
const byte DIGIT_PINS[] = {8, 6, 5, 2}; // digit pins, digits 4 - 1 ( Left to right)
const byte SEG_PINS[]   = {3, 7, 10, 12, 13, 4, 9}; // segment pins A - G
const byte digitSegVals[10][7] {  // [digits 0 - 9], [segments A - G]
  {0, 0, 0, 0, 0, 0, 1}, //0
  {1, 0, 0, 1, 1, 1, 1}, //1
  {0, 0, 1, 0, 0, 1, 0}, //2
  {0, 0, 0, 0, 1, 1, 0}, //3
  {1, 0, 0, 1, 1, 0, 0}, //4
  {0, 1, 0, 0, 1, 0, 0}, //5
  {0, 1, 0, 0, 0, 0, 0}, //6
  {0, 0, 0, 1, 1, 1, 1}, //7
  {0, 0, 0, 0, 0, 0, 0}, //8
  {0, 0, 0, 1, 1, 0, 0}, //9
};
const int DP_PIN  = 11;
const int RUN_PIN = A5;
const int RST_PIN = A4;
const long DELAY_VAL = 100;

unsigned long prevTime = 0;
unsigned long lastBtn1Time = 0;
unsigned long lastBtn2Time = 0;
bool lastBtn1State = false;
bool lastBtn2State = false;
bool stateOne = false;
bool stateTwo = false;

void setup() {
  Serial.begin(9600);
  pinMode(RUN_PIN, INPUT_PULLUP);
  pinMode(RST_PIN, INPUT_PULLUP);
  for(int segVal = 0; segVal < (sizeof(SEG_PINS) / sizeof(SEG_PINS[0])); segVal++) {
    pinMode(SEG_PINS[segVal], OUTPUT);
  }
  for(int digitVal = 0; digitVal < NUM_DIGITS; digitVal++) {
    pinMode(SEG_PINS[digitVal], OUTPUT); 
  }
  pinMode(DP_PIN, OUTPUT);
  //digitalWrite(DP_PIN, HIGH); // turns DP off
}

void loop() {
  static int countVal = 0;

  checkButtons();
  if(stateOne == true)  {
    if(millis() - prevTime >= DELAY_VAL) {
      prevTime = millis();
      showDigits(countVal);
      countVal++;
      if(countVal >= pow(10, NUM_DIGITS)) countVal = 0;   // reset count
    }
  } else{
    showDigits(countVal);
  }
  if(stateTwo == true)  {
    countVal = 0;
  }
}

void showDigits(int value)  {
  int digitsToDisplay = 0;

  // Leading zero suppression, not great..
  //if(value < 10) {
    //digitsToDisplay = 0;
  //} else if(value < 100) {
  if(value < 100) {
    digitsToDisplay = 1;
  } else if(value < 1000) {
    digitsToDisplay = 2;
  } else {
    digitsToDisplay = 3;
  }

  for(int digit = digitsToDisplay; digit >= 0; digit--)  { // High digits first, higher power first
    driveSegments(int(value/pow(10, digit)) % 10);  // setup segment pins
    if (digit == DP_POS) digitalWrite(DP_PIN, LOW);  // turn on DP?
    digitalWrite(DIGIT_PINS[digit], HIGH);          // turn digit on
    digitalWrite(DIGIT_PINS[digit], LOW);           // turn digit & DP off
    digitalWrite(DP_PIN, HIGH); 
  }
}

void driveSegments(int digitVal) {
  for (int segVal = 0; segVal < (sizeof(SEG_PINS) / sizeof(SEG_PINS[0])); segVal++) {
    digitalWrite(SEG_PINS[segVal], digitSegVals[digitVal][segVal]);
  }
}

void checkButtons()  {
  // Read the pushbutton one input pin:
  int btn1State = digitalRead(RUN_PIN);
  // Compare the button reading to its previous reading
  if (btn1State != lastBtn1State) {
    // If the reading has changed, update the state based on the reading
    if (btn1State == LOW) {
      // If the current reading is LOW then the button went from off to on:
      stateOne = ! stateOne; //true; // set state one
      if(stateOne == true)  {
        Serial.println(F("Start"));
      } else{
        Serial.println(F("Stop"));
      }
    } else {
      // If the current state is HIGH then the button went from on to off:
      //Serial.println(F("Start released"));
    }
    // Save the current reading as the last reading, for next time through the loop
    lastBtn1State = btn1State;
    // Delay a little bit to avoid bouncing
    delay(20);
  }
    // Read the pushbutton two input pin:
  int btn2State = digitalRead(RST_PIN);
  // Compare the button reading to its previous reading
  if (btn2State != lastBtn2State) {
    // If the reading has changed, update the state based on the reading
    if (btn2State == LOW) {
      // If the current reading is LOW then the button went from off to on:
      stateTwo = true; // set state two
      Serial.println(F("Reset"));
    } else {
      // If the current state is HIGH then the button went from on to off:
      stateTwo = false; // set state two
      //Serial.println(F("Reset released"));
    }
    // Save the current reading as the last reading, for next time through the loop
    lastBtn2State = btn2State;
    // Delay a little bit to avoid bouncing
    delay(20);
  }
}