/*
  Arduino Mega Peristaltic Pump Control (Standalone B/C)
  - 3 pumps run simultaneously based on keypad input volumes
  - 2 additional relays (4 & 5) toggled anytime by B/C, independent of A
  - Each B/C key press toggles its relay state
  - D key stops all operations immediately
  - Keypad: digits to input volumes and '#' to confirm per pump
  - A key starts pumps sequence
  - LCD1602 I2C (SDA->20, SCL->21) displays status
*/

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>

// I2C LCD setup
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Keypad setup
const byte ROWS = 4, COLS = 4;
char keys[ROWS][COLS] = {
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};
byte rowPins[ROWS] = {2, 3, 4, 5};
byte colPins[COLS] = {6, 7, A0, A1};
Keypad keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Relay pins
#define RELAY1_PIN 8
#define RELAY2_PIN 9
#define RELAY3_PIN 10
#define RELAY4_PIN 11  // B toggle
#define RELAY5_PIN 12  // C toggle

// States and timers
unsigned int volumes[3];       // ml per pump
unsigned long durations[3];    // ms per pump
bool r4State = false;
bool r5State = false;
bool readyToStart = false;
int inputPump = 0;

void setup() {
  Wire.begin();
  lcd.init(); lcd.backlight();

  // Configure relay outputs
  pinMode(RELAY1_PIN, OUTPUT);
  pinMode(RELAY2_PIN, OUTPUT);
  pinMode(RELAY3_PIN, OUTPUT);
  pinMode(RELAY4_PIN, OUTPUT);
  pinMode(RELAY5_PIN, OUTPUT);
  stopAll();

  // Initial prompt
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Peris.Pump Setup");
  delay(1000);
  promptPumpInput();
}

void loop() {
  char key = keypad.getKey();
  if (key) {
    // Always handle B/C/D immediately
    if (key == 'B') {
      r4State = !r4State;
      digitalWrite(RELAY4_PIN, r4State ? HIGH : LOW);
      updateStatus();
      return;
    }
    if (key == 'C') {
      r5State = !r5State;
      digitalWrite(RELAY5_PIN, r5State ? HIGH : LOW);
      updateStatus();
      return;
    }
    if (key == 'D') {
      stopAll();
      lcd.clear(); lcd.setCursor(0,0);
      lcd.print("Emergency Stop");
      delay(1000);
      readyToStart = false;
      promptPumpInput();
      return;
    }

    // Handle input or start
    if (!readyToStart) {
      handleVolumeInput(key);
    } else {
      if (key == 'A') {
        runSimultaneous();
        readyToStart = false;
        promptPumpInput();
      }
    }
  }
}

// Prompt volumes
void promptPumpInput() {
  inputPump = 0;
  for (int i = 0; i < 3; i++) volumes[i] = 0;
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("P1 ml: ");
  lcd.setCursor(0,1);
}

// Process numeric volume entry
void handleVolumeInput(char key) {
  if (isdigit(key)) {
    volumes[inputPump] = volumes[inputPump] * 10 + (key - '0');
    lcd.setCursor(0,1);
    lcd.print(volumes[inputPump]);
  }
  else if (key == '#') {
    durations[inputPump] = volumes[inputPump] * 600UL;
    inputPump++;
    if (inputPump < 3) {
      lcd.clear(); lcd.setCursor(0,0);
      lcd.print("P"); lcd.print(inputPump+1); lcd.print(" ml: ");
      lcd.setCursor(0,1);
    } else {
      readyToStart = true;
      lcd.clear(); lcd.setCursor(0,0);
      lcd.print("A:START B:R4");
      lcd.setCursor(0,1);
      lcd.print("C:R5 D:STOP");
    }
  }
}

// Run pumps together
void runSimultaneous() {
  // Activate pumps
  digitalWrite(RELAY1_PIN, HIGH);
  digitalWrite(RELAY2_PIN, HIGH);
  digitalWrite(RELAY3_PIN, HIGH);

  unsigned long startT = millis();
  unsigned long maxDur = max(durations[0], max(durations[1], durations[2]));
  bool stopFlag = false;

  while (millis() - startT < maxDur) {
    // Display each pump remaining sequentially
    for (int i = 0; i < 3; i++) {
      unsigned long elapsed = millis() - startT;
      int remMl = (durations[i] > elapsed) ? (durations[i] - elapsed) / 600UL : 0;
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.print("P"); lcd.print(i+1);
      lcd.print(" Rem:"); lcd.print(remMl); lcd.print("ml");
      updateStatus();
      delay(200);
    }
  }

  // Deactivate pumps
  digitalWrite(RELAY1_PIN, LOW);
  digitalWrite(RELAY2_PIN, LOW);
  digitalWrite(RELAY3_PIN, LOW);
  lcd.clear(); lcd.setCursor(0,0);
  lcd.print("Process Done");
  delay(2000);
}

// Update LCD with relay statuses
void updateStatus() {
  lcd.setCursor(0,1);
  lcd.print("R4:"); lcd.print(r4State?"On ":"Off");
  lcd.print(" R5:"); lcd.print(r5State?"On ":"Off");
}

// Stop all relays
void stopAll() {
  digitalWrite(RELAY1_PIN, LOW);
  digitalWrite(RELAY2_PIN, LOW);
  digitalWrite(RELAY3_PIN, LOW);
  digitalWrite(RELAY4_PIN, LOW);
  digitalWrite(RELAY5_PIN, LOW);
  r4State = false;
  r5State = false;
}