/**
   Arduino Electronic Safe

   Copyright (C) 2020, Uri Shaked.
   Released under the MIT License.
*/

#include <LiquidCrystal.h>
#include <Keypad.h>
/* Display */
LiquidCrystal lcd(12, 11, 10, 9, 8, 13);

/* Keypad setup */
const byte KEYPAD_ROWS = 4;
const byte KEYPAD_COLS = 4;
byte rowPins[KEYPAD_ROWS] = {7, 6,5 , 4};
byte colPins[KEYPAD_COLS] = {A3, A2, A1, A0};
char keys[KEYPAD_ROWS][KEYPAD_COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, KEYPAD_ROWS, KEYPAD_COLS);
const int heaterValues[] = {4, 6, 10, 12, 15, 18, 35, 35, 70, 70, 70, 140}; // Heater power values
const int numHeaters = sizeof(heaterValues) / sizeof(heaterValues[0]);
const int maxLoad = 485;

int currentLoad = 0; // Initial load value
String input = "";

void setup() {
  lcd.begin(16, 2);
  for (int pin = 22; pin <= 33; pin++) {
    pinMode(pin, OUTPUT); // Set digital output pins for SSRs
    digitalWrite(pin, LOW); // Initially turn off all SSRs
  }
  lcd.print("Welcome!");
  delay(2000); // Display welcome for 2 seconds
  lcd.clear();
  updateDisplay();
}

void loop() {
  char key = keypad.getKey();
  if (key) {
    if (key == '#') { // Confirm input
      if (input.length() > 0) {
        int newLoad = input.toInt();
        if (newLoad >= 0 && newLoad <= 880) {
          currentLoad = newLoad; // Update current load
          calculateAndControlLoad(currentLoad);
        }
        input = ""; // Clear input
        updateDisplay();
      }
    } else if (key == '*') { // Clear input
      input = "";
    } else {
      if (input.length() < 3) {
        input += key; // Append key to input
      }
    }
    updateInputDisplay();
  }
}

void calculateAndControlLoad(int targetLoad) {
  int bestCombination[numHeaters] = {0}; // Track which heaters are on
  int bestLoad = 0;

  for (int i = 0; i < (1 << numHeaters); i++) { // Iterate through all combinations
    int totalLoad = 0;
    for (int j = 0; j < numHeaters; j++) {
      if (i & (1 << j)) {
        totalLoad += heaterValues[j]; // Add heater load if it's on
      }
    }
    // Check if this combination is valid and closer to the target load
    if (totalLoad <= maxLoad && totalLoad <= targetLoad && totalLoad > bestLoad) {
      bestLoad = totalLoad;
      for (int j = 0; j < numHeaters; j++) {
        bestCombination[j] = (i & (1 << j)) ? 1 : 0; // Store the combination
      }
    }
  }

  // Control the SSRs based on the best combination
  for (int pin = 22; pin <= 33; pin++) {
    digitalWrite(pin, LOW); // Turn off all SSRs
  }
  for (int j = 0; j < numHeaters; j++) {
    if (bestCombination[j]) {
      digitalWrite(22 + j, HIGH); // Turn on selected SSRs
    }
  }

  // Update the display with the best load applied
  currentLoad = bestLoad; // Update current load to the best load found
}

void updateDisplay() {
  lcd.clear();
  lcd.print("Load: ");
  lcd.print(currentLoad < 100 ? "0" : ""); // Leading zeros
  lcd.print(currentLoad < 10 ? "0" : "");
  lcd.print(currentLoad);
  lcd.print(" kw");
}

void updateInputDisplay() {
  lcd.setCursor(0, 1);
  lcd.print("Input: ");
  lcd.print(input);
  lcd.print("   "); // Clear the rest of the line
}