/**
  //   Arduino Display Keypad
  //
  //   Copyright (C) 2023, Bins.
*/

#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
#include <ctype.h>
#include <EEPROM.h>

/* Display setup */
LiquidCrystal_I2C lcd(0x27, 20, 4);

/* Keypad setup */
const byte KEYPAD_ROWS = 4;
const byte KEYPAD_COLS = 4;
byte rowPins[KEYPAD_ROWS] = { 2, 3, 4, 5 };
byte colPins[KEYPAD_COLS] = { 6, 7, 8, 9 };
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);

unsigned int mode = 0;
unsigned int settingsMode = 0;

// System States
bool confirm = false;
bool charging = false;
bool cancelled = false;
bool completed = false;

String input = "";

// VARIABLES: Amount Mode
float amount = 0.00f;

// VARIABLES: Time Mode
int seconds = 0;
int minutes = 0;
String timeString = "";

// Sensor values
float voltage = 0.00;
float current = 0.00;

// VARIABLES: Rate
float rate = 0.00f;
float price = 0.00;
float area_last_inner_segment = 0.0;
float area_inner = 0.0;
float area = 0.5 * area_inner;

unsigned long charging_time = 0;

unsigned long lastExecutedMillis = 0;

unsigned long lastMillisAbout = 0;
int aboutInterval = 3000;
bool aboutFirstPage = true;

bool cancelLED = false;
int interval = 2000;

unsigned int address = 0;
unsigned int length = EEPROM.length();

void setup() {
  Serial.begin(115200);
  Serial.println("E-Jeep Charging");

  Serial.println("Initializing LCD");
  lcd.init();
  lcd.backlight();
  lcd.noBlink();
  Serial.println("LCD Initialized.");

  pinMode(11, OUTPUT);
  pinMode(12, OUTPUT);
  pinMode(13, OUTPUT);

  // ======== EEPROM ===========
  Serial.println("Initialize EEPROM...");
  Serial.print("EEPROM Length: ");
  Serial.println(length);

  // Read from EEPROM
  EEPROM.get(address, rate);

  if (isnan(rate)) {
    Serial.println("EEPROM: EMPTY. Adding default values.");
    EEPROM.put(address, 0.00f);  // Set value
    EEPROM.get(address, rate);   // Read again
    Serial.print("EEPROM data added: ");
    Serial.println(rate);
  } else {
    Serial.println("EEPROM: Has value.");
    Serial.print("EEPROM data: ");
    Serial.println(rate);
  }

  // showSplashScreen();
  showMenuScreen();
}

void loop() {
  unsigned long currentMillis = millis();

  voltage = map(analogRead(A0), 0, 1023, 0, 70.0);
  current = map(analogRead(A1), 0, 1023, 0, 10.0);

  if (charging) {
    if (mode == 1) showChargingScreen();
    if (mode == 2) showChargingScreenTime();
  }

  if (completed) {
    if (mode == 2) showChargeCompleteTime();
    charging = false;
  }

  char key = keypad.getKey();
  if (key) {
    processInput(key);
  }

  digitalWrite(12, cancelLED);

  if (charging) {
    digitalWrite(11, HIGH);
    digitalWrite(12, HIGH);
    digitalWrite(13, LOW);
  } else {
    if (cancelled) {
      digitalWrite(11, LOW);
      if (currentMillis - lastExecutedMillis >= interval) {
        lastExecutedMillis = currentMillis;
        cancelLED = !cancelLED;
      }

    } else {
      digitalWrite(11, LOW);
      digitalWrite(12, LOW);
      digitalWrite(13, HIGH);
    }
  }

  if (mode == 3 && settingsMode == 2) {
    if (currentMillis - lastMillisAbout >= aboutInterval) {
      lastMillisAbout = currentMillis;
      if (aboutFirstPage) {
        lcd.setCursor(0, 1);
        lcd.print("                    ");
        lcd.setCursor(0, 2);
        lcd.print("                    ");
        lcd.setCursor(0, 1);
        lcd.print("* Alemania, Ronn");
        lcd.setCursor(0, 2);
        lcd.print("* Carmona, Andrea");
      } else {
        lcd.setCursor(0, 1);
        lcd.print("                    ");
        lcd.setCursor(0, 2);
        lcd.print("                    ");
        lcd.setCursor(0, 1);
        lcd.print("* Ngalatan, Francis");
        lcd.setCursor(0, 2);
        lcd.print("* Quizon, John Lloyd");
      }
      aboutFirstPage = !aboutFirstPage;
    }
  }
}

String getTimeFromSeconds(int seconds) {
  unsigned int sec = seconds;
  unsigned int mins = seconds / 60;
  unsigned int hour = seconds / 3600;
  char buffer[40];
  sprintf(buffer, "%dh %dm %ds", hour, int(mins % 60), int(sec % 60));
  String timeString = buffer;
  return timeString;
}


void writeRate(float newRate) {
  EEPROM.put(address, newRate);
  EEPROM.get(address, rate);
  Serial.print("EEPROM: Data updated: ");
  Serial.println(rate);
}



void showSplashScreen() {
  lcd.clear();
  lcd.setCursor(2, 1);
  lcd.print("E-Jeep Prepaid");
  lcd.setCursor(2, 2);
  String message = "Charging Station";
  for (byte i = 0; i < message.length(); i++) {
    lcd.print(message[i]);
    delay(50);
  }
  delay(2000);
}

void showMenuScreen() {
  lcd.clear();
  lcd.noBlink();
  lcd.setCursor(0, 0);
  lcd.print("E-Jeep Charging");
  lcd.setCursor(0, 1);
  lcd.print("[A] Amount Mode");
  lcd.setCursor(0, 2);
  lcd.print("[B] Time Mode");
  lcd.setCursor(0, 3);
  lcd.print("[C] Set Mode");
  lcd.setCursor(17, 0);
  lcd.write(255);
  lcd.print(" M");
  lcd.setCursor(17, 1);
  lcd.write(255);
  lcd.print(" E");
  lcd.setCursor(17, 2);
  lcd.write(255);
  lcd.print(" N");
  lcd.setCursor(17, 3);
  lcd.write(255);
  lcd.print(" U");
}

void showChargingScreen() {
  lcd.noBlink();
  lcd.setCursor(0, 0);
  lcd.print("CHARGING: AMOUNT");
  lcd.setCursor(0, 1);
  lcd.print("PHP ");
  lcd.print(amount);
  lcd.setCursor(0, 2);
  lcd.print("12.23");
  lcd.print("/12.23 Ah");
  lcd.setCursor(0, 3);
  lcd.print("V: ");
  lcd.print(voltage);
  lcd.setCursor(9, 3);
  lcd.print(" A: ");
  lcd.print(current);
}

unsigned long lastMillisChargeScreen = 0;
unsigned long lastMillisUpdateTime = 0;
bool chargingScreenTimeInfo = false;
bool chargingScreenClean = false;
bool updateTime = true;

void showChargingScreenTime() {
  if (seconds == 0) {
    charging = 0;
    completed = 1;
    Serial.println("Charging Completed");
    lcd.setCursor(0, 3);
    lcd.clear();
  }

  unsigned long currentMillis = millis();
  if (currentMillis - lastMillisChargeScreen >= 4000) {
    lastMillisChargeScreen = currentMillis;
    chargingScreenTimeInfo = !chargingScreenTimeInfo;
  }
  if (currentMillis - lastMillisUpdateTime >= 1000) {
    lastMillisUpdateTime = currentMillis;
    seconds -= 1;
    updateTime = true;
  }

  lcd.noBlink();
  lcd.setCursor(0, 0);
  lcd.print("CHARGING: TIME");
  if (updateTime) {
    lcd.setCursor(0, 1);
    lcd.print("                    ");
    lcd.setCursor(0, 1);
    lcd.print("Time ");
    lcd.print(getTimeFromSeconds(seconds));
    updateTime = false;
  }

  lcd.setCursor(0, 2);
  lcd.print(currentMillis * current);
  lcd.print(" Ah");
  if (chargingScreenTimeInfo) {
    if (chargingScreenClean) {
      lcd.setCursor(0, 3);
      lcd.print("                    ");
      chargingScreenClean = false;
    }
    lcd.setCursor(0, 3);
    lcd.print("V: ");
    lcd.print(voltage);
    lcd.setCursor(9, 3);
    lcd.print(" A: ");
    lcd.print(current);

  } else {
    lcd.setCursor(0, 3);
    lcd.print("            [D] Stop");
    chargingScreenClean = true;
  }
}

void showChargeCompleteTime() {
  lcd.noBlink();
  lcd.setCursor(0, 0);
  lcd.print("CHARGING COMPLETE");
  lcd.setCursor(0, 1);
  lcd.print("Time: ");
  lcd.print(getTimeFromSeconds(input.toInt() * 60));
  lcd.setCursor(0, 2);
  lcd.print("Pay : PHP ");
  lcd.print("10500.00");
  lcd.setCursor(0, 3);
  lcd.print("Ah: ");
  lcd.print("100.00");
  lcd.print("  [D] OK");
}

void showCancelledScreen() {
  lcd.clear();
  lcd.noBlink();
  lcd.setCursor(0, 0);
  lcd.print("CHARGING Cancelled");
}

void enterAmountMode() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("--- Enter Amount ---");
  lcd.setCursor(0, 2);
  lcd.print("          [#] ENTER");
  lcd.setCursor(0, 3);
  lcd.print("[C] DEL   [D] CANCEL");
  lcd.setCursor(0, 1);
  lcd.print("PHP ");
  lcd.setCursor(4, 1);
  lcd.print(input);
  lcd.blink();
}

void showAmountComfirmScreen() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Confirm Amount");
  lcd.setCursor(0, 1);
  lcd.print("PHP ");
  lcd.print(input);
  lcd.setCursor(0, 2);
  lcd.print("Rate: ");
  lcd.print(rate);
  lcd.print("/Ah");
  lcd.setCursor(0, 3);
  lcd.print("    [D]CANCEL  [#]OK");
  lcd.noBlink();
}

void enterTimeMode() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("--- Enter Time ---");
  lcd.setCursor(0, 2);
  lcd.print("          [#] ENTER");
  lcd.setCursor(0, 3);
  lcd.print("[C] DEL   [D] CANCEL");
  lcd.setCursor(0, 1);
  lcd.print("Min ");
  lcd.setCursor(4, 1);
  lcd.print(input);
  lcd.blink();
}

void showTimeComfirmScreen() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Confirm Time");
  lcd.setCursor(0, 1);
  lcd.print("Time ");
  lcd.print(getTimeFromSeconds(input.toInt() * 60));
  lcd.setCursor(0, 2);
  lcd.print("Rate: PHP ");
  lcd.print(rate);
  lcd.print("/Ah");
  lcd.setCursor(0, 3);
  lcd.print("    [D]CANCEL  [#]OK");
  lcd.noBlink();
}

void showSettingsSetRate() {
  input = rate;
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("----- Set Rate -----");
  lcd.setCursor(0, 2);
  lcd.print("/kWh      [#] ENTER");
  lcd.setCursor(0, 3);
  lcd.print("[C] DEL   [D] CANCEL");
  lcd.setCursor(0, 1);
  lcd.print("PHP ");
  lcd.setCursor(4, 1);
  lcd.print(input);
  lcd.blink();
}

void showSettingsAbout() {
  lcd.clear();
  lcd.noBlink();
  lcd.setCursor(0, 0);
  lcd.print("       MEMBERS      ");
  lcd.setCursor(0, 3);
  lcd.print("            [D] Back");
}

void showSettingsSaved() {
  lcd.clear();
  lcd.noBlink();
  lcd.setCursor(0, 0);
  lcd.print("------ SAVED! ------");
  lcd.setCursor(0, 1);
  lcd.write(255);
  lcd.print(" Rate: ");
  lcd.print(rate);
  lcd.setCursor(0, 2);
  lcd.write(255);
  lcd.setCursor(8, 2);
  lcd.print("PHP/Ah");
  lcd.setCursor(0, 3);
  lcd.write(255);
  lcd.print("           [#] OK ");
  lcd.setCursor(19, 1);
  lcd.write(255);
  lcd.setCursor(19, 2);
  lcd.write(255);
  lcd.setCursor(19, 3);
  lcd.write(255);
}

void enterSetMode() {
  lcd.clear();
  lcd.noBlink();
  lcd.setCursor(0, 0);
  lcd.print("      SETTINGS      ");
  lcd.setCursor(0, 1);
  lcd.print("[A] Set Rate");
  lcd.setCursor(0, 2);
  lcd.print("[B] About");
  lcd.setCursor(0, 3);
  lcd.print("            [D] Back");
}


void keyInput(char key) {
  // Limit input to 4 charcaters for time, 12 characters for amount.
  if (mode == 2) {
    if (input.length() > 3) {
      return;
    }
  }
  if (input.length() > 12) {
    return;
  }


  // Check if input is digit.
  if (key >= '0' && key <= '9') {
    // Check if input has decimal and limit decimal to 2 places.
    if (mode != 3) {
      if (input.indexOf(".") != -1 && input.substring(input.indexOf(".") + 1, input.length()).length() == 2) {
        return;
      }

    } else {
      if (input.indexOf(".") != -1 && input.substring(input.indexOf(".") + 1, input.length()).length() == 4) {
        return;
      }
    }

    input += key;
    lcd.print(key);

  } else if (key == '.') {
    if (mode == 2 || mode == 3) {
      // Restrict input to only one decimal.
      if (input.indexOf('.') < 0) {
        input += key;
        lcd.print(key);
      }
    }
  }
}


void processInput(char key) {
  switch (mode) {
    case 0:
      switch (key) {
        case 'A':
          mode = 1;
          enterAmountMode();
          break;
        case 'B':
          mode = 2;
          enterTimeMode();
          break;
        case 'C':
          mode = 3;
          enterSetMode();
          break;
        default: break;
      }
      break;
    case 1:
      if (charging) {
        if (key == 'D') {
          charging = false;
          cancelled = true;
          break;
        } else {
          return;
        }
      }

      if (cancelled) {}

      if (completed) {
        if (key == 'D') {
          showMenuScreen();
          input = "";
          mode = 0;
          break;
        }
      }

      if (confirm) {
        if (key == '#') {
          if (input.length() <= 0) return;
          charging = true;
          confirm = false;
          amount = input.toFloat();
          lcd.clear();
          break;
        }
        if (key == 'D') {
          confirm = false;
          enterAmountMode();
          break;
        }
      }

      if (!confirm && key == 'C') {
        input.remove(input.length() - 1);
        lcd.setCursor(4 + input.length(), 1);
        lcd.print(" ");
        lcd.setCursor(4, 1);
        lcd.print(input);
        break;
      }

      if (key == '#') {
        confirm = true;
        showAmountComfirmScreen();
        break;
      }

      if (key == 'D') {
        showMenuScreen();
        input = "";
        mode = 0;
        break;
      }

      keyInput(key);

      break;
    case 2:
      if (charging) {
        if (key == 'D') {
          charging = false;
          cancelled = true;
          break;
        } else {
          return;
        }
      }

      if (cancelled) {
        // input = "";
        // mode = 0;
      }

      if (completed) {
        if (key == 'D') {
          showMenuScreen();
          input = "";
          completed = false;
          mode = 0;
          break;
        }
      }

      if (confirm) {
        if (key == '#') {
          if (input.length() <= 0) return;
          charging = true;
          confirm = false;
          seconds = input.toInt() * 60;
          lcd.clear();
          break;
        }
        if (key == 'D') {
          confirm = false;
          enterTimeMode();
          break;
        }
      }

      if (!confirm && key == 'C') {
        input.remove(input.length() - 1);
        lcd.setCursor(4 + input.length(), 1);
        lcd.print(" ");
        lcd.setCursor(4, 1);
        lcd.print(input);
        break;
      }

      if (key == '#') {
        if (input.toInt() == 0) return;
        confirm = true;
        showTimeComfirmScreen();
        break;
      }

      if (key == 'D') {
        showMenuScreen();
        input = "";
        mode = 0;
        break;
      }

      keyInput(key);

      break;
    case 3:
      switch (settingsMode) {
        case 0:
          if (key == 'A') {
            showSettingsSetRate();
            settingsMode = 1;
            break;
          }
          if (key == 'B') {
            showSettingsAbout();
            settingsMode = 2;
            break;
          }
          if (key == 'D') {
            showMenuScreen();
            mode = 0;
            break;
          }
          break;
        case 1:
          if (key == 'C') {
            input.remove(input.length() - 1);
            lcd.setCursor(4 + input.length(), 1);
            lcd.print(" ");
            lcd.setCursor(4, 1);
            lcd.print(input);
            break;
          }
          if (key == 'D') {
            enterSetMode();
            settingsMode = 0;
            input = "";
            break;
          }
          if (key == '#') {
            writeRate(input.toFloat() * ((float)(6 / 125)));
            Serial.println(input.toFloat());
            Serial.println(float(input.toFloat() * ((float)(6 / 125))));
            showSettingsSaved();
            settingsMode = 3;
            input = "";
            break;
          }
          keyInput(key);
          break;
        case 2:
          if (key == 'D') {
            enterSetMode();
            settingsMode = 0;
            break;
          }
          break;
        case 3:
          if (key == '#') {
            enterSetMode();
            settingsMode = 0;
            break;
          }
          break;
      }
      break;
  }

  Serial.println("mode " + String(mode));
  Serial.println("settings " + String(settingsMode));
  Serial.println("input " + String(input));
  Serial.println("confirm " + String(confirm));
  Serial.println("cancelled " + String(cancelled));
  Serial.println("charging " + String(charging));
  Serial.println("complete " + String(completed));
  Serial.println();
}