#include <Arduino.h>         
#include <Wire.h>
#include <Adafruit_SSD1306.h> 

#define SSD1306_NO_SPLASH                       // Turn off oled splashscreen
#define encoderPinA 2                           // Rotary encoder GPIO pin (CLK)
#define encoderPinB  3                          // Rotary encoder GPIO pin (DT)
#define encoderPress 4                          // Rotary encoder GPIO button (SW)
#define OLED_ADDR 0x3C                          // OLED i2c address
#define SCREEN_WIDTH 128                        // OLED display width in pixels
#define SCREEN_HEIGHT 64                        // OLED display height in pixels 
#define OLED_RESET -1                           // Reset pin GPIO 
#define buttonPressedState 0                    // Logic level when button is pressed
#define debounceDelay 20                        // Debounce delay
#define waterLevelPin A3                        // Float sensor GPIO pin
#define moistureSensorPin 6                     // Soil moisture sensor GPIO pin
#define pumpPin 12                              // Pump GPIO pin (via transistor)
#define whiteLED 5                              // White status LED GPIO pin
#define redLED 8                                // Red status LED GPIO pin
#define greenLED 9                              // Green status LED GPIO pin
#define buzzer 7                                // Buzzer

  const byte serialDebug = 0;                   // Serial debugging flag
  const byte menuTimeout = 10;                  // Menu inactivity timeout (seconds)
  const bool menuLargeText = 0;                 // Larger text 
  const byte maxmenuItems = 9;                  // Number of items used in the menus
  const byte itemTrigger = 2;                   // Rotary encoder detents
  const byte topLine = 18;                      // Y position of lower area display
  const byte lineSpace1 = 8;                    // Line spacing for textsize 1 (small text)
  const byte lineSpace2 = 17;                   // Line spacing for textsize 2 (large text)
  const byte displayMaxLines = 9;               // Max lines that can be displayed in lower section of display
  const byte MaxmenuTitleLength = 10;           // Max characters per line when using text size 2

  double checkInterval = 500;                   // Time to check soil moisture sensor
  int timeToPump = 5000;                        // Time to run water pump
  int moistureSensor = 0;                       // Moisture sensor value
  int waterLevelSensor = 0;                     // Low water level value

  enum menuModes {
    off,                                        // Display off
    menu,                                       // Menu active
    message,                                    // Displaying message
  };
  menuModes menuMode= off;                      // Default mode at startup

    String menuTitle = "";                      // The title of active mode
    byte noOfmenuItems = 0;                     // Number of menu items
    byte selectedMenuItem = 0;                  // Selected menu flag
    byte highlightedMenuItem = 0;               // Highlighted menu item
    String menuItems[maxmenuItems+1];           // Menu items
    uint32_t lastMenuActivity = 0;              // Time the menu last saw activity
    byte waterTankEmpty = 0;                    // Flag to keep water pump off
    byte mValueLow = 0;                         // Spare variable
    byte mValueHigh = 0;                        // Spare variable
    byte mValueStep = 0;                        // Spare variable
    volatile int encoderPos = 0;                // Current value selected with rotary encoder
    volatile bool encoderPrevA;                 // Used to debounce rotary encoder
    volatile bool encoderPrevB;                 // Used to debounce rotary encoder
    uint32_t reLastButtonChange = 0;            // Last time state of button changed
    bool encoderPrevButton = 0;                 // Used to debounce button
    byte reButtonDebounced = 0;                 // Debounced current button state (1 when pressed)
    const bool rebuttonPressedState = buttonPressedState;  // Logic level when the button is pressed
    const byte redebounceDelay = debounceDelay;        // Button debounce delay setting
    bool reButtonPressed = 0;                   // Flag set when the button is pressed

// oled SSD1306 display connected to I2C
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

void defaultMenu() {
  demoMenu();
}

void demoMenu() {
  resetMenu();                          
  menuMode = menu;                     
  noOfmenuItems = 9;           
  menuTitle = "Menu";     
  menuItems[1] = "Soil H20 %";     
  menuItems[2] = "Frequency";
  menuItems[3] = "Amount";
  menuItems[4] = "Add H2O";
  menuItems[5] = "Last H20";
  menuItems[6] = "Warnings";
  menuItems[7] = "Buzz Off";
  menuItems[8] = "Reset";
  menuItems[9] = "Menu Off";
}  

void menuActions() {

  if(selectedMenuItem == 1 && reButtonPressed == 1) {
    moistLevel();
  }
    
  if(selectedMenuItem == 2 && reButtonPressed == 1)  {
    freqSet();
  }

  if(selectedMenuItem == 3 && reButtonPressed == 1) {
    amountWater();
  }

  if(selectedMenuItem == 4 && reButtonPressed == 1) {
    manualWater();
  }

  if(selectedMenuItem == 5 && reButtonPressed == 1) {
    lastWater();
  }

  if(selectedMenuItem == 6 && reButtonPressed == 1) {
    listWarnings();
  }

  if(selectedMenuItem == 7 && reButtonPressed == 1) {
    buzzerState();
  }

  if(selectedMenuItem == 8 && reButtonPressed == 1) {
    resetSettings();
  }

  if(selectedMenuItem == 9 && reButtonPressed == 1) {
    menuOff();
  }
}
 
void moistLevel() {

  resetMenu();
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0,10);
  display.print(F("The soil moisture    level is: "));
//  display.print(mValueLow);
  display.print(F("%"));
  display.display();
}

void freqSet() {

  resetMenu();
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0,0);
  display.print(F("How often should I   check the soil       moisture level?"));
  display.setCursor(0,30);
  display.println(F(">24 hours"));
  display.println(F(" 72 hours"));
  display.println(F(" 120 hours"));
  display.display();
}

void amountWater() {

  resetMenu();
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0,0);
  display.print(F("How long should I    pump water?"));
  display.setCursor(0,20);
  display.println(F(">5 seconds"));
  display.println(F(" 10 seconds"));
  display.println(F(" 15 seconds"));
  display.display();
}

void manualWater() {

  resetMenu();
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0,0);
  display.print(F("Manually watering the plant."));
  display.display();
  runPump();
}

void lastWater() {

  resetMenu();
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0,0);
  display.print(F("The plant was watered "));
//  display.print(mValueHigh);
  display.print(F(" hours ago."));
  display.display();
}

void listWarnings() {

  resetMenu();
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0,0);
  display.print(F("No warnings to report."));
  display.display();
}

void buzzerState() {

  resetMenu();
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0,0);
  display.print(F("The buzzer is ON."));
  display.display();
}

void resetSettings() {

  resetMenu();
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0,0);
  display.print(F("All settings reset to default."));
  display.display();
}

void menuOff() {

  resetMenu();
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0,0);
  display.print(F("Turning screen off."));
  display.display();
}

void readMoistureSensor() {

  moistureSensor = analogRead(moistureSensorPin);
  if(moistureSensor >= 500 && moistureSensor <= 850 && waterTankEmpty !=0)  {
    runPump();
    flashGreenLED();
  }
}

void readWaterSensor()  {

  waterLevelSensor = digitalRead(waterLevelPin);
  if(waterLevelSensor == 0) {
    flashRedLED();
    waterTankEmpty = 0;
  } else  {
    waterTankEmpty = 1;
  }
}

void runPump()  {

  digitalWrite(pumpPin, HIGH);
  delay(timeToPump);
  digitalWrite(pumpPin, LOW);
}

void soundBuzzer()  {

  tone(buzzer, 250);
  delay(50);
  noTone(buzzer);
  delay(50);
}

void flashWhiteLED() {
  for(int i = 0; i <= 4; i++);
    digitalWrite(whiteLED, HIGH);
    delay(300);
    digitalWrite(whiteLED, LOW);
    delay(300);
}

void flashRedLED() {
  for(int i = 0; i <= 4; i++);
    digitalWrite(redLED, HIGH);
    delay(300);
    digitalWrite(redLED, LOW);
    delay(300);
}

void flashGreenLED() {
  for(int i = 0; i <= 4; i++);
    digitalWrite(greenLED, HIGH);
    delay(300);
    digitalWrite(greenLED, LOW);
    delay(300);
}

void setup() {

  Serial.begin(115200);                                             // Start serial comms

  pinMode(whiteLED, OUTPUT);  
  pinMode(redLED, OUTPUT);
  pinMode(greenLED, OUTPUT);
  pinMode(buzzer, OUTPUT);  
  pinMode(pumpPin, OUTPUT);
  pinMode(encoderPress, INPUT_PULLUP);
  pinMode(encoderPinA, INPUT);
  pinMode(encoderPinB, INPUT);

  if(!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
    if (serialDebug) Serial.println(("\nError initialising the oled display"));
  }
    
  Wire.setClock(100000);

  encoderPos = 0;

  attachInterrupt(digitalPinToInterrupt(encoderPinA), readEncoder, CHANGE);

  attachInterrupt(digitalPinToInterrupt(encoderPress), updateButton, RISING);

  defaultMenu();    
  flashWhiteLED(); 
}

void loop() {

  updateButton();     
  menuUpdate();          

// Flash onboard led - debugging
//  static uint32_t ledTimer = millis();
//  if ( (unsigned long)(millis() - ledTimer) > 500 ) {
//    digitalWrite(LED, !digitalRead(LED));
//    ledTimer = millis();
//  }
}  

void updateButton() {

  bool tReading = digitalRead(encoderPress);                                   // Read current button state

  if (tReading != encoderPrevButton) reLastButtonChange = millis();            // If it has changed reset timer
    if ( (unsigned long)(millis() - reLastButtonChange) > redebounceDelay ) {  // If button state is stable
      if (encoderPrevButton == rebuttonPressedState) {
        if (reButtonDebounced == 0) {                                          // If the button has been pressed
          reButtonPressed = 1;                                                 // Flag set when the button has been pressed
          if (menuMode == off) defaultMenu();                                  // If the display is off start the default menu
        }
        reButtonDebounced = 1;                                                 // Debounced button status  (1 when pressed)
      } else {
        reButtonDebounced = 0;
      }
    }
    encoderPrevButton = tReading;                                              // Update last state read
}

void menuUpdate() {

  if (menuMode == off) return;                                                 // If menu system is turned off do nothing more

  // if no recent activity then turn oled off
    if ( (unsigned long)(millis() - lastMenuActivity) > (menuTimeout * 1000) ) {
      resetMenu();
      return;
    }

  switch (menuMode) {

    // if there is an active menu
    case menu:
      drawMenu();
      menuActions();
      break;

    // if a message is being displayed
    case message:
      if (reButtonPressed == 1) defaultMenu();    // if button has been pressed return to default menu
      break;
    }
}

void drawMenu() {

  // rotary encoder
  if (encoderPos >= itemTrigger) {
    encoderPos -= itemTrigger;
    highlightedMenuItem++;
    lastMenuActivity = millis();   // log time
    }
      if (encoderPos <= -itemTrigger) {
        encoderPos += itemTrigger;
        highlightedMenuItem--;
        lastMenuActivity = millis();   // log time
      }
      if (reButtonPressed == 1) {
        selectedMenuItem = highlightedMenuItem;     // flag that the item has been selected
        lastMenuActivity = millis();   // log time
        if (serialDebug) Serial.println("menu '" + menuTitle + "' item '" + menuItems[highlightedMenuItem] + "' selected");
      }

    const int _centreLine = displayMaxLines / 6 + 1;    // mid list point
    display.clearDisplay();
    display.setTextColor(WHITE); 

    // verify valid highlighted item
      if (highlightedMenuItem > noOfmenuItems) highlightedMenuItem = noOfmenuItems;
      if (highlightedMenuItem < 1) highlightedMenuItem = 1;

    // title  
      display.setCursor(40, 0);
      if (menuLargeText) {
        display.setTextSize(2);
        display.println(menuItems[highlightedMenuItem].substring(0, MaxmenuTitleLength));
      } else {
        if (menuTitle.length() > MaxmenuTitleLength) display.setTextSize(1);
        else display.setTextSize(2);
        display.println(menuTitle);
      }
      display.drawLine(0, topLine-1, display.width(), topLine-1, WHITE);       // draw horizontal line under title

    // menu
      display.setTextSize(2);
      display.setCursor(0, topLine + 4);
      for (int i=1; i <= displayMaxLines; i++) {
        int item = highlightedMenuItem - _centreLine + i;
        if (item == highlightedMenuItem) display.setTextColor(BLACK, WHITE);
        else display.setTextColor(WHITE);
        if (item > 0 && item <= noOfmenuItems) display.println(menuItems[item]);
        else display.println(" ");
      }
 
    display.display();
}

void resetMenu() {

  menuMode = off;
  selectedMenuItem = 0;
  encoderPos = 0;
  noOfmenuItems = 0;
  menuTitle = "";
  highlightedMenuItem = 0;
  reButtonPressed = 0;
  lastMenuActivity = millis();   // log time
  display.clearDisplay();
  display.display();
}

void readEncoder() {

  bool pinA = digitalRead(encoderPinA);
  bool pinB = digitalRead(encoderPinB);

  if ( (encoderPrevA == pinA && encoderPrevB == pinB) ) return;  // no change since last time (i.e. reject bounce)

  // same direction (alternating between 0,1 and 1,0 in one direction or 1,1 and 0,0 in the other direction)
         if (encoderPrevA == 1 && encoderPrevB == 0 && pinA == 0 && pinB == 1) encoderPos -= 1;
    else if (encoderPrevA == 0 && encoderPrevB == 1 && pinA == 1 && pinB == 0) encoderPos -= 1;
    else if (encoderPrevA == 0 && encoderPrevB == 0 && pinA == 1 && pinB == 1) encoderPos += 1;
    else if (encoderPrevA == 1 && encoderPrevB == 1 && pinA == 0 && pinB == 0) encoderPos += 1;

  // change of direction
    else if (encoderPrevA == 1 && encoderPrevB == 0 && pinA == 0 && pinB == 0) encoderPos += 1;
    else if (encoderPrevA == 0 && encoderPrevB == 1 && pinA == 1 && pinB == 1) encoderPos += 1;
    else if (encoderPrevA == 0 && encoderPrevB == 0 && pinA == 1 && pinB == 0) encoderPos -= 1;
    else if (encoderPrevA == 1 && encoderPrevB == 1 && pinA == 0 && pinB == 1) encoderPos -= 1;

  // update previous readings
    encoderPrevA = pinA;
    encoderPrevB = pinB;
}