// Mario's Ideas
// Morse Code transmiter

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// Oled display size
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

//Potentiometer PIN A1
  int Potentiometer=A1;

// Variables capturing current and newly calculated position on the letter board (Values 0-26)
  int New_Position=0;
  int Old_Position=0;

// Variable capturing Potentimeter read (Values 0 1023)
  int Pot_read=0;

// Variable used for calculating moving average of potentiometer reading to stabilise the input
  int Count_For_Moving_Average=0;

// String variable holding the text to transmit
  String To_Transmit="";

// Length of the text to transmit
  int To_Transmit_Length=0;

// Flag indicating the letter was entered on the leter board to be added to To_Transmit string
  int Letter_Entered=0;
  int Transmit=0;


// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
  #define OLED_RESET     4 // Reset pin # (or -1 if sharing Arduino reset pin)
  Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Array holding all Morse code letter dot dash combinations
char MorseCode[26][6] = {
  {'.','-','x','x','x','A'},
  {'-','.','.','.','x','B'},
  {'-','.','-','.','x','C'},
  {'-','.','.','x','x','D'},
  {'.','x','x','x','x','E'},
  {'.','.','-','.','x','F'},
  {'-','-','.','x','x','G'},
  {'.','.','.','.','x','H'},
  {'.','.','x','x','x','I'},
  {'.','-','-','-','x','J'},
  {'-','.','-','x','x','K'},
  {'.','-','.','.','x','L'},
  {'-','-','x','x','x','M'},
  {'-','.','x','x','x','N'},
  {'-','-','-','x','x','O'},
  {'.','-','-','.','x','P'},
  {'-','-','.','-','x','Q'},
  {'.','-','.','x','x','R'},
  {'.','.','.','x','x','S'},
  {'-','x','x','x','x','T'},
  {'.','.','-','x','x','U'},
  {'.','.','.','-','x','V'},
  {'.','-','-','.','x','X'},
  {'-','-','.','-','x','Y'},
  {'.','-','.','x','x','Z'},
  };

// Used for displaying Leter board
char Letters[28]="ABCDEFGHIJKLMNOPQRSTUVWXYZ_";

// Play/Display Morse code representation of the letter
void Play_Letter (char Letter){
  // searching in MorseCode array for the corresponding letter
  if (Letter=='_') delay(350); else {
    for (int j=0; j<27; j++){
      if (MorseCode[j][5]==Letter)
        // if the right letter is detected run Play_Dot_Dash for . or -
        for (int k=0; k<4;k++){
          if (MorseCode[j][k]!='x') Play_Dot_Dash(MorseCode[j][k]);
        }
    }
    delay(200);
  }
}

// Playing/Displaying . or -

void Play_Dot_Dash(char sign){
  if (sign=='.'){
    digitalWrite(5, 100);
    digitalWrite(4, HIGH);
    delay(100);
    digitalWrite(5, LOW);
    digitalWrite(4, LOW);
    delay(100);
  }
  if (sign=='-'){
    digitalWrite(5, 100);
    digitalWrite(4, HIGH);
    delay(300);
    digitalWrite(5, LOW);
    digitalWrite(4, LOW);
    delay(100);
  }
}

void Add_To_String(){

  Letter_Entered=1;
  
}

void Triger_Transmit(){
  
  Transmit=1;

}

void setup() {
  Serial.begin(9600);
  // Define two interrupts
  // D2- when button pressed the current letter on the letter board is entered to To_Transmit
  // D3- When button is pressed To_Transmit string is output in Morse code 
  attachInterrupt(0,Add_To_String, FALLING);
  attachInterrupt(1,Triger_Transmit, FALLING);

  
  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3D for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  
  // Buzzer PIN
  pinMode(5, OUTPUT);
  digitalWrite(5, LOW);
  // LED PIN
  pinMode(4, OUTPUT);
  digitalWrite(4, LOW);
  
  // Show initial display buffer contents on the screen --
  // the library initializes this with an Adafruit splash screen.
  display.display();
  delay(2000); // Pause for 2 seconds
  
  // Clear the buffer
  display.clearDisplay();
  display.display();
  
  // Display Letter Board 3 rows 9 character in each row 
  display.setTextSize(2);            
  display.setTextColor(SSD1306_WHITE);       
  for (int j=0; j<3;j++){
  for (int i=0; i<9;i++){
     display.setCursor(i*12+2*i+1,j*16+17);           
     display.println(Letters[i+j*9]);
     //display.fillRect(i*12+2*i, j*16 +16, 12, 16, SSD1306_INVERSE);
     display.display();
  }
  }
  // Display filled in rect in the top section of the display when To_Transfer would be output
  display.fillRect(0, 0, 128, 15, SSD1306_INVERSE);
  // Highlight character A by displaying Inverse rect at first position
  display.fillRect(0, 16, 12, 16, SSD1306_INVERSE);

  display.display();
}

void Highlight_letter(int New_Pos, int Old_Pos){
  // When position changes from Old_Pos to New_Pos
  // Draw the inverse rect in the Old_pos to deactivate  the highlight in the old spot
  // Draw the inverse rect to Highlite the new spot
  int X_pos;
  int Y_pos;
  
  // Calculate X and Y coordinates of the New_Pos on the letter board
  X_pos=New_Pos - ((int)New_Pos/9)*9;
  Y_pos=(int)New_Pos/9;
  // Displaying Inverse rect
  display.fillRect(X_pos*12+2*X_pos, Y_pos*16 +16, 12, 16, SSD1306_INVERSE);
  
  // Calculate X and Y coordinates of the Old_Pos on the letter board
  X_pos=Old_Pos - ((int)Old_Pos/9)*9;
  Y_pos=(int)Old_Pos/9;
  // Displaying Inverse rect
  display.fillRect(X_pos*12+2*X_pos, Y_pos*16 +16, 12, 16, SSD1306_INVERSE);
  
  display.display();
}


void loop() 
{
  // Increase Count_For_Moving_Average 30 times before calcluating moving average
  Count_For_Moving_Average++;
  
  Pot_read =Pot_read + analogRead(Potentiometer);
  if (Count_For_Moving_Average==30){
    // Calculate moving average for 30 potentiometer reads
    // Without calculating moving average reads are to volatile
    Pot_read=(int)Pot_read/30;

    // As potentiometer read was not stable around 0 and 1023 values
    // Here is the code to fix it and make sure that values 0 and 26 are properly mapped
    // Between values 101 and 899 the potentiometer read is mapped to the range 0,26
    // New_Position is the new position calculated on the letter board corresponding to 
    //potentiometer read
    
    if (Pot_read<100 or Pot_read==100) New_Position=0;
    if (Pot_read >100 or Pot_read<900) New_Position= map(Pot_read,101,899,0,26);
    if (Pot_read>900 or Pot_read==900) New_Position=26;

    // If new position differes fro the previous one
    // remove highlight from the old one and Highlight a new one
    // New position becomes also the current position now
    if (Old_Position!=New_Position){
       Highlight_letter (New_Position,Old_Position);
       Old_Position=New_Position;
    }

    // reset Count_For_Moving_Average and Pot_read to start calculating the new moving average
    Count_For_Moving_Average=0;
    Pot_read=0;
  }
  delay(5);
  // Wait 100 loop cycles before checking if the new letter was entered
  
  // If letter was entered add the letter to To_Transmit and output it on the display
  if (Letter_Entered==1 ){
      To_Transmit=To_Transmit + Letters[New_Position];
      To_Transmit_Length++;
      display.setCursor(3,0);
      display.setTextColor(BLACK     );
      display.fillRect(0, 0, 128, 15, SSD1306_WHITE);
      display.println(To_Transmit);
      display.display();
      Letter_Entered=0;
      delay(100);
  }
  // If Transmit button was pressed start morse code transmition
  
  if (Transmit==1){
    for (int i=0; i<To_Transmit_Length;i++ ){
      Play_Letter(To_Transmit.charAt(i));
      Transmit=0;
    }
  }
}