// https://arduinointro.com/lcdcustomcharacter

uint8_t block[][8] = {
  { 0,  0,  0,  0,  0,  0,  0, 31},  // 1/8
  { 0,  0,  0,  0,  0,  0, 31, 31},  // 2/8
  { 0,  0,  0,  0,  0, 31, 31, 31},  // 3/8
  { 0,  0,  0,  0, 31, 31, 31, 31},  // 4/8
  { 0,  0,  0, 31, 31, 31, 31, 31},  // 5/8
  { 0,  0, 31, 31, 31, 31, 31, 31},  // 6/8
  { 0, 31, 31, 31, 31, 31, 31, 31},  // 7/8
  {31, 31, 31, 31, 31, 31, 31, 31},  // 8/8
};

uint8_t line[][8] = {
  {0, 0, 0, 0, 0, 0, 0, 31},
  {0, 0, 0, 0, 0, 0, 31, 0},
  {0, 0, 0, 0, 0, 31, 0, 0},
  {0, 0, 0, 0, 31, 0, 0, 0},
  {0, 0, 0, 31, 0, 0, 0, 0},
  {0, 0, 31, 0, 0, 0, 0, 0},
  {0, 31, 0, 0, 0, 0, 0, 0},
  {31, 0, 0, 0, 0, 0, 0, 0},
};

uint8_t grid[][8] = {
  {16, 16, 16, 16, 16, 16, 16, 31}, // 0
  { 8,  8,  8,  8,  8,  8, 31,  8}, // 1
  { 8,  8,  8,  8,  8, 31,  8,  8}, // 2
  { 4,  4,  4,  4, 31,  4,  4,  4}, // 3
  { 4,  4,  4, 31,  4,  4,  4,  4}, // 4
  { 2,  2, 31,  2,  2,  2,  2,  2}, // 5
  { 2, 31,  2,  2,  2,  2,  2,  2}, // 6
  {31,  1,  1,  1,  1,  1,  1,  1}, // 7
};

uint8_t swirl[][8] = {
  {31,  0,  0,  0,  0,  0,  0,  0},
  {31,  1,  1,  1,  1,  1,  1,  1},
  {31,  1,  1,  1,  1,  1,  1, 31},
  {31, 17, 17, 17, 17, 17, 17, 31},
  {31, 31, 17, 17, 17, 17, 17, 31},
  {31, 31, 19, 19, 19, 19, 19, 31},
  {31, 31, 19, 19, 19, 19, 31, 31},
  {31, 31, 27, 27, 27, 27, 31, 31},
};

#include <LiquidCrystal.h>
int RS = 12, EN = 10, D4 = 5, D5 = 4, D6 = 3, D7 = 2;
LiquidCrystal lcd(RS, EN, D4, D5, D6, D7);
#define COLS 20
#define ROWS 4

int counter, col, row, dir = 1, i, j, mark = 255, space = 32;
bool done = 0;
unsigned long timer, timeout = 5000;

void setup() {
}

void loop() {
  switch (counter) {
    case 0: cylon(); break;
    case 1: fill(); break;
    case 2: blink(); break;
    case 3: grassy(); break;
    case 4: steps(); break;
    case 5: linear(); break;
    case 6: sifter(); break;
    case 7: swirls(); break;
    default: break;
  }
  if (millis() - timer > timeout) {
    timer = millis();
    counter++;
    if (counter == 8)
      counter = 0;
  }
}

void swirls() {
  // non-I2C must define characters before initializing object
  for (int i = 0; i < 8; i++) {
    lcd.createChar(i, swirl[i]);
  }
  lcd.begin(20, 4);
  for (int i = 0; i < 2; i++) {
    for (int j = 0; j < 8; j++) {
      for (int k = 0; k < 4; k++) {
        for (int l = 0; l < 20; l++) {
          lcd.setCursor(l, k);
          if (i)
            lcd.write(j);
          else
            lcd.write(7 - j);
        }
      }
    }
  }
}

void sifter() {
  getGrid();
  int d = 50;
  for (int j = 0; j < 2; j++) {
    for (int i = 0; i < 8; i++) {
      for (int k = 0; k < 4; k++) {
        for (int m = 0; m < 20; m++) {
          lcd.setCursor(m, k);
          if (j)
            lcd.write(i);
          else
            lcd.write(7 - i);
        }
      }
    }
  }
}

void linear() {
  getLines();
  int d = 5;
  for (int i = 0; i < 4; i++) { // four rows
    for (int j = 0; j < 20; j++) { // twenty columns
      lcd.setCursor(j, 3 - i); // in every cell...
      lcd.write(32); // ... write a space
    }
    delay(d); // pause before next character
    for (int k = 0; k < 8; k++) { // eight custom characters
      delay(d);
      for (int j = 0; j < 20; j++) {
        lcd.setCursor(j, 3 - i);
        lcd.write(k); // ... write custom characters
      }
    }
    delay(d);
    for (int j = 0; j < 20; j++) {
      lcd.setCursor(j, 3 - i);
      lcd.write(32); // ... write block character
    }
  }
  delay(500);
  lcd.clear();
}

void grassy() {
  getBlocks();
  int d = 10;
  for (int i = 0; i < 4; i++) { // four rows
    for (int j = 0; j < 20; j++) { // twenty columns
      lcd.setCursor(j, 3 - i); // in every cell...
      lcd.write(32); // ... write a space
    }
    delay(d); // pause before next character
    for (int k = 0; k < 8; k++) { // eight custom characters
      delay(d);
      for (int j = 0; j < 20; j++) {
        lcd.setCursor(j, 3 - i);
        lcd.write(k); // ... write custom characters
      }
    }
    delay(d);
    for (int j = 0; j < 20; j++) {
      lcd.setCursor(j, 3 - i);
      lcd.write(255); // ... write block character
    }
  }
  delay(500);
  lcd.clear();
}

void steps() {
  getBlocks();
  lcd.setCursor(0, 0);
  for (int i = 0; i < 8; i++) {
    lcd.write(i);
  }
}

void getBlocks() {
  if (!done) { // moved from setup() to loop(), run one time only
    done = 1;
    for (int i = 0; i < 8; i++) {
      lcd.createChar(i, block[i]);
    }
    lcd.begin(20, 4);
  }
}

void getLines() {
  if (!done) { // run one time
    done = 1;
    for (int i = 0; i < 8; i++) {
      lcd.createChar(i, line[i]);
    }
    lcd.begin(20, 4);
  }
}

void getGrid() {
  if (!done) { // run one time
    done = 1;
    for (int i = 0; i < 8; i++) {
      lcd.createChar(i, grid[i]);
    }
    lcd.begin(20, 4);
  }
}

void fill() {
  int speed = 25;
  for (int k = 0; k < 2; k++) {
    for (int j = 0; j < ROWS; j++) {
      for (int i = 0; i < COLS; i++) {
        lcd.setCursor(i, j);
        if (k)
          lcd.write(space);
        else
          lcd.write(mark);
        delay(speed);
      }
    }
  }
}

void cylon() {
  int speed = 25;
  for (int j = 0; j < 2; j++) {
    dir = -dir;
    for (int i = 0; i < COLS; i++) {
      for (row = 0; row < 4; row++) {
        lcd.setCursor(j * (COLS - 1) - i * dir, row);
        lcd.write(mark);
      }
      delay(speed);
      for (row = 0; row < 4; row++) {
        lcd.setCursor(j * (COLS - 1) - i * dir, row);
        lcd.write(space);
      }
    }
  }
}

void blink() {
  lcd.setCursor(8, 2);
  lcd.print("BLINK");
  delay(500);
  lcd.clear();
  delay(500);
}