// Original by domjules:
//   https://wokwi.com/arduino/projects/308344217332089409
//
// Improved by Tim2000:
//   https://wokwi.com/arduino/projects/308364652939575872
//
// Changes by Koepel:
//   https://wokwi.com/arduino/projects/308383904908182081
//   - Pattern as bit pattern
//   - Range-based for-loops in setup
//   - function with array "by reference"
//   - re-ordered the leds and resistors and connections
//
// Changes by Tim2000:
//   https://wokwi.com/arduino/projects/309204710595756610
//   - Scrolling message using bit shifting of a composite glyph.


const byte Rows[] = { 22, 23, 24, 25, 26, 27, 28, 29 };
const byte Cols[] = { 46, 47, 48, 49, 50, 51, 52, 53 };

const byte glyphs[][8] =
{
	{
		0b00000000,
		0b00000000,
		0b00000000,
		0b00000000,
		0b00000000,
		0b00000000,
		0b00000000,
		0b00000000
	},
	{
		0b00000000,
		0b00010000,
		0b00010000,
		0b00010000,
		0b00010000,
		0b00000000,
		0b00010000,
		0b00000000
	},
	{
		0b00000000,
		0b00011000,
		0b00100100,
		0b00100100,
		0b00111100,
		0b00100100,
		0b00100100,
		0b00000000
	},
	{
		0b00000000,
		0b01110000,
		0b01001000,
		0b01111000,
		0b01000100,
		0b01000100,
		0b01111000,
		0b00000000
	},
	{
		0b00000000,
		0b00111000,
		0b01000100,
		0b01000000,
		0b01000000,
		0b01000100,
		0b00111000,
		0b00000000
	},
	{
		0b00000000,
		0b01110000,
		0b01001000,
		0b01000100,
		0b01000100,
		0b01001000,
		0b01110000,
		0b00000000
	},
	{
		0b00000000,
		0b00111100,
		0b00100000,
		0b00111000,
		0b00100000,
		0b00100000,
		0b00111100,
		0b00000000
	},
	{
		0b00000000,
		0b00111100,
		0b00100000,
		0b00111000,
		0b00100000,
		0b00100000,
		0b00100000,
		0b00000000
	},
	{
		0b00000000,
		0b00111000,
		0b01000100,
		0b01000000,
		0b01001110,
		0b01000100,
		0b00111100,
		0b00000000
	},
	{
		0b00000000,
		0b00100100,
		0b00100100,
		0b00111100,
		0b00100100,
		0b00100100,
		0b00100100,
		0b00000000
	},
	{
		0b00000000,
		0b00111000,
		0b00010000,
		0b00010000,
		0b00010000,
		0b00010000,
		0b00111000,
		0b00000000
	},
	{
		0b00000000,
		0b00011100,
		0b00001000,
		0b00001000,
		0b00001000,
		0b00101000,
		0b00111000,
		0b00000000
	},
	{
		0b00000000,
		0b00100100,
		0b00101000,
		0b00110000,
		0b00101000,
		0b00100100,
		0b00100100,
		0b00000000
	},
	{
		0b00000000,
		0b00100000,
		0b00100000,
		0b00100000,
		0b00100000,
		0b00100000,
		0b00111100,
		0b00000000
	},
	{
		0b00000000,
		0b01000010,
		0b01100110,
		0b01011010,
		0b01000010,
		0b01000010,
		0b01000010,
		0b00000000
	},
	{
		0b00000000,
		0b01000100,
		0b01100100,
		0b01010100,
		0b01001100,
		0b01000100,
		0b01000100,
		0b00000000
	},
	{
		0b00000000,
		0b00111100,
		0b01000010,
		0b01000010,
		0b01000010,
		0b01000010,
		0b00111100,
		0b00000000
	},
	{
		0b00000000,
		0b00111000,
		0b00100100,
		0b00100100,
		0b00111000,
		0b00100000,
		0b00100000,
		0b00000000
	},
	{
		0b00000000,
		0b00111100,
		0b01000010,
		0b01000010,
		0b01001010,
		0b01000110,
		0b00111110,
		0b00000001
	},
	{
		0b00000000,
		0b00111000,
		0b00100100,
		0b00100100,
		0b00111000,
		0b00100100,
		0b00100100,
		0b00000000
	},
	{
		0b00000000,
		0b00011100,
		0b00100000,
		0b00010000,
		0b00001000,
		0b00000100,
		0b00111000,
		0b00000000
	},
	{
		0b00000000,
		0b01111100,
		0b00010000,
		0b00010000,
		0b00010000,
		0b00010000,
		0b00010000,
		0b00000000
	},
	{
		0b00000000,
		0b01000100,
		0b01000100,
		0b01000100,
		0b01000100,
		0b01000100,
		0b00111000,
		0b00000000
	},
	{
		0b00000000,
		0b01000100,
		0b01000100,
		0b01000100,
		0b01000100,
		0b00101000,
		0b00010000,
		0b00000000
	},
	{
		0b00000000,
		0b01000010,
		0b01000010,
		0b01000010,
		0b01000010,
		0b01011010,
		0b00100100,
		0b00000000
	},
	{
		0b00000000,
		0b01000010,
		0b00100100,
		0b00011000,
		0b00011000,
		0b00100100,
		0b01000010,
		0b00000000
	},
	{
		0b00000000,
		0b01000100,
		0b01000100,
		0b00101000,
		0b00010000,
		0b00010000,
		0b00010000,
		0b00000000
	},
	{
		0b00000000,
		0b00111100,
		0b00000100,
		0b00001000,
		0b00010000,
		0b00100000,
		0b00111100,
		0b00000000
	}
};

// Prototyping, because the Arduino pre-processor fails on a array "by reference"
void drawGlyph(const byte (&glyph)[8]);

String message = "";  // User message.
byte composite_glyph[8];

void setup()
{
	Serial.begin(112500);
	for (const auto a:Rows)
	{
		pinMode(a, OUTPUT);
		digitalWrite(a, HIGH);  // Switch off the rows.
	}
	for (const auto a:Cols)
	{
		pinMode(a, OUTPUT);
		digitalWrite(a, LOW);  // Switch off the columns.
	}
  pinMode(LED_BUILTIN, OUTPUT);
	Serial.println(sizeof(glyphs));
	Serial.println(sizeof(glyphs[0]));

  Serial.println("Enter the message you would like displayed: ");
  while (Serial.available() == 0) continue;
  message = Serial.readString();  // Get user message.
	message.trim();
	message.toUpperCase();
	Serial.println(message);
	message = " " + message;
	byte glyph1_index = ComputeGlyphIndexFromMessageIndex(message, 0);
	byte glyph2_index = ComputeGlyphIndexFromMessageIndex(message, 1);
	for (byte row = 0; row < 8; row++)
	{
		composite_glyph[row] = CompositeRow(glyphs[glyph1_index][row], glyphs[glyph2_index][row], 0);
	}
}

void loop()
{
	uint16_t timestamp = millis();

  //
  // TASK 1: Display the composite glyph and scroll it every interval.
  //

	const uint16_t SCROLL_STEP_INTERVAL = 200;
	static uint16_t scroll_step_previous_timestamp = timestamp;
	static byte scroll_step = 0;
	static byte message_index = 0;
	static byte glyph1_index = ComputeGlyphIndexFromMessageIndex(message, message_index);
	static byte glyph2_index = ComputeGlyphIndexFromMessageIndex(message, message_index + 1);

  // Draw the composite glyph.
	drawGlyph(composite_glyph);

	// Change the scroll step every interval.
	if (timestamp - scroll_step_previous_timestamp >= SCROLL_STEP_INTERVAL)
	{
		scroll_step++;
		if (scroll_step >= 8)
		{
			scroll_step = 0;

			// Change the glyphs when fully scrolled to the next glyph.
			message_index++;
			if (message_index >= message.length())
			{
				message_index = 0;
			}
			glyph1_index = ComputeGlyphIndexFromMessageIndex(message, message_index);
			glyph2_index = ComputeGlyphIndexFromMessageIndex(message, message_index + 1);
		}
		for (byte row = 0; row < 8; row++)
		{
			composite_glyph[row] = CompositeRow(glyphs[glyph1_index][row], glyphs[glyph2_index][row], scroll_step);
		}
		scroll_step_previous_timestamp += SCROLL_STEP_INTERVAL;
	}

  //
  // TASK 2: Blink the inbuilt LED.
  //

  const uint16_t LED_BLINK_INTERVAL = 100;
  static uint16_t led_blink_previous_timestamp = timestamp;
  static bool led_state = false;
  if (timestamp - led_blink_previous_timestamp >= LED_BLINK_INTERVAL)
  {
    led_state = !led_state;
    digitalWrite(LED_BUILTIN, led_state);
    led_blink_previous_timestamp += LED_BLINK_INTERVAL;
  }
}

//void drawGlyph(const byte glyph[8])          // normal, but what fun is that ?
void drawGlyph(const byte (&glyph)[8])          // an array "by reference"
{
	const uint16_t COLUMN_ON_TIME = 100;
	uint16_t timestamp = micros();
	static uint16_t previous_timestamp = timestamp;
	static byte column = 0;

	if (timestamp - previous_timestamp >= COLUMN_ON_TIME)
	{
		digitalWrite(Cols[column], LOW);
		column++;
		if (column >= 8)
		{
			column = 0;
		}
		for (byte row = 0; row < 8; row++)
		{
			// The first led on the left is column 0 is bit 7
			byte ledState = (bitRead( glyph[row], 7 - column) == 1) ? HIGH : LOW;
			digitalWrite(Rows[row], ledState);
		}
		digitalWrite(Cols[column], HIGH);
		previous_timestamp += COLUMN_ON_TIME;
	}
}

uint8_t CompositeRow(const uint8_t glyph1_row, const uint8_t glyph2_row, const uint8_t scroll_step)
{
		uint16_t composite_row = glyph1_row << (8 + scroll_step);
		composite_row |= glyph2_row << scroll_step;
		composite_row >>= 8;
		return (uint8_t)composite_row;
}

uint8_t ComputeGlyphIndexFromMessageIndex(const String& message, uint8_t message_index)
{
	if (message_index >= message.length())
	{
		message_index = 0;
	}
	uint8_t glyph_index = message[message_index] - 'A' + 2;
	if (glyph_index >= sizeof(glyphs) / sizeof(glyphs[0]))
	{
		glyph_index = 0;
	}
	return glyph_index;
}