// https://www.reddit.com/user/ferrybig
/*  OLED SSD1306 <-> Arduino (nano/uno)
     D0--------------10
     D1--------------9
     RST-------------13
     DC--------------11
     VCC-------------5V
     GND-------------GND
     CS--------------12
    Others:
     Button active low: 2
     > Used for placing the blocks
     Led active high: A5 (Optional)
     > Used for death indication
     Buzzer: 3 (Optional)
     > Feedback for button press
 */
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

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

// Declaration for SSD1306 display connected using software SPI (default case):
#define OLED_MOSI   9
#define OLED_CLK   10
#define OLED_DC    11
#define OLED_CS    12
#define OLED_RESET 13
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT,
  OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);

const int pin_button = 2;
const int pin_led = A5;
const int pin_buzzer = 3;

const int initial_delay_timer = 32;
const int initial_x = 32;
const int initial_width = 8;
const int height = 4;
const int initial_y = 128 - height;
const int speed = 2;

int valid_x = 0;
int x = initial_x;
int width = initial_width;
int y = initial_y;
bool direction_inverse = false;
bool has_released = false;
bool first_block = true;
int delayTimer = initial_delay_timer;
bool game_over = false;


void setup() {
	// put your setup code here, to run once:

	Serial.begin(9600);
	pinMode(pin_button, INPUT_PULLUP);
	pinMode(pin_led, OUTPUT);
	pinMode(pin_buzzer, OUTPUT);

	ADCSRA = 0; // We don't need analog read functionality in this project
	
	// SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
	if(!display.begin(SSD1306_SWITCHCAPVCC)) {
		Serial.println(F("SSD1306 allocation failed"));
		for(;;); // Don't proceed, loop forever
	}
	display.clearDisplay();
	//display.invertDisplay(true);
	draw();
}

void restart() {
	//digitalWrite(pin_reset, LOW); // Reset arduino
	//pinMode(pin_reset, OUTPUT);
	y = initial_y;
	x = initial_x;
	width = initial_width;
	delayTimer = initial_delay_timer;
	first_block = true;
	display.clearDisplay();
	//display.invertDisplay(true);
}

void gameOver() {
	game_over = true;
	digitalWrite(pin_led, HIGH);
	// Wait till button is released
	while(digitalRead(pin_button) == LOW);
	
	while(true) {
    	fillRect(x, y, width, height, SSD1306_INVERSE);
		display.display();
    	delay(100);
    	if(digitalRead(pin_button) == LOW) {
    		restart();
    		break;
    	}
	}
	digitalWrite(pin_led, LOW);
}

void fillRect(int x, int y, int width, int height, int color) {
	// Perform screen rotation here
	display.fillRect(128 - y - height, x, height, width, color);
}

void input() {
	if (digitalRead(pin_button) == LOW) {
		if(has_released) {
			if(first_block) {
				valid_x = x;
				first_block = false;
			} else {
				const int old_width = width;
				if(x + width < valid_x) {
					// ##
					//   ##
					gameOver();
				} else if (x + width < valid_x + width) {
					// ##
					//  ##
					width = width - (valid_x - x);
				} else if (x < valid_x + width) {
					//   ##
					//  ##
					width = valid_x + width - x;
					valid_x = x;
				} else {
					//   ##
					// ##
					gameOver();
				}
				if(width == 0) {
					// strange bug
					width = old_width;
					gameOver();
				}
			}
			has_released = false;
			if(!game_over) {
				fillRect(valid_x, y, width, height, SSD1306_INVERSE);
				if(y == 0) {
					// win
				}
				y -= height;
				delayTimer--;
			} else {
				game_over = false;
			}
			tone(pin_buzzer, 3000, 10);
		}
	} else {
		has_released = true;
	}
}

void update() {
	if(direction_inverse) {
		if(x == 0) {
			direction_inverse = false;
		} else {
			x -= speed;
		}
	} else {
		if(x == 64 - width) {
			direction_inverse = true;
		} else {
			x += speed;
		}
	}
}

void draw() {
	fillRect(x, y, width, height, SSD1306_INVERSE);
}

void clearDraw() {
	fillRect(x, y, width, height, SSD1306_INVERSE);
}

void loop() {
	// put your main code here, to run repeatedly:
	clearDraw();
	input();
	update();
	draw();
    display.display();
    if(delayTimer > 1) {
    	delay(delayTimer);
    }
}