#include <LiquidCrystal.h>
#define RESET 0x100
#define READY 0x1
#define BEGIN 0x2
#define PAUSE 0x3
#define STOP 0x4
#define BEEPING 0x5
#define STATUS_FIELD 0xf
#define STATUS_CHANGED 0x10

const int rs_pin = 13, en_pin = 12, d4_pin = 7, d5_pin = 6, d6_pin = 5, d7_pin = 4;
const int switch_pin = 2;
const int x_pin = A0, y_pin = A1;

int status = 0;
int last_tick;
int last_start_tick = 0;
int timed_length = 0;
LiquidCrystal LCD(rs_pin, en_pin, d4_pin, d5_pin, d6_pin, d7_pin);


void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(switch_pin, INPUT_PULLUP);
  attachInterrupt(0, switch_pressed, FALLING);
  LCD.begin(16, 2);
}

void loop() {
  // put your main code here, to run repeatedly:

  if (status & RESET) {
    // Serial.println("Reset");
    timed_length = 0;
    LCD.clear();
    LCD.setCursor(0, 0);
    LCD.print("WAIT...");
    status = READY | STATUS_CHANGED;
    delay(1000);
  } else {
    switch (status & STATUS_FIELD) {
      case READY:
        {
          // Serial.println("Ready");
          if (status & STATUS_CHANGED) {
            LCD.clear();
            LCD.print("READY");
            status = READY;
          }
          if (analogRead(y_pin) > 800) {
            last_tick = millis();
            status = BEGIN | STATUS_CHANGED;
            last_start_tick = last_tick;
          }
          break;
        }
      case BEGIN:
        {
          // Serial.println("Begin");
          if (status & STATUS_CHANGED) {
            LCD.clear();
            LCD.print("BEGIN");
            // delay(500);
            status = BEGIN;
          }

          delay(10);
          int cur_tick = millis();
          timed_length += cur_tick - last_tick;
          last_tick = cur_tick;

          if (timed_length > 10000) {
            status = BEEPING | STATUS_CHANGED;
            break;
          }

          LCD.setCursor(0, 1);
          LCD.print(timed_length / 10 * 10);

          if (analogRead(y_pin) > 800 && cur_tick - last_start_tick > 200) {
            status = STOP | STATUS_CHANGED;
            break;
          }

          if (analogRead(x_pin) > 800) {
            status = PAUSE | STATUS_CHANGED;
            break;
          }
          break;
        }
      case PAUSE:
        {
          // Serial.println("Pause");
          if (status & STATUS_CHANGED) {
            LCD.clear();
            LCD.print("PAUSED");
            LCD.setCursor(0, 1);
            LCD.print(timed_length);
            delay(500);
            status = PAUSE;
          }

          if (analogRead(x_pin) < 200) {
            status = BEGIN | STATUS_CHANGED;
            last_tick = millis();
            break;
          }
          break;
        }
      case STOP:
        {
          // Serial.println("Stop");
          if (status & STATUS_CHANGED) {
            LCD.clear();
            LCD.print("STOPPED");
            status = STOP;
            break;
          }
          break;
        }
      case BEEPING:
        {
          // Serial.println("Beep");
          if (status & STATUS_CHANGED) {
            LCD.clear();
            LCD.print("BEEP");
            status = BEEPING;
          }

          int y_cmd = analogRead(x_pin);
          if (y_cmd > 800) {
            timed_length = 0;
            status = READY | STATUS_CHANGED;
          } else if (y_cmd < 200) {
            timed_length = 0;
            last_tick = millis();
            status = BEGIN | STATUS_CHANGED;
          }
          break;
        }
    }
  }
}

void switch_pressed() {
  status = RESET;
  Serial.println("Pressed");
}