#include <Arduino.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd = LiquidCrystal_I2C(0x27, 16, 2);

enum menuStates
{
  ST_INIT = 0,
  ST_MAIN,
  ST_WIPE
};

enum menuReturns
{
  MN_CONTINUE = 0,
  MN_DONE
};

enum swReturns_e
{
  NO_SW = 0,
  UP,
  DN,
  SEL
};

const uint32_t BLNK_LEDDLY = 250ul;
const uint32_t BLNK_BIGDLY = 2000ul;

const uint8_t
    grSwReturns[] = {NO_SW, UP, DN, SEL};
const uint8_t
    grControlButtons[3] = {2, 3, 4};
const uint8_t pinLED = LED_BUILTIN;

bool bBlinkEnable = false;
uint8_t grPinLasts[3];
uint8_t numBlinks = 10;

typedef uint8_t (*pFunc_t)(uint8_t);
pFunc_t activeFunc;

uint8_t readButtons(void)
{
  static uint8_t
      idx = 0;
  static uint32_t
      tRead = 0ul;
  uint32_t
      tNow = millis();
  uint8_t
      retval,
      swNow;

  retval = NO_SW;
  if (tNow - tRead >= 10ul)
  {
    tRead = tNow;
    swNow = digitalRead(grControlButtons[idx]);
    if (swNow != grPinLasts[idx])
    {
      grPinLasts[idx] = swNow;
      if (swNow == LOW)
        retval = grSwReturns[idx + 1];
    }

    idx++;
    if (idx == 3)
      idx = 0;
  }

  return retval;
}

void doLED(void)
{
  static bool
      lastEnable = bBlinkEnable;
  static uint8_t
      nBlinks = 10,
      bLEDState = false;
  static uint32_t
      tBlink = 0ul,
      tDelay = BLNK_BIGDLY;
  uint32_t
      tNow = millis();

  if ((tNow - tBlink) < tDelay || bBlinkEnable == false)
    return;

  if (lastEnable != bBlinkEnable)
  {
    lastEnable = bBlinkEnable;
    if (bBlinkEnable == true)
      nBlinks = numBlinks;
  }

  tBlink = tNow;
  bLEDState ^= true;
  digitalWrite(pinLED, bLEDState ? HIGH : LOW);
  tDelay = BLNK_LEDDLY;
  if (bLEDState == false)
  {
    nBlinks--;
    if (nBlinks == 0)
    {
      tDelay = BLNK_BIGDLY;
      nBlinks = numBlinks;
    }
  }
}

bool WipeMenu(void)
{
  static uint8_t
      col = 0;
  static uint32_t
      tChar = 0ul;
  uint32_t
      tNow = micros();

  if (tNow - tChar >= 15000ul)
  {
    tChar = tNow;
    for (uint8_t i = 0; i < 2; i++)
    {
      lcd.setCursor(col, i);
      lcd.print(F(" "));
    }

    col++;
    if (col == 16)
    {
      col = 0;
      return true;
    }
  }

  return false;
}

void mnMainPage(uint8_t ctlButton)
{
  static int8_t
      highlight = 0;
  static uint8_t
      state = ST_INIT;

  switch (state)
  {
  case ST_INIT:
    lcd.clear();
    lcd.setCursor(1, 0);
    lcd.print(F("Set#LEDblnk"));
    lcd.setCursor(1, 1);
    lcd.print(F("TglLEDblnk"));

    highlight = 0;
    lcd.setCursor(0, highlight);
    lcd.print(F(">"));

    state = ST_MAIN;
    break;

  case ST_MAIN:
    switch (ctlButton)
    {
    case UP:
      lcd.setCursor(0, highlight);
      lcd.print(F(" "));
      highlight--;
      if (highlight < 0)
        highlight = 1;
      lcd.setCursor(0, highlight);
      lcd.print(F(">"));
      break;

    case DN:
      lcd.setCursor(0, highlight);
      lcd.print(F(" "));
      highlight++;
      if (highlight > 1)
        highlight = 0;
      lcd.setCursor(0, highlight);
      lcd.print(F(">"));
      break;

    case SEL:
      state = ST_WIPE;
      break;
    }

    break;

  case ST_WIPE:
    if (WipeMenu() == true)
    {
      activeFunc = (highlight == 0) ? &mnSetNumBlinks : &mnEnableBlinks;
      state = ST_INIT;
    }
    break;
  }
}

void mnSetNumBlinks(uint8_t ctlButton)
{
  char
      szStr[10];
  static int8_t
      highlight = 0;
  static uint8_t
      state = ST_INIT;

  switch (state)
  {
  case ST_INIT:
    lcd.clear();
    lcd.setCursor(1, 0);
    lcd.print(F("Set#Blinks"));
    lcd.setCursor(4, 1);
    sprintf(szStr, "%3d", numBlinks);
    lcd.print(szStr);

    state = ST_MAIN;
    break;

  case ST_MAIN:
    switch (ctlButton)
    {
    case UP:
      if (numBlinks < 255)
        numBlinks++;
      lcd.setCursor(4, 1);
      sprintf(szStr, "%3d", numBlinks);
      lcd.print(szStr);
      break;

    case DN:
      if (numBlinks > 10)
        numBlinks--;
      lcd.setCursor(4, 1);
      sprintf(szStr, "%3d", numBlinks);
      lcd.print(szStr);
      break;

    case SEL:
      state = ST_WIPE;
      break;
    }

    break;

  case ST_WIPE:
    if (WipeMenu() == true)
    {
      activeFunc = &mnMainPage;
      state = ST_INIT;
    }
    break;
  }
}

void mnEnableBlinks(uint8_t ctlButton)
{
  char
      szStr[10];
  static int8_t
      highlight = 0;
  static uint8_t
      state = ST_INIT;

  switch (state)
  {
  case ST_INIT:
    lcd.clear();
    lcd.setCursor(1, 0);
    lcd.print(F("Enable"));
    lcd.setCursor(1, 1);
    lcd.print(F("Disable"));

    highlight = 0;
    lcd.setCursor(0, highlight);
    lcd.print(F(">"));

    state = ST_MAIN;
    break;

  case ST_MAIN:
    switch (ctlButton)
    {
    case UP:
      lcd.setCursor(0, highlight);
      lcd.print(F(" "));
      highlight--;
      if (highlight < 0)
        highlight = 1;
      lcd.setCursor(0, highlight);
      lcd.print(F(">"));
      break;

    case DN:
      lcd.setCursor(0, highlight);
      lcd.print(F(" "));
      highlight++;
      if (highlight > 1)
        highlight = 0;
      lcd.setCursor(0, highlight);
      lcd.print(F(">"));
      break;

    case SEL:
      state = ST_WIPE;
      break;
    }

    break;

  case ST_WIPE:
    if (WipeMenu() == true)
    {
      activeFunc = &mnMainPage;
      bBlinkEnable = (highlight == 0) ? true : false;
      state = ST_INIT;
    }
    break;
  }
}

void setup()
{
  for (uint8_t i = 0; i < 3; i++)
  {
    pinMode(grControlButtons[i], INPUT_PULLUP);
    grPinLasts[i] = digitalRead(grControlButtons[i]);
  }

  lcd.init();
  lcd.backlight();
  pinMode(pinLED, OUTPUT);
  activeFunc = &mnMainPage;
}

void loop()
{
  doLED();
  activeFunc(readButtons());
}