#include <U8g2lib.h>
#include <Wire.h> // library requires for IIC communication
#include <FastLED.h>

#define NUM_LEDS 8
#define ENCODER_BTN 4
#define ENCODER_CLK 2
#define ENCODER_DT  3

#define LINE_HEIGHT 13
#define TEXT_HEIGHT 9

long time = 0;
CRGB leds[NUM_LEDS];
byte initial = 0;     // изменение оттенка LED

U8G2_SSD1306_128X64_NONAME_2_HW_I2C u8g2(U8G2_R0, U8X8_PIN_NONE); // initialization for the used OLED display

/* States */
class State {
 protected:
  int lines;

 public:
  virtual void RenderLed();
  virtual void RenderText(int, bool);
  virtual void KeyUp(int);
  virtual void KeyDown(int);

  int GetLinesCount() {
    return lines;
  }
};

class StaticState : public State {
 private:
  uint8_t arr[4]{12, 13, 230, 255};

 public:
  StaticState() {
    lines = 5;
  }
  
  void RenderLed() {
    for (int i = 0; i < NUM_LEDS; i++) {
      leds[i].setRGB(arr[0], arr[1], arr[2]);
    }
    FastLED.setBrightness(arr[3]);
    FastLED.show();
  }

  void RenderText(int activeLine, bool isSelected) {
    u8g2.firstPage();
    u8g2.setFont(u8g2_font_t0_14_mr);
    u8g2.setFontMode(1); 
    u8g2.setDrawColor(1);
    
    do {
      if (!isSelected) {
        u8g2.drawStr(115, (activeLine + 1) * LINE_HEIGHT - 2, "<-");
      } else {
        u8g2.drawBox(0, activeLine * LINE_HEIGHT, 128, LINE_HEIGHT);  
      }
  
      u8g2.setDrawColor(2);
      u8g2.drawStr(5, LINE_HEIGHT - 2, "mode");
      u8g2.drawStr(60, LINE_HEIGHT - 2, "static");

      char strTmp[5] = {0};
      sprintf(strTmp, "%d", arr[0]);
      u8g2.drawStr(5, 2 * LINE_HEIGHT - 2, "red");
      u8g2.drawStr(60, 2 * LINE_HEIGHT - 2, strTmp);

      sprintf(strTmp, "%d", arr[1]);
      u8g2.drawStr(5, 3 * LINE_HEIGHT - 2, "green");
      u8g2.drawStr(60, 3 * LINE_HEIGHT - 2, strTmp);

      sprintf(strTmp, "%d", arr[2]);
      u8g2.drawStr(5, 4 * LINE_HEIGHT - 2, "blue");
      u8g2.drawStr(60, 4 * LINE_HEIGHT - 2, strTmp);
      
      sprintf(strTmp, "%d", arr[3]);
      u8g2.drawStr(5, 5 * LINE_HEIGHT - 2, "bright");
      u8g2.drawStr(60, 5 * LINE_HEIGHT - 2, strTmp);

    } while ( u8g2.nextPage() );  
  
  }

  void KeyUp(int activeLine) {
    if (activeLine == 0) return;
    arr[activeLine - 1]++;
  }

  void KeyDown(int activeLine) {
    if (activeLine == 0) return;
    arr[activeLine - 1]--;
  }

};

class FireState : public State {
 private:
  uint8_t arr[1]{255};
  long lastRendered = 0;

 public:
  FireState() {
    lines = 2;
  }

  void RenderLed() {
    fadeToBlackBy(leds, NUM_LEDS, 2);
    int pos = beatsin16(13, 0, NUM_LEDS - 1);
    leds[pos] += CHSV(initial++, 255, 192);
    
    FastLED.setBrightness(arr[0]);
    FastLED.show();
  }

  void RenderText(int activeLine, bool isSelected) {
    u8g2.firstPage();
    u8g2.setFont(u8g2_font_t0_14_mr); // set custom font
    u8g2.setFontMode(1); 
    u8g2.setDrawColor(1);
    
    do {
      if (!isSelected) {
        u8g2.drawStr(115, (activeLine + 1) * LINE_HEIGHT - 2, "<-");
      } else {
        u8g2.drawBox(0, activeLine * LINE_HEIGHT, 128, LINE_HEIGHT);  
      }

      u8g2.setDrawColor(2);
      u8g2.drawStr(5, LINE_HEIGHT - 2, "mode");
      u8g2.drawStr(60, LINE_HEIGHT - 2, "fire");

      char strTmp[5] = {0};
      sprintf(strTmp, "%d", arr[0]);
      u8g2.drawStr(5, 2 * LINE_HEIGHT - 2, "hue");
      u8g2.drawStr(60, 2 * LINE_HEIGHT - 2, strTmp);
    } while ( u8g2.nextPage() );  
  }

  void KeyUp(int activeLine) {
    if (activeLine == 0) return;
    arr[activeLine - 1]++;
  }

  void KeyDown(int activeLine) {
    if (activeLine == 0) return;
    arr[activeLine - 1]--;
  }
};

class SnakeState : public State {
 private:
  long lastRendered = 0;
  uint8_t arr[4]{100, 100, 100, 100}; //r g b speed
  int snakeLength;
  int headPos;

 public:
  SnakeState() {
    lines = 5;
    snakeLength = 5; 
    headPos = 0;
  }

  void RenderLed() {
    uint8_t red = arr[0];
    uint8_t green = arr[1];
    uint8_t blue = arr[2];
    uint8_t speed = arr[3];
    
    if ((time - lastRendered) * 2 > (255 - (long)arr[3]) * 3) {

      fill_solid(leds, NUM_LEDS, CRGB::Black);



      for (int i = 0; i < snakeLength; i++) {
        int pos = (headPos - i + NUM_LEDS) % NUM_LEDS;
        leds[pos] = CRGB(red, green, blue);
      }

      headPos = (headPos + 1 + NUM_LEDS) % NUM_LEDS;

      lastRendered = time;
    }

    FastLED.setBrightness(255);
    FastLED.show();
  }

  void RenderText(int activeLine, bool isSelected) {
    u8g2.firstPage();
    u8g2.setFont(u8g2_font_t0_14_mr); 
    u8g2.setFontMode(1); 
    u8g2.setDrawColor(1);
    
    do {
      if (!isSelected) {
        u8g2.drawStr(115, (activeLine + 1) * LINE_HEIGHT - 2, "<-");
      } else {
        u8g2.drawBox(0, activeLine * LINE_HEIGHT, 128, LINE_HEIGHT);  
      }

      u8g2.setDrawColor(2);
      u8g2.drawStr(5, LINE_HEIGHT - 2, "mode");
      u8g2.drawStr(60, LINE_HEIGHT - 2, "snake");

      char strTmp[5] = {0};
      sprintf(strTmp, "%d", arr[0]);
      u8g2.drawStr(5, 2 * LINE_HEIGHT - 2, "red");
      u8g2.drawStr(60, 2 * LINE_HEIGHT - 2, strTmp);

      sprintf(strTmp, "%d", arr[1]);
      u8g2.drawStr(5, 3 * LINE_HEIGHT - 2, "green");
      u8g2.drawStr(60, 3 * LINE_HEIGHT - 2, strTmp);

      sprintf(strTmp, "%d", arr[2]);
      u8g2.drawStr(5, 4 * LINE_HEIGHT - 2, "blue");
      u8g2.drawStr(60, 4 * LINE_HEIGHT - 2, strTmp);

      sprintf(strTmp, "%d", arr[3]);
      u8g2.drawStr(5, 5 * LINE_HEIGHT - 2, "speed");
      u8g2.drawStr(60, 5 * LINE_HEIGHT - 2, strTmp);

    } while ( u8g2.nextPage() );  
  }

  void KeyUp(int activeLine) {
    if (activeLine == 0) return;
    arr[activeLine - 1]++;
  }

  void KeyDown(int activeLine) {
    if (activeLine == 0) return;
    arr[activeLine - 1]--;
  }
};


/* StateManager */
class StateManager {
 private:
  int statesNumber = 3;
  State* states[3]{new StaticState(), new SnakeState(), new FireState()};
  int currentState = 0;
  int activeLine = 0;  
  bool isSelected = 0;
  bool stateChanged = 1;

 public:
  
  void RenderText() {
    if (stateChanged) {
      states[currentState]->RenderText(activeLine, isSelected);
      stateChanged = 0;
    }
  }

  void RenderLed() {
    states[currentState]->RenderLed();
  }
  
  void LineUp() {
    activeLine++;
    if (activeLine == states[currentState]->GetLinesCount()) {
      activeLine = 0;
    }
  }

  void LineDown() {
    activeLine--;
    if (activeLine == -1) {
      activeLine = states[currentState]->GetLinesCount() - 1;
    }
  }

  void button () {
    isSelected = !isSelected;
    stateChanged = 1;
  }

  void Up() {
    if (isSelected) {
      if (activeLine == 0) {
        currentState++;
        if (currentState == statesNumber) {
          currentState = 0;
        }
      } else {
        states[currentState]->KeyUp(activeLine);
      }
    } else {
      LineDown();
    }
    stateChanged = true;
  }

  void Down() {
    if (isSelected) {
      if (activeLine == 0) {
        currentState--;
        if (currentState == -1) {
          currentState = statesNumber - 1;
        }
      } else {
        states[currentState]->KeyDown(activeLine);
      }  
    } else {
      LineUp();
    }
    stateChanged = true;
  }
};

class Actions {
 private:
  int lastClk = HIGH;
  bool lastBtn = 0;

 public:  
  void handleAction(StateManager &stateManager) {
    int cur = !digitalRead(ENCODER_BTN); 
    if (cur != lastBtn && cur == 1) {
      stateManager.button();
      Serial.println("button");
    }
    lastBtn = cur;

    int newClk = digitalRead(ENCODER_CLK);
    if (newClk != lastClk) {
      lastClk = newClk;
      int dtValue = digitalRead(ENCODER_DT);
      if (newClk == LOW && dtValue == HIGH) {
        Serial.println("Up");
        stateManager.Up();
      }
      if (newClk == LOW && dtValue == LOW) {
        Serial.println("Down");
        stateManager.Down();
      }
    }
  }
};


static Actions actions;
static StateManager stateManager;

void setup() {
  pinMode(ENCODER_BTN, INPUT_PULLUP);
  pinMode(ENCODER_CLK, INPUT);
  pinMode(ENCODER_DT, INPUT);

  Serial.begin(9600);
  FastLED.addLeds<NEOPIXEL, 5>(leds, NUM_LEDS);

  u8g2.begin(); // start the u8g2 library
  stateManager.RenderText();
}


void loop() {
  time = millis();
  actions.handleAction(stateManager);
  stateManager.RenderText();
  stateManager.RenderLed();  
}