#include <Arduino.h>
#include <U8g2lib.h> // u8g2 library for drawing on OLED display - needs to be installed in Arduino IDE first
#include <Wire.h> // wire library for IIC communication with the OLED display

#include "anims.h"

// U8G2_SSD1306_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0); // set the OLED display to 128x64px, HW IIC, no rotation, used in WOKWI
U8G2_SH1107_128X128_1_HW_I2C u8g2(U8G2_R0); // final display, 128x128px [page buffer, size = 128 bytes], HW IIC connection

// IIC connection of the OLED display and Arduino UNO
// +5V > +5V
// GND > GND
// SCL (serial clock) > A5 or SCL
// SDA (serial data) > A4 or SDA

const unsigned char upir_logo [] PROGMEM = {   // upir logo 
  0xEA, 0x3A, 0xAA, 0x28, 0x6A, 0x1A, 0x26, 0x2A, };

int center_x = 64; // display x center, 64px for the 128x128px display
int center_y = 64; // display y center, 64px for the 128x128px display

// hardcoded time values
int time_minutes = 10;
int time_hours = 10;
int time_seconds = 45;

// HW Pins required
#define BUTTON_UP 4
#define BUTTON_DOWN 7
#define BUTTON_LEFT 3
#define BUTTON_RIGHT 6
#define BUTTON_ENTER 5

//FPS
bool          SHOW_FPS    = false;          // < SHOW FPS ON SCREEN
unsigned int  LIMITFPSTO  = 60;             // < LIMIT SCREEN FPS
unsigned long millisFPS   = 0;
unsigned long lastMillis  = 0;
unsigned int  frameCount  = 0;
unsigned int  fps         = 0;

//Calendar App
bool exitCalendarApp = false;
#define MAX_CALENDAR_EVENTS 99
struct CalendarEvent {unsigned long unixTime;String eventName;};
CalendarEvent calendarEvents[MAX_CALENDAR_EVENTS];

void displayFrame() {
  if (millis() - millisFPS >= int(1000/LIMITFPSTO)) {
    millisFPS = millis();
    fpsCounter();
    u8g2.sendBuffer();
    u8g2.clearBuffer();
  }
}
void updateAnims() {
  unsigned long currentMillis30FPS = millis();
  if (step30FPS) {step30FPS = false;}
  if (currentMillis30FPS - lastMillis30FPS >= 33) {
    step1FPSInt++;
    if (step1FPSInt > 30) {
      step1FPS = true;
      step1FPSInt = 0;
    }
    else {step1FPS = false;}

    // Save the current time
    lastMillis30FPS = currentMillis30FPS;
    step30FPS = true;
  }

  if (animFrames[0] == 1) { //Page Flip
    u8g2.setBitmapMode(1);
    pageFlipAnim();
  }
  if (animFrames[1] != 0) { //Big Gear 2
    u8g2.drawXBMP(77,4,50,120,bigGear2allArray[animFrames[1]-1]);
  }
}

void fpsCounter() {
  if (SHOW_FPS){
    frameCount++;
    if (millis() - lastMillis >= 1000) {            //FPS COUNTER
      fps = frameCount;
      // Serial.print("FPS: "); Serial.println(fps);
      frameCount = 0;lastMillis = millis();
    }
    u8g2.drawStr(0,128,("FPS: "+String(fps)).c_str()); //Show current FPS
  }
}

void setup(void) { // Arduino setup
  u8g2.begin();  // begin the u8g2 library
  u8g2.setContrast(255); // set display contrast/brightness

  pinMode(BUTTON_UP, INPUT_PULLUP);
  pinMode(BUTTON_DOWN, INPUT_PULLUP);
  pinMode(BUTTON_LEFT, INPUT_PULLUP);
  pinMode(BUTTON_RIGHT, INPUT_PULLUP);
  pinMode(BUTTON_ENTER, INPUT_PULLUP);

}

int          dayToday        = 12;
int          monthToday      = 3;
int          yearToday       = 2024;
volatile int selectedDay     = dayToday;
volatile int selectedMonth   = monthToday;
volatile int selectedYear    = yearToday;
enum CalendarAppState {HOME, DAY_VIEW, ADD_EVENT};
CalendarAppState calendarCurrentState = HOME;

bool testOnce = false;

int daysInMonth(int month, int year);

void updateCalendarInputs() {
  // aButton.update();
  // bButton.update();  
  // int sEncoder_change = sEncoder.getCount();
  // int lEncoder_change = lEncoder.getCount();

  switch (calendarCurrentState) {
    case HOME:
      // if (sEncoder_change) {
      //   if ((sEncoder_change < 0)) {
      //     selectedDay++;
      //     if (selectedDay > daysInMonth(selectedMonth, selectedYear)) {
      //       selectedDay = 1;
      //       selectedMonth++;
      //       animFrames[0] = 1;
      //       if (selectedMonth > 12) {
      //         selectedMonth = 1;
      //         selectedYear++;
      //       }
      //     }
      //   }
      //   else if (sEncoder_change > 0) {
      //     selectedDay--;
      //     if (selectedDay < 1) {
      //       animFrames[0] = 1;
      //       if (selectedMonth == 1) {
      //         selectedMonth = 12;
      //         selectedYear--;
      //       }
      //       else {
      //         selectedMonth--;
      //       }
      //       selectedDay = daysInMonth(selectedMonth, selectedYear);
      //     }
      //   }
      //   sEncoder.setCount(0);
      // }
      // if (lEncoder_change) {
      //   if (lEncoder_change < 0) {
      //     selectedMonth++;
      //     if (selectedMonth > 12) {
      //       selectedMonth = 1;
      //       selectedYear++;
      //     }
      //   }
      //   if (lEncoder_change > 0) {
      //     if (selectedMonth == 1) {
      //         selectedMonth = 12;
      //         selectedYear--;
      //     }
      //     else {
      //       selectedMonth--;
      //     }
      //   }
      //   if (selectedDay > daysInMonth(selectedMonth, selectedYear)) {
      //     selectedDay = daysInMonth(selectedMonth, selectedYear);
      //   }
      //   animFrames[0] = 1;
      // }

      // if (aButton.fell()) {
      //   calendarCurrentState = DAY_VIEW;
      // }

      // if (bButton.fell()) {
      //   exitCalendarApp = true;
      //   break;
      // }
      break;

    case DAY_VIEW:
      // if (aButton.fell()) { 
      // }
      // if (bButton.fell()) {
      //   calendarCurrentState = HOME;
      //   delay(250);
      // }
      break;
  }
  
}

int getDayFromUnixTime(unsigned long unixTime) {
  return (unixTime / 86400L) % 31 + 1; // Assuming every month has 31 days
}

int getMonthFromUnixTime(unsigned long unixTime) {
  return ((unixTime / 2629743L) % 12) + 1; // Approximate calculation assuming a 30-day month
}

int getYearFromUnixTime(unsigned long unixTime) {
  return (unixTime / 31556926L) + 1970; // Approximate calculation assuming 365.25 days per year
}

// void addEvent(unsigned long time, const String& name) {
//   // Find the first available slot in the array
//   for (int i = 0; i < MAX_CALENDAR_EVENTS; ++i) {
//     if (calendarEvents[i].unixTime == 0) {
//       // Found an empty slot, add the event
//       calendarEvents[i].unixTime = time;
//       calendarEvents[i].eventName = name;
//       break;
//     }
//   }
//   // saveCalendarEventsToFile();
// }

// std::vector<int> findEventsOnDay(int day, int month, int year) {
//   // Create a vector to store indices of events
//   std::vector<int> eventIndices;

//   // Iterate through events list
//   for (int i = 0; i < MAX_CALENDAR_EVENTS; ++i) {
//     // Extract day, month, and year from event's unix time
//     int eventDay = getDayFromUnixTime(calendarEvents[i].unixTime);
//     int eventMonth = getMonthFromUnixTime(calendarEvents[i].unixTime);
//     int eventYear = getYearFromUnixTime(calendarEvents[i].unixTime);

//     // Check if event occurs on the specified day, month, and year
//     if (eventDay == day && eventMonth == month && eventYear == year) {
//       // Add index of the event to the vector
//       eventIndices.push_back(i);
//     }
//   }

//   // Return the vector containing indices of events
//   return eventIndices;
// }

// void saveCalendarEventsToFile() {
//   File calendarEventsFile = SPIFFS.open("/events.txt", FILE_WRITE);
//   if (!calendarEventsFile) {
//     //Serial.println("Failed to open calendar events file for writing");
//     return;
//   }

//   // Write each calendar event to file
//   for (int i = 0; i < MAX_CALENDAR_EVENTS; i++) {
//     calendarEventsFile.println(calendarEvents[i].unixTime);
//     calendarEventsFile.println(calendarEvents[i].eventName);
//   }

//   calendarEventsFile.close();
//   //Serial.println("Calendar events saved to file");
// }

// void loadCalendarEventsFromFile() {
//   File calendarEventsFile = SPIFFS.open("/events.txt", FILE_READ);
//   if (!calendarEventsFile) {
//     //Serial.println("Failed to open calendar events file for reading");
//     return;
//   }

//   // Read each calendar event from file
//   for (int i = 0; i < MAX_CALENDAR_EVENTS; i++) {
//     if (calendarEventsFile.available()) {
//       calendarEvents[i].unixTime = calendarEventsFile.readStringUntil('\n').toInt();
//       calendarEvents[i].eventName = calendarEventsFile.readStringUntil('\n');
//     }
//   }

//   calendarEventsFile.close();
//   //Serial.println("Calendar events loaded from file");
// }

int zellersCongruence(int day, int month, int year) {
  String dayOfWeekString;
  int iso = 0;

  if (month < 3) {
    month += 12;
    year--;
  }
  int h = (day + 13 * (month + 1) / 5 + year + year / 4 - year / 100 + year / 400) % 7;
  iso = (h + 6) % 7;// + 1; //0 is sunday, 1 is monday, ... ,  6 is saturday

  return iso;
}

int daysInMonth(int month, int year) {
  if (month < 1 || month > 12) {
    // Invalid month
    return -1;
  }

  switch (month) {
    case 1: case 3: case 5: case 7: case 8: case 10: case 12:
      return 31;
    case 4: case 6: case 9: case 11:
      return 30;
    case 2:
      // Check for leap year
      if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) {
        return 29; // Leap year
      } else {
        return 28; // Non-leap year
      }
    default:
      return -1; // Invalid month
  }
}

String getMonthName(int month) {
  static const char* monthNames[] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};

  if (month < 1 || month > 12) {
    return "Invalid Month";
  }

  return String(monthNames[month - 1]);
}

void drawMonth () {
  int i = zellersCongruence(1, selectedMonth, selectedYear);
  int daysInSelectedMonth = daysInMonth(selectedMonth, selectedYear);
  int j = 0;
  int k = 1;

  u8g2.setFont(u8g2_font_6x10_tf);
  u8g2.drawStr(4, 10, (getMonthName(selectedMonth) + " " + String(selectedYear)).c_str());

  while (k <= daysInSelectedMonth) { // Draw the month day by day
    u8g2.drawStr((i*18)+4,(j*18)+30,String(k).c_str());

    if (k == dayToday && selectedMonth == monthToday && selectedYear == yearToday) {
      u8g2.drawCircle((i*18)+9,(j*18)+28, 9);
    }
    else {
      u8g2.drawRFrame((i*18)+1,(j*18)+20,18,18,5);
    }

    if (k == selectedDay) {
      u8g2.drawHLine((i*18)+14,(j*18)+33,3);
      u8g2.drawVLine((i*18)+14,(j*18)+33,3);
      u8g2.drawLine((i*18)+14,(j*18)+33,(i*18)+14+4,(j*18)+33+4);
    }

    k++;i++;
    if (i > 6) {i = 0; j++;}
  }
}

void loadCalendar() {
  switch (calendarCurrentState) {
    case HOME:
      drawMonth();
      break;
    
    case DAY_VIEW:
      drawMonth();
      u8g2.setDrawColor(0);
      u8g2.drawXBMP(0, 0, 128, 128, fuzzallArray[0]);
      u8g2.drawBox(24,3,78,118);
      u8g2.setDrawColor(1);
      u8g2.drawFrame(23,2,80,120);
      u8g2.drawXBMP(60,-2,25,25,iconsallArray[2]);
      String dayName = "";
      switch (zellersCongruence(selectedDay, selectedMonth, selectedYear)) {
        case 0:
          dayName = "Sunday,";
          break;
        case 1:
          dayName = "Monday,";
          break;
        case 2:
          dayName = "Tuesday,";
          break;
        case 3:
          dayName = "Wednesday,";
          break;
        case 4:
          dayName = "Thursday,";
          break;
        case 5:
          dayName = "Friday,";
          break;
        case 6:
          dayName = "Saturday,";
          break;
      }
      u8g2.drawStr(30,26,dayName.c_str());
      u8g2.drawStr(30,34,(String(selectedMonth) + "/" + String(selectedDay) + "/" + String(selectedYear)).c_str());
      u8g2.drawHLine(26,36,75);
      //Add menu script to load events on day
      // std::vector<int> indices = findEventsOnDay(selectedDay, selectedMonth, selectedYear);
      // int eventY = 0;
      // for (int index : indices) {
      //   u8g2.drawStr(26, 37+(8*eventY), (calendarEvents[index].eventName).c_str());
      //   eventY++;
      // }
      break;
  } 
}

void calendarLoop() {
  /*if (testOnce) {
    // Add some sample events
    addEvent(1710280728, "Meeting");
    addEvent(1710280800, "Appointment");

    // Save events to file
    saveCalendarEventsToFile();
    testOnce = false;

    std::vector<int> indices = findEventsOnDay(selectedDay, selectedMonth, selectedYear);
    int eventY = 0;
    for (int index : indices) {
      u8g2.drawStr(26, 37+(8*eventY), (calendarEvents[index].eventName).c_str());
      eventY++;
    }
    u8g2.sendBuffer();
    delay(5000);
  }*/

  updateCalendarInputs();
  updateAnims();
  loadCalendar();
  displayFrame();
}


void loop(void) { // main Arduino loop

    static bool state_up = false;
    static bool state_down = false;
    static bool state_left = false;
    static bool state_right = false;
    static bool state_enter = false;

    state_up    |= (digitalRead(BUTTON_UP) == LOW);
    state_down  |= (digitalRead(BUTTON_DOWN) == LOW);
    state_left  |= (digitalRead(BUTTON_LEFT) == LOW);
    state_right |= (digitalRead(BUTTON_RIGHT) == LOW);
    state_enter |= (digitalRead(BUTTON_ENTER) == LOW);

  calendarLoop();


  // u8g2.firstPage(); // select the first page of the display (page is 128x8px), since we are using the page drawing method of the u8g2 library
  // do { // draw
  //   u8g2.setFont(u8g2_font_8x13B_mn); // set the u8g2 font
  //   u8g2.drawStr(57,20,"12");
  //   u8g2.drawStr(112,69,"3");
  //   u8g2.drawStr(61,120,"6");
  //   u8g2.drawStr(9,69,"9");            
  // } while ( u8g2.nextPage() ); // go over all the pages until the whole display is updated
  // // for(;;);
}