#include <Arduino.h>
#include <U8g2lib.h>
#include <Wire.h>
// #include "fonts/Pixel_Operator.c"

U8G2_SSD1306_128X64_NONAME_F_HW_I2C display(U8G2_R0, /* reset=*/U8X8_PIN_NONE); // initialization for the used OLED display

struct MenuOffset
{
    int id;
    int offset;
    int size;
};

struct MenuItem
{
    const char *title;
    const int subMenuIdx;
};

struct MenuItem HOME_MENU[] = {
    {"Display", 1},
    {"Sound", 2},
    {"Connection", 3},
    {"About", 0},
    {"Exit", 0},
};

struct MenuItem DISP_MENU[] = {
    {"Brightness", 0},
    {"Contrast", 0},
    {"Sleep Time", 0},
    {"Screen Saver", 0}};

struct MenuItem SND_MENU[] = {
    {"Profile", 0},
    {"Boost", 0},
    {"Dlg Enhance", 0},
    {"Bass Boost", 0},
};

struct MenuItem CONN_MENU[] = {
    {"BT Name", 0},
    {"BT Switch", 0},
    {"Wi-Fi Switch", 0},
};

const uint8_t *ALL_MENU[] = {
    reinterpret_cast<uint8_t *>(&HOME_MENU),
    reinterpret_cast<uint8_t *>(&DISP_MENU),
    reinterpret_cast<uint8_t *>(&SND_MENU),
    reinterpret_cast<uint8_t *>(&CONN_MENU),
};

const unsigned int ALL_MENU_SIZE[] = {
    sizeof(HOME_MENU) / sizeof(HOME_MENU[0]),
    sizeof(DISP_MENU) / sizeof(DISP_MENU[0]),
    sizeof(SND_MENU) / sizeof(SND_MENU[0]),
    sizeof(CONN_MENU) / sizeof(CONN_MENU[0]),
};

const int BTN_U = 2;
const int BTN_D = 3;
const int BTN_O = 4;
const int LCD_H = 64;
const int LCD_W = 128;

int currMenuIdx;
int pos;

bool debounce(int time, unsigned long *lastInterrupt)
{
    if ((*lastInterrupt) == 0)
    {
        (*lastInterrupt) = millis();
        return true;
    }
    unsigned long now = millis();
    bool isDebounced = (now - (*lastInterrupt)) > time;
    if (isDebounced)
        *lastInterrupt = now;
    return isDebounced;
}

void drawMenuText(int pos, const MenuItem *menuText, int menuSize)
{
    int currPos = pos - 1;
    for (int y = 14; y < LCD_H; y += 21)
    {
        if (currPos - pos == 0)
            display.setFont(u8g2_font_tenthinnerguys_tr);
        else
            display.setFont(u8g2_font_glasstown_nbp_tr);
        if (currPos >= 0 && currPos < menuSize)
            display.drawStr(30, y, (menuText + currPos)->title);
        ++currPos;
    }
}

void drawMenuGraphics(int pos, int menuSize)
{
    const int scrollWidth = 4;
    int scrollHeight = LCD_H / menuSize + 1;
    int scrollPos = scrollHeight * pos;
    if (scrollPos > LCD_H)
        scrollPos = LCD_H;
    // draw selection frame
    display.drawRFrame(2, 20, 120, 20, 3);
    display.drawHLine(5, 40, 115);
    display.drawVLine(120, 22, 17);

    // draw scrollbar
    display.drawFrame(LCD_W - scrollWidth, 0, scrollWidth, LCD_H);
    display.drawBox(LCD_W - scrollWidth + 1, scrollPos + 1, scrollWidth - 2, scrollHeight);
}

void setup(void)
{
    currMenuIdx = 0;
    Serial.begin(9600);
    display.begin(); // start the u8g2 library
    pinMode(BTN_O, INPUT_PULLUP);
    pinMode(BTN_U, INPUT_PULLUP);
    pinMode(BTN_D, INPUT_PULLUP);
}

void loop(void)
{
    static unsigned long lastLcdInterrupt;
    static unsigned long lastBtnInterrupt;
    static unsigned long lastLogInterrupt;
    const int menuSize = ALL_MENU_SIZE[currMenuIdx];
    uint8_t currMenuAddr = *ALL_MENU[currMenuIdx];
    MenuItem *currMenu = reinterpret_cast<MenuItem *>(currMenuAddr);
    char *logText;

    if (debounce(1000, &lastLogInterrupt))
    {
        sprintf(logText, "currMenuIdx: %d; currMenuAddr: %d; pos: %d; title: %s;",
                currMenuIdx, currMenuAddr, pos, (currMenu + pos)->title);
        Serial.println(logText);
    }

    if (digitalRead(BTN_U) == LOW)
    {
        if (debounce(150, &lastBtnInterrupt))
        {
            pos -= pos > 0 ? 1 : 0;
        }
    }

    if (digitalRead(BTN_D) == LOW)
    {
        if (debounce(150, &lastBtnInterrupt))
        {
            pos += pos < (menuSize - 1) ? 1 : 0;
        }
    }

    if (digitalRead(BTN_O) == LOW)
    {
        if (debounce(150, &lastBtnInterrupt))
        {
            currMenuIdx = (currMenu + pos)->subMenuIdx;
        }
    }

    if (debounce(16, &lastLcdInterrupt))
    {
        display.clearBuffer();
        drawMenuText(pos, currMenu, menuSize);
        drawMenuGraphics(pos, menuSize);
        display.sendBuffer();
    }
}