#include <Arduino.h>
#include <U8g2lib.h>

// initialization for the 128x64px OLED display
U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE);
// U8G2_SH1106_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, U8X8_PIN_NONE);

static const unsigned char full_btn_bits[] = {0xfc,0xff,0xff,0xff,0x0f,0xfe,0xff,0xff,0xff,0x1f,0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f};
static const unsigned char frame_btn_bits[] = {0xfc,0xff,0xff,0xff,0x07,0x02,0x00,0x00,0x00,0x08,0x01,0x00,0x00,0x00,0x10,0x01,0x00,0x00,0x00,0x10,0x01,0x00,0x00,0x00,0x10,0x01,0x00,0x00,0x00,0x10,0x01,0x00,0x00,0x00,0x10,0x01,0x00,0x00,0x00,0x10,0x01,0x00,0x00,0x00,0x10,0x01,0x00,0x00,0x00,0x10};

static const uint8_t NUM_SLIDERS = 1;
static const uint8_t analogInputs[NUM_SLIDERS] = {4};

unsigned short analogSliderValues[NUM_SLIDERS];

void setup() {
    Serial.begin(9600);
    u8g2.begin();
    u8g2.clear();

    for (int i = 0; i < NUM_SLIDERS; i++)
        pinMode(analogInputs[i], INPUT);

    u8g2.setFontMode(1);
    u8g2.setBitmapMode(1);

    u8g2.setFont(u8g2_font_4x6_tr);
}

void loop() {
    updateSliderValues();
    drawScreen();
}

void drawScreen() {
    u8g2.clearBuffer();

    u8g2.drawRFrame(1, 1, 126, 46, 3);
    
    u8g2.setFont(u8g2_font_NokiaSmallBold_tr);
    u8g2.drawStr(15, 14, "Slider Configuration");

    // convert the slider value to a string
    const String sliderStr = String(analogSliderValues[0]);

    // calculate the width of the slider string
    unsigned short sliderWidth = u8g2.getStrWidth(sliderStr.c_str());

    // calculate the X position to center the text
    unsigned short valueX = (128 - sliderWidth) / 2;

    // draw the value in the center of the screen
    u8g2.drawStr(valueX, 39, sliderStr.c_str());

    // adjust the line start and end based on the sliderStr width + padding
    unsigned short lineStartX = valueX - 2;  // start the line 2 pixels before the string
    unsigned short lineEndX = valueX + sliderWidth + 1;  // end the line 1 pixels after the string

    // draw the line with dynamic width
    u8g2.drawLine(lineStartX, 41, lineEndX, 41);

    u8g2.setFont(u8g2_font_5x7_tf);
    u8g2.drawStr(40, 26, "max value:");

    u8g2.setFont(u8g2_font_6x10_tr);
    u8g2.drawStr(7, 63, "Back");
    u8g2.drawStr(98, 63, "Next");

    u8g2.setDrawColor(2);
    u8g2.drawStr(53, 63, "Save");

    u8g2.drawXBM(0, 54, 37, 10, frame_btn_bits);
    u8g2.drawXBM(91, 54, 37, 10, frame_btn_bits);
    u8g2.drawXBM(45, 54, 38, 10, full_btn_bits);

    u8g2.sendBuffer();
}

void updateSliderValues() {
    for (int i = 0; i < NUM_SLIDERS; i++)
        analogSliderValues[i] = analogRead(analogInputs[i]);
}