#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Tone.h>

// TEA5767 I2C address
#define TEA5767_ADDR 0x60

// Button pins
#define BUTTON_UP 4
#define BUTTON_DOWN 2
#define BUTTON_MINUTE 6
#define BUTTON_TEN_MINUTES 7

// Buzzer pin
#define BUZZER_PIN 13

// Frequency variables
float frequency = 101.3;  // Initial frequency in MHz
const float frequencyStep = 0.1;  // Step size in MHz
const float minFrequency = 87.5;  // Minimum FM frequency in MHz
const float maxFrequency = 108.0; // Maximum FM frequency in MHz

// Timer variables
unsigned long timer = 0;  // Timer in seconds
unsigned long previousMillis = 0;  // Last time the timer was updated
const unsigned long interval = 1000;  // Interval for timer countdown in milliseconds
bool timerEnded = true;  // Flag to indicate if the timer has ended
bool timerStarted = false;  // Flag to indicate if the timer has started
unsigned long blinkStartMillis = 0;  // Time when blinking started
const unsigned long blinkDuration = 3000;  // Duration of the blinking effect in milliseconds

// OLED display settings
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 32
#define OLED_RESET -1  // Reset pin (or -1 if sharing Arduino reset pin)
#define OLED_I2C_ADDRESS 0x3C // I2C address for the OLED display
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

Tone buzzer;  // Create a Tone object for the buzzer

void setup() {
  Serial.begin(9600);
  Wire.begin();

  // Initialize buttons
  pinMode(BUTTON_UP, INPUT_PULLUP);
  pinMode(BUTTON_DOWN, INPUT_PULLUP);
  pinMode(BUTTON_MINUTE, INPUT_PULLUP);
  pinMode(BUTTON_TEN_MINUTES, INPUT_PULLUP);

  // Initialize the TEA5767
  setFrequency(frequency);

  // Initialize the OLED display
  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_I2C_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;); // Don't proceed, loop forever
  }

  buzzer.begin(BUZZER_PIN);

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);
  display.print("Frequency: ");
  display.print(frequency, 1);
  display.println(" MHz");
  display.setCursor(0, 10);
  display.print("Alarm: 0 min 0 sec");
  display.display();
}

void loop() {
  // Check if the UP button is pressed
  if (digitalRead(BUTTON_UP) == LOW) {
    increaseFrequency();
    delay(300);  // Debounce delay
  }

  // Check if the DOWN button is pressed
  if (digitalRead(BUTTON_DOWN) == LOW) {
    decreaseFrequency();
    delay(300);  // Debounce delay
  }

  // Check if the MINUTE button is pressed
  if (digitalRead(BUTTON_MINUTE) == LOW) {
    increaseTimer(5);  // Increase timer by 1 minute
    delay(300);  // Debounce delay
  }

  // Check if the TEN MINUTES button is pressed
  if (digitalRead(BUTTON_TEN_MINUTES) == LOW) {
    increaseTimer(600);  // Increase timer by 10 minutes
    delay(300);  // Debounce delay
  }

  // Update the timer
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;
    if (timer > 0) {
      timer--;
      updateDisplay();
    } else if (timer == 0 && timerStarted) {
      timerEnded = false;
      timerStarted = false;
      blinkStartMillis = currentMillis;
    }
  }

  if (!timerEnded) {
    if (currentMillis - blinkStartMillis <= blinkDuration) {
      // Blink the screen
      if ((currentMillis / 100) % 2 == 0) {
        display.clearDisplay();
      } else {
        updateDisplay();
      }
      display.display();
      buzzer.play(NOTE_C4);  // Play a tone (middle C)
    } else {
      // Stop blinking and reset timerEnded flag
      timerEnded = true;
      buzzer.stop();  // Stop the tone
      updateDisplay();
    }
  }
}

void setFrequency(float frequency) {
  byte frequencyH = 0;
  byte frequencyL = 0;
  int frequencyB;

  // Calculate PLL word
  frequencyB = 4 * (frequency * 1000000 + 225000) / 32768;

  // Extract high and low bytes
  frequencyH = frequencyB >> 8;
  frequencyL = frequencyB & 0XFF;

  // Send the frequency to the TEA5767
  Wire.beginTransmission(TEA5767_ADDR);
  Wire.write(frequencyH);
  Wire.write(frequencyL);
  Wire.write(0xB0);  // High side injection, PLL ref enable, Mute disable
  Wire.write(0x10);  // Search mode disable, Search stop level 0 (lowest), Soft mute disable
  Wire.write(0x00);  // PLL disable
  Wire.write(0x00);  // Reserved
  Wire.endTransmission();

  Serial.print("Set frequency to: ");
  Serial.print(frequency);
  Serial.println(" MHz");

  updateDisplay();
}

void increaseFrequency() {
  if (frequency < maxFrequency) {
    frequency += frequencyStep;
    setFrequency(frequency);
    Serial.print("Frequency increased to: ");
    Serial.print(frequency);
    Serial.println(" MHz");
  } else {
    Serial.println("Maximum frequency reached");
  }
}

void decreaseFrequency() {
  if (frequency > minFrequency) {
    frequency -= frequencyStep;
    setFrequency(frequency);
    Serial.print("Frequency decreased to: ");
    Serial.print(frequency);
    Serial.println(" MHz");
  } else {
    Serial.println("Minimum frequency reached");
  }
}

void increaseTimer(unsigned long seconds) {
  timer += seconds;
  Serial.print("Timer increased by ");
  Serial.print(seconds / 60);
  Serial.println(" minutes");
  timerStarted = true;
  updateDisplay();
}

void updateDisplay() {
  unsigned long minutes = timer / 60;
  unsigned long seconds = timer % 60;

  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Frequency: ");
  display.print(frequency, 1);
  display.println(" MHz");
  display.setCursor(0, 10);
  display.print("Alarm: ");
  display.print(minutes);
  display.print(" min ");
  display.print(seconds);
  display.println(" sec");
  display.display();
}