#include <Wire.h>
#include <Adafruit_BMP085.h>
#include <Adafruit_SSD1306.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#include <math.h>

// ---------------- PIN CONFIG ----------------
#define ONE_WIRE_BUS 4
#define SDA_PIN 8
#define SCL_PIN 9
#define ANEMO_PIN 5
#define WIND_DIR_PIN 6

// ---------------- OBJECTS ----------------
Adafruit_BMP085 bmp;
Adafruit_SSD1306 display(128, 64, &Wire);
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

// ---------------- VELOCITY ----------------
volatile unsigned long lastPulseTime = 0;
volatile unsigned long period = 0;

float velocity = 0;

// ---------------- VARIABLES ----------------
float temperature = 0;
float pressure = 0;
float angle = 0;

// ---------------- INTERRUPT ----------------
void IRAM_ATTR countPulse() {
  unsigned long now = micros();
  period = now - lastPulseTime;
  lastPulseTime = now;
}

// ---------------- ANGLE ----------------
float getAngle(int val) {
  return (val / 4095.0) * 360.0;   // calibrate if needed
}

// ---------------- DRAW LARGE VECTOR ----------------
void drawBigVector(float angle, float velocity) {

  int cx = 64;
  int cy = 40;

  float rad = angle * PI / 180.0;

  float maxVel = 10.0;
  int length = (velocity / maxVel) * 25;

  if (length > 25) length = 25;
  if (length < 5) length = 5;

  int dx = length * cos(rad);
  int dy = length * sin(rad);

  // Main arrow
  display.drawLine(cx, cy, cx + dx, cy - dy, SSD1306_WHITE);

  // Arrow head
  display.drawLine(cx + dx, cy - dy, cx + dx - dy/2, cy - dy - dx/2, SSD1306_WHITE);
  display.drawLine(cx + dx, cy - dy, cx + dx + dy/2, cy - dy + dx/2, SSD1306_WHITE);

  display.fillCircle(cx, cy, 2, SSD1306_WHITE);
}

// ---------------- SETUP ----------------
void setup() {
  Serial.begin(115200);

  Wire.begin(SDA_PIN, SCL_PIN);

  sensors.begin();

  if (!bmp.begin()) {
    Serial.println("BMP180 not found!");
    while (1);
  }

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("OLED not found!");
    while (1);
  }

  pinMode(ANEMO_PIN, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(ANEMO_PIN), countPulse, FALLING);

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
}

// ---------------- LOOP ----------------
void loop() {

  // 🌪️ Velocity (REAL-TIME)
  if (period > 0) {
    velocity = 500000.0 / period;  // calibrate this constant
  }

  // 🌡️ Temperature
  sensors.requestTemperatures();
  temperature = sensors.getTempCByIndex(0);

  // 🌬️ Pressure
  pressure = bmp.readPressure() / 100.0;

  // 🧭 Direction
  int dirValue = analogRead(WIND_DIR_PIN);
  angle = getAngle(dirValue);

  // ---------------- OLED ----------------
  display.clearDisplay();

  // TOP LINE
  display.setCursor(0, 0);
  display.print("T:");
  display.print(temperature, 1);
  display.print("C");

  display.setCursor(70, 0);
  display.print("P:");
  display.print(pressure, 0);

  // SECOND LINE
  display.setCursor(0, 12);
  display.print("V:");
  display.print(velocity, 2);
  display.print("m/s");

  display.setCursor(70, 12);
  display.print("A:");
  display.print(angle, 0);
  display.print((char)247);

  // BIG VECTOR
  drawBigVector(angle, velocity);

  display.display();

  // SERIAL LOG (for analysis)
  Serial.print(temperature); Serial.print(",");
  Serial.print(pressure); Serial.print(",");
  Serial.print(velocity); Serial.print(",");
  Serial.println(angle);

  delay(200);
}