// ============================================================
//  PERSONALITY BOT — Optimised & Bug-Fixed
//  Sensors : MPU6050 (I2C) + DHT22 (digital)
//  Display  : SSD1306 128x64 OLED (I2C)
//  Extras   : Passive buzzer, momentary button
// ============================================================

#include <Wire.h>
#include <Adafruit_MPU6050.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <DHT.h>

// ===== PIN DEFINITIONS =====
#define DHTPIN        10
#define DHTTYPE       DHT22
#define BUTTON_PIN    11
#define BUZZER_PIN    6

// ===== OLED CONFIG =====
#define SCREEN_WIDTH  128
#define SCREEN_HEIGHT 64
#define OLED_ADDR     0x3C

// ===== THRESHOLDS (gravity-compensated) =====
// At rest, raw magnitude ≈ 9.8 m/s²  →  we subtract baseline
// so 0 = still, positive = actual movement.
#define GRAVITY_BASELINE  9.8f
#define HAPPY_THRESH      3.0f   // gentle shake  (raw ~12.8)
#define ANGRY_THRESH      8.0f   // hard shake    (raw ~17.8)

// ===== TIMING =====
#define LOOP_DELAY        100    // ms between sensor polls
#define BUTTON_DEBOUNCE   300    // ms button lockout
#define BUZZER_HAPPY_FREQ 1000
#define BUZZER_HAPPY_DUR  200
#define BUZZER_ANGRY_FREQ 200
#define BUZZER_ANGRY_DUR  500

// ===== OBJECTS =====
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
Adafruit_MPU6050 mpu;
DHT dht(DHTPIN, DHTTYPE);

// ===== STATE MACHINE =====
enum Mood { CALM, HAPPY, ANGRY };
Mood currentMood = CALM;

// ===== CACHED SENSOR VALUES =====
float cachedTemp = 0.0f;
float cachedHum  = 0.0f;
unsigned long lastDHTRead = 0;
#define DHT_INTERVAL 2000   // DHT22 max sample rate ~0.5 Hz

// ============================================================
//  FACE DRAWING HELPERS
// ============================================================

// Shared face outline so all moods look consistent
void drawFaceOutline() {
  display.drawCircle(64, 30, 28, WHITE);   // head circle
}

// Eyes: normal round eyes
void drawNormalEyes() {
  display.fillCircle(50, 22, 4, WHITE);    // left eye
  display.fillCircle(78, 22, 4, WHITE);    // right eye
}

// Eyes: angry — small and narrowed (filled triangles as brows above dots)
void drawAngryEyes() {
  // Pupils (smaller to look tense)
  display.fillCircle(50, 24, 3, WHITE);
  display.fillCircle(78, 24, 3, WHITE);

  // Eyebrows angled inward toward nose bridge (V-shape)
  // Left brow: high outside, low inside → right-leaning
  display.drawLine(40, 14, 54, 19, WHITE);
  // Right brow: low inside, high outside → left-leaning
  display.drawLine(74, 19, 88, 14, WHITE);
}

// Mouth: flat / neutral line
void drawNeutralMouth() {
  display.drawLine(52, 44, 76, 44, WHITE);
}

// Mouth: smile — two angled lines forming a V-arc
void drawSmileMouth() {
  display.drawLine(50, 42, 64, 50, WHITE);
  display.drawLine(64, 50, 78, 42, WHITE);
}

// Mouth: frown — inverted smile
void drawFrownMouth() {
  display.drawLine(52, 48, 64, 41, WHITE);
  display.drawLine(64, 41, 76, 48, WHITE);
}

// ============================================================
//  FULL FACE RENDERERS
// ============================================================

void drawCalmFace(float temp, float hum) {
  display.clearDisplay();
  drawFaceOutline();
  drawNormalEyes();
  drawNeutralMouth();

  // Temp + humidity bar along the bottom
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(2, 56);
  display.print(temp, 1);
  display.print((char)247);   // degree symbol
  display.print("C  ");
  display.print(hum, 1);
  display.print("%");

  display.display();
}

void drawHappyFace() {
  display.clearDisplay();
  drawFaceOutline();

  // Bigger, excited eyes
  display.fillCircle(50, 22, 5, WHITE);
  display.fillCircle(78, 22, 5, WHITE);

  drawSmileMouth();

  // Little cheek blush dots
  display.fillCircle(38, 34, 2, WHITE);
  display.fillCircle(90, 34, 2, WHITE);

  display.display();
}

void drawAngryFace() {
  display.clearDisplay();
  drawFaceOutline();
  drawAngryEyes();
  drawFrownMouth();

  // Warning text below face
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(6, 57);
  display.print("STOP SHAKING ME!");

  display.display();
}

// ============================================================
//  SETUP
// ============================================================

void setup() {
  Serial.begin(115200);

  pinMode(BUTTON_PIN, INPUT_PULLUP);
  pinMode(BUZZER_PIN, OUTPUT);

  Wire.begin();

  // --- OLED ---
  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
    Serial.println(F("OLED init failed — check wiring/address"));
    while (true);
  }
  display.setTextColor(WHITE);

  // Splash screen
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(18, 20);
  display.println(F("Personality Bot"));
  display.setCursor(30, 36);
  display.println(F("Starting..."));
  display.display();
  delay(1500);

  // --- MPU6050 (try 0x68 then 0x69) ---
  if (!mpu.begin(0x68)) {
    Serial.println(F("MPU6050 not on 0x68, trying 0x69..."));
    if (!mpu.begin(0x69)) {
      Serial.println(F("MPU6050 init failed — check wiring"));
      while (true);
    }
  }
  // Reduce accel range for better shake sensitivity
  mpu.setAccelerometerRange(MPU6050_RANGE_4_G);
  mpu.setFilterBandwidth(MPU6050_BAND_21_HZ);

  // --- DHT22 ---
  dht.begin();

  // Prime DHT cache
  delay(2000);
  cachedTemp = dht.readTemperature();
  cachedHum  = dht.readHumidity();
  if (isnan(cachedTemp)) cachedTemp = 0.0f;
  if (isnan(cachedHum))  cachedHum  = 0.0f;
  lastDHTRead = millis();

  Serial.println(F("Boot complete."));
}

// ============================================================
//  LOOP
// ============================================================

void loop() {
  unsigned long now = millis();

  // ===== 1. READ MPU6050 =====
  sensors_event_t a, g, temp;
  mpu.getEvent(&a, &g, &temp);

  float rawMag = sqrt(
    a.acceleration.x * a.acceleration.x +
    a.acceleration.y * a.acceleration.y +
    a.acceleration.z * a.acceleration.z
  );

  // Subtract gravity so 0 = truly at rest
  float moveMag = rawMag - GRAVITY_BASELINE;

  // ===== 2. READ DHT22 (non-blocking, rate-limited) =====
  if (now - lastDHTRead >= DHT_INTERVAL) {
    float h = dht.readHumidity();
    float t = dht.readTemperature();
    if (!isnan(h)) cachedHum  = h;
    if (!isnan(t)) cachedTemp = t;
    lastDHTRead = now;
  }

  // ===== 3. BUTTON — triggers HAPPY (with debounce) =====
  static unsigned long lastButtonTime = 0;
  if (digitalRead(BUTTON_PIN) == LOW && (now - lastButtonTime > BUTTON_DEBOUNCE)) {
    lastButtonTime = now;
    currentMood = HAPPY;
  }

  // ===== 4. SHAKE DETECTION (only update if not already reacting) =====
  // Button press takes priority over motion detection
  if (currentMood == CALM) {
    if (moveMag > ANGRY_THRESH) {
      currentMood = ANGRY;
    } else if (moveMag > HAPPY_THRESH) {
      currentMood = HAPPY;
    }
  }

  // ===== 5. REACT TO MOOD =====
  switch (currentMood) {

    case CALM:
      drawCalmFace(cachedTemp, cachedHum);
      noTone(BUZZER_PIN);
      break;

    case HAPPY:
      drawHappyFace();
      tone(BUZZER_PIN, BUZZER_HAPPY_FREQ, BUZZER_HAPPY_DUR);
      delay(BUZZER_HAPPY_DUR);
      currentMood = CALM;
      break;

    case ANGRY:
      drawAngryFace();
      tone(BUZZER_PIN, BUZZER_ANGRY_FREQ, BUZZER_ANGRY_DUR);
      delay(BUZZER_ANGRY_DUR);
      currentMood = CALM;
      break;
  }

  // ===== 6. DEBUG OUTPUT =====
  Serial.print(F("moveMag: "));
  Serial.print(moveMag, 2);
  Serial.print(F("  T: "));
  Serial.print(cachedTemp, 1);
  Serial.print(F("C  H: "));
  Serial.print(cachedHum, 1);
  Serial.println(F("%"));

  delay(LOOP_DELAY);
}