#include <esp_now.h>
#include <WiFi.h>
#include <Wire.h>
#include <Adafruit_SSD1306.h>

// ── Car fixed MAC ─────────────────────────────────────────────
uint8_t carMAC[] = {0x36, 0x33, 0x33, 0x33, 0x33, 0x33};

// ── Pin Definitions ───────────────────────────────────────────
#define PIN_VRX    2
#define PIN_VRY    3
#define PIN_BATT   4
#define PIN_SW     5
#define PIN_SDA    6
#define PIN_SCL    7
#define PIN_POWER  21
#define PIN_LED    10

// ── OLED ──────────────────────────────────────────────────────
#define SCREEN_W 128
#define SCREEN_H 64
Adafruit_SSD1306 display(SCREEN_W, SCREEN_H, &Wire, -1);

// ── Game config ───────────────────────────────────────────────
#define TOTAL_COINS 5

// ── Joystick Calibration Constants ────────────────────────────
#define JOY_CENTER 2048    // Center position of a 12-bit ADC
#define JOY_DEADZONE 500   // Increase this value to require MORE physical stick movement

// ── Payloads ──────────────────────────────────────────────────
typedef struct {
  int   vrx;
  int   vry;
  bool  sw;
  float battPct;
} JoyData;

typedef struct {
  int           coins;
  int           timeLeft;
  bool          coinJustCollected;
  bool          win;
  bool          gameover;
  bool          waiting;
  unsigned long winTimeMs;
} CarData;

JoyData  joyData;
CarData  carData;
volatile bool newCarData = false;

// ── ESP-NOW callbacks ─────────────────────────────────────────
void onSent(const wifi_tx_info_t *info, esp_now_send_status_t status) { }

void onReceive(const esp_now_recv_info_t *info,
               const uint8_t *data, int len) {
  if (len == sizeof(CarData)) {
    memcpy(&carData, data, sizeof(CarData));
    newCarData = true;
  }
}

// ── Battery percentage ────────────────────────────────────────
float readBattPct() {
  int raw = analogRead(PIN_BATT);
  float voltage = raw * (3.3f / 4095.0f) * 3.0f;
  float pct = (voltage - 6.0f) / (8.4f - 6.0f) * 100.0f;
  return constrain(pct, 0.0f, 100.0f);
}

// ── Draw faces ────────────────────────────────────────────────
void drawSadFace(int cx, int cy) {
  display.drawCircle(cx, cy, 14, SSD1306_WHITE);
  display.fillCircle(cx - 5, cy - 4, 2, SSD1306_WHITE);
  display.fillCircle(cx + 5, cy - 4, 2, SSD1306_WHITE);
  for (int x = -6; x <= 6; x++) {
    int y = cy + 6 + (x * x) / 8;
    display.drawPixel(cx + x, y, SSD1306_WHITE);
  }
}

void drawHappyFace(int cx, int cy) {
  display.drawCircle(cx, cy, 14, SSD1306_WHITE);
  display.fillCircle(cx - 5, cy - 4, 2, SSD1306_WHITE);
  display.fillCircle(cx + 5, cy - 4, 2, SSD1306_WHITE);
  for (int x = -6; x <= 6; x++) {
    int y = cy + 8 - (x * x) / 8;
    display.drawPixel(cx + x, y, SSD1306_WHITE);
  }
}

// ── OLED screens ──────────────────────────────────────────────
void showWaiting() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(20, 5);
  display.println("COIN COLLECTOR");

  display.setCursor(10, 17);
  display.setTextSize(2);
  display.println(" Press SW  to start");

  display.setTextColor(SSD1306_BLACK, SSD1306_WHITE); 
  display.setTextSize(1);
  display.setCursor(30, 55);
  display.println("  Good luck!  ");
  display.display();
}

void showPlaying(int coins, int timeLeft, float batt) {
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);

  // Timer countdown (big)
  display.setTextSize(2);
  display.setCursor(0, 0);
  int m = timeLeft / 60;
  int s = timeLeft % 60;
  display.printf("%02d:%02d", m, s);

  // Coins count
  display.setTextSize(1);
  display.setCursor(80, 4);
  display.printf("C:%d/%d", coins, TOTAL_COINS);

  // Battery
  display.setCursor(80, 16);
  display.printf("B:%.0f%%", batt);

  // Divider
  display.drawLine(0, 25, 128, 25, SSD1306_WHITE);

  // Coin icons
  display.setCursor(5, 30);
  display.setTextSize(1);
  display.print("Coins:");
  for (int i = 0; i < TOTAL_COINS; i++) {
    int x = 12 + i * 24;
    int y = 42;
    if (i < coins) {
      display.fillCircle(x, y+6, 9, SSD1306_WHITE);
      display.setTextColor(SSD1306_BLACK);
      display.setCursor(x - 3, y+3);
      display.print(i + 1);
      display.setTextColor(SSD1306_WHITE);
    } else {
      display.drawCircle(x, y+6, 9, SSD1306_WHITE);
      display.setCursor(x - 3, y+3);
      display.print(i + 1);
    }
  }

  display.display();
}

void showGameOver(int coins) {
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
  drawSadFace(108, 22);
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println("GAME OVER :(");
  display.drawLine(0, 12, 90, 12, SSD1306_WHITE);
  display.setCursor(0, 18);
  display.printf("Coins: %d/%d", coins, TOTAL_COINS);
  display.setCursor(0, 32);
  display.println("Better luck");
  display.println("next time!");
  display.setCursor(0, 52);
  display.println("SW = restart");
  display.display();
}

void showWin(unsigned long winMs, int coins) {
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
  drawHappyFace(108, 22);
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println("YOU WON! :)");
  display.drawLine(0, 12, 90, 12, SSD1306_WHITE);
  display.setCursor(0, 18);
  int m  = (winMs / 1000) / 60;
  int s  = (winMs / 1000) % 60;
  int ms = (winMs % 1000) / 10;
  display.printf("Time:%02d:%02d.%02d", m, s, ms);
  display.setCursor(0, 32);
  display.printf("All %d coins!", coins);
  display.setCursor(0, 46);
  display.println("Congratulations!");
  display.setCursor(0, 56);
  display.println("SW = play again");
  display.display();
}

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

  pinMode(PIN_BATT, INPUT);
  pinMode(PIN_SW,    INPUT_PULLUP);
  pinMode(PIN_POWER, INPUT_PULLUP);
  pinMode(PIN_LED,   OUTPUT);
  digitalWrite(PIN_LED, HIGH);

  Wire.begin(PIN_SDA, PIN_SCL);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.setTextColor(SSD1306_WHITE);
  display.clearDisplay();
  display.setCursor(0, 0);
  display.setTextSize(1);
  display.println("Starting...");
  display.display();

  WiFi.mode(WIFI_STA);
  esp_now_init();
  esp_now_register_send_cb(onSent);
  esp_now_register_recv_cb(onReceive);

  esp_now_peer_info_t peer = {};
  memcpy(peer.peer_addr, carMAC, 6);
  peer.channel = 0;
  peer.encrypt = false;
  esp_now_add_peer(&peer);

  showWaiting();
}

void loop() {
  // ── Power switch ──────────────────────────────────────────
  if (digitalRead(PIN_POWER) == LOW) {
    display.clearDisplay();
    display.display();
    display.ssd1306_command(SSD1306_DISPLAYOFF);
    digitalWrite(PIN_LED, LOW);

    joyData.vrx = 2139; joyData.vry = 2248;
    joyData.sw  = false; joyData.battPct = 0;
    esp_now_send(carMAC, (uint8_t*)&joyData, sizeof(joyData));

    while (digitalRead(PIN_POWER) == LOW) { delay(100); }

    display.ssd1306_command(SSD1306_DISPLAYON);
    digitalWrite(PIN_LED, HIGH);
    showWaiting();
    delay(300);
  }

  // ── Read raw joystick values ──────────────────────────────
  int rawX = analogRead(PIN_VRX);
  int rawY = analogRead(PIN_VRY);

  // ── Apply Deadzone Filter ─────────────────────────────────
  // If the movement is small (inside the deadzone), force it to center
  if (abs(rawX - JOY_CENTER) < JOY_DEADZONE) {
    joyData.vrx = JOY_CENTER; 
  } else {
    joyData.vrx = rawX;
  }

  if (abs(rawY - JOY_CENTER) < JOY_DEADZONE) {
    joyData.vry = JOY_CENTER; 
  } else {
    joyData.vry = rawY;
  }

  joyData.sw      = (digitalRead(PIN_SW) == LOW);
  joyData.battPct = readBattPct();

  esp_now_send(carMAC, (uint8_t*)&joyData, sizeof(joyData));

  // ── Handle incoming car data ──────────────────────────────
  if (newCarData) {
    newCarData = false;

    if (carData.coinJustCollected) {
      for (int i = 0; i < 3; i++) {
        digitalWrite(PIN_LED, LOW);  delay(150);
        digitalWrite(PIN_LED, HIGH); delay(150);
      }
    }

    if (carData.waiting) {
      showWaiting();
    } else if (carData.win) {
      showWin(carData.winTimeMs, carData.coins);
    } else if (carData.gameover) {
      showGameOver(carData.coins);
    } else {
      showPlaying(carData.coins, carData.timeLeft, joyData.battPct);
    }
  }

  delay(50);
}