/*
  ESP32-S3 + ILI9341 (240x320) Spiral Animation + Gradient Backgrounds
  -------------------------------------------------------------------
  Companion firmware for esp32_ili9341_spiral_simulator.html

  Libraries required:
    - Adafruit GFX Library
    - Adafruit ILI9341 Library

  Arvind Patil / AI Centre Nandurbar
*/

#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>
#include <SPI.h>

// ---------- Pin configuration ----------
#define TFT_CS   10
#define TFT_DC   11
#define TFT_RST  12
#define TFT_SCLK 13
#define TFT_MOSI 14
#define TFT_MISO 21
#define BTN_NEXT 0   // BOOT button, active LOW

#define SCREEN_W 240
#define SCREEN_H 320

Adafruit_ILI9341 tft = Adafruit_ILI9341(&SPI, TFT_DC, TFT_CS, TFT_RST);

const int cx = SCREEN_W / 2;
const int cy = SCREEN_H / 2;

int spiralIndex = 0;
bool autoAdvance = true;
unsigned long lastAdvance = 0;
const unsigned long ADVANCE_MS = 1400;

bool lastBtnState = HIGH;

// 10 palettes, one per spiral mode (RGB565)
const uint16_t palettes[10][4] = {
  {0xFA4A, 0xFEA3, 0x0740, 0x4E5F},   // 1
  {0xFCE3, 0xFDF3, 0xCF9E, 0x2E6D},   // 2
  {0xF9B1, 0xB8D3, 0x7205, 0x580B},   // 3
  {0x07FA, 0x05FD, 0xF7E1, 0xF2DA},   // 4
  {0xADFD, 0x43D3, 0x1DAB, 0xF7DE},   // 5
  {0xFBA0, 0xFC40, 0xFE80, 0xFF95},   // 6
  {0x7996, 0x9A5D, 0xC7BE, 0xE555},   // 7
  {0x07FF, 0x1FFF, 0x67FD, 0xB7F6},   // 8
  {0xF80D, 0xFACB, 0xFDE0, 0x81DF},   // 9
  {0xFFFF, 0x7FFF, 0x0537, 0x01AA}    // 10
};

uint16_t colorFor(int mode, int i) {
  return palettes[mode % 10][i % 4];
}

// ---------- Gradient Backgrounds ----------
void drawGradientBackground(int mode, unsigned long timeMs) {
  for (int y = 0; y < SCREEN_H; y++) {
    uint16_t color;
    switch (mode % 5) {
      case 0: // Blue → Purple
        color = tft.color565(
          (y * 255) / SCREEN_H,
          0,
          255 - (y * 128) / SCREEN_H
        );
        break;
      case 1: // Green → Yellow
        color = tft.color565(
          (y * 255) / SCREEN_H,
          255,
          0
        );
        break;
      case 2: // Red → Orange
        color = tft.color565(
          255,
          (y * 180) / SCREEN_H,
          0
        );
        break;
      case 3: // Cyan → Blue
        color = tft.color565(
          0,
          255 - (y * 128) / SCREEN_H,
          255
        );
        break;
      case 4: // Rainbow wave (animated)
        color = tft.color565(
          (sin((y + timeMs * 0.01f) * 0.05f) * 127 + 128),
          (sin((y + timeMs * 0.01f) * 0.07f) * 127 + 128),
          (sin((y + timeMs * 0.01f) * 0.09f) * 127 + 128)
        );
        break;
    }
    tft.drawFastHLine(0, y, SCREEN_W, color);
  }
}

// ---------- Spiral Drawing ----------
void drawSpiral(int n, unsigned long timeMs) {
  int mode = n % 10;

  // Gradient background first
  drawGradientBackground(mode, timeMs);

  float turns = 4.5f + mode * 0.35f;
  float maxR  = (18.0f + mode * 2.6f) * 1.14f;
  const int loops = 220;

  for (int i = 0; i < loops; i++) {
    float p = (float)i / loops;
    float angle = p * TWO_PI * turns + timeMs * 0.0015f * (1 + mode * 0.08f);
    float radius = p * maxR * 10.2f;

    switch (mode) {
      case 1: radius = pow(p, 0.82f) * maxR * 10.5f; break;
      case 2: radius = (1 - cos(p * PI * turns)) * 12.0f; break;
      case 3: radius = p * maxR * 9.4f + sin(p * 16 + timeMs * 0.002f) * 3.0f; break;
      case 4: radius = (p * maxR * 8.8f) * (0.7f + 0.3f * sin(angle * 3)); break;
      case 5: radius = p * maxR * 9.8f + cos(p * 22 + timeMs * 0.003f) * 5.0f; break;
      case 6: radius = p * maxR * 10.0f + sin(angle * 5) * 2.5f; break;
      case 7: radius = p * maxR * 8.7f + sin(p * 30 + timeMs * 0.001f) * 4.0f; break;
      case 8: radius = p * maxR * 10.2f; break;
      case 9: radius = p * maxR * 9.6f + sin(p * 12 * PI + timeMs * 0.002f) * 6.0f; break;
      default: break;
    }

    int x = cx + (int)(cos(angle) * radius);
    int y = cy + (int)(sin(angle) * radius);

    if (x < 0 || x >= SCREEN_W || y < 0 || y >= SCREEN_H) continue;

    uint16_t c = colorFor(mode, i);
    float size = 2.1f - p * 1.6f;
    int r = max(1, (int)size);
    tft.fillCircle(x, y, r, c);
  }

  // Header text
  tft.setCursor(6, 6);
  tft.setTextColor(ILI9341_WHITE);
  tft.setTextSize(1);
  tft.print("Spiral ");
  tft.print(n + 1);
  tft.print(" / 10");

  tft.setCursor(6, 18);
  tft.setTextColor(0x7BCF);
  tft.print("ESP32-S3  ILI9341 240x320");
}

void setup() {
  Serial.begin(115200);
  pinMode(BTN_NEXT, INPUT_PULLUP);

  SPI.begin(TFT_SCLK, TFT_MISO, TFT_MOSI, TFT_CS);
  tft.begin();
  tft.setRotation(0); // portrait
}

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

  // Manual advance
  bool btn = digitalRead(BTN_NEXT);
  if (lastBtnState == HIGH && btn == LOW) {
    spiralIndex = (spiralIndex + 1) % 10;
    lastAdvance = now;
  }
  lastBtnState = btn;

  // Auto advance
  if (autoAdvance && now - lastAdvance > ADVANCE_MS) {
    spiralIndex = (spiralIndex + 1) % 10;
    lastAdvance = now;
  }

  drawSpiral(spiralIndex, now);
}