#include <TFT_eSPI.h>
#include <driver/i2s.h>

TFT_eSPI tft = TFT_eSPI();
TFT_eSprite ds = TFT_eSprite(&tft);

#define SAMPLES 1024
#define SAMPLE_RATE 200000 

uint16_t buffer[SAMPLES];
uint32_t delays[] = {1, 2, 4, 8, 16, 32};
const char* labels[] = {"MAX", "x2", "x4", "x8", "x16", "x32"};
int mode = 0;
uint32_t lastUpdate = 0;
float smooth_f = 0;

void setup_i2s() {
  i2s_driver_uninstall(I2S_NUM_0);
  i2s_config_t i2s_config = {
    .mode = (i2s_mode_t)(I2S_MODE_MASTER | I2S_MODE_RX | I2S_MODE_ADC_BUILT_IN),
    .sample_rate = SAMPLE_RATE,
    .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,
    .channel_format = I2S_CHANNEL_FMT_ONLY_RIGHT,
    .communication_format = I2S_COMM_FORMAT_I2S_MSB,
    .intr_alloc_flags = ESP_INTR_FLAG_LEVEL1,
    .dma_buf_count = 8,
    .dma_buf_len = 512,
    .use_apll = false
  };
  i2s_driver_install(I2S_NUM_0, &i2s_config, 0, NULL);
  i2s_set_adc_mode(ADC_UNIT_1, ADC1_CHANNEL_7); 
  i2s_adc_enable(I2S_NUM_0);
}

void touch_calibrate() {
  uint16_t calData[5];
  tft.fillScreen(TFT_BLACK);
  tft.setTextColor(TFT_WHITE);
  tft.drawCentreString("TOUCH CORNERS", 160, 100, 2);
  tft.calibrateTouch(calData, TFT_GREEN, TFT_BLACK, 15);
  tft.setTouch(calData);
  tft.fillScreen(TFT_BLACK);
}

void setup() {
  pinMode(27, OUTPUT); digitalWrite(27, HIGH);
  pinMode(21, OUTPUT); digitalWrite(21, HIGH);
  tft.init();
  tft.setRotation(1);
  tft.invertDisplay(false);
  touch_calibrate();
  ds.setColorDepth(8);
  ds.createSprite(320, 160);
  setup_i2s();
}

void loop() {
  uint16_t tx, ty;
  if (tft.getTouch(&tx, &ty)) {
    if (ty > 190) {
      mode = tx / 53; if (mode > 5) mode = 5;
      delay(150);
    }
  }

  size_t bytes_read = 0;
  uint16_t raw_buf[SAMPLES * 2];
  i2s_read(I2S_NUM_0, (void*)raw_buf, SAMPLES * 4, &bytes_read, portMAX_DELAY);

  int v_max = 0, v_min = 4096;
  for (int i = 0; i < SAMPLES; i++) {
    buffer[i] = raw_buf[i * 2] & 0x0FFF; 
    if (buffer[i] > v_max) v_max = buffer[i];
    if (buffer[i] < v_min) v_min = buffer[i];
  }

  int amp = v_max - v_min;
  float mid = (v_max + v_min) / 2.0;
  int hyst = amp / 6; if (hyst < 60) hyst = 60;

  int first = -1, last = -1, p_count = 0;
  bool state = false;
  if (amp > 100) {
    for (int i = 1; i < SAMPLES; i++) {
      if (!state && buffer[i-1] < mid && buffer[i] >= mid) {
        if (first == -1) first = i;
        last = i; p_count++; state = true;
      } else if (state && buffer[i] < mid - hyst) state = false;
    }
  }

  float inst_f = 0;
  if (p_count > 1 && (last - first) > 0) {
    inst_f = (((float)(p_count - 1) * SAMPLE_RATE) / (float)(last - first) / 2.0);
    
    // --- ТОЧЕЧНАЯ КОРРЕКЦИЯ ПО ЗАПРОСУ ---
    if (inst_f < 500) inst_f -= 1.0;          // До 500 Гц убираем 1 Гц
    else if (inst_f < 1000) inst_f -= 2.0;   // После 500 Гц убираем 2 Гц
    else inst_f -= 20.0;                     // У Килогерц отнимаем 0.02 кГц (20 Гц)
    
    if (inst_f < 0) inst_f = 0;
  }

  if (inst_f > 0) {
    float k = (inst_f > 5000) ? 0.3 : 0.1; 
    smooth_f = smooth_f * (1.0 - k) + inst_f * k;
  } else smooth_f = 0;

  int trig = 0;
  for (int i = 1; i < SAMPLES / 2; i++) {
    if (buffer[i-1] < mid && buffer[i] >= mid) { trig = i; break; }
  }

  ds.fillSprite(TFT_BLACK);
  for(int x=0; x<=320; x+=40) ds.drawFastVLine(x, 0, 160, 0x2104);
  for(int y=0; y<=160; y+=40) ds.drawFastHLine(0, y, 320, 0x2104);

  int window = (SAMPLES / 2) / delays[mode];
  int py = map(buffer[trig], v_min, v_max, 155, 5);
  for (int i = 1; i < 320; i++) {
    int idx = trig + (i * window / 320);
    if (idx >= SAMPLES) break;
    int cy = map(buffer[idx], v_min, v_max, 155, 5);
    ds.drawLine(i - 1, py, i, cy, TFT_GREEN);
    py = cy;
  }
  ds.pushSprite(0, 30);

  if (millis() - lastUpdate > 300) {
    tft.fillRect(0, 0, 320, 30, TFT_BLACK);
    tft.setTextColor(TFT_YELLOW, TFT_BLACK); tft.setTextSize(2);
    tft.setCursor(5, 5);
    float vpp = amp * 3.3 / 4095.0;
    if (amp > 80) {
      if (smooth_f >= 1000) tft.printf("%.2fV  %.2fkHz", vpp, smooth_f/1000.0);
      else tft.printf("%.2fV  %.0fHz", vpp, smooth_f);
    } else tft.print("0.00V  0.0Hz");
    
    tft.setTextSize(1);
    for (int i = 0; i < 6; i++) {
      tft.drawRect(i * 53, 195, 52, 44, (i == mode) ? TFT_YELLOW : 0x7BEF);
      tft.setTextColor((i == mode) ? TFT_YELLOW : 0x7BEF);
      tft.drawCentreString(labels[i], i * 53 + 26, 210, 1);
    }
    lastUpdate = millis();
  }
}