#include <Arduino.h>

#define HEADER 0xAA55
#define WINDOW_SIZE 5

typedef struct __attribute__((packed)) {
  uint16_t header;
  int16_t temp_centi;      // Temperature x100
  uint16_t hum_centi;      // Humidity x100
  uint16_t volt_milli;     // Voltage x1000
  uint8_t checksum;
} SensorFrame;

/* Simulated sensor values */
int16_t tempSamples[5]  = {2840, 2910, 2760, 3030, 2980};
uint16_t humSamples[5]  = {5230, 5480, 5110, 5670, 5520};
uint16_t voltSamples[5] = {3610, 3540, 3470, 3290, 3180};

/* Moving average buffers */
int16_t tempBuffer[WINDOW_SIZE] = {0};
uint16_t humBuffer[WINDOW_SIZE] = {0};
uint16_t voltBuffer[WINDOW_SIZE] = {0};

int bufferIndex = 0;
int sampleCount = 0;

uint8_t calculateChecksum(uint8_t *data, int length) {
  uint8_t sum = 0;

  for (int i = 0; i < length; i++) {
    sum += data[i];
  }

  return sum;
}

int32_t movingAverageTemp(int16_t value) {
  tempBuffer[bufferIndex] = value;

  int count = sampleCount < WINDOW_SIZE ? sampleCount + 1 : WINDOW_SIZE;
  int32_t sum = 0;

  for (int i = 0; i < count; i++) {
    sum += tempBuffer[i];
  }

  return sum / count;
}

uint32_t movingAverageUint(uint16_t *buffer, uint16_t value) {
  buffer[bufferIndex] = value;

  int count = sampleCount < WINDOW_SIZE ? sampleCount + 1 : WINDOW_SIZE;
  uint32_t sum = 0;

  for (int i = 0; i < count; i++) {
    sum += buffer[i];
  }

  return sum / count;
}

void printCenti(int32_t value) {
  Serial.print(value / 100);
  Serial.print(".");
  if ((value % 100) < 10) {
    Serial.print("0");
  }
  Serial.print(value % 100);
}

void printMilli(uint32_t value) {
  Serial.print(value / 1000);
  Serial.print(".");
  uint32_t frac = value % 1000;

  if (frac < 100) Serial.print("0");
  if (frac < 10) Serial.print("0");

  Serial.print(frac);
}

void generateSTM32Frame(int index) {
  int16_t rawTemp = tempSamples[index];
  uint16_t rawHum = humSamples[index];
  uint16_t rawVolt = voltSamples[index];

  int32_t filteredTemp = movingAverageTemp(rawTemp);
  uint32_t filteredHum = movingAverageUint(humBuffer, rawHum);
  uint32_t filteredVolt = movingAverageUint(voltBuffer, rawVolt);

  bufferIndex = (bufferIndex + 1) % WINDOW_SIZE;

  if (sampleCount < WINDOW_SIZE) {
    sampleCount++;
  }

  SensorFrame frame;

  frame.header = HEADER;
  frame.temp_centi = filteredTemp;
  frame.hum_centi = filteredHum;
  frame.volt_milli = filteredVolt;
  frame.checksum = calculateChecksum((uint8_t *)&frame, sizeof(SensorFrame) - 1);

  Serial.println();
  Serial.println("[STM32] New sensor values generated");

  Serial.print("[STM32] Raw Data: Temp=");
  printCenti(rawTemp);
  Serial.print(" C, Hum=");
  printCenti(rawHum);
  Serial.print(" %, Volt=");
  printMilli(rawVolt);
  Serial.println(" V");

  Serial.print("[STM32] Filtered Data: Temp=");
  printCenti(filteredTemp);
  Serial.print(" C, Hum=");
  printCenti(filteredHum);
  Serial.print(" %, Volt=");
  printMilli(filteredVolt);
  Serial.println(" V");

  Serial.print("[STM32] FRAME_TO_COPY=");
  Serial.print(frame.header, HEX);
  Serial.print(",");
  Serial.print(frame.temp_centi);
  Serial.print(",");
  Serial.print(frame.hum_centi);
  Serial.print(",");
  Serial.print(frame.volt_milli);
  Serial.print(",");
  Serial.println(frame.checksum, HEX);
}

void setup() {
  Serial.begin(115200);
  delay(1000);

  Serial.println("STM32 Sensor Data Generator Started");
  Serial.println("STM32 Arduino-style Wokwi Simulation");
  Serial.println("Output format: <HEADER>,<TEMP>,<HUM>,<VOLT>,<CHECKSUM>");
}

void loop() {
  static int index = 0;

  generateSTM32Frame(index);

  index++;
  if (index >= 5) {
    index = 0;
  }

  delay(1000);
}