software/ampel-firmware/csv_writer.cpp

#include "csv_writer.h"

//TODO: Allow CSV download via USB Serial, when requested (e.g. via a Python script)

namespace config {
  // Values should be defined in config.h
  uint16_t csv_interval = CSV_INTERVAL; // [s]
}
namespace csv_writer {
  unsigned long last_written_at = 0;
  String last_successful_write = "";

#if defined(ESP8266)
  /**
   * SPECIFIC FUNCTIONS FOR LITTLEFS
   */
  FSInfo fs_info;

  bool mountFS() {
    return LittleFS.begin(); // format if needed.
  }

  void updateFsInfo() {
    FS_LIB.info(fs_info);
  }

  int getTotalSpace() {
    return fs_info.totalBytes;
  }

  int getUsedSpace() {
    return fs_info.usedBytes;
  }

  void showFilesystemContent() {
    Dir dir = FS_LIB.openDir("/");
    while (dir.next()) {
      Serial.print("  ");
      Serial.print(dir.fileName());
      Serial.print(" - ");
      if (dir.fileSize()) {
        File f = dir.openFile("r");
        Serial.println(f.size());
        f.close();
      } else {
        Serial.println("0");
      }
    }
  }
#elif defined(ESP32)
  /**
   * SPECIFIC FUNCTIONS FOR SPIFFS
   */
  bool mountFS() {
    return SPIFFS.begin(true); // format if needed.
  }

  void updateFsInfo() {
    // Nothing to do.
  }

  int getTotalSpace() {
    return SPIFFS.totalBytes();
  }

  int getUsedSpace() {
    return SPIFFS.usedBytes();
  }

  void showFilesystemContent() {
    File root = SPIFFS.open("/");
    File file = root.openNextFile();
    while (file) {
      Serial.print("  ");
      Serial.print(file.name());
      Serial.print(" - ");
      Serial.println(file.size());
      file = root.openNextFile();
    }
  }
#endif

  const String filename = "/" + SENSOR_ID + ".csv";

  int getAvailableSpace() {
    return getTotalSpace() - getUsedSpace();
  }

  void initialize() {
    Serial.print(F("Initializing FS..."));
    if (mountFS()) {
      Serial.println(F("done."));
    } else {
      Serial.println(F("fail."));
      return;
    }

    updateFsInfo();

    Serial.println(F("File system info:"));

    Serial.print(F("  Total space    : "));
    Serial.print(getTotalSpace() / 1024);
    Serial.println("kB");

    Serial.print(F("  Used space     : "));
    Serial.print(getUsedSpace() / 1024);
    Serial.println("kB");

    Serial.print(F("  Available space: "));
    Serial.print(getAvailableSpace() / 1024);
    Serial.println("kB");
    Serial.println();

    // Open dir folder
    Serial.println("Filesystem content:");
    showFilesystemContent();
    Serial.println();
  }

  File openOrCreate() {
    File csv_file;
    if (FS_LIB.exists(filename)) {
      csv_file = FS_LIB.open(filename, "a+");
    } else {
      csv_file = FS_LIB.open(filename, "w");
      csv_file.print(F("Sensor time;CO2 concentration;Temperature;Humidity\r\n"));
      csv_file.print(F("YYYY-MM-DD HH:MM:SS+ZZ;ppm;degC;%\r\n"));
    }
    return csv_file;
  }

  void log(const String &timeStamp, const int16_t &co2, const float &temperature, const float &humidity) {
    led_effects::onBoardLEDOn();
    File csv_file = openOrCreate();
    char csv_line[42];
    snprintf(csv_line, sizeof(csv_line), "%s;%d;%.1f;%.1f\r\n", timeStamp.c_str(), co2, temperature, humidity);
    if (csv_file) {
      size_t written_bytes = csv_file.print(csv_line);
      csv_file.close();
      if (written_bytes == 0) {
        Serial.println(F("Nothing written. Disk full?"));
      } else {
        Serial.print(F("CSV - Wrote : "));
        Serial.print(csv_line);
        last_successful_write = ntp::getLocalTime();
      }
      updateFsInfo();
      delay(50);
    } else {
      //NOTE: Can it ever happen that outfile is false?
      Serial.println(F("Problem on create file!"));
    }
    led_effects::onBoardLEDOff();
  }

  void logIfTimeHasCome(const String &timeStamp, const int16_t &co2, const float &temperature, const float &humidity) {
    unsigned long now = seconds();
    if (now - last_written_at > config::csv_interval) {
      last_written_at = now;
      log(timeStamp, co2, temperature, humidity);
    }
  }
}