<?php
/*
 *  VE.Direct-Text-Reader
 *  worker.php
 *  Command line tool to fetch text protocol data from
 *  VE.Direct interfaces and store it into a database
 *  for further processing
 *
 *  Licensed under the GPL 3.0
 *  https://git.schauaus.at/VE-Tools/VE.Direct-Text-Reader
 */
  $startAt = date('Y-m-d H:i:s');
  $scriptPath = dirname(__FILE__);
  $config = json_decode( file_get_contents($scriptPath . '/config.json') );

  $loglevel = 0;
  switch ($config->loglevel) {
    case 'debug':
      $loglevel = 4;
      break;
    case 'info':
      $loglevel = 3;
      break;
    case 'warn':
      $loglevel = 2;
      break;
    case 'error':
      $loglevel = 1;
      break;
  }
  if ($loglevel > 0) {
    $logfile = (!str_starts_with($config->logfile, '/')) ? fopen($scriptPath . '/' . $config->logfile, 'a') : fopen($config->logfile, 'a');
    writeLog("===================================================\r\n", 1);
    writeLog("worker startet at $startAt\r\n", 1);
    writeLog("loglevel: $loglevel (" . $config->loglevel . ")\r\n\r\n", 1);
  }

  //create database if it does not exist yet
  if(!is_file((!str_starts_with($config->database, '/')) ? $scriptPath. '/' . $config->database : $config->database)) {
    writeLog('Database not found! I will create it! ', 3);
    if( !initializeDB() ) {
      writeLog("failed! Exit!\r\n\r\n");
      cleanUp('with errors ');
    }
    else writeLog("succeess!\r\n\r\n", 3);
  }

  $data = readData();
  if( !$data )
    cleanUp('with errors ');

  if( !processData($data, $startAt) )
    cleanUp('with errors ');

  cleanUp('successfully ');

  /*
   *  cleanup
   */
  function cleanUp($status) {
    global $loglevel;
    if( $loglevel > 0) {
      global $logfile;
      writeLog('worker finished ' . $status . 'at ' . date('Y-m-d H:i:s') . "\r\n", 1);
      writeLog("===================================================\r\n\r\n", 1);
      fclose($logfile);
    }
    exit();
  }

  /*
   * global function to write new data to logifle
   */
  function writeLog($strData, $minLogLevel) {
    global $config, $logfile, $loglevel;
    if($loglevel >= $minLogLevel)
      fwrite($logfile, $strData);
  }

  /*
   * read data stream from VE Direct USB serial interface
   */
  function readData() {
    global $config;
    writeLog("Open VE Direct interface:\r\n" . $config->device . "\r\n", 3);
    $VEinterface = dio_open($config->device, O_RDONLY | O_NONBLOCK);
    if($VEinterface === false) {
      writeLog("unable to open VE Direct interface!\r\n", 1);
      return false;
    }
    writeLog("success!\r\n\r\n", 3);

    //set up the interface to properly communicate with the interface
    dio_tcsetattr( $VEinterface, array(
      'baud'	=> 19200,
      'bits'	=> 8,
      'stop'	=> 1,
      'parity'	=> 0,
      'flow_control' => 0,
      'is_canonical' => 0)
   );

    $bytesToRead = 1024; // read 1KB by default
    if(isset($config->bytesToRead))
      $bytesToRead = $config->bytesToRead;
    writeLog("Reading $bytesToRead Byte from VE.Direct interface\r\n", 3);
    $dataStream = "";
    $startTime = time();
    while(strlen($dataStream) < $bytesToRead && time() < $startTime + $config->timeout)
      $dataStream .= dio_read($VEinterface, $bytesToRead);
    dio_close($VEinterface);
    writeLog($dataStream . "\r\n\r\n", 4);

    //split data stream into array and remove checksums
    $dataArray = explode("\n", $dataStream);
    $collect = false;
    $returnData = array();

    for($i=0; $i < count($dataArray); $i++) {
      if(!$collect && str_starts_with($dataArray[$i], 'PID'))
        $collect = true;
      else if($collect && str_starts_with($dataArray[$i], 'PID'))
        break;

      if($collect) {
        $dataLine = trim($dataArray[$i]);
        if( strlen($dataLine) == 0 || str_starts_with($dataLine, 'Checksum') || str_starts_with($dataLine, ':') ) //skip empty lines and checksums
          continue;
        $dataFields = explode("\t", $dataLine);
        $returnData[$dataFields[0]] = $dataFields[1];
      }
    }
    ksort($returnData);
    writeLog("Collected data:\r\n" . print_r($returnData, true) . "\r\n", 3);
    return $returnData;
  }

  function processData($data, $collectionDateTime) {
    global $config, $scriptPath;
    $db = (!str_starts_with($config->database, '/')) ? new SQLITE3($scriptPath . '/' . $config->database) : new SQLITE3($config->database);

    $dbTableName = $data['PID'] . '-' . $data['SER#'];
    $sql = "SELECT name FROM sqlite_schema WHERE type='table' AND name='$dbTableName';";
    $tableNames = $db->query($sql);
    if( !$tableNames->fetchArray(SQLITE3_NUM) ) {
      writeLog('New Victron Energy Device found. Crating a new database table... ', 3);
      if( $db->exec("CREATE TABLE '$dbTableName' (date TEXT, time TEXT, data TEXT);") )
        writeLog("success!\r\n", 3);
      else {
        writeLog("failed! Cancel!\r\n", 3);
        return false;
      }
    }

    $dateTime = explode(" ", $collectionDateTime);
    unset($data['PID']);
    unset($data['SER#']);
    $dataJson = json_encode($data);

    writeLog('Add dataset to database... ', 3);
    $sql = "INSERT INTO '$dbTableName' (date, time, data) VALUES('$dateTime[0]', '$dateTime[1]', '$dataJson')";
    if( !$db->exec($sql) ) {
      writeLog("failed!\r\n\r\n", 3);
      return false;
    }
    writeLog("success!\r\n\r\n", 3);
    return true;
  }

  function initializeDB() {
    global $config, $scriptPath;
    $dateTime = date('Y-m-d H:m:s');
    $db = (!str_starts_with($config->database, '/')) ? new SQLITE3($scriptPath . '/' . $config->database) : new SQLITE3($config->database);
    if( !$db->exec('CREATE TABLE meta (data TEXT);') ) return false;
    if( !$db->exec("INSERT INTO meta (data) VALUES ('{\"creation\": \"$dateTime\"');") ) return false;
    return true;
  }
?>