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/*
 * sensorconfig.cpp
 *
 *  Created on: May 19, 2015
 *      Author: Axel Auweter
 */

#include <cstring>
#include <iostream>

#include "cassandra.h"

#include "sensorconfig_internal.h"
#include "dcdbglobals.h"

/*
 * DCDBPublicSensor functions.
 */
DCDBPublicSensor::DCDBPublicSensor()
{
  name = "";
  pattern = "";
  scaling_factor = 1.0;
  unit = "";
}

DCDBPublicSensor::DCDBPublicSensor (const DCDBPublicSensor &copy)
{
  name = copy.name;
  pattern = copy.pattern;
  scaling_factor = copy.scaling_factor;
  unit = copy.unit;
}


/*
 * SensorConfig functions
 */
SCError SensorConfig::publishSensor(const char* publicName, const char* sensorPattern)
{
  return impl->publishSensor(publicName, sensorPattern);
}

SCError SensorConfig::getPublicSensors(std::list<DCDBPublicSensor>& publicSensors)
{
  return impl->getPublicSensors(publicSensors);
}

SensorConfig::SensorConfig(DCDBConnection* conn)
{
  /* Allocate impl object */
  impl = new SensorConfigImpl(conn);
}

SensorConfig::~SensorConfig()
{
  if (impl) {
      delete impl;
  }
}

/*
 * SensorConfigImpl protected functions
 */

/*
 * Validate the pattern for a Sensor to be published
 * Patterns may only consist of hex numbers and forward slashes
 * and at most one wildcard character (*). Also, the total number of
 * bits may not exceed 128.
 */
bool SensorConfigImpl::validateSensorPattern(const char* sensorPattern)
{
  unsigned int wildcards, bits;

  /* 128 bits in HEX is at most 32 characters. Considering forward-slash separators, 64 is a reasonable maxmimum string length */
  if (strlen(sensorPattern) > 64) {
      return false;
  }

  /* Iterate through the string and validate/count the characters */
  bits = 0;
  wildcards = 0;
  for (unsigned int c = 0; c < strlen(sensorPattern); c++) {
      switch (sensorPattern[c]) {

      /* Regular HEX digit */
      case '0':
      case '1':
      case '2':
      case '3':
      case '4':
      case '5':
      case '6':
      case '7':
      case '8':
      case '9':
      case 'a':
      case 'A':
      case 'b':
      case 'B':
      case 'c':
      case 'C':
      case 'd':
      case 'D':
      case 'e':
      case 'E':
      case 'f':
      case 'F':
        bits += 4;
        break;

      /* Wildcard */
      case '*':
        wildcards++;
        break;

      /* Forward slash */
      case '/':
        break;

      /* Everything else is not allowed */
      default:
        return false;
      }
  }

  /* More than one wildcard is not allowed */
  if (wildcards > 1)
    return false;

  /* In case of a wildcard, there should be some bits left for the wildcard to fill in */
  if (wildcards == 1 && bits >= 128)
    return false;

  /* Looks good */
  return true;
}


/*
 * SensorConfigImpl public functions
 */
SCError SensorConfigImpl::publishSensor(const char* publicName, const char* sensorPattern)
{
  /* Check if the pattern matches the requirements */
  if (!validateSensorPattern(sensorPattern)) {
      return SC_INVALIDPATTERN;
  }

  /* Check if the session is valid */
  if (!session) {
      return SC_INVALIDSESSION;
  }

  /* Insert the entry */
  CassError rc = CASS_OK;
  CassStatement* statement = nullptr;
  CassFuture* future = nullptr;
  const CassPrepared* prepared = nullptr;
  const char* query = "INSERT INTO " CONFIG_KEYSPACE_NAME "." CF_PUBLISHEDSENSORS " (name, pattern) VALUES (?,?);";

  future = cass_session_prepare(session, query);
  cass_future_wait(future);

  rc = cass_future_error_code(future);
  if (rc != CASS_OK) {
    connection->printError(future);
    cass_future_free(future);
    return SC_UNKNOWNERROR;
  } else {
    prepared = cass_future_get_prepared(future);
  }

  cass_future_free(future);

  statement = cass_prepared_bind(prepared);

  cass_statement_bind_string_by_name(statement, "name", publicName);
  cass_statement_bind_string_by_name(statement, "pattern", sensorPattern);

  future = cass_session_execute(session, statement);
  cass_future_wait(future);

  rc = cass_future_error_code(future);
  if (rc != CASS_OK) {
    connection->printError(future);

    cass_prepared_free(prepared);
    cass_future_free(future);
    cass_statement_free(statement);

    return SC_UNKNOWNERROR;
  }

  cass_prepared_free(prepared);
  cass_future_free(future);
  cass_statement_free(statement);

  return SC_OK;
}

SCError SensorConfigImpl::getPublicSensors(std::list<DCDBPublicSensor>& publicSensors)
{
  /* Check if the session is valid */
  if (!session) {
      return SC_INVALIDSESSION;
  }

  /* Fill the list with all public sensors */
  CassError rc = CASS_OK;
  CassStatement* statement = nullptr;
  CassFuture* future = nullptr;
  const char* query = "SELECT * FROM dcdb_config.publishedsensors;";

  statement = cass_statement_new(query, 0);

  future = cass_session_execute(session, statement);
  cass_future_wait(future);

  rc = cass_future_error_code(future);
  if (rc != CASS_OK) {
     connection->printError(future);
     cass_future_free(future);
     cass_statement_free(statement);
     return SC_UNKNOWNERROR;
  } else {
      const CassResult* result = cass_future_get_result(future);
      CassIterator* iterator = cass_iterator_from_result(result);

      while (cass_iterator_next(iterator)) {
          const char* name;
          size_t      name_len;
          const char* pattern;
          size_t      pattern_len;
          double      scaling_factor;
          const char* unit;
          size_t      unit_len;
          DCDBPublicSensor sensor;

          const CassRow* row = cass_iterator_get_row(iterator);

          if (cass_value_get_string(cass_row_get_column_by_name(row, "name"), &name, &name_len) != CASS_OK) {
              name = ""; name_len = 0;
          }
          if (cass_value_get_string(cass_row_get_column_by_name(row, "pattern"), &pattern, &pattern_len) != CASS_OK) {
              pattern = ""; pattern_len = 0;
          }
          if (cass_value_get_double(cass_row_get_column_by_name(row, "scaling_factor"), &scaling_factor) != CASS_OK) {
              scaling_factor = 1.0;
          }
          if (cass_value_get_string(cass_row_get_column_by_name(row, "unit"), &unit, &unit_len) != CASS_OK) {
              unit = ""; unit_len = 0;
          }

          sensor.name = std::string(name, name_len);
          sensor.pattern = std::string(pattern, pattern_len);
          sensor.scaling_factor = scaling_factor;
          sensor.unit = std::string(unit, unit_len);

          publicSensors.push_back(sensor);
      }
      cass_result_free(result);
      cass_iterator_free(iterator);
  }

  cass_future_free(future);
  cass_statement_free(statement);
  return SC_OK;
}

SensorConfigImpl::SensorConfigImpl(DCDBConnection* conn)
{
  connection = conn;
  session = connection->getSessionHandle();
}

SensorConfigImpl::~SensorConfigImpl()
{
  connection = nullptr;
  session = nullptr;
}