room:
- id
- name
- description
- colour


device
- id
- name
- room
- location
- description

mqtt-topic:
- id
- deviceId
- mqttTopic
- mqttDataType (num, json)


value:
- id
- topicId
- value type (temp, humidity, speed, door, length, width, counter, gauge)
- units
- dataPath (for JSON)




datapoint:
- value id
- timestamp
- value


lastDatapoint: (DB: no rollback, otherwise db would double in size)
- module id
- timestamp
- value



Processing MQTT publish messages:
- create data point
- set timestamp in data point
- find MQTT_TOPIC for topic string
  - mqttType:
    - num:
      - lookup first value
      - store data in data point
    - json: parse data
      - for every VALUE assigned to that topic:
        - store data in data point
- write data point to long term db
- write data point to lastValues db


Storage API:
- handleMqttPublish(AQH_STORAGE *st, const char *topic, const char *value)

- addDevice(AQH_STORAGE *st, AQH_DEVICE *dev)
- getDeviceList(const AQH_STORAGE *st)
- getDeviceById(const AQH_STORAGE *st, uint32_t id)

- addMqttTopic(AQH_STORAGE *st, AQH_MQTT_TOPIC *t);
- getMqttTopicList(const AQH_STORAGE *st)
- getMqttTopicById(const AQH_STORAGE *st, uint32_t id)
- getMqttTopicByTopic(const AQH_STORAGE *st, const char *topic)

- addValue(AQH_STORAGE *st, AQH_VALUE *value)
- getValueList(const AQH_STORAGE *st)
- getValueById(const AQH_STORAGE *st, uint32_t id)




datafile:
- valueId
- filename
- number of entries
- fd
- getNumOfEntries()
- readRecord(id, &record)
- addRecord(record)

datarecord in file:
- 8 bytes timestamp
- 8 bytes value