package database


import (
  "log"
  //"time"
  "fmt"
  "gorm.io/driver/postgres"
  "gorm.io/gorm"
)

type DatabaseHandle struct {
  initialized bool
  dbh *gorm.DB 
}

func NewDatabaseHandle(dsn string) *DatabaseHandle {
  var db DatabaseHandle
  conn, err := gorm.Open(postgres.Open(dsn))
  if err != nil {
    log.Printf("Unable to open database connection: %s", err)
    db.initialized = false
  } else {
    db.dbh = conn
    db.initialized = true
    log.Println("Database connection opened")
  }
  return &db
}

func (self *DatabaseHandle) StoreMeasurement(measurement *Measurement) {
  if ! self.initialized {
    log.Printf("Database connection not initialized, can not store, measurement %s lost", measurement)
    return
  }

  result := self.dbh.Create(measurement)
  if result.Error != nil {
    log.Printf("Unable to insert, measurement %s lost, error: %s", measurement, result.Error)
    return
  }

  log.Println("Successfully stored measurement")
}

func (self *DatabaseHandle) GetDeviceByLabelAndApplication(applicationLabel string, deviceLabel string) (*Device, error) {
  if ! self.initialized {
    err := fmt.Errorf("Database connection not initialized")
    return nil, err
  }

  var device Device
  result := self.dbh.
    Preload("Application").
    Preload("DeviceType").
    Joins("JOIN applications ON devices.application_id = applications.id").
    Where("devices.label = ? AND applications.label = ?", deviceLabel, applicationLabel).
    First(&device)

  if result.Error != nil {
    err := fmt.Errorf("Query failed: %s", result.Error)
    return nil, err
  }

  return &device, nil
}