ecodash/cache.go

package main

import (
	"fmt"
	"time"
)

type CacheEntry struct {
	Date                       int64
	GreenEnergyPercentage      float32
	PolledSmartEnergySummation float32
}
type CacheData []CacheEntry

func (config Config) updateCache() {

	// in order to avoid querying and storing each day's data from 0001-01-01 in future versions
	if config.HomeAssistant.InstallationDate.IsZero() {
		return
	}

	now := time.Now()
	h, m, s := now.Clock()
	start := now.AddDate(0, 0, -7).Add(-(time.Duration(h)*time.Hour + time.Duration(m)*time.Minute + time.Duration(s)*time.Second))

	greenEnergyPercentage, err := config.historyAverageAndConvertToGreen(config.Sensors.FossilPercentage, start, now)
	if err != nil {
		fmt.Println("Error updating cached data for FossilPercentage -" + err.Error())
		return
	}
	historyPolledSmartEnergySummation, err := config.historyDelta(config.Sensors.PolledSmartEnergySummation, start, now)
	if err != nil {
		fmt.Println("Error updating cached data for PolledSmartEnergySummation -" + err.Error())
		return
	}

	_, err = config.db.Exec("DELETE FROM cache")
	if err != nil {
		fmt.Println("Error deleting previous records to cache: -", err.Error())
		return
	}

	for key, day := range greenEnergyPercentage {
		_, err := config.db.Exec("INSERT INTO cache(time,green_energy_percentage,energy_consumption) VALUES (?,?,?);", day.DayTime.Unix(), greenEnergyPercentage[key].Value, historyPolledSmartEnergySummation[key].Value)
		if err != nil {
			fmt.Println("Error adding record to cache: -", err.Error())
			return
		}
	}

}

func (config Config) readCache() (CacheData, error) {

	rows, err := config.db.Query("SELECT time, green_energy_percentage, energy_consumption FROM cache")
	if err != nil {
		return CacheData{}, err
	}
	defer rows.Close()
	var ret CacheData

	for rows.Next() {
		var (
			date                         int64
			greenEnergyPercentage        float32
			polledSmartEnergyConsumption float32
		)
		err = rows.Scan(&date, &greenEnergyPercentage, &polledSmartEnergyConsumption)
		ret = append(ret, CacheEntry{date, greenEnergyPercentage, polledSmartEnergyConsumption})
	}

	return ret, nil

}