main.go

package csv

import (
	"encoding/csv"
	"encoding/json"
	"os"

	"jonasled.dev/jonasled/ems-esp-logger/helper"
)

func JsonToCsv(jsonData string) {
	var data map[string]interface{}
	if err := json.Unmarshal([]byte(jsonData), &data); err != nil {
		panic(err)
	}

	file, err := os.OpenFile(os.Getenv("OUTPUT_FILE_NAME"), os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		panic(err)
	}
	defer file.Close()

	writer := csv.NewWriter(file)
	defer writer.Flush()

	fileInfo, err := file.Stat()
	if err != nil {
		panic(err)
	}

	if fileInfo.Size() == 0 {
		header := make([]string, 0, len(data))
		for key := range data {
			header = append(header, key)
		}
		if err := writer.Write(header); err != nil {
			panic(err)
		}
	}

	row := make([]string, 0, len(data))
	for _, value := range data {
		row = append(row, helper.AnyToString(value))
	}
	if err := writer.Write(row); err != nil {
		panic(err)
	}
}