CIiP-WS-2021-2022-Projektarbeit_Lithium/settings/settings.go

package settings

import (
	"encoding/json"
	"os"
	"path/filepath"

	"github.com/spf13/afero"
)

const (
	Local FileSystemType = iota
)

type FileSystemType int

type Settings struct {
	Endpoint        string                 `json:"endpoint"`
	Authentication  AuthenticationSettings `json:"authentication"`
	RateLimiter     RateLimiterSettings    `json:"rate_limiter"`
	StorageProvider StorageSettings        `json:"storage_provider"`
}

type StorageSettings struct {
	Type     FileSystemType `json:"type"`
	BasePath string         `json:"base_path"`
}

type AuthenticationSettings struct {
	Enabled bool   `json:"enabled"`
	Token   string `json:"token"`
}

type RateLimiterSettings struct {
	Enabled           bool `json:"enabled"`
	RequestsPerMinute int  `json:"requests_per_minute"`
	AllowedBurst      int  `json:"allowed_burst"`
}

func parseSettings(data []byte) Settings {
	settings := Settings{}

	err := json.Unmarshal(data, &settings)
	if err != nil {
		return Settings{}
	}

	return settings
}

func LoadSettings(fileSystem afero.Fs) (Settings, error) {
	workingDirectory, _ := os.Getwd()
	path := filepath.Join(workingDirectory, "settings.json")

	// Load file and parse file
	data, err := afero.ReadFile(fileSystem, path)

	if err == nil {
		return parseSettings(data), nil
	}

	// If file does not exist, create default settings
	defaultSettings := Settings{
		Endpoint: "127.0.0.1:8000",
		Authentication: AuthenticationSettings{
			Enabled: true,
			Token:   "changeme",
		},
		RateLimiter: RateLimiterSettings{
			Enabled:           true,
			RequestsPerMinute: 20,
			AllowedBurst:      5,
		},
		StorageProvider: StorageSettings{
			Type:     Local,
			BasePath: "assets",
		},
	}

	serializedSettings, err := json.MarshalIndent(defaultSettings, "", "\t")
	if err != nil {
		return Settings{}, err
	}

	err = afero.WriteFile(fileSystem, path, serializedSettings, os.ModePerm)
	if err != nil {
		return Settings{}, err
	}

	return defaultSettings, nil
}