Refactoring

src/main/config.go

@@ -0,0 +1,136 @@
+package main
+
+import (
+	"crypto/sha256"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"reflect"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/gofiber/fiber/v2"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+type Config struct {
+	db            *sql.DB
+	HomeAssistant HomeAssistant `json:"home_assistant"`
+	Sensors       Sensors       `json:"sensors"`
+	Administrator Administrator `json:"administrator"`
+	Dashboard     Dashboard     `json:"dashboard"`
+}
+
+type HomeAssistant struct {
+	InstallationDate time.Time `json:"installation_date"`
+	BaseURL          string    `json:"base_url"`
+	APIKey           string    `json:"api_key"`
+}
+type Sensors struct {
+	PolledSmartEnergySummation string `json:"polled_smart_energy_summation"`
+	FossilPercentage           string `json:"fossil_percentage"`
+}
+type Administrator struct {
+	Username     string `json:"username"`
+	PasswordHash string `json:"password_hash"`
+}
+type Dashboard struct {
+	Name        string `json:"name"`
+	Theme       string `json:"theme"`
+	FooterLinks []Link `json:"footer_links"`
+	HeaderLinks []Link `json:"header_links"`
+}
+
+var errBadHAFormat = errors.New("HomeAssistant base URL is badly formatted")
+
+func formatURL(url string) (string, error) {
+	// the URL we want is: protocol://hostname[:port] without a final /
+
+	if !strings.HasPrefix(url, "http://") && !strings.HasPrefix(url, "https://") {
+		url = "http://" + url
+	}
+	url = strings.TrimSuffix(url, "/")
+
+	test := regexp.MustCompile(`(?m)https?://[^/]*`).ReplaceAllString(url, "")
+	if test != "" {
+		return "", errBadHAFormat
+	}
+
+	return url, nil
+}
+
+func loadConfig() (config *Config, isFirstRun bool, err error) {
+	db, err := sql.Open("sqlite3", "./database.db")
+	if err != nil {
+		return &Config{}, false, err
+	}
+
+	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS "cache" (
+		"time"	NUMERIC NOT NULL,
+		"green_energy_percentage"	REAL NOT NULL,
+		"energy_consumption"	REAL NOT NULL,
+		PRIMARY KEY("time")
+	);`)
+	if err != nil {
+		return &Config{}, false, err
+	}
+
+	defaultConfig := &Config{}
+	defaultConfig.Dashboard.Theme = "default"
+	defaultConfig.Dashboard.Name = "EcoDash"
+	defaultConfig.Dashboard.HeaderLinks = append(defaultConfig.Dashboard.HeaderLinks, Link{
+		Label:       "Admin",
+		Destination: "/admin",
+	}, Link{
+		Label:       "EcoDash",
+		Destination: "https://ecodash.xyz",
+		NewTab:      true,
+		Primary:     true,
+	})
+	defaultConfig.db = db
+
+	data, err := os.ReadFile("config.json")
+	if err != nil {
+		// if the data file doesn't exist, we consider it a first run
+		if os.IsNotExist(err) {
+			return defaultConfig, true, nil
+		}
+		return &Config{}, false, err
+	}
+
+	// if the data file is empty, we consider it as a first run
+	if len(data) == 0 {
+		return defaultConfig, true, nil
+	}
+
+	conf := &Config{}
+	err = json.Unmarshal(data, &conf)
+	if err != nil {
+		return &Config{}, false, err
+	}
+	conf.db = db
+
+	return conf, false, nil
+}
+
+// just a little utility function to SHA256 strings (for hashing passwords).
+func hash(toHash string) string {
+	return fmt.Sprintf("%x", sha256.Sum256([]byte(toHash)))
+}
+
+func (config *Config) isAuthorized(c *fiber.Ctx) bool {
+	if config.Administrator.PasswordHash == "" {
+		return true
+	}
+	return c.Cookies("admin_username") == config.Administrator.Username && c.Cookies("admin_password_hash") == config.Administrator.PasswordHash
+}
+
+func (config *Config) Equals(c *Config) bool {
+	return reflect.DeepEqual(c.HomeAssistant, config.HomeAssistant) &&
+		reflect.DeepEqual(c.Sensors, config.Sensors) &&
+		reflect.DeepEqual(c.Administrator, config.Administrator) &&
+		reflect.DeepEqual(c.Dashboard, config.Dashboard)
+}