general cleanup - removed old comments, enforced naming conventions etc

backend/internal/config/config.go

@@ -0,0 +1,111 @@
+//loads environment-based configuration.
+package config
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+const (
+	defaultPort = 3001
+	defaultDBPort = 5432
+	defaultPollIntervalMS = 60000
+	minPollIntervalMS = 1000
+	defaultDigestIntervalHours = 24
+)
+
+type Config struct {
+	Port              int
+	APIBasePath       string
+	DatabaseURL       string
+	DBHost            string
+	DBPort            int
+	DBUser            string
+	DBPassword        string
+	DBName            string
+	FirebaseProjectID string
+	EthRPCURL         string
+	PollIntervalMS    int
+	NodeEnv           string
+	ResendAPIKey         string
+	EmailFrom            string
+	DigestIntervalHours  int
+	StripeSecretKey      string
+	StripeWebhookSecret  string
+	StripePriceID        string
+	StripePublishableKey string
+	FrontendURL          string
+}
+
+// Load reads configuration from environment variables and returns a Config.
+func Load() (*Config, error) {
+	cfg := &Config{
+		Port:              getEnvInt("PORT", defaultPort),
+		APIBasePath:       getEnv("API_BASE_PATH", "/v1"),
+		DatabaseURL:       os.Getenv("DATABASE_URL"),
+		DBHost:            getEnv("DB_HOST", "localhost"),
+		DBPort:            getEnvInt("DB_PORT", defaultDBPort),
+		DBUser:            os.Getenv("DB_USER"),
+		DBPassword:        os.Getenv("DB_PASSWORD"),
+		DBName:            os.Getenv("DB_NAME"),
+		FirebaseProjectID: os.Getenv("FIREBASE_PROJECT_ID"),
+		EthRPCURL:         os.Getenv("ETH_RPC_URL"),
+		PollIntervalMS:    getEnvInt("POLL_INTERVAL_MS", defaultPollIntervalMS),
+		NodeEnv:           getEnv("NODE_ENV", "development"),
+		ResendAPIKey:        os.Getenv("RESEND_API_KEY"),
+		EmailFrom:           getEnv("EMAIL_FROM", "Koin Ping <alerts@koinping.com>"),
+		DigestIntervalHours:  getEnvInt("DIGEST_INTERVAL_HOURS", defaultDigestIntervalHours),
+		StripeSecretKey:      os.Getenv("STRIPE_SECRET_KEY"),
+		StripeWebhookSecret:  os.Getenv("STRIPE_WEBHOOK_SECRET"),
+		StripePriceID:        os.Getenv("STRIPE_PRICE_ID"),
+		StripePublishableKey: os.Getenv("STRIPE_PUBLISHABLE_KEY"),
+		FrontendURL:          getEnv("FRONTEND_URL", "http://localhost:3000"),
+	}
+
+	if cfg.PollIntervalMS < minPollIntervalMS {
+		return nil, fmt.Errorf("POLL_INTERVAL_MS must be >= 1000, got %d", cfg.PollIntervalMS) //nolint:err113
+	}
+
+	return cfg, nil
+}
+
+func (c *Config) DSN() string {
+	if c.DatabaseURL != "" {
+		// Append sslmode=disable if not already specified.
+		if !strings.Contains(c.DatabaseURL, "sslmode=") {
+			sep := "?"
+			if strings.Contains(c.DatabaseURL, "?") {
+				sep = "&"
+			}
+
+			return c.DatabaseURL + sep + "sslmode=disable"
+		}
+
+		return c.DatabaseURL
+	}
+
+	return fmt.Sprintf(
+		"host=%s port=%d user=%s password=%s dbname=%s sslmode=disable",
+		c.DBHost, c.DBPort, c.DBUser, c.DBPassword, c.DBName,
+	)
+}
+
+func getEnv(key, fallback string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+
+	return fallback
+}
+
+func getEnvInt(key string, fallback int) int {
+	if v := os.Getenv(key); v != "" {
+		if n, err := strconv.Atoi(v); err == nil {
+			return n
+		}
+	}
+
+	return fallback
+}