package config

import (
	"crypto/rand"
	"encoding/hex"
	"log/slog"
	"os"
)

type Config struct {
	Port          string
	DBPath        string
	SessionSecret string
	FrontendDir   string
}

func Load() Config {
	c := Config{
		Port:          envOr("GOFLARE_PORT", ":42069"),
		DBPath:        envOr("GOFLARE_DB_PATH", "goflare.db"),
		SessionSecret: os.Getenv("GOFLARE_SESSION_SECRET"),
		FrontendDir:   envOr("GOFLARE_FRONTEND_DIR", "frontend/dist"),
	}

	if c.SessionSecret == "" {
		c.SessionSecret = randomHex(32)
		slog.Warn("GOFLARE_SESSION_SECRET not set, using random value (sessions won't survive restarts)")
	}

	return c
}

func envOr(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}

func randomHex(n int) string {
	b := make([]byte, n)
	_, err := rand.Read(b)
	if err != nil {
		panic("failed to generate random bytes: " + err.Error())
	}
	return hex.EncodeToString(b)
}