package config

import (
	"crypto/rand"
	"encoding/hex"
	"log"
	"os"
	"strconv"

	"github.com/joho/godotenv"
)

type Config struct {
	AdminUsername    string
	AdminPassword   string
	SecretKey       string
	JWTExpireMinutes int
	DatabaseURL     string
	Port            string
}

var Cfg Config

func Load() {
	// Load .env file from multiple locations (ignore errors if not found)
	_ = godotenv.Load()
	_ = godotenv.Load("backend/.env")

	dbURL := getEnv("DATABASE_URL", "data/airwallex.db")
	// Strip sqlite:/// prefix if present (Python SQLAlchemy format)
	for _, prefix := range []string{"sqlite:///./", "sqlite:///", "sqlite://"} {
		if len(dbURL) > len(prefix) && dbURL[:len(prefix)] == prefix {
			dbURL = dbURL[len(prefix):]
			break
		}
	}

	Cfg = Config{
		AdminUsername:    getEnv("ADMIN_USERNAME", "admin"),
		AdminPassword:   getEnv("ADMIN_PASSWORD", "admin123"),
		SecretKey:       getEnv("SECRET_KEY", generateRandomKey(32)),
		JWTExpireMinutes: getEnvInt("JWT_EXPIRE_MINUTES", 480),
		DatabaseURL:     dbURL,
		Port:            getEnv("PORT", "8000"),
	}
}

func getEnv(key, fallback string) string {
	if val, ok := os.LookupEnv(key); ok {
		return val
	}
	return fallback
}

func getEnvInt(key string, fallback int) int {
	val, ok := os.LookupEnv(key)
	if !ok {
		return fallback
	}
	n, err := strconv.Atoi(val)
	if err != nil {
		log.Printf("warning: invalid integer for %s: %s, using default %d", key, val, fallback)
		return fallback
	}
	return n
}

func generateRandomKey(length int) string {
	b := make([]byte, length)
	if _, err := rand.Read(b); err != nil {
		log.Fatalf("failed to generate random key: %v", err)
	}
	return hex.EncodeToString(b)
}