package config

import (
	"fmt"
	"os"
	"strconv"
	"time"
)

type Config struct {
	HTTPAddr       string
	DatabaseURL    string
	ReadTimeout    time.Duration
	WriteTimeout   time.Duration
	SessionTTL     time.Duration
	CookieSecure   bool
}

func Load() (Config, error) {
	port := env("APP_PORT", "8080")
	cfg := Config{
		HTTPAddr:     ":" + port,
		DatabaseURL:  os.Getenv("DATABASE_URL"),
		ReadTimeout:  durationEnv("HTTP_READ_TIMEOUT", 10*time.Second),
		WriteTimeout: durationEnv("HTTP_WRITE_TIMEOUT", 30*time.Second),
		SessionTTL:   sessionTTL(),
		CookieSecure: env("COOKIE_SECURE", "false") == "true",
	}
	if cfg.DatabaseURL == "" {
		return cfg, fmt.Errorf("DATABASE_URL is required")
	}
	return cfg, nil
}

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

func sessionTTL() time.Duration {
	if v := os.Getenv("SESSION_TTL_HOURS"); v != "" {
		if h, err := strconv.Atoi(v); err == nil && h > 0 {
			return time.Duration(h) * time.Hour
		}
	}
	return 168 * time.Hour
}

func durationEnv(key string, fallback time.Duration) time.Duration {
	v := os.Getenv(key)
	if v == "" {
		return fallback
	}
	sec, err := strconv.Atoi(v)
	if err != nil || sec <= 0 {
		return fallback
	}
	return time.Duration(sec) * time.Second
}