package main

import (
	"fmt"
	"os"
	"strconv"
	"strings"

	"github.com/joho/godotenv"
)

type Config struct {
	Port           string
	ListenNetwork  string
	ListenAddress  string
	UnixSocketPerm os.FileMode
	DatabaseURL    string
	StorageDir     string
	DevMode        bool
}

func LoadConfig() (Config, error) {
	_ = godotenv.Load()

	cfg := Config{
		Port:          envOrDefault("PORT", "8080"),
		ListenNetwork: strings.ToLower(envOrDefault("LISTEN_NETWORK", "tcp")),
		ListenAddress: strings.TrimSpace(os.Getenv("LISTEN_ADDRESS")),
		DatabaseURL:   os.Getenv("DATABASE_URL"),
		StorageDir:    envOrDefault("STORAGE_DIR", "uploads"),
		DevMode:       strings.EqualFold(envOrDefault("DEV_MODE", "false"), "true"),
	}
	if cfg.ListenAddress == "" {
		cfg.ListenAddress = ":" + cfg.Port
	}
	socketPerm, err := parseFileMode(envOrDefault("UNIX_SOCKET_PERM", "0660"))
	if err != nil {
		return Config{}, fmt.Errorf("invalid UNIX_SOCKET_PERM: %w", err)
	}
	cfg.UnixSocketPerm = socketPerm

	if cfg.DatabaseURL == "" {
		return Config{}, fmt.Errorf("DATABASE_URL is required")
	}
	switch cfg.ListenNetwork {
	case "tcp", "unix":
	default:
		return Config{}, fmt.Errorf("LISTEN_NETWORK must be tcp or unix")
	}
	if cfg.ListenNetwork == "unix" && cfg.ListenAddress == "" {
		return Config{}, fmt.Errorf("LISTEN_ADDRESS is required when LISTEN_NETWORK=unix")
	}
	return cfg, nil
}

func envOrDefault(key, fallback string) string {
	value := os.Getenv(key)
	if value == "" {
		return fallback
	}
	return value
}

func parseFileMode(value string) (os.FileMode, error) {
	trimmed := strings.TrimSpace(value)
	perm, err := strconv.ParseUint(trimmed, 8, 32)
	if err != nil {
		return 0, err
	}
	return os.FileMode(perm), nil
}