package config

import (
	"encoding/json"
	"errors"
	"os"
)

// Config holds all backend runtime configuration.
type Config struct {
	StoragePath string     `json:"storage_path"`
	DBPath      string     `json:"db_path"`
	LDAP        LDAPConfig `json:"ldap"`
	JWTSecret   string     `json:"jwt_secret"`
	ListenAddr  string     `json:"listen_addr"`
}

type LDAPConfig struct {
	Host         string `json:"host"`
	Port         int    `json:"port"`
	BaseDN       string `json:"base_dn"`
	BindDN       string `json:"bind_dn"`
	BindPassword string `json:"bind_password"`
}

// ErrRequireSetup is returned when config is missing or empty,
// signalling that the frontend should start the Setup Wizard.
var ErrRequireSetup = errors.New("REQUIRE_SETUP")

func Load(path string) (*Config, error) {
	data, err := os.ReadFile(path)
	if err != nil {
		if errors.Is(err, os.ErrNotExist) {
			return nil, ErrRequireSetup
		}
		return nil, err
	}

	var cfg Config
	if err := json.Unmarshal(data, &cfg); err != nil {
		return nil, err
	}

	if cfg.StoragePath == "" || cfg.JWTSecret == "" {
		return nil, ErrRequireSetup
	}

	if cfg.ListenAddr == "" {
		cfg.ListenAddr = ":4000"
	}

	return &cfg, nil
}

func Save(path string, cfg *Config) error {
	data, err := json.MarshalIndent(cfg, "", "  ")
	if err != nil {
		return err
	}
	return os.WriteFile(path, data, 0600)
}