package config

import (
	"errors"
	"sync/atomic"
)

var ErrInvalidStore = errors.New("invalid configuration store")

// Store publishes complete validated configurations with one atomic pointer swap.
type Store struct {
	current atomic.Pointer[Config]
}

func NewStore(initial *Config) (*Store, error) {
	if err := Validate(initial); err != nil {
		return nil, errors.Join(ErrInvalidStore, err)
	}
	store := &Store{}
	store.Publish(initial)
	return store, nil
}

func (store *Store) Current() *Config {
	if store == nil {
		return nil
	}
	current := store.current.Load()
	if current == nil {
		return nil
	}
	cloned := cloneConfig(*current)
	return &cloned
}

// Publish accepts a non-nil configuration already validated by the caller.
func (store *Store) Publish(configuration *Config) {
	if store == nil || configuration == nil {
		return
	}
	cloned := cloneConfig(*configuration)
	store.current.Store(&cloned)
}