entity_map.go

package types

import (
	"encoding/json"
	"slices"
	"strings"

	"golang.org/x/exp/maps"
)

// An EntityGetter is an interface for retrieving an Entity by EntityUID.
type EntityGetter interface {
	Get(uid EntityUID) (Entity, bool)
}

var _ EntityGetter = EntityMap{}

// An EntityMap is a collection of all the entities that are needed to evaluate
// authorization requests.  The key is an EntityUID which uniquely identifies
// the Entity (it must be the same as the UID within the Entity itself.)
type EntityMap map[EntityUID]Entity

func (e EntityMap) MarshalJSON() ([]byte, error) {
	s := maps.Values(e)
	slices.SortFunc(s, func(a, b Entity) int {
		return strings.Compare(a.UID.String(), b.UID.String())
	})
	return json.Marshal(s)
}

func (e *EntityMap) UnmarshalJSON(b []byte) error {
	var s []Entity
	if err := json.Unmarshal(b, &s); err != nil {
		return err
	}
	var res = EntityMap{}
	for _, e := range s {
		res[e.UID] = e
	}
	*e = res
	return nil
}

func (e EntityMap) Clone() EntityMap {
	return maps.Clone(e)
}

func (e EntityMap) Get(uid EntityUID) (Entity, bool) {
	ent, ok := e[uid]
	return ent, ok
}