// Package redisstate hosts the small surface of Redis state that survived the
// PG_PLAN.md §4 migration: the inbound `mail:delivery_commands` stream and
// the persisted offset of its consumer. Every other durable record (auth and
// generic acceptance, attempt execution, malformed commands, dead letters,
// operator listing) now lives in PostgreSQL via `mailstore`.
package redisstate

import "encoding/base64"

const defaultPrefix = "mail:"

// Keyspace builds the small surviving Mail Service Redis keyspace. Dynamic
// segments (the stream key embedded in the offset key) are encoded with
// base64url so raw key structure does not depend on caller-provided
// characters.
type Keyspace struct{}

// StreamOffset returns the primary Redis key for one persisted stream-consumer
// offset.
func (Keyspace) StreamOffset(stream string) string {
	return defaultPrefix + "stream_offsets:" + encodeKeyComponent(stream)
}

// DeliveryCommands returns the frozen async ingress Redis Stream key.
func (Keyspace) DeliveryCommands() string {
	return defaultPrefix + "delivery_commands"
}

func encodeKeyComponent(value string) string {
	return base64.RawURLEncoding.EncodeToString([]byte(value))
}