// Package notificationpublisher provides the Redis-Streams-backed
// notification-intent publisher Runtime Manager uses to emit admin-only
// failure notifications. The adapter is a thin shim over
// `galaxy/notificationintent.Publisher` that drops the entry id at the
// wrapper boundary; rationale lives in
// `rtmanager/docs/domain-and-ports.md §7`.
package notificationpublisher

import (
	"context"
	"errors"
	"fmt"

	"github.com/redis/go-redis/v9"

	"galaxy/notificationintent"
	"galaxy/rtmanager/internal/ports"
)

// Config groups the dependencies and stream name required to
// construct a Publisher.
type Config struct {
	// Client appends entries to Redis Streams. Must be non-nil.
	Client *redis.Client

	// Stream stores the Redis Stream key intents are published to.
	// When empty, `notificationintent.DefaultIntentsStream` is used.
	Stream string
}

// Publisher implements `ports.NotificationIntentPublisher` on top of
// the shared `notificationintent.Publisher`. The wrapper is the single
// point that drops the entry id returned by the underlying publisher.
type Publisher struct {
	inner *notificationintent.Publisher
}

// NewPublisher constructs a Publisher from cfg. It wraps the shared
// publisher and delegates validation; transport errors and validation
// errors propagate verbatim.
func NewPublisher(cfg Config) (*Publisher, error) {
	if cfg.Client == nil {
		return nil, errors.New("new rtmanager notification publisher: nil redis client")
	}
	inner, err := notificationintent.NewPublisher(notificationintent.PublisherConfig{
		Client: cfg.Client,
		Stream: cfg.Stream,
	})
	if err != nil {
		return nil, fmt.Errorf("new rtmanager notification publisher: %w", err)
	}
	return &Publisher{inner: inner}, nil
}

// Publish forwards intent to the underlying notificationintent
// publisher and discards the resulting Redis Stream entry id. A failed
// publish surfaces as the underlying error.
func (publisher *Publisher) Publish(ctx context.Context, intent notificationintent.Intent) error {
	if publisher == nil || publisher.inner == nil {
		return errors.New("publish notification intent: nil publisher")
	}
	if _, err := publisher.inner.Publish(ctx, intent); err != nil {
		return err
	}
	return nil
}

// Compile-time assertion: Publisher implements
// ports.NotificationIntentPublisher.
var _ ports.NotificationIntentPublisher = (*Publisher)(nil)