// Package intentpubstub provides an in-process
// ports.IntentPublisher implementation for service-level tests. The
// stub records every Publish call and lets tests inject failures to
// verify that publication errors do not roll back already-committed
// business state.
package intentpubstub

import (
	"context"
	"errors"
	"strconv"
	"sync"

	"galaxy/lobby/internal/ports"
	"galaxy/notificationintent"
)

// Publisher is a concurrency-safe in-memory implementation of
// ports.IntentPublisher. The zero value is not usable; call NewPublisher
// to construct.
type Publisher struct {
	mu        sync.Mutex
	published []notificationintent.Intent
	nextID    int
	err       error
}

// NewPublisher constructs an empty Publisher ready for use.
func NewPublisher() *Publisher {
	return &Publisher{}
}

// SetError preloads err to be returned by every Publish call. Pass nil
// to reset.
func (publisher *Publisher) SetError(err error) {
	if publisher == nil {
		return
	}
	publisher.mu.Lock()
	defer publisher.mu.Unlock()
	publisher.err = err
}

// Publish records intent and returns a synthetic stream entry id.
func (publisher *Publisher) Publish(ctx context.Context, intent notificationintent.Intent) (string, error) {
	if publisher == nil {
		return "", errors.New("publish notification intent: nil publisher")
	}
	if ctx == nil {
		return "", errors.New("publish notification intent: nil context")
	}

	publisher.mu.Lock()
	defer publisher.mu.Unlock()

	if publisher.err != nil {
		return "", publisher.err
	}

	publisher.nextID++
	publisher.published = append(publisher.published, intent)
	return strconv.Itoa(publisher.nextID), nil
}

// Published returns a snapshot of every Publish-accepted intent in the
// order it was received.
func (publisher *Publisher) Published() []notificationintent.Intent {
	if publisher == nil {
		return nil
	}
	publisher.mu.Lock()
	defer publisher.mu.Unlock()
	out := make([]notificationintent.Intent, len(publisher.published))
	copy(out, publisher.published)
	return out
}

// Compile-time interface assertion.
var _ ports.IntentPublisher = (*Publisher)(nil)