// Package userlifecyclestub provides an in-process
// ports.UserLifecycleConsumer used by worker-level tests that do not
// need a real Redis stream. Production code never wires this stub.
package userlifecyclestub

import (
	"context"
	"errors"
	"sync"

	"galaxy/lobby/internal/ports"
)

// Consumer is an in-memory ports.UserLifecycleConsumer. Tests publish
// events synchronously through Deliver and observe handler errors via
// the returned value.
type Consumer struct {
	mu      sync.Mutex
	handler ports.UserLifecycleHandler
}

// NewConsumer constructs an empty Consumer.
func NewConsumer() *Consumer {
	return &Consumer{}
}

// OnEvent installs handler as the dispatch target. A second call
// replaces the previous handler.
func (consumer *Consumer) OnEvent(handler ports.UserLifecycleHandler) {
	if consumer == nil {
		return
	}
	consumer.mu.Lock()
	consumer.handler = handler
	consumer.mu.Unlock()
}

// Run blocks until ctx is cancelled. The stub does not pull events from
// any backend; test code drives delivery via Deliver.
func (consumer *Consumer) Run(ctx context.Context) error {
	if consumer == nil {
		return errors.New("run user lifecycle stub: nil consumer")
	}
	if ctx == nil {
		return errors.New("run user lifecycle stub: nil context")
	}
	<-ctx.Done()
	return ctx.Err()
}

// Shutdown is a no-op.
func (consumer *Consumer) Shutdown(ctx context.Context) error {
	if ctx == nil {
		return errors.New("shutdown user lifecycle stub: nil context")
	}
	return nil
}

// Deliver dispatches event to the registered handler synchronously and
// returns the handler's error. It is the test-only entry point used by
// worker_test fixtures.
func (consumer *Consumer) Deliver(ctx context.Context, event ports.UserLifecycleEvent) error {
	if consumer == nil {
		return errors.New("deliver user lifecycle stub: nil consumer")
	}
	if ctx == nil {
		return errors.New("deliver user lifecycle stub: nil context")
	}
	consumer.mu.Lock()
	handler := consumer.handler
	consumer.mu.Unlock()
	if handler == nil {
		return errors.New("deliver user lifecycle stub: no handler registered")
	}
	return handler(ctx, event)
}

// Compile-time assertion: Consumer satisfies the port interface.
var _ ports.UserLifecycleConsumer = (*Consumer)(nil)