// Copyright 2026 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package pubsub

import (
	"testing"
	"time"

	"gitea.dev/modules/test"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// TestRedisBroker runs the shared broker scenarios against a real Redis-backed
// RedisBroker, plus the backend-specific ones. Delivery crosses a Redis
// round-trip (hence the wider timeout) and HasTopicSubscribers answers
// conservatively true, so subscriber tracking is not exact.
// One redis-server is shared by all of them; starting one per test dominated
// the package runtime.
func TestRedisBroker(t *testing.T) {
	redisConn := test.PrepareTestRedis(t)

	newBroker := func(t *testing.T) Broker {
		broker, err := NewRedisBroker(redisConn)
		require.NoError(t, err)
		return broker
	}
	testBrokerBasic(t, newBroker, 2*time.Second)

	// RedisBroker cannot see other processes' subscribers, so it answers true even
	// with none locally rather than risk dropping a push.
	t.Run("HasTopicSubscribersWithoutAny", func(t *testing.T) {
		assert.True(t, newBroker(t).HasTopicSubscribers("topic"))
	})

	// RedisBroker tears down its per-topic Redis subscription and internal
	// state once the last local subscriber cancels.
	t.Run("CancelCleansTopicState", func(t *testing.T) {
		b := newBroker(t).(*RedisBroker)
		ch, cancel := b.Subscribe(t.Name())
		cancel()

		_, ok := <-ch
		assert.False(t, ok, "channel must be closed after cancel")

		b.mu.RLock()
		_, present := b.topics[t.Name()]
		b.mu.RUnlock()
		assert.False(t, present, "topic state must be removed after last subscriber cancels")
	})

	// Two RedisBroker instances sharing one Redis simulate two Gitea processes -
	// a publish on one must reach a subscriber on the other.
	t.Run("CrossBroker", func(t *testing.T) {
		publisher, subscriber := newBroker(t), newBroker(t)

		ch, cancel := subscriber.Subscribe(t.Name())
		defer cancel()
		waitSubscribed(t, subscriber, t.Name())

		publisher.Publish(t.Name(), []byte("cross-process"))

		select {
		case msg := <-ch:
			assert.Equal(t, []byte("cross-process"), msg)
		case <-time.After(2 * time.Second):
			t.Fatal("subscriber on second broker did not receive message")
		}
	})
}