package inventory

import (
	"context"
	"errors"
	"sync/atomic"
	"testing"
	"time"

	"github.com/docker/docker/api/types/events"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

type fakeEvents struct {
	msgs chan events.Message
	errs chan error
}

func newFakeEvents() *fakeEvents {
	return &fakeEvents{msgs: make(chan events.Message, 10), errs: make(chan error, 1)}
}

func (f *fakeEvents) Events(context.Context, events.ListOptions) (<-chan events.Message, <-chan error) {
	return f.msgs, f.errs
}

func TestWatch_DebouncesBursts(t *testing.T) {
	src := newFakeEvents()
	var calls atomic.Int32
	ctx, cancel := context.WithCancel(context.Background())
	done := make(chan error, 1)
	go func() { done <- Watch(ctx, src, 30*time.Millisecond, func() { calls.Add(1) }) }()

	for range 3 {
		src.msgs <- events.Message{Type: events.ContainerEventType, Action: "start"}
	}
	require.Eventually(t, func() bool { return calls.Load() == 1 }, time.Second, 5*time.Millisecond)

	src.msgs <- events.Message{Type: events.ServiceEventType, Action: "update"}
	require.Eventually(t, func() bool { return calls.Load() == 2 }, time.Second, 5*time.Millisecond)

	cancel()
	assert.NoError(t, <-done)
}

func TestWatch_ReturnsStreamError(t *testing.T) {
	src := newFakeEvents()
	src.errs <- errors.New("daemon restarted")
	err := Watch(context.Background(), src, time.Millisecond, func() {})
	assert.ErrorContains(t, err, "daemon restarted")
}