package eventbus

import (
	"fmt"
	"regexp"
	"sort"
	"sync"
	"testing"
	"time"

	"github.com/stretchr/testify/require"

	"go.skia.org/infra/go/testutils"
	"go.skia.org/infra/go/testutils/unittest"
)

func TestEventBus(t *testing.T) {
	unittest.SmallTest(t)
	eventBus := New()

	ch := make(chan int, 5)
	eventBus.SubscribeAsync("channel1", func(e interface{}) { ch <- 1 })
	eventBus.SubscribeAsync("channel2", func(e interface{}) { ch <- (e.(int)) + 1 })
	eventBus.SubscribeAsync("channel2", func(e interface{}) { ch <- e.(int) })

	eventBus.Publish("channel1", nil, false)
	eventBus.Publish("channel2", 2, false)
	require.NoError(t, testutils.EventuallyConsistent(time.Second*3, func() error {
		if len(ch) < 3 {
			return testutils.TryAgainErr
		}
		return nil
	}))

	vals := []int{<-ch, <-ch, <-ch}
	sort.Ints(vals)
	require.Equal(t, []int{1, 2, 3}, vals)
}

const (
	TEST_BUCKET = "test-bucket"
	TEST_PREFIX = "some/path"
	JSON_REGEX  = `^.*\.json$`
)

func TestSynStorageEvents(t *testing.T) {
	unittest.LargeTest(t)

	eventBus := New()

	noPrefixEvt, err := eventBus.RegisterStorageEvents(TEST_BUCKET, "", nil, nil)
	require.NoError(t, err)

	withPrefixEvt, err := eventBus.RegisterStorageEvents(TEST_BUCKET, TEST_PREFIX, nil, nil)
	require.NoError(t, err)

	jsonRegex := regexp.MustCompile(JSON_REGEX)
	noPrefixRegExEvt, err := eventBus.RegisterStorageEvents(TEST_BUCKET, "", jsonRegex, nil)
	require.NoError(t, err)

	// Gather the actual events fired.
	var mutex sync.Mutex
	var actNoPrefix, actWithPrefix, actNoPrefixRegEx []*StorageEvent

	eventBus.SubscribeAsync(noPrefixEvt, func(e interface{}) {
		mutex.Lock()
		defer mutex.Unlock()
		actNoPrefix = append(actNoPrefix, e.(*StorageEvent))
	})
	eventBus.SubscribeAsync(withPrefixEvt, func(e interface{}) {
		mutex.Lock()
		defer mutex.Unlock()
		actWithPrefix = append(actWithPrefix, e.(*StorageEvent))
	})
	eventBus.SubscribeAsync(noPrefixRegExEvt, func(e interface{}) {
		mutex.Lock()
		defer mutex.Unlock()
		actNoPrefixRegEx = append(actNoPrefixRegEx, e.(*StorageEvent))
	})

	// Gather the expectations.
	expNoPrefix := []*StorageEvent{}
	expWithPrefix := []*StorageEvent{}
	expNoPrefixRegEx := []*StorageEvent{}

	nEvents := 10
	now := time.Now().Unix()
	for i := 0; i < nEvents; i++ {
		evt := NewStorageEvent(TEST_BUCKET, fmt.Sprintf("1/whatever/path/somefile-%d", i), now, "")
		eventBus.PublishStorageEvent(evt)
		expNoPrefix = append(expNoPrefix, evt)

		evt = NewStorageEvent(TEST_BUCKET, fmt.Sprintf(TEST_PREFIX+"/2/whatever/path/somefile-%d", i), now, "")
		eventBus.PublishStorageEvent(evt)
		expNoPrefix = append(expNoPrefix, evt)
		expWithPrefix = append(expWithPrefix, evt)

		evt = NewStorageEvent(TEST_BUCKET, fmt.Sprintf(TEST_PREFIX+"/3/whatever/path/somefile-%d.json", i), now, "")
		eventBus.PublishStorageEvent(evt)
		expNoPrefix = append(expNoPrefix, evt)
		expWithPrefix = append(expWithPrefix, evt)
		expNoPrefixRegEx = append(expNoPrefixRegEx, evt)
	}

	require.NoError(t, testutils.EventuallyConsistent(time.Second*2, func() error {
		mutex.Lock()
		defer mutex.Unlock()
		if len(actNoPrefix) < len(expNoPrefix) ||
			len(actWithPrefix) < len(expWithPrefix) ||
			len(actNoPrefixRegEx) < len(expNoPrefixRegEx) {
			return testutils.TryAgainErr
		}
		return nil
	}))

	assertEventsMatch(t, expNoPrefix, actNoPrefix)
	assertEventsMatch(t, expWithPrefix, actWithPrefix)
	assertEventsMatch(t, expNoPrefixRegEx, actNoPrefixRegEx)
}

func assertEventsMatch(t *testing.T, expected, actual []*StorageEvent) {
	sort.Slice(actual, func(i, j int) bool { return actual[i].ObjectID < actual[j].ObjectID })
	sort.Slice(expected, func(i, j int) bool { return expected[i].ObjectID < expected[j].ObjectID })
	require.Equal(t, expected, actual)
}

func TestNotificationsMap(t *testing.T) {
	unittest.SmallTest(t)

	notifyMap := NewNotificationsMap()
	notifyID := GetNotificationID(TEST_BUCKET, TEST_PREFIX)
	evtType_1 := notifyMap.Add(notifyID, nil)
	require.Equal(t, []string{evtType_1}, notifyMap.Matches(TEST_BUCKET, TEST_PREFIX+"/path.json"))
	require.Equal(t, []string{}, notifyMap.Matches(TEST_BUCKET, "other-prefix/path.json"))

	evtType_2 := notifyMap.Add(notifyID, regexp.MustCompile(`^.*\.json$`))

	compareSortStrings(t, []string{evtType_1, evtType_2}, notifyMap.Matches(TEST_BUCKET, TEST_PREFIX+"/path.json"))
	compareSortStrings(t, []string{evtType_1}, notifyMap.Matches(TEST_BUCKET, TEST_PREFIX+"/path.txt"))

	compareSortStrings(t, []string{evtType_1, evtType_2}, notifyMap.MatchesByID(notifyID, TEST_PREFIX+"/path.json"))
	compareSortStrings(t, []string{evtType_1}, notifyMap.MatchesByID(notifyID, TEST_PREFIX+"/path.txt"))

	wrongNotificationID := GetNotificationID("other-bucket", "")
	require.Equal(t, []string{}, notifyMap.MatchesByID(wrongNotificationID, TEST_PREFIX+"/path.txt"))
}

func compareSortStrings(t *testing.T, expected, actual []string) {
	sort.Strings(expected)
	sort.Strings(actual)
	require.Equal(t, expected, actual)
}