package component

import (
	"context"
	"io"
	"sync"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"google.golang.org/grpc"

	metadataPb "homelab.lan/music-agregator/gen/metadata/v1"
	pb "homelab.lan/music-agregator/gen/music_agregator/v1"
	"homelab.lan/music-agregator/internal/indexer"
	"homelab.lan/music-agregator/internal/torrent"
)

func startAutomaticWorkflow(t *testing.T, client pb.MusicAgregatorServiceClient, albumID string) {
	t.Helper()
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	stream, err := client.MonitorAlbumStream(ctx)
	require.NoError(t, err)

	err = stream.Send(&pb.MonitorAlbumStreamRequest{
		Message: &pb.MonitorAlbumStreamRequest_Start{
			Start: &pb.StartMonitorRequest{
				AlbumId: albumID,
				Quality: pb.QualityType_QUALITY_LOSSLESS,
				Mode:    pb.InteractionMode_INTERACTION_MODE_AUTOMATIC,
			},
		},
	})
	require.NoError(t, err)

	for {
		_, err := stream.Recv()
		if err != nil {
			break
		}
	}
}

func collectSubscribeEvents(
	t *testing.T,
	stream grpc.ServerStreamingClient[pb.AlbumEvent],
	timeout time.Duration,
) []*pb.AlbumEvent {
	t.Helper()

	if timeout == 0 {
		timeout = 5 * time.Second
	}

	ctx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()

	var events []*pb.AlbumEvent
	done := make(chan struct{})

	go func() {
		defer close(done)
		for {
			event, err := stream.Recv()
			if err == io.EOF {
				return
			}
			if err != nil {
				return
			}
			events = append(events, event)
		}
	}()

	select {
	case <-done:
	case <-ctx.Done():
	}

	return events
}

func TestSubscribeEvents_ReceivesWorkflowEvents(t *testing.T) {
	suite := setupSuite(t)
	cleanTables(t, suite.pool)

	suite.mocks.metadata.GetAlbumFunc = func(ctx context.Context, in *metadataPb.GetAlbumRequest, opts ...grpc.CallOption) (*metadataPb.GetAlbumResponse, error) {
		return &metadataPb.GetAlbumResponse{
			Album: newMetadataAlbum("test-album-ext-id", "Test Album", "artist-ext-id", "Test Artist"),
		}, nil
	}

	suite.mocks.indexer.SearchFunc = func(query string, limit int32, idx string) (*indexer.SearchResponse, error) {
		return newSearchResponse(
			newSearchItem("Test Artist - Test Album [FLAC]", 50, "magnet:?xt=urn:btih:abc123&dn=test"),
		), nil
	}

	suite.mocks.magnet.ResolveFunc = func(magnetURI string) ([]byte, error) {
		return newTorrentData(), nil
	}

	suite.mocks.torrent.FindFunc = func(opts torrent.FindOptions) ([]torrent.TorrentInfo, error) {
		return []torrent.TorrentInfo{}, nil
	}

	suite.mocks.torrent.AddMagnetFunc = func(magnetURI string, savePath string) error {
		return nil
	}

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	subStream, err := suite.client.SubscribeEvents(ctx, &pb.SubscribeEventsRequest{})
	require.NoError(t, err)

	var events []*pb.AlbumEvent
	var mu sync.Mutex
	done := make(chan struct{})

	go func() {
		defer close(done)
		for {
			event, err := subStream.Recv()
			if err != nil {
				return
			}
			mu.Lock()
			events = append(events, event)
			mu.Unlock()
		}
	}()

	time.Sleep(100 * time.Millisecond)

	startAutomaticWorkflow(t, suite.client, "test-album-ext-id")

	time.Sleep(500 * time.Millisecond)
	cancel()
	<-done

	mu.Lock()
	defer mu.Unlock()

	require.NotEmpty(t, events, "expected to receive events from workflow")

	var hasStatusEvent bool
	for _, e := range events {
		if e.EventType == "status" {
			hasStatusEvent = true
			break
		}
	}
	assert.True(t, hasStatusEvent, "expected at least one status event")

	var prevSeq int64
	for _, e := range events {
		if e.Seq > 0 {
			assert.Greater(t, e.Seq, prevSeq, "seq numbers should be monotonically increasing")
			prevSeq = e.Seq
		}
	}
}

func TestSubscribeEvents_MultipleWorkflows(t *testing.T) {
	suite := setupSuite(t)
	cleanTables(t, suite.pool)

	suite.mocks.metadata.GetAlbumFunc = func(ctx context.Context, in *metadataPb.GetAlbumRequest, opts ...grpc.CallOption) (*metadataPb.GetAlbumResponse, error) {
		albumID := in.GetId()
		if albumID == "" {
			albumID = "test-album"
		}
		return &metadataPb.GetAlbumResponse{
			Album: newMetadataAlbum(albumID, "Test Album", "artist-ext-id", "Test Artist"),
		}, nil
	}

	suite.mocks.indexer.SearchFunc = func(query string, limit int32, idx string) (*indexer.SearchResponse, error) {
		return newSearchResponse(
			newSearchItem("Test Artist - Test Album [FLAC]", 50, "magnet:?xt=urn:btih:abc123&dn=test"),
		), nil
	}

	suite.mocks.magnet.ResolveFunc = func(magnetURI string) ([]byte, error) {
		return newTorrentData(), nil
	}

	suite.mocks.torrent.FindFunc = func(opts torrent.FindOptions) ([]torrent.TorrentInfo, error) {
		return []torrent.TorrentInfo{}, nil
	}

	suite.mocks.torrent.AddMagnetFunc = func(magnetURI string, savePath string) error {
		return nil
	}

	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer cancel()

	subStream, err := suite.client.SubscribeEvents(ctx, &pb.SubscribeEventsRequest{})
	require.NoError(t, err)

	var events []*pb.AlbumEvent
	var mu sync.Mutex
	done := make(chan struct{})

	go func() {
		defer close(done)
		for {
			event, err := subStream.Recv()
			if err != nil {
				return
			}
			mu.Lock()
			events = append(events, event)
			mu.Unlock()
		}
	}()

	time.Sleep(100 * time.Millisecond)

	var wg sync.WaitGroup
	wg.Add(2)

	go func() {
		defer wg.Done()
		startAutomaticWorkflow(t, suite.client, "album-1")
	}()

	go func() {
		defer wg.Done()
		startAutomaticWorkflow(t, suite.client, "album-2")
	}()

	wg.Wait()
	time.Sleep(500 * time.Millisecond)
	cancel()
	<-done

	mu.Lock()
	defer mu.Unlock()

	require.NotEmpty(t, events, "expected to receive events from workflows")

	albumIDs := make(map[string]bool)
	for _, e := range events {
		if e.AlbumId != "" {
			albumIDs[e.AlbumId] = true
		}
	}

	assert.True(t, len(albumIDs) >= 1, "expected events from at least one workflow")
}

func TestSubscribeEvents_ClientDisconnect(t *testing.T) {
	suite := setupSuite(t)
	cleanTables(t, suite.pool)

	suite.mocks.metadata.GetAlbumFunc = func(ctx context.Context, in *metadataPb.GetAlbumRequest, opts ...grpc.CallOption) (*metadataPb.GetAlbumResponse, error) {
		time.Sleep(300 * time.Millisecond)
		return &metadataPb.GetAlbumResponse{
			Album: newMetadataAlbum("test-album-ext-id", "Test Album", "artist-ext-id", "Test Artist"),
		}, nil
	}

	suite.mocks.indexer.SearchFunc = func(query string, limit int32, idx string) (*indexer.SearchResponse, error) {
		return newSearchResponse(
			newSearchItem("Test Artist - Test Album [FLAC]", 50, "magnet:?xt=urn:btih:abc123&dn=test"),
		), nil
	}

	suite.mocks.magnet.ResolveFunc = func(magnetURI string) ([]byte, error) {
		return newTorrentData(), nil
	}

	suite.mocks.torrent.FindFunc = func(opts torrent.FindOptions) ([]torrent.TorrentInfo, error) {
		return []torrent.TorrentInfo{}, nil
	}

	suite.mocks.torrent.AddMagnetFunc = func(magnetURI string, savePath string) error {
		return nil
	}

	ctx, cancel := context.WithTimeout(context.Background(), 200*time.Millisecond)
	defer cancel()

	subStream, err := suite.client.SubscribeEvents(ctx, &pb.SubscribeEventsRequest{})
	require.NoError(t, err)

	go startAutomaticWorkflow(t, suite.client, "test-album-ext-id")

	for {
		_, err := subStream.Recv()
		if err != nil {
			break
		}
	}

	time.Sleep(2 * time.Second)

	bgCtx := context.Background()
	var workflowCount int
	err = suite.pool.QueryRow(bgCtx, "SELECT COUNT(*) FROM workflow_runs").Scan(&workflowCount)
	require.NoError(t, err)
	assert.GreaterOrEqual(t, workflowCount, 1, "workflow should have been created")
}

func TestSubscribeEvents_ReplayFromSeq(t *testing.T) {
	suite := setupSuite(t)
	cleanTables(t, suite.pool)

	suite.mocks.metadata.GetAlbumFunc = func(ctx context.Context, in *metadataPb.GetAlbumRequest, opts ...grpc.CallOption) (*metadataPb.GetAlbumResponse, error) {
		return &metadataPb.GetAlbumResponse{
			Album: newMetadataAlbum("test-album-ext-id", "Test Album", "artist-ext-id", "Test Artist"),
		}, nil
	}

	suite.mocks.indexer.SearchFunc = func(query string, limit int32, idx string) (*indexer.SearchResponse, error) {
		return newSearchResponse(
			newSearchItem("Test Artist - Test Album [FLAC]", 50, "magnet:?xt=urn:btih:abc123&dn=test"),
		), nil
	}

	suite.mocks.magnet.ResolveFunc = func(magnetURI string) ([]byte, error) {
		return newTorrentData(), nil
	}

	suite.mocks.torrent.FindFunc = func(opts torrent.FindOptions) ([]torrent.TorrentInfo, error) {
		return []torrent.TorrentInfo{}, nil
	}

	suite.mocks.torrent.AddMagnetFunc = func(magnetURI string, savePath string) error {
		return nil
	}

	startAutomaticWorkflow(t, suite.client, "test-album-ext-id")

	bgCtx := context.Background()
	var firstSeq int64
	err := suite.pool.QueryRow(bgCtx, "SELECT MIN(seq) FROM album_events").Scan(&firstSeq)
	require.NoError(t, err)
	require.Greater(t, firstSeq, int64(0), "expected events to be persisted")

	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()

	subStream, err := suite.client.SubscribeEvents(ctx, &pb.SubscribeEventsRequest{
		SinceSeq: firstSeq,
	})
	require.NoError(t, err)

	events := collectSubscribeEvents(t, subStream, 2*time.Second)

	require.NotEmpty(t, events, "expected replayed events")

	for _, e := range events {
		assert.Greater(t, e.Seq, firstSeq, "replayed events should have seq > since_seq")
	}
}