package e2e

import (
	"context"
	"net"
	"testing"
	"time"

	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"

	"github.com/metadata-agregator/internal/server"
	metadatav1 "github.com/metadata-agregator/pkg/gen/metadata/v1"
)

const (
	radioheadMBID   = "a74b1b7f-71a5-4011-9441-d0b5e4122711"
	okComputerMBID  = "b1392450-e666-3926-a536-22c65f834433"
	paranoidAndroid = "9f9cf187-d6f9-437f-9d98-d59cdbd52757"
)

type testServer struct {
	addr   string
	server *grpc.Server
}

func startTestServer(t *testing.T) *testServer {
	t.Helper()

	lis, err := net.Listen("tcp", "localhost:0")
	if err != nil {
		t.Fatalf("failed to listen: %v", err)
	}

	grpcServer := grpc.NewServer()
	metadatav1.RegisterMetadataServiceServer(grpcServer, server.NewMetadataServer())

	go func() {
		if err := grpcServer.Serve(lis); err != nil {
			t.Logf("server stopped: %v", err)
		}
	}()

	return &testServer{
		addr:   lis.Addr().String(),
		server: grpcServer,
	}
}

func (s *testServer) stop() {
	s.server.GracefulStop()
}

func newClient(t *testing.T, addr string) metadatav1.MetadataServiceClient {
	t.Helper()

	conn, err := grpc.NewClient(addr, grpc.WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
		t.Fatalf("failed to connect: %v", err)
	}

	t.Cleanup(func() { conn.Close() })

	return metadatav1.NewMetadataServiceClient(conn)
}

func TestSearchArtists(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping e2e test in short mode")
	}

	srv := startTestServer(t)
	defer srv.stop()

	client := newClient(t, srv.addr)
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	resp, err := client.SearchArtists(ctx, &metadatav1.SearchArtistsRequest{
		Query: "Radiohead",
		Limit: 5,
	})
	if err != nil {
		t.Fatalf("SearchArtists failed: %v", err)
	}

	if len(resp.Artists) == 0 {
		t.Fatal("expected at least one artist")
	}

	found := false
	for _, a := range resp.Artists {
		if a.Id == radioheadMBID {
			found = true
			if a.Name != "Radiohead" {
				t.Errorf("expected name 'Radiohead', got %q", a.Name)
			}
			if a.Country != "GB" {
				t.Errorf("expected country 'GB', got %q", a.Country)
			}
			break
		}
	}

	if !found {
		t.Error("Radiohead not found in search results")
	}
}

func TestGetArtist(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping e2e test in short mode")
	}

	srv := startTestServer(t)
	defer srv.stop()

	client := newClient(t, srv.addr)
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	artist, err := client.GetArtist(ctx, &metadatav1.GetArtistRequest{
		Identifier: &metadatav1.GetArtistRequest_Id{Id: radioheadMBID},
	})
	if err != nil {
		t.Fatalf("GetArtist failed: %v", err)
	}

	if artist.Id != radioheadMBID {
		t.Errorf("expected ID %q, got %q", radioheadMBID, artist.Id)
	}

	if artist.Name != "Radiohead" {
		t.Errorf("expected name 'Radiohead', got %q", artist.Name)
	}

	if artist.ArtistType != "Group" {
		t.Errorf("expected type 'Group', got %q", artist.ArtistType)
	}

	if len(artist.Genres) == 0 {
		t.Error("expected genres to be populated")
	}

	if len(artist.ExternalIds) == 0 {
		t.Error("expected external IDs to be populated")
	}

	hasMusicBrainz := false
	for _, ext := range artist.ExternalIds {
		if ext.Source == "musicbrainz" {
			hasMusicBrainz = true
			break
		}
	}
	if !hasMusicBrainz {
		t.Error("expected musicbrainz external ID")
	}
}

func TestGetArtistAlbums(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping e2e test in short mode")
	}

	srv := startTestServer(t)
	defer srv.stop()

	client := newClient(t, srv.addr)
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	resp, err := client.GetArtistAlbums(ctx, &metadatav1.GetArtistAlbumsRequest{
		ArtistId: radioheadMBID,
		Limit:    10,
	})
	if err != nil {
		t.Fatalf("GetArtistAlbums failed: %v", err)
	}

	if len(resp.Albums) == 0 {
		t.Fatal("expected at least one album")
	}

	if resp.Total == 0 {
		t.Error("expected total to be greater than 0")
	}

	foundOKComputer := false
	for _, album := range resp.Albums {
		if album.Id == okComputerMBID {
			foundOKComputer = true
			if album.Title != "OK Computer" {
				t.Errorf("expected title 'OK Computer', got %q", album.Title)
			}
			break
		}
	}

	if !foundOKComputer {
		t.Log("OK Computer not in first 10 results (pagination)")
	}

	for _, album := range resp.Albums {
		if album.AlbumType == "" {
			t.Errorf("album %q missing type", album.Title)
		}
		if len(album.Artists) == 0 {
			t.Errorf("album %q missing artists", album.Title)
		}
	}
}

func TestGetAlbum(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping e2e test in short mode")
	}

	srv := startTestServer(t)
	defer srv.stop()

	client := newClient(t, srv.addr)
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	album, err := client.GetAlbum(ctx, &metadatav1.GetAlbumRequest{
		Identifier: &metadatav1.GetAlbumRequest_Id{Id: okComputerMBID},
	})
	if err != nil {
		t.Fatalf("GetAlbum failed: %v", err)
	}

	if album.Id != okComputerMBID {
		t.Errorf("expected ID %q, got %q", okComputerMBID, album.Id)
	}

	if album.Title != "OK Computer" {
		t.Errorf("expected title 'OK Computer', got %q", album.Title)
	}

	if album.AlbumType != "Album" {
		t.Errorf("expected type 'Album', got %q", album.AlbumType)
	}

	if album.ReleaseDate == "" {
		t.Error("expected release date to be populated")
	}

	if len(album.Artists) == 0 {
		t.Error("expected artists to be populated")
	}
}

func TestGetAlbumTracks(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping e2e test in short mode")
	}

	srv := startTestServer(t)
	defer srv.stop()

	client := newClient(t, srv.addr)
	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
	defer cancel()

	resp, err := client.GetAlbumTracks(ctx, &metadatav1.GetAlbumTracksRequest{
		AlbumId: okComputerMBID,
	})
	if err != nil {
		t.Fatalf("GetAlbumTracks failed: %v", err)
	}

	if len(resp.Tracks) == 0 {
		t.Fatal("expected tracks")
	}

	if len(resp.Tracks) != 12 {
		t.Errorf("expected 12 tracks for OK Computer, got %d", len(resp.Tracks))
	}

	expectedTracks := []string{
		"Airbag",
		"Paranoid Android",
		"Subterranean Homesick Alien",
		"Exit Music (for a Film)",
		"Let Down",
		"Karma Police",
		"Fitter Happier",
		"Electioneering",
		"Climbing Up the Walls",
		"No Surprises",
		"Lucky",
		"The Tourist",
	}

	for i, track := range resp.Tracks {
		if track.TrackNumber != int32(i+1) {
			t.Errorf("track %d: expected track number %d, got %d", i, i+1, track.TrackNumber)
		}

		if i < len(expectedTracks) && track.Title != expectedTracks[i] {
			t.Errorf("track %d: expected title %q, got %q", i+1, expectedTracks[i], track.Title)
		}

		if track.DurationMs == 0 {
			t.Errorf("track %q: missing duration", track.Title)
		}

		if track.Isrc == "" {
			t.Errorf("track %q: missing ISRC", track.Title)
		}
	}
}

func TestGetTrack(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping e2e test in short mode")
	}

	srv := startTestServer(t)
	defer srv.stop()

	client := newClient(t, srv.addr)
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	track, err := client.GetTrack(ctx, &metadatav1.GetTrackRequest{
		Identifier: &metadatav1.GetTrackRequest_Id{Id: paranoidAndroid},
	})
	if err != nil {
		t.Fatalf("GetTrack failed: %v", err)
	}

	if track.Id != paranoidAndroid {
		t.Errorf("expected ID %q, got %q", paranoidAndroid, track.Id)
	}

	if track.Title != "Paranoid Android" {
		t.Errorf("expected title 'Paranoid Android', got %q", track.Title)
	}

	if track.DurationMs == 0 {
		t.Error("expected duration to be populated")
	}

	if track.Isrc == "" {
		t.Error("expected ISRC to be populated")
	}

	if len(track.Artists) == 0 {
		t.Error("expected artists to be populated")
	}
}

func TestGetTrackByISRC(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping e2e test in short mode")
	}

	srv := startTestServer(t)
	defer srv.stop()

	client := newClient(t, srv.addr)
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	track, err := client.GetTrack(ctx, &metadatav1.GetTrackRequest{
		Identifier: &metadatav1.GetTrackRequest_Isrc{Isrc: "GBAYE9701376"},
	})
	if err != nil {
		t.Fatalf("GetTrack by ISRC failed: %v", err)
	}

	if track.Title != "Paranoid Android" {
		t.Errorf("expected title 'Paranoid Android', got %q", track.Title)
	}
}

func TestProviderSelection(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping e2e test in short mode")
	}

	srv := startTestServer(t)
	defer srv.stop()

	client := newClient(t, srv.addr)
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	resp, err := client.SearchArtists(ctx, &metadatav1.SearchArtistsRequest{
		Query:    "Radiohead",
		Limit:    1,
		Provider: metadatav1.Provider_PROVIDER_MUSICBRAINZ,
	})
	if err != nil {
		t.Fatalf("SearchArtists with provider failed: %v", err)
	}

	if len(resp.Artists) == 0 {
		t.Fatal("expected at least one artist")
	}

	hasMB := false
	for _, ext := range resp.Artists[0].ExternalIds {
		if ext.Source == "musicbrainz" {
			hasMB = true
			break
		}
	}

	if !hasMB {
		t.Error("expected musicbrainz source when provider=MUSICBRAINZ")
	}
}