package server

import (
	"context"
	"errors"

	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"

	"github.com/metadata-agregator/internal/provider/musicbrainz"
	"github.com/metadata-agregator/internal/repository"
	"github.com/metadata-agregator/internal/service"
	metadatav1 "github.com/metadata-agregator/pkg/gen/metadata/v1"
)

type MetadataServer struct {
	metadatav1.UnimplementedMetadataServiceServer
	services map[metadatav1.Provider]*service.MetadataService
}

func NewMetadataServer(services map[metadatav1.Provider]*service.MetadataService) *MetadataServer {
	return &MetadataServer{services: services}
}

func (s *MetadataServer) getService(p metadatav1.Provider) (*service.MetadataService, error) {
	if p == metadatav1.Provider_PROVIDER_UNSPECIFIED {
		p = metadatav1.Provider_PROVIDER_MUSICBRAINZ
	}

	svc, ok := s.services[p]
	if !ok {
		return nil, status.Errorf(codes.InvalidArgument, "unknown provider: %v", p)
	}

	return svc, nil
}

func (s *MetadataServer) GetArtist(ctx context.Context, req *metadatav1.GetArtistRequest) (*metadatav1.Artist, error) {
	svc, err := s.getService(req.Provider)
	if err != nil {
		return nil, err
	}

	var id string
	switch v := req.Identifier.(type) {
	case *metadatav1.GetArtistRequest_Id:
		id = v.Id
	case *metadatav1.GetArtistRequest_External:
		id = v.External.SourceId
	default:
		return nil, status.Error(codes.InvalidArgument, "identifier required")
	}

	artist, err := svc.GetArtist(ctx, id)
	if err != nil {
		return nil, toGRPCError(err)
	}

	return toProtoArtist(artist), nil
}

func (s *MetadataServer) SearchArtists(ctx context.Context, req *metadatav1.SearchArtistsRequest) (*metadatav1.SearchArtistsResponse, error) {
	svc, err := s.getService(req.Provider)
	if err != nil {
		return nil, err
	}

	limit := int(req.Limit)
	if limit <= 0 {
		limit = 25
	}

	result, err := svc.SearchArtists(ctx, req.Query, limit, int(req.Offset))
	if err != nil {
		return nil, toGRPCError(err)
	}

	resp := &metadatav1.SearchArtistsResponse{
		Total: int32(result.Total),
	}

	for _, a := range result.Items {
		resp.Artists = append(resp.Artists, toProtoArtist(&a))
	}

	return resp, nil
}

func (s *MetadataServer) SearchAlbums(ctx context.Context, req *metadatav1.SearchAlbumsRequest) (*metadatav1.SearchAlbumsResponse, error) {
	svc, err := s.getService(req.Provider)
	if err != nil {
		return nil, err
	}

	limit := int(req.Limit)
	if limit <= 0 {
		limit = 25
	}

	result, err := svc.SearchAlbums(ctx, req.Query, req.Artist, limit, int(req.Offset))
	if err != nil {
		return nil, toGRPCError(err)
	}

	resp := &metadatav1.SearchAlbumsResponse{
		Total: int32(result.Total),
	}

	for _, a := range result.Items {
		resp.Albums = append(resp.Albums, toProtoAlbum(&a))
	}

	return resp, nil
}

func (s *MetadataServer) GetAlbum(ctx context.Context, req *metadatav1.GetAlbumRequest) (*metadatav1.Album, error) {
	svc, err := s.getService(req.Provider)
	if err != nil {
		return nil, err
	}

	var id string
	switch v := req.Identifier.(type) {
	case *metadatav1.GetAlbumRequest_Id:
		id = v.Id
	case *metadatav1.GetAlbumRequest_External:
		id = v.External.SourceId
	default:
		return nil, status.Error(codes.InvalidArgument, "identifier required")
	}

	album, err := svc.GetAlbum(ctx, id)
	if err != nil {
		return nil, toGRPCError(err)
	}

	return toProtoAlbum(album), nil
}

func (s *MetadataServer) GetArtistAlbums(ctx context.Context, req *metadatav1.GetArtistAlbumsRequest) (*metadatav1.GetArtistAlbumsResponse, error) {
	svc, err := s.getService(req.Provider)
	if err != nil {
		return nil, err
	}

	limit := int(req.Limit)
	if limit <= 0 {
		limit = 25
	}

	result, err := svc.GetArtistAlbums(ctx, req.ArtistId, limit, int(req.Offset))
	if err != nil {
		return nil, toGRPCError(err)
	}

	resp := &metadatav1.GetArtistAlbumsResponse{
		Total: int32(result.Total),
	}

	for _, a := range result.Items {
		resp.Albums = append(resp.Albums, toProtoAlbum(&a))
	}

	return resp, nil
}

func (s *MetadataServer) GetTrack(ctx context.Context, req *metadatav1.GetTrackRequest) (*metadatav1.Track, error) {
	svc, err := s.getService(req.Provider)
	if err != nil {
		return nil, err
	}

	var track *metadatav1.Track

	switch v := req.Identifier.(type) {
	case *metadatav1.GetTrackRequest_Id:
		t, err := svc.GetTrack(ctx, v.Id)
		if err != nil {
			return nil, toGRPCError(err)
		}
		track = toProtoTrack(t)

	case *metadatav1.GetTrackRequest_External:
		t, err := svc.GetTrack(ctx, v.External.SourceId)
		if err != nil {
			return nil, toGRPCError(err)
		}
		track = toProtoTrack(t)

	case *metadatav1.GetTrackRequest_Isrc:
		t, err := svc.GetTrackByISRC(ctx, v.Isrc)
		if err != nil {
			return nil, toGRPCError(err)
		}
		track = toProtoTrack(t)

	default:
		return nil, status.Error(codes.InvalidArgument, "identifier required")
	}

	return track, nil
}

func (s *MetadataServer) GetAlbumTracks(ctx context.Context, req *metadatav1.GetAlbumTracksRequest) (*metadatav1.GetAlbumTracksResponse, error) {
	svc, err := s.getService(req.Provider)
	if err != nil {
		return nil, err
	}

	tracks, err := svc.GetAlbumTracks(ctx, req.AlbumId)
	if err != nil {
		return nil, toGRPCError(err)
	}

	resp := &metadatav1.GetAlbumTracksResponse{}
	for _, t := range tracks {
		resp.Tracks = append(resp.Tracks, toProtoTrack(&t))
	}

	return resp, nil
}

func (s *MetadataServer) SyncArtist(ctx context.Context, req *metadatav1.SyncArtistRequest) (*metadatav1.SyncArtistResponse, error) {
	return nil, status.Error(codes.Unimplemented, "sync not yet implemented")
}

func toGRPCError(err error) error {
	if err == nil {
		return nil
	}

	if errors.Is(err, repository.ErrNotFound) {
		return status.Error(codes.NotFound, "not found")
	}

	if errors.Is(err, musicbrainz.ErrNotFound) {
		return status.Error(codes.NotFound, "not found")
	}

	if errors.Is(err, musicbrainz.ErrRateLimited) {
		return status.Error(codes.ResourceExhausted, "rate limited")
	}

	return status.Errorf(codes.Internal, "internal error: %v", err)
}