package greeter

import (
	"context"
	"errors"
	"fmt"
	"io"

	"gitea.dwysokinski.me/Kichiyaki/grpc-demo/proto"
	"go.uber.org/zap"
	"google.golang.org/genproto/googleapis/rpc/errdetails"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/metadata"
	"google.golang.org/grpc/status"
)

type Server struct {
	proto.UnimplementedGreeterServer
	logger *zap.Logger
}

func NewServer(logger *zap.Logger) *Server {
	return &Server{logger: logger}
}

func (s *Server) SayHello(ctx context.Context, r *proto.HelloRequest) (*proto.HelloReply, error) {
	md, ok := metadata.FromIncomingContext(ctx)
	if ok {
		s.logger.Debug("received metadata", zap.Any("metadata", md))
	}
	return &proto.HelloReply{
		Message: buildHelloMsg(r.GetName()),
	}, nil
}

func (s *Server) SayHelloToJames(_ context.Context, r *proto.HelloRequest) (*proto.HelloReply, error) {
	name := r.GetName()

	if name != "James" {
		st, err := status.
			New(codes.InvalidArgument, "invalid name").
			WithDetails(&errdetails.BadRequest{
				FieldViolations: []*errdetails.BadRequest_FieldViolation{
					{
						Field:       "name",
						Description: "must be James",
					},
				},
			})
		if err != nil {
			return nil, status.New(codes.Internal, "internal server error").Err()
		}
		return nil, st.Err()
	}

	return &proto.HelloReply{
		Message: buildHelloMsg(name),
	}, nil
}

func (s *Server) SayHelloServerStream(r *proto.MultiHelloRequest, stream proto.Greeter_SayHelloServerStreamServer) error {
	for _, n := range r.GetNames() {
		if err := stream.Send(&proto.HelloReply{
			Message: buildHelloMsg(n),
		}); err != nil {
			return err
		}
	}
	return nil
}

func (s *Server) SayHelloClientStream(stream proto.Greeter_SayHelloClientStreamServer) error {
	var messages []string
	for {
		r, err := stream.Recv()
		if errors.Is(err, io.EOF) {
			return stream.SendAndClose(&proto.MultiHelloReply{
				Messages: messages,
			})
		}
		if err != nil {
			return fmt.Errorf("stream returned error: %w", err)
		}

		messages = append(messages, buildHelloMsg(r.GetName()))
	}
}

func (s *Server) SayHelloBidirectionalStream(stream proto.Greeter_SayHelloBidirectionalStreamServer) error {
	for {
		r, err := stream.Recv()
		if errors.Is(err, io.EOF) {
			return nil
		}
		if err != nil {
			return fmt.Errorf("stream returned error: %w", err)
		}

		if err = stream.Send(&proto.HelloReply{Message: buildHelloMsg(r.GetName())}); err != nil {
			return fmt.Errorf("couldn't send reply: %w", err)
		}
	}
}

func buildHelloMsg(name string) string {
	return "Hello " + name + "!"
}