// Copyright 2016 Michal Witkowski. All Rights Reserved.
// See LICENSE for licensing terms.

package grpc_middleware

import (
	"golang.org/x/net/context"
	"google.golang.org/grpc"
)

// WrappedServerStream is a thin wrapper around grpc.ServerStream that allows modifying context.
type WrappedServerStream struct {
	grpc.ServerStream
	// WrappedContext is the wrapper's own Context. You can assign it.
	WrappedContext context.Context
}

// Context returns the wrapper's WrappedContext, overwriting the nested grpc.ServerStream.Context()
func (w *WrappedServerStream) Context() context.Context {
	return w.WrappedContext
}

// WrapServerStream returns a ServerStream that has the ability to overwrite context.
func WrapServerStream(stream grpc.ServerStream) *WrappedServerStream {
	if existing, ok := stream.(*WrappedServerStream); ok {
		return existing
	}
	return &WrappedServerStream{ServerStream: stream, WrappedContext: stream.Context()}
}