package server

import (
	"fmt"
	"git.rodere.systems/stream-service/api"
	"golang.org/x/net/context"
	"google.golang.org/grpc"
	"google.golang.org/grpc/metadata"
	"log"
	"strings"
)

// private type for Context keys
type contextKey int

const (
	clientIDKey contextKey = iota
)

func credMatcher(headerName string) (mdName string, ok bool) {
	if headerName == "Login" || headerName == "Password" {
		return headerName, true
	}
	return "", false
}

// authenticateAgent check the client credentials
func authenticateClient(ctx context.Context, s *api.Server) (string, error) {
	if md, ok := metadata.FromIncomingContext(ctx); ok {
		clientLogin := strings.Join(md["login"], "")
		clientPassword := strings.Join(md["password"], "")

		if clientLogin != "john" {
			return "", fmt.Errorf("unknown user %s", clientLogin)
		}
		if clientPassword != "doe" {
			return "", fmt.Errorf("bad password %s", clientPassword)
		}

		log.Printf("authenticated client: %s", clientLogin)

		return "42", nil
	}
	return "", fmt.Errorf("missing credentials")
}

// unaryInterceptor call authenticateClient with current context
func unaryInterceptor(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
	s, ok := info.Server.(*api.Server)
	if !ok {
		return nil, fmt.Errorf("unable to cast server")
	}
	clientID, err := authenticateClient(ctx, s)
	if err != nil {
		return nil, err
	}

	ctx = context.WithValue(ctx, clientIDKey, clientID)

	return handler(ctx, req)
}