Skill Based Match Function

matchfunction.go

func makeMatches(p *pb.MatchProfile, poolTickets map[string][]*pb.Ticket) ([]*pb.Match, error) {
	// Create a colletion to hold match proposals
	var matches []*pb.Match
	count := 0
	for {
		insufficientTickets := false
		// Create a collection to hold tickets selected for a match
		matchTickets := []*pb.Ticket{}
		for pool, tickets := range poolTickets {
			// Set flag if there are not enough tickets to create a match
			if len(tickets) < ticketsPerPoolPerMatch {
				insufficientTickets = true
				break
			}
			// Sort the tickets based on skill
			sort.Slice(tickets, func(i, j int) bool {
				return tickets[i].SearchFields.DoubleArgs["mmr"] < tickets[j].SearchFields.DoubleArgs["mmr"]
			})

			// Remove the Tickets from this pool and add to the match proposal.
			matchTickets = append(matchTickets, tickets[0:ticketsPerPoolPerMatch]...)
			poolTickets[pool] = tickets[ticketsPerPoolPerMatch:]
		}

		if insufficientTickets {
			break
		}
		// Compute the match quality/score
		matchQuality := computeQuality(matchTickets)
		evaluationInput, err := ptypes.MarshalAny(&pb.DefaultEvaluationCriteria{
			Score: matchQuality,
		})

		if err != nil {
			log.Printf("Failed to marshal DefaultEvaluationCriteria, got %s.", err.Error())
			return nil, fmt.Errorf("Failed to marshal DefaultEvaluationCriteria, got %w", err)
		}
		// Output the match quality for our sanity
		log.Printf("Quality for the generated match is %v", matchQuality)
		// Create a match proposal
		matches = append(matches, &pb.Match{
			MatchId:       fmt.Sprintf("profile-%v-time-%v-%v", p.GetName(), time.Now().Format("2006-01-02T15:04:05.00"), count),
			MatchProfile:  p.GetName(),
			MatchFunction: matchName,
			Tickets:       matchTickets,
			Extensions: map[string]*any.Any{
				"evaluation_input": evaluationInput,
			},
		})

		count++
	}

	return matches, nil
}

// Compute the quality as a difference in the highest and lowest player skill levels. This can be used to determine if the match is outside a given skill differential
func computeQuality(tickets []*pb.Ticket) float64 {
	quality := 0.0
	high := 0.0
	low := tickets[0].SearchFields.DoubleArgs["mmr"]
	for _, ticket := range tickets {
		if high < ticket.SearchFields.DoubleArgs["mmr"] {
			high = ticket.SearchFields.DoubleArgs["mmr"]
		}
		if low > ticket.SearchFields.DoubleArgs["mmr"] {
			low = ticket.SearchFields.DoubleArgs["mmr"]
		}
	}
	quality = high - low

	return quality
}