go: Implement trust calculation

GoBot/db.go

@@ -31,4 +31,8 @@ func init() {
 	if err != nil {
 		panic(err)
 	}
+	_, err = db.Exec("CREATE TABLE IF NOT EXISTS trustVote (sourceUser INTEGER, targetUser INTEGER, trust INTEGER, UNIQUE(sourceUser, targetUser))")
+	if err != nil {
+		panic(err)
+	}
 }

GoBot/db_trust.go

@@ -0,0 +1,23 @@
+package main
+
+import "errors"
+
+var errForceRejectionOnApprovedPerson = errors.New("db: attempt to force reject a user that is already approved")
+
+func getTrustVote(targetID string) ([]int, error) {
+	rows, err := db.Query("SELECT trust FROM trustVote WHERE targetUser=?", targetID)
+	if err != nil {
+		return nil, err
+	}
+
+	defer rows.Close()
+
+	array := make([]int, 0)
+	for rows.Next() {
+		var trust int
+		rows.Scan(&trust)
+		array = append(array, trust)
+	}
+
+	return array, nil
+}

GoBot/trust.go

@@ -1,11 +1,58 @@
 package main
 
-func getTrust(discordID string) int {
-	//TODO This is a stub. Everyone has same weight for now.
-	return 1
+import "github.com/bwmarrin/discordgo"
+
+var trustCache map[string]float64
+
+func getTrust(discordID string) (float64, error) {
+	if v, ok := trustCache[discordID]; ok {
+		return v, nil
+	}
+	votes, err := getTrustVote(discordID)
+	if err != nil {
+		return 0.0, err
+	}
+	votes = append(votes, 3)
+	var total float64
+	for _, v := range votes {
+		total += float64(v)
+	}
+	return total / float64(len(votes)), nil
+}
+
+func getTotalTrust(s *discordgo.Session) (float64, error) {
+	members, err := getAllMembers(s)
+	if err != nil {
+		return 0.0, err
+	}
+	var total float64
+	for _, member := range members {
+		trust, err := getTrust(member.User.ID)
+		if err != nil {
+			return 0.0, err
+		}
+		total += trust
+	}
+	return total, nil
 }
 
-func getTotalTrust() int {
-	//TODO This is a stub. It returns 1 for easier testing for now.
-	return 1
+func getAllMembers(s *discordgo.Session) ([]*discordgo.Member, error) {
+	initial, err := s.GuildMembers(guildID, "", 1000)
+	if err != nil {
+		return nil, err
+	}
+	next := initial[len(initial)-1].User.ID
+	for next != "" {
+		nextArray, err := s.GuildMembers(guildID, next, 1000)
+		if err != nil {
+			return nil, err
+		}
+		if len(nextArray) == 0 {
+			next = ""
+		} else {
+			next = nextArray[len(nextArray)-1].User.ID
+			initial = append(initial, nextArray...)
+		}
+	}
+	return initial, nil
 }

GoBot/vote_result.go

@@ -53,13 +53,23 @@ func checkForVoteResult(s *discordgo.Session, id int) {
 		if vote.Value == forceRejectionVote {
 			absoluteRejectionVote = true
 		}
-		currentScore += float64(vote.Value * getTrust(vote.UserID))
-		totalTrust += float64(getTrust(vote.UserID))
+		trust, err := getTrust(vote.UserID)
+		if err != nil {
+			auditLog(s, fmt.Sprintf("Error while getting vote trust for user ID %d: %s", vote.UserID, err.Error()))
+			return
+		}
+		currentScore += float64(vote.Value) * trust
+		totalTrust += float64(trust)
 	}
 
-	remainingTrust := float64(getTotalTrust()) - totalTrust
-	lowestPossible := (currentScore + remainingTrust) / float64(getTotalTrust())
-	highestPossible := (currentScore + remainingTrust*5) / float64(getTotalTrust())
+	totalGlobalTrust, err := getTotalTrust(s)
+	if err != nil {
+		auditLog(s, fmt.Sprintf("Error while getting total vote trust: %s", err.Error()))
+		return
+	}
+	remainingTrust := totalGlobalTrust - totalTrust
+	lowestPossible := (currentScore + remainingTrust) / totalGlobalTrust
+	highestPossible := (currentScore + remainingTrust*5) / totalGlobalTrust
 
 	if highestPossible <= 3.5 || absoluteRejectionVote {
 		//Rejection confirmed.