feat: add initial connect no-show policy

server/domain/noshow.go

@@ -0,0 +1,101 @@
+package domain
+
+import (
+	"fmt"
+	"sort"
+	"time"
+)
+
+const (
+	InitialConnectWindow = 30 * time.Second
+	CasualBotStartAfter  = 60 * time.Second
+	CasualNoShowCooldown = 60 * time.Second
+)
+
+type ConnectParticipant struct {
+	PlayerID  string
+	Team      int
+	Connected bool
+}
+
+type InitialConnectAction string
+
+const (
+	InitialConnectWait         InitialConnectAction = "WAIT"
+	InitialConnectCancel       InitialConnectAction = "CANCEL"
+	InitialConnectStartWithBot InitialConnectAction = "START_WITH_BOTS"
+)
+
+type InitialConnectDecision struct {
+	Action   InitialConnectAction
+	NoShows  []Abandonment
+	Innocent []string
+}
+
+// EvaluateInitialConnect only decides pre-live admission. It never computes a
+// game result or rating update; those remain unavailable until a match is
+// genuinely live and produces an authoritative result.
+func EvaluateInitialConnect(playlist Playlist, readyAt, now time.Time, participants []ConnectParticipant, priorAbandons map[string][]time.Time) (InitialConnectDecision, error) {
+	if playlist != Ranked && playlist != Casual || readyAt.IsZero() || len(participants) == 0 {
+		return InitialConnectDecision{}, fmt.Errorf("invalid initial-connect policy input")
+	}
+	if now.Before(readyAt.Add(InitialConnectWindow)) {
+		return InitialConnectDecision{Action: InitialConnectWait}, nil
+	}
+	missing := make([]ConnectParticipant, 0)
+	connected := make([]string, 0)
+	teamConnected := map[int]bool{}
+	for _, participant := range participants {
+		if participant.PlayerID == "" || participant.Team < 0 {
+			return InitialConnectDecision{}, fmt.Errorf("invalid participant")
+		}
+		if participant.Connected {
+			connected = append(connected, participant.PlayerID)
+			teamConnected[participant.Team] = true
+		} else {
+			missing = append(missing, participant)
+		}
+	}
+	if playlist == Ranked {
+		if len(participants) != 6 {
+			return InitialConnectDecision{}, fmt.Errorf("ranked requires six participants")
+		}
+		return InitialConnectDecision{Action: InitialConnectCancel, NoShows: rankedNoShows(missing, now, priorAbandons), Innocent: sortedIDs(connected)}, nil
+	}
+	if now.Before(readyAt.Add(CasualBotStartAfter)) {
+		return InitialConnectDecision{Action: InitialConnectWait}, nil
+	}
+	if teamConnected[0] && teamConnected[1] {
+		noShows := make([]Abandonment, 0, len(missing))
+		for _, participant := range missing {
+			noShows = append(noShows, Abandonment{PlayerID: participant.PlayerID, Cooldown: CasualNoShowCooldown, AbandonedAt: now})
+		}
+		sort.Slice(noShows, func(i, j int) bool { return noShows[i].PlayerID < noShows[j].PlayerID })
+		return InitialConnectDecision{Action: InitialConnectStartWithBot, NoShows: noShows, Innocent: sortedIDs(connected)}, nil
+	}
+	return InitialConnectDecision{Action: InitialConnectCancel, NoShows: casualNoShows(missing, now), Innocent: sortedIDs(connected)}, nil
+}
+
+func rankedNoShows(missing []ConnectParticipant, now time.Time, history map[string][]time.Time) []Abandonment {
+	result := make([]Abandonment, 0, len(missing))
+	for _, participant := range missing {
+		result = append(result, Abandonment{PlayerID: participant.PlayerID, Cooldown: abandonCooldown(history[participant.PlayerID], now), AbandonedAt: now})
+	}
+	sort.Slice(result, func(i, j int) bool { return result[i].PlayerID < result[j].PlayerID })
+	return result
+}
+
+func casualNoShows(missing []ConnectParticipant, now time.Time) []Abandonment {
+	result := make([]Abandonment, 0, len(missing))
+	for _, participant := range missing {
+		result = append(result, Abandonment{PlayerID: participant.PlayerID, Cooldown: CasualNoShowCooldown, AbandonedAt: now})
+	}
+	sort.Slice(result, func(i, j int) bool { return result[i].PlayerID < result[j].PlayerID })
+	return result
+}
+
+func sortedIDs(participants []string) []string {
+	result := append([]string(nil), participants...)
+	sort.Strings(result)
+	return result
+}