feat: add durable matcher worker orchestration

server/matcher/worker.go

@@ -0,0 +1,88 @@
+// Package matcher contains the provider-neutral orchestration around the
+// durable proposal claim transaction.
+package matcher
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/cosmic-clash/cosmic-clash/server/domain"
+)
+
+type CandidateSource func(context.Context, time.Time, int) ([]domain.Candidate, error)
+
+type ProposalCreator interface {
+	CreateProposal(context.Context, domain.Proposal, map[string]string, time.Time) error
+}
+
+type ProposalCreatorFunc func(context.Context, domain.Proposal, map[string]string, time.Time) error
+
+func (f ProposalCreatorFunc) CreateProposal(ctx context.Context, proposal domain.Proposal, ticketIDs map[string]string, now time.Time) error {
+	return f(ctx, proposal, ticketIDs, now)
+}
+
+type PrepareFunc func(string, domain.Playlist, domain.MatchFormation, time.Time) (domain.PreparedProposal, error)
+
+type Worker struct {
+	Source   CandidateSource
+	Creator  ProposalCreator
+	Playlist domain.Playlist
+	Size     int
+	Now      func() time.Time
+	NextID   func() string
+	Prepare  PrepareFunc
+}
+
+// RunOnce performs one bounded matchmaking attempt. The source may be Redis
+// backed, but the creator must be the durable transaction that claims tickets;
+// a stale cache therefore fails safely and can be retried on the next pass.
+func (w Worker) RunOnce(ctx context.Context) (bool, error) {
+	if w.Source == nil || w.Creator == nil || w.Now == nil || w.NextID == nil || w.Prepare == nil {
+		return false, fmt.Errorf("matcher worker is not configured")
+	}
+	if w.Playlist != domain.Casual && w.Playlist != domain.Ranked {
+		return false, fmt.Errorf("unsupported matcher playlist")
+	}
+	if w.Size < 2 || w.Size > 6 {
+		return false, fmt.Errorf("invalid matcher size")
+	}
+	now := w.Now()
+	candidates, err := w.Source(ctx, now, w.Size)
+	if err != nil {
+		return false, err
+	}
+	if len(candidates) < w.Size {
+		return false, nil
+	}
+	queue := domain.NewQueue()
+	for _, candidate := range candidates {
+		if _, err := queue.Create(candidate.PlayerID, candidate.TicketID, "matcher-"+candidate.TicketID, candidate, now); err != nil {
+			return false, err
+		}
+	}
+	formation, err := domain.FormFromQueue(queue, w.Size, now)
+	if err != nil {
+		return false, err
+	}
+	prepared, err := w.Prepare(w.NextID(), w.Playlist, formation, now)
+	if err != nil {
+		return false, err
+	}
+	ticketIDs := make(map[string]string, len(prepared.Proposal.Participants))
+	for _, participant := range prepared.Proposal.Participants {
+		for _, candidate := range formation.Selection.Players {
+			if candidate.PlayerID == participant.PlayerID {
+				ticketIDs[participant.PlayerID] = candidate.TicketID
+				break
+			}
+		}
+	}
+	if len(ticketIDs) != len(prepared.Proposal.Participants) {
+		return false, fmt.Errorf("proposal participant is not in formed selection")
+	}
+	if err := w.Creator.CreateProposal(ctx, prepared.Proposal, ticketIDs, now); err != nil {
+		return false, err
+	}
+	return true, nil
+}