feat(multiplayer): wire production proposal outbox delivery

server/api/outbox.go

@@ -0,0 +1,85 @@
+package api
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"github.com/cosmic-clash/cosmic-clash/server/store"
+)
+
+// RunProposalOutboxDispatcher delivers committed proposal changes to the
+// authenticated WebSocket subscribers. It only reads proposal_changed rows;
+// result and other outbox event types remain owned by their own consumers.
+// Delivery is at-least-once because the row is acknowledged only after every
+// participant publication succeeds.
+func RunProposalOutboxDispatcher(ctx context.Context, db *sql.DB, service *Service) {
+	if db == nil || service == nil {
+		return
+	}
+	ticker := time.NewTicker(100 * time.Millisecond)
+	defer ticker.Stop()
+	dispatcher := store.NewOutboxDispatcher(db, func(deliveryCtx context.Context, event store.OutboxEvent) error {
+		return deliverProposalOutboxEvent(deliveryCtx, event, service)
+	})
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			events, err := store.ReadUnpublishedProposalOutbox(ctx, db, 100)
+			if err != nil {
+				continue
+			}
+			_ = dispatchOutboxEvents(ctx, dispatcher, events)
+		}
+	}
+}
+
+func dispatchOutboxEvents(ctx context.Context, dispatcher *store.OutboxDispatcher, events []store.OutboxEvent) error {
+	if len(events) == 0 {
+		return nil
+	}
+	// Use the same delivery-before-ack contract as the general dispatcher,
+	// while keeping the already-filtered batch from being read a second time.
+	for _, event := range events {
+		if event.EventID == "" {
+			return fmt.Errorf("outbox event has no ID")
+		}
+		if err := dispatcher.Deliver(ctx, event); err != nil {
+			return err
+		}
+		if err := dispatcher.Ack(ctx, event.EventID, time.Now().UTC()); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func deliverProposalOutboxEvent(_ context.Context, event store.OutboxEvent, service *Service) error {
+	var envelope struct {
+		Event      string    `json:"event"`
+		Revision   uint64    `json:"revision"`
+		ResourceID string    `json:"resource_id"`
+		OccurredAt time.Time `json:"occurred_at"`
+		State      string    `json:"state"`
+		PlayerIDs  []string  `json:"player_ids"`
+	}
+	if err := json.Unmarshal(event.Payload, &envelope); err != nil {
+		return fmt.Errorf("decode proposal outbox event: %w", err)
+	}
+	if envelope.Event != "proposal_changed" || envelope.ResourceID == "" || len(envelope.PlayerIDs) == 0 {
+		return fmt.Errorf("invalid proposal outbox event")
+	}
+	for _, playerID := range envelope.PlayerIDs {
+		if err := service.PublishControlPlaneEvent(ControlPlaneEvent{
+			Event: envelope.Event, Revision: envelope.Revision, ResourceID: envelope.ResourceID,
+			OccurredAt: envelope.OccurredAt, State: envelope.State, PlayerID: playerID,
+		}); err != nil {
+			return err
+		}
+	}
+	return nil
+}