implemented federation

internal/domain/federation/outbox.go

@@ -0,0 +1,84 @@
+package federation
+
+import (
+	"xorm.io/xorm"
+
+	"github.com/forgeo/forgebucket/internal/models"
+)
+
+const activitiesPerPage = 20
+
+// Collection builds an ActivityStreams OrderedCollection (or page) for an actor's outbox.
+// page=0 returns the collection summary; page≥1 returns a paginated OrderedCollectionPage.
+func Collection(db *xorm.Engine, actorAPID string, outboxURL string, page int) map[string]any {
+	total, _ := db.Where("actor_ap_id = ? AND direction = 'outbound'", actorAPID).
+		Count(&models.FederationActivity{})
+
+	if page == 0 {
+		return map[string]any{
+			"@context":   "https://www.w3.org/ns/activitystreams",
+			"id":         outboxURL,
+			"type":       "OrderedCollection",
+			"totalItems": total,
+			"first":      outboxURL + "?page=1",
+		}
+	}
+
+	offset := (page - 1) * activitiesPerPage
+	var activities []models.FederationActivity
+	db.Where("actor_ap_id = ? AND direction = 'outbound'", actorAPID).
+		Desc("published").
+		Limit(activitiesPerPage, offset).
+		Find(&activities)
+
+	items := make([]any, 0, len(activities))
+	for _, a := range activities {
+		items = append(items, rawJSON(a.ObjectJSON))
+	}
+
+	coll := map[string]any{
+		"@context":     "https://www.w3.org/ns/activitystreams",
+		"id":           outboxURL + "?page=" + itoa(page),
+		"type":         "OrderedCollectionPage",
+		"partOf":       outboxURL,
+		"orderedItems": items,
+	}
+	if int64(offset+activitiesPerPage) < total {
+		coll["next"] = outboxURL + "?page=" + itoa(page+1)
+	}
+	return coll
+}
+
+// StubCollection returns a minimal OrderedCollection with zero items.
+// Used for followers/following until the social graph is implemented.
+func StubCollection(collectionURL string) map[string]any {
+	return map[string]any{
+		"@context":   "https://www.w3.org/ns/activitystreams",
+		"id":         collectionURL,
+		"type":       "OrderedCollection",
+		"totalItems": 0,
+		"orderedItems": []any{},
+	}
+}
+
+func itoa(n int) string {
+	if n == 0 {
+		return "0"
+	}
+	result := ""
+	for n > 0 {
+		result = string(rune('0'+n%10)) + result
+		n /= 10
+	}
+	return result
+}
+
+// rawJSON wraps a JSON string so it marshals as-is (not double-encoded).
+type rawJSON string
+
+func (r rawJSON) MarshalJSON() ([]byte, error) {
+	if r == "" {
+		return []byte("null"), nil
+	}
+	return []byte(r), nil
+}