feat(backend): implement HTTP API, auth, chat, and admin surfaces

Expose learning, registration controls, mentor chat, realtime WebSocket, and staff administration.

backend/internal/api/scheduler.go

@@ -0,0 +1,127 @@
+package api
+
+import (
+	"context"
+	"time"
+
+	"pargar/backend/internal/config"
+	"pargar/backend/internal/store"
+)
+
+// Scheduler runs periodic background jobs.
+type Scheduler struct {
+	store *store.Store
+	srv   *Server
+	cfg   *config.Config
+	stop  chan struct{}
+}
+
+// reminder windows (relative to event start)
+var reminderWindows = []struct {
+	kind string
+	dur  time.Duration
+}{
+	{"1h", time.Hour},
+	{"15m", 15 * time.Minute},
+}
+
+func NewScheduler(srv *Server, st *store.Store, cfg *config.Config) *Scheduler {
+	return &Scheduler{store: st, srv: srv, cfg: cfg, stop: make(chan struct{})}
+}
+
+func (sh *Scheduler) Run() {
+	ticker := time.NewTicker(30 * time.Second)
+	for {
+		select {
+		case <-sh.stop:
+			return
+		case <-ticker.C:
+			sh.runOnce()
+		}
+	}
+}
+
+func (sh *Scheduler) Stop() { close(sh.stop) }
+
+func (sh *Scheduler) runOnce() {
+	ctx := context.Background()
+	// 1. event reminders for RSVPers
+	now := time.Now()
+	for _, win := range reminderWindows {
+		startFrom := now.Add(-time.Minute)
+		endAt := now.Add(win.dur + time.Minute)
+		rows, err := sh.store.Pool().Query(ctx, `
+			SELECT DISTINCT r.event_id, r.user_id
+			FROM event_rsvps r JOIN events e ON e.id = r.event_id
+			WHERE e.is_active AND e.starts_at BETWEEN $1 AND $2`, startFrom, endAt)
+		if err != nil {
+			continue
+		}
+		for rows.Next() {
+			var eventID, userID int64
+			if rows.Scan(&eventID, &userID) != nil {
+				continue
+			}
+			ref := "event:" + itoa(eventID) + ":" + win.kind
+			sent, err := sh.store.ReminderSent(ctx, userID, "event_reminder", ref)
+			if err != nil || sent {
+				continue
+			}
+			e, err := sh.store.GetEvent(ctx, eventID)
+			if err != nil {
+				continue
+			}
+			_ = sh.srv.notify.Notify(ctx, userID, "event", "event_reminder",
+				"رویداد "+reminderLabel(win.kind)+" آغاز می‌شود",
+				"رویداد «"+e.Title+"» "+reminderHuman(win.kind)+" آغاز می‌شود. نوع برگزاری: "+e.EventType+"؛ برای پیوستن وارد بخش رویدادها شوید.",
+				"/unwrap?tab=events", map[string]any{"eventId": eventID})
+			_ = sh.store.MarkReminderSent(ctx, userID, "event_reminder", ref)
+		}
+		rows.Close()
+	}
+
+	// 3. streak at risk (missed a day of activity)
+	rows2, err := sh.store.Pool().Query(ctx, `
+		SELECT id FROM users
+		WHERE is_active AND NOT is_locked AND streak_current > 0
+		  AND last_activity_date IS NOT NULL AND last_activity_date = (now() - interval '1 day')::date`)
+	if err == nil {
+		for rows2.Next() {
+			var uid int64
+			if rows2.Scan(&uid) != nil {
+				continue
+			}
+			ref := time.Now().Format("2006-01-02")
+			sent, err := sh.store.ReminderSent(ctx, uid, "streak_at_risk", ref)
+			if err != nil || sent {
+				continue
+			}
+			u, err := sh.store.GetUserByID(ctx, uid)
+			if err != nil {
+				continue
+			}
+			_ = sh.srv.notify.Notify(ctx, uid, "gamification", "streak_at_risk",
+				"زنجیرهٔ فعالیت در خطر است",
+				"امروز یک درس را کامل کنید تا زنجیرهٔ "+itoa(int64(u.StreakCurrent))+"روزهٔ شما حفظ شود.",
+				"/cap", nil)
+			_ = sh.store.MarkReminderSent(ctx, uid, "streak_at_risk", ref)
+		}
+		rows2.Close()
+	}
+
+	if _, err := sh.store.PurgeOldHeartbeats(ctx, 30*24*time.Hour); err != nil {
+		// non-fatal: log via notify path would be overkill; ignore
+		_ = err
+	}
+}
+
+func reminderLabel(kind string) string {
+	if kind == "15m" {
+		return "به‌زودی"
+	}
+	return "تا یک ساعت دیگر"
+}
+
+func reminderHuman(kind string) string {
+	return "حدوداً " + reminderLabel(kind)
+}