added ability to broadcast

internal/app/broadcast/service.go

@@ -0,0 +1,159 @@
+// Package broadcast implements admin-triggered system message campaigns:
+// sending a message from the official system account (domain.OfficialSystemUserID,
+// 777000) to every user or a hand-picked list. Delivery is a durable outbox
+// (store.BroadcastStore's recipient rows) drained by a periodic Worker,
+// mirroring internal/app/verification's notification outbox -- the admin
+// action only snapshots the recipient list and returns, never sending
+// potentially thousands of messages inline within one HTTP request.
+package broadcast
+
+import (
+	"context"
+	"fmt"
+	"hash/fnv"
+	"strconv"
+	"strings"
+
+	"go.uber.org/zap"
+
+	"telesrv/internal/domain"
+	"telesrv/internal/store"
+)
+
+// messageSender is the narrow port this package needs from
+// store.MessageStore: sending a message with an arbitrary SenderUserID, the
+// way internal/app/bots's sendServiceBotReplyResult calls it directly at the
+// store layer rather than through the auth-checked app.messages.Service
+// wrapper (which requires SenderUserID == the authenticated caller).
+type messageSender interface {
+	SendPrivateText(ctx context.Context, req domain.SendPrivateTextRequest) (domain.SendPrivateTextResult, error)
+}
+
+// Service creates broadcasts and drains their delivery outbox.
+type Service struct {
+	store    store.BroadcastStore
+	messages messageSender
+	log      *zap.Logger
+}
+
+// Option adjusts an optional Service dependency.
+type Option func(*Service)
+
+// NewService builds the broadcast service.
+func NewService(st store.BroadcastStore, opts ...Option) *Service {
+	s := &Service{store: st, log: zap.NewNop()}
+	for _, opt := range opts {
+		opt(s)
+	}
+	return s
+}
+
+// WithMessageSender injects the store used to actually deliver a message.
+func WithMessageSender(m messageSender) Option {
+	return func(s *Service) {
+		if m != nil {
+			s.messages = m
+		}
+	}
+}
+
+// WithLogger injects a logger (default zap.NewNop()).
+func WithLogger(log *zap.Logger) Option {
+	return func(s *Service) {
+		if log != nil {
+			s.log = log
+		}
+	}
+}
+
+// Ready reports whether both the store and the sender are wired.
+func (s *Service) Ready() bool { return s != nil && s.store != nil && s.messages != nil }
+
+// Create validates and snapshots a new broadcast's recipient set, then
+// returns immediately: delivery happens asynchronously via RunSendCycle, so
+// this never blocks an admin HTTP request on however many recipients there
+// are.
+func (s *Service) Create(ctx context.Context, message string, targetMode domain.BroadcastTargetMode, recipientUserIDs []int64, createdBy string) (domain.Broadcast, error) {
+	if s == nil || s.store == nil {
+		return domain.Broadcast{}, fmt.Errorf("broadcast store is not configured")
+	}
+	message = strings.TrimSpace(message)
+	if message == "" {
+		return domain.Broadcast{}, domain.ErrBroadcastMessageEmpty
+	}
+	if targetMode != domain.BroadcastTargetAll && targetMode != domain.BroadcastTargetSelected {
+		return domain.Broadcast{}, domain.ErrBroadcastInvalid
+	}
+	return s.store.CreateBroadcast(ctx, message, targetMode, recipientUserIDs, createdBy)
+}
+
+// List pages broadcasts newest-first.
+func (s *Service) List(ctx context.Context, beforeID int64, limit int) ([]domain.Broadcast, bool, error) {
+	if s == nil || s.store == nil {
+		return nil, false, nil
+	}
+	return s.store.ListBroadcasts(ctx, beforeID, limit)
+}
+
+// Get returns one broadcast.
+func (s *Service) Get(ctx context.Context, id int64) (domain.Broadcast, bool, error) {
+	if s == nil || s.store == nil {
+		return domain.Broadcast{}, false, nil
+	}
+	return s.store.BroadcastByID(ctx, id)
+}
+
+// RunSendCycle drains up to limit pending recipient rows, sending each from
+// domain.OfficialSystemUserID. One recipient's failure (blocked account,
+// deleted account, transient error) never blocks the rest of the batch.
+func (s *Service) RunSendCycle(ctx context.Context, limit int) (sent int, err error) {
+	if s == nil || !s.Ready() {
+		return 0, nil
+	}
+	pending, err := s.store.PendingBroadcastRecipients(ctx, limit)
+	if err != nil {
+		return 0, err
+	}
+	for _, recipient := range pending {
+		if err := ctx.Err(); err != nil {
+			return sent, err
+		}
+		_, sendErr := s.messages.SendPrivateText(ctx, domain.SendPrivateTextRequest{
+			SenderUserID:    domain.OfficialSystemUserID,
+			RecipientUserID: recipient.UserID,
+			// A stable id derived from (broadcast, recipient) makes reprocessing
+			// this exact row idempotent at the store layer's random_id dedup,
+			// instead of risking a duplicate message if this worker crashes
+			// between sending and marking the row delivered.
+			RandomID: stableBroadcastRandomID(recipient.BroadcastID, recipient.UserID),
+			Message:  recipient.Message,
+		})
+		if sendErr != nil {
+			if markErr := s.store.MarkBroadcastRecipientFailed(ctx, recipient.RecipientID, sendErr.Error()); markErr != nil {
+				s.log.Warn("mark broadcast recipient failed",
+					zap.Int64("recipient_id", recipient.RecipientID), zap.Error(markErr))
+			}
+			continue
+		}
+		if markErr := s.store.MarkBroadcastRecipientSent(ctx, recipient.RecipientID); markErr != nil {
+			s.log.Warn("mark broadcast recipient sent",
+				zap.Int64("recipient_id", recipient.RecipientID), zap.Error(markErr))
+			continue
+		}
+		sent++
+	}
+	return sent, nil
+}
+
+// stableBroadcastRandomID derives a random_id from (broadcastID, userID) so
+// re-processing the same recipient row (after a crash, before it was marked
+// delivered) resolves to the same send instead of a duplicate message.
+func stableBroadcastRandomID(broadcastID, userID int64) int64 {
+	h := fnv.New64a()
+	_, _ = h.Write([]byte(strconv.FormatInt(broadcastID, 10) + ":" + strconv.FormatInt(userID, 10)))
+	v := int64(h.Sum64())
+	if v == 0 {
+		v = 1
+	}
+	return v
+}