Photo upload notification: only notify explicit friends of new explicit photo

pkg/controller/photo/upload.go

@@ -157,10 +157,16 @@ func notifyFriendsNewPhoto(photo *models.Photo, currentUser *models.User) {
 		friendIDs = models.PrivateGranteeUserIDs(currentUser.ID)
 		log.Info("Notify %d private grantees about the new photo by %s", len(friendIDs), currentUser.Username)
 	} else {
-		// Friends
+		// Get all our friend IDs. If this photo is Explicit, only select
+		// the friends who've opted-in for Explicit photo visibility.
+		if photo.Explicit {
+			friendIDs = models.FriendIDsAreExplicit(currentUser.ID)
+			log.Info("Notify %d EXPLICIT friends about the new photo by %s", len(friendIDs), currentUser.Username)
+		} else {
 			friendIDs = models.FriendIDs(currentUser.ID)
 			log.Info("Notify %d friends about the new photo by %s", len(friendIDs), currentUser.Username)
 		}
+	}
 
 	for _, fid := range friendIDs {
 		notif := &models.Notification{

pkg/controller/photo/user_gallery.go

@@ -5,6 +5,7 @@ import (
 	"regexp"
 
 	"code.nonshy.com/nonshy/website/pkg/config"
+	"code.nonshy.com/nonshy/website/pkg/log"
 	"code.nonshy.com/nonshy/website/pkg/models"
 	"code.nonshy.com/nonshy/website/pkg/session"
 	"code.nonshy.com/nonshy/website/pkg/templates"
@@ -114,6 +115,9 @@ func UserPhotos() http.HandlerFunc {
 		}
 		pager.ParsePage(r)
 		photos, err := models.PaginateUserPhotos(user.ID, visibility, explicit, pager)
+		if err != nil {
+			log.Error("PaginateUserPhotos(%s): %s", user.Username, err)
+		}
 
 		// Get the count of explicit photos if we are not viewing explicit photos.
 		var explicitCount int64

pkg/models/friend.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"time"
 
+	"code.nonshy.com/nonshy/website/pkg/log"
 	"gorm.io/gorm"
 )
 
@@ -104,6 +105,32 @@ func FriendIDs(userId uint64) []uint64 {
 	return userIDs
 }
 
+// FriendIDsAreExplicit returns friend IDs who have opted-in for Explicit content,
+// e.g. to notify only them when you uploaded a new Explicit photo so that non-explicit
+// users don't need to see that notification.
+func FriendIDsAreExplicit(userId uint64) []uint64 {
+	var (
+		userIDs = []uint64{}
+	)
+
+	err := DB.Table(
+		"friends",
+	).Joins(
+		"JOIN users ON (users.id = friends.target_user_id)",
+	).Select(
+		"friends.target_user_id AS friend_id",
+	).Where(
+		"friends.source_user_id = ? AND friends.approved = ? AND users.explicit = ?",
+		userId, true, true,
+	).Scan(&userIDs)
+
+	if err.Error != nil {
+		log.Error("SQL error collecting explicit FriendIDs for %d: %s", userId, err)
+	}
+
+	return userIDs
+}
+
 // CountFriendRequests gets a count of pending requests for the user.
 func CountFriendRequests(userID uint64) (int64, error) {
 	var count int64