feat: Display list of remote users who liked a post

This change implements the ability to display a list of remote users
who have liked a post on an individual entry page (collection post).

Key changes include:
- Added a `RemoteLikers []*RemoteUser` field to the `PublicPost` struct in `posts.go`.
- Implemented a new database function `getRemoteLikersForPost(postID string)` in `database.go` to fetch likers by joining `remote_likes` and `remoteusers` tables.
- Modified the `GetPost` function in `database.go` to call `getRemoteLikersForPost` and populate the `RemoteLikers` field.
- Updated the `templates/collection-post.tmpl` template to iterate over `RemoteLikers` and display each user's handle as a link to their profile.

database.go

@@ -1132,6 +1132,19 @@ func (db *datastore) GetEditablePost(id, editToken string) (*PublicPost, error)
 		res.Owner = &PublicUser{Username: ownerName.String}
 	}
 
+	// Get remote likers for the post
+	likers, err := db.getRemoteLikersForPost(p.ID)
+	if err != nil {
+		// Log the error but don't block returning the post
+		// getRemoteLikersForPost is expected to return an empty slice on sql.ErrNoRows
+		log.Error("GetPost: Failed to get remote likers for post %s: %v", p.ID, err)
+		// If likers is nil due to an unexpected error, ensure it's an empty slice
+		if likers == nil {
+			likers = []*RemoteUser{}
+		}
+	}
+	res.RemoteLikers = likers
+
 	return &res, nil
 }
 
@@ -1462,6 +1475,57 @@ func (db *datastore) GetPostsTagged(cfg *config.Config, c *Collection, tag strin
 	return &posts, nil
 }
 
+// getRemoteLikersForPost retrieves a list of remote users who liked a specific post.
+func (db *datastore) getRemoteLikersForPost(postID string) ([]*RemoteUser, error) {
+	rows, err := db.Query(`
+		SELECT ru.id, ru.actor_id, ru.url, ru.handle, ru.created, ru.inbox, ru.shared_inbox
+		FROM remoteusers ru
+		JOIN remote_likes rl ON ru.id = rl.remote_user_id
+		WHERE rl.post_id = ?
+		ORDER BY rl.created DESC
+	`, postID)
+	if err != nil {
+		// sql.ErrNoRows is not an error in this case, just means no likers.
+		// It's handled by the loop below which won't execute.
+		return nil, err
+	}
+	defer rows.Close()
+
+	var likers []*RemoteUser
+	for rows.Next() {
+		var u RemoteUser
+		var handle sql.NullString
+		var created sql.NullTime
+		var url sql.NullString
+		var inbox sql.NullString
+		var sharedInbox sql.NullString
+
+		err := rows.Scan(&u.ID, &u.ActorID, &url, &handle, &created, &inbox, &sharedInbox)
+		if err != nil {
+			return nil, err
+		}
+		u.URL = url.String
+		u.Handle = handle.String
+		if created.Valid {
+			u.Created = created.Time
+		}
+		u.Inbox = inbox.String
+		u.SharedInbox = sharedInbox.String
+		likers = append(likers, &u)
+	}
+
+	if err = rows.Err(); err != nil {
+		return nil, err
+	}
+
+	// If likers slice is still nil (e.g. no rows found), initialize it to an empty slice.
+	if likers == nil {
+		likers = []*RemoteUser{}
+	}
+
+	return likers, nil
+}
+
 func (db *datastore) GetCollLangTotalPosts(collID int64, lang string) (uint64, error) {
 	var articles uint64
 	err := db.QueryRow("SELECT COUNT(*) FROM posts WHERE collection_id = ? AND language = ? AND created <= "+db.now(), collID, lang).Scan(&articles)

posts.go

@@ -135,6 +135,7 @@ type (
 		DisplayDate string         `json:"-"`
 		Views       int64          `json:"views"`
 		Likes       int64          `json:"likes"`
+	RemoteLikers []*RemoteUser `json:"remote_likers,omitempty"` // New field
 		Owner       *PublicUser    `json:"-"`
 		IsOwner     bool           `json:"-"`
 		URL         string         `json:"url,omitempty"`

templates/collection-post.tmpl

@@ -56,6 +56,20 @@
 				{{end}}
 				{{ if and .IsOwner .IsFound }}<span class="views" dir="ltr"><strong>{{largeNumFmt .Views}}</strong> {{pluralize "view" "views" .Views}}</span>
                 {{if .Likes}}<span class="views" dir="ltr"><strong>{{largeNumFmt .Likes}}</strong> {{pluralize "like" "likes" .Likes}}</span>{{end}}
+
+        {{/* New section for Remote Likers */}}
+        {{if .RemoteLikers}}
+          <div class="remote-likers views" dir="ltr"> {{/* Borrowing "views" class for similar styling */}}
+            <p style="margin-top: 5px; margin-bottom: 2px; font-size: 0.9em;">Liked by:</p>
+            <ul style="list-style-type: none; padding-left: 0; margin-top: 0;">
+              {{range .RemoteLikers}}
+                <li style="display: inline-block; margin-right: 5px;">
+                  <a href="{{.URL}}" target="_blank" rel="noopener noreferrer" title="{{.ActorID}}">{{.EstimatedHandle}}</a>
+                </li>
+              {{end}}
+            </ul>
+          </div>
+        {{end}}
 				<a href="/{{if not .SingleUser}}{{.Collection.Alias}}/{{end}}{{.Slug.String}}/edit" dir="{{.Direction}}">Edit</a>
 				{{if .IsPinned}}<a class="xtra-feature unpin" href="/{{.Collection.Alias}}/{{.Slug.String}}/unpin" dir="{{.Direction}}" onclick="unpinPost(event, '{{.ID}}')">Unpin</a>{{end}}
 				{{ end }}