wp-fedistream/includes/ActivityPub/ArtistActor.php

<?php
/**
 * Artist ActivityPub Actor.
 *
 * @package WP_FediStream
 */

namespace WP_FediStream\ActivityPub;

// Prevent direct file access.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Represents an artist as an ActivityPub actor.
 */
class ArtistActor {

	/**
	 * The artist post.
	 *
	 * @var \WP_Post
	 */
	private \WP_Post $artist;

	/**
	 * Constructor.
	 *
	 * @param \WP_Post $artist The artist post.
	 */
	public function __construct( \WP_Post $artist ) {
		$this->artist = $artist;
	}

	/**
	 * Get the actor ID (URI).
	 *
	 * @return string
	 */
	public function get_id(): string {
		return get_permalink( $this->artist->ID );
	}

	/**
	 * Get the actor type.
	 *
	 * @return string Person for solo, Group for bands.
	 */
	public function get_type(): string {
		$artist_type = get_post_meta( $this->artist->ID, '_fedistream_artist_type', true );

		// Bands, duos, collectives are Groups.
		if ( in_array( $artist_type, array( 'band', 'duo', 'collective', 'orchestra' ), true ) ) {
			return 'Group';
		}

		return 'Person';
	}

	/**
	 * Get the preferred username.
	 *
	 * @return string
	 */
	public function get_preferred_username(): string {
		return 'artist-' . $this->artist->ID;
	}

	/**
	 * Get the display name.
	 *
	 * @return string
	 */
	public function get_name(): string {
		return $this->artist->post_title;
	}

	/**
	 * Get the actor summary/bio.
	 *
	 * @return string
	 */
	public function get_summary(): string {
		if ( ! empty( $this->artist->post_excerpt ) ) {
			return wp_kses_post( $this->artist->post_excerpt );
		}

		// Use first paragraph of content as summary.
		$content = wp_strip_all_tags( $this->artist->post_content );
		$parts   = explode( "\n\n", $content, 2 );

		return ! empty( $parts[0] ) ? wp_trim_words( $parts[0], 50 ) : '';
	}

	/**
	 * Get the actor URL (profile page).
	 *
	 * @return string
	 */
	public function get_url(): string {
		return get_permalink( $this->artist->ID );
	}

	/**
	 * Get the inbox URL.
	 *
	 * @return string
	 */
	public function get_inbox(): string {
		return trailingslashit( get_permalink( $this->artist->ID ) ) . 'inbox';
	}

	/**
	 * Get the outbox URL.
	 *
	 * @return string
	 */
	public function get_outbox(): string {
		return trailingslashit( get_permalink( $this->artist->ID ) ) . 'outbox';
	}

	/**
	 * Get the followers URL.
	 *
	 * @return string
	 */
	public function get_followers(): string {
		return trailingslashit( get_permalink( $this->artist->ID ) ) . 'followers';
	}

	/**
	 * Get the following URL.
	 *
	 * @return string
	 */
	public function get_following(): string {
		return trailingslashit( get_permalink( $this->artist->ID ) ) . 'following';
	}

	/**
	 * Get the avatar/icon.
	 *
	 * @return array|null
	 */
	public function get_icon(): ?array {
		$thumbnail_id = get_post_thumbnail_id( $this->artist->ID );
		if ( ! $thumbnail_id ) {
			return null;
		}

		$image = wp_get_attachment_image_src( $thumbnail_id, 'thumbnail' );
		if ( ! $image ) {
			return null;
		}

		return array(
			'type'      => 'Image',
			'mediaType' => get_post_mime_type( $thumbnail_id ),
			'url'       => $image[0],
			'width'     => $image[1],
			'height'    => $image[2],
		);
	}

	/**
	 * Get the header/banner image.
	 *
	 * @return array|null
	 */
	public function get_image(): ?array {
		$banner_id = get_post_meta( $this->artist->ID, '_fedistream_artist_banner', true );
		if ( ! $banner_id ) {
			// Fall back to featured image at larger size.
			$banner_id = get_post_thumbnail_id( $this->artist->ID );
		}

		if ( ! $banner_id ) {
			return null;
		}

		$image = wp_get_attachment_image_src( $banner_id, 'large' );
		if ( ! $image ) {
			return null;
		}

		return array(
			'type'      => 'Image',
			'mediaType' => get_post_mime_type( $banner_id ),
			'url'       => $image[0],
			'width'     => $image[1],
			'height'    => $image[2],
		);
	}

	/**
	 * Get the public key.
	 *
	 * @return array
	 */
	public function get_public_key(): array {
		$key = get_post_meta( $this->artist->ID, '_fedistream_activitypub_public_key', true );

		if ( ! $key ) {
			// Generate key pair if not exists.
			$this->generate_keys();
			$key = get_post_meta( $this->artist->ID, '_fedistream_activitypub_public_key', true );
		}

		return array(
			'id'           => $this->get_id() . '#main-key',
			'owner'        => $this->get_id(),
			'publicKeyPem' => $key,
		);
	}

	/**
	 * Generate RSA key pair for the artist.
	 *
	 * @return bool True on success.
	 */
	private function generate_keys(): bool {
		$config = array(
			'private_key_bits' => 2048,
			'private_key_type' => OPENSSL_KEYTYPE_RSA,
		);

		$resource = openssl_pkey_new( $config );
		if ( ! $resource ) {
			return false;
		}

		// Export private key.
		openssl_pkey_export( $resource, $private_key );

		// Get public key.
		$details    = openssl_pkey_get_details( $resource );
		$public_key = $details['key'] ?? '';

		if ( ! $private_key || ! $public_key ) {
			return false;
		}

		update_post_meta( $this->artist->ID, '_fedistream_activitypub_private_key', $private_key );
		update_post_meta( $this->artist->ID, '_fedistream_activitypub_public_key', $public_key );

		return true;
	}

	/**
	 * Get attachment properties (social links, etc.).
	 *
	 * @return array
	 */
	public function get_attachment(): array {
		$attachments = array();

		// Add website.
		$website = get_post_meta( $this->artist->ID, '_fedistream_artist_website', true );
		if ( $website ) {
			$attachments[] = array(
				'type'  => 'PropertyValue',
				'name'  => __( 'Website', 'wp-fedistream' ),
				'value' => sprintf( '<a href="%s" rel="me nofollow noopener" target="_blank">%s</a>', esc_url( $website ), esc_html( $website ) ),
			);
		}

		// Add location.
		$location = get_post_meta( $this->artist->ID, '_fedistream_artist_location', true );
		if ( $location ) {
			$attachments[] = array(
				'type'  => 'PropertyValue',
				'name'  => __( 'Location', 'wp-fedistream' ),
				'value' => esc_html( $location ),
			);
		}

		// Add social links.
		$social_links = get_post_meta( $this->artist->ID, '_fedistream_artist_social_links', true );
		if ( is_array( $social_links ) ) {
			foreach ( $social_links as $link ) {
				$platform = $link['platform'] ?? '';
				$url      = $link['url'] ?? '';

				if ( $platform && $url ) {
					$attachments[] = array(
						'type'  => 'PropertyValue',
						'name'  => esc_html( ucfirst( $platform ) ),
						'value' => sprintf( '<a href="%s" rel="me nofollow noopener" target="_blank">%s</a>', esc_url( $url ), esc_html( $url ) ),
					);
				}
			}
		}

		// Add formed date.
		$formed = get_post_meta( $this->artist->ID, '_fedistream_artist_formed_date', true );
		if ( $formed ) {
			$attachments[] = array(
				'type'  => 'PropertyValue',
				'name'  => __( 'Active Since', 'wp-fedistream' ),
				'value' => esc_html( $formed ),
			);
		}

		return $attachments;
	}

	/**
	 * Get the full actor object as an array.
	 *
	 * @return array
	 */
	public function to_array(): array {
		$actor = array(
			'@context'          => array(
				'https://www.w3.org/ns/activitystreams',
				'https://w3id.org/security/v1',
				array(
					'manuallyApprovesFollowers' => 'as:manuallyApprovesFollowers',
					'PropertyValue'             => 'schema:PropertyValue',
					'value'                     => 'schema:value',
				),
			),
			'id'                => $this->get_id(),
			'type'              => $this->get_type(),
			'preferredUsername' => $this->get_preferred_username(),
			'name'              => $this->get_name(),
			'summary'           => $this->get_summary(),
			'url'               => $this->get_url(),
			'inbox'             => $this->get_inbox(),
			'outbox'            => $this->get_outbox(),
			'followers'         => $this->get_followers(),
			'following'         => $this->get_following(),
			'publicKey'         => $this->get_public_key(),
			'manuallyApprovesFollowers' => false,
			'published'         => get_the_date( 'c', $this->artist ),
			'updated'           => get_the_modified_date( 'c', $this->artist ),
		);

		// Add icon if available.
		$icon = $this->get_icon();
		if ( $icon ) {
			$actor['icon'] = $icon;
		}

		// Add image if available.
		$image = $this->get_image();
		if ( $image ) {
			$actor['image'] = $image;
		}

		// Add attachments.
		$attachments = $this->get_attachment();
		if ( ! empty( $attachments ) ) {
			$actor['attachment'] = $attachments;
		}

		return $actor;
	}

	/**
	 * Get webfinger data for the artist.
	 *
	 * @return array
	 */
	public function get_webfinger(): array {
		$host     = wp_parse_url( home_url(), PHP_URL_HOST );
		$resource = 'acct:' . $this->get_preferred_username() . '@' . $host;

		return array(
			'subject' => $resource,
			'aliases' => array(
				$this->get_id(),
				$this->get_url(),
			),
			'links'   => array(
				array(
					'rel'  => 'self',
					'type' => 'application/activity+json',
					'href' => $this->get_id(),
				),
				array(
					'rel'  => 'http://webfinger.net/rel/profile-page',
					'type' => 'text/html',
					'href' => $this->get_url(),
				),
			),
		);
	}

	/**
	 * Get the outbox collection.
	 *
	 * @param int $page The page number (0 for summary).
	 * @param int $per_page Items per page.
	 * @return array
	 */
	public function get_outbox_collection( int $page = 0, int $per_page = 20 ): array {
		// Get all tracks and albums by this artist.
		$args = array(
			'post_type'      => array( 'fedistream_track', 'fedistream_album' ),
			'post_status'    => 'publish',
			'posts_per_page' => -1,
			'meta_query'     => array( // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query
				'relation' => 'OR',
				array(
					'key'   => '_fedistream_album_artist',
					'value' => $this->artist->ID,
				),
				array(
					'key'     => '_fedistream_artist_ids',
					'value'   => $this->artist->ID,
					'compare' => 'LIKE',
				),
			),
		);

		$query = new \WP_Query( $args );
		$total = $query->found_posts;

		// Return summary if page 0.
		if ( $page === 0 ) {
			return array(
				'@context'   => 'https://www.w3.org/ns/activitystreams',
				'id'         => $this->get_outbox(),
				'type'       => 'OrderedCollection',
				'totalItems' => $total,
				'first'      => $this->get_outbox() . '?page=1',
				'last'       => $this->get_outbox() . '?page=' . max( 1, ceil( $total / $per_page ) ),
			);
		}

		// Get paginated items.
		$args['posts_per_page'] = $per_page;
		$args['paged']          = $page;
		$args['orderby']        = 'date';
		$args['order']          = 'DESC';

		$query = new \WP_Query( $args );
		$items = array();

		foreach ( $query->posts as $post ) {
			$items[] = $this->post_to_create_activity( $post );
		}

		$collection = array(
			'@context'     => 'https://www.w3.org/ns/activitystreams',
			'id'           => $this->get_outbox() . '?page=' . $page,
			'type'         => 'OrderedCollectionPage',
			'partOf'       => $this->get_outbox(),
			'orderedItems' => $items,
		);

		// Add prev/next links.
		if ( $page > 1 ) {
			$collection['prev'] = $this->get_outbox() . '?page=' . ( $page - 1 );
		}

		$total_pages = ceil( $total / $per_page );
		if ( $page < $total_pages ) {
			$collection['next'] = $this->get_outbox() . '?page=' . ( $page + 1 );
		}

		return $collection;
	}

	/**
	 * Convert a post to a Create activity.
	 *
	 * @param \WP_Post $post The post.
	 * @return array
	 */
	private function post_to_create_activity( \WP_Post $post ): array {
		$object = array(
			'type'         => 'fedistream_track' === $post->post_type ? 'Audio' : 'Collection',
			'id'           => get_permalink( $post->ID ),
			'name'         => $post->post_title,
			'content'      => wp_strip_all_tags( $post->post_content ),
			'attributedTo' => $this->get_id(),
			'published'    => get_the_date( 'c', $post ),
			'url'          => get_permalink( $post->ID ),
		);

		// Add track-specific properties.
		if ( 'fedistream_track' === $post->post_type ) {
			$duration = get_post_meta( $post->ID, '_fedistream_duration', true );
			if ( $duration ) {
				$object['duration'] = $this->format_duration_iso8601( (int) $duration );
			}

			$audio_id  = get_post_meta( $post->ID, '_fedistream_audio_file', true );
			$audio_url = $audio_id ? wp_get_attachment_url( $audio_id ) : '';
			if ( $audio_url ) {
				$object['attachment'] = array(
					'type'      => 'Audio',
					'mediaType' => 'audio/mpeg',
					'url'       => $audio_url,
				);
			}
		}

		// Add thumbnail.
		$thumbnail_id = get_post_thumbnail_id( $post->ID );
		if ( $thumbnail_id ) {
			$image = wp_get_attachment_image_src( $thumbnail_id, 'medium' );
			if ( $image ) {
				$object['image'] = array(
					'type'      => 'Image',
					'mediaType' => get_post_mime_type( $thumbnail_id ),
					'url'       => $image[0],
				);
			}
		}

		return array(
			'type'      => 'Create',
			'id'        => get_permalink( $post->ID ) . '#activity-create',
			'actor'     => $this->get_id(),
			'published' => get_the_date( 'c', $post ),
			'object'    => $object,
		);
	}

	/**
	 * Format duration as ISO 8601.
	 *
	 * @param int $seconds The duration in seconds.
	 * @return string ISO 8601 duration.
	 */
	private function format_duration_iso8601( int $seconds ): string {
		$hours   = floor( $seconds / 3600 );
		$minutes = floor( ( $seconds % 3600 ) / 60 );
		$secs    = $seconds % 60;

		$duration = 'PT';
		if ( $hours > 0 ) {
			$duration .= $hours . 'H';
		}
		if ( $minutes > 0 ) {
			$duration .= $minutes . 'M';
		}
		if ( $secs > 0 || ( $hours === 0 && $minutes === 0 ) ) {
			$duration .= $secs . 'S';
		}

		return $duration;
	}

	/**
	 * Get the followers collection.
	 *
	 * @param int $page The page number (0 for summary).
	 * @param int $per_page Items per page.
	 * @return array
	 */
	public function get_followers_collection( int $page = 0, int $per_page = 20 ): array {
		global $wpdb;

		$table = $wpdb->prefix . 'fedistream_followers';

		// Get total count.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
		$total = (int) $wpdb->get_var(
			$wpdb->prepare(
				"SELECT COUNT(*) FROM {$table} WHERE artist_id = %d",
				$this->artist->ID
			)
		);

		// Return summary if page 0.
		if ( $page === 0 ) {
			return array(
				'@context'   => 'https://www.w3.org/ns/activitystreams',
				'id'         => $this->get_followers(),
				'type'       => 'OrderedCollection',
				'totalItems' => $total,
				'first'      => $this->get_followers() . '?page=1',
			);
		}

		// Get paginated items.
		$offset = ( $page - 1 ) * $per_page;

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
		$followers = $wpdb->get_col(
			$wpdb->prepare(
				"SELECT follower_uri FROM {$table} WHERE artist_id = %d ORDER BY followed_at DESC LIMIT %d OFFSET %d",
				$this->artist->ID,
				$per_page,
				$offset
			)
		);

		$collection = array(
			'@context'     => 'https://www.w3.org/ns/activitystreams',
			'id'           => $this->get_followers() . '?page=' . $page,
			'type'         => 'OrderedCollectionPage',
			'partOf'       => $this->get_followers(),
			'orderedItems' => $followers ?: array(),
		);

		// Add prev/next links.
		if ( $page > 1 ) {
			$collection['prev'] = $this->get_followers() . '?page=' . ( $page - 1 );
		}

		$total_pages = ceil( $total / $per_page );
		if ( $page < $total_pages ) {
			$collection['next'] = $this->get_followers() . '?page=' . ( $page + 1 );
		}

		return $collection;
	}
}