<?php
/**
 * Removes everything Stand Chat stored in WordPress.
 *
 * Stand data (the Site, Stand-ins, knowledge, History) is not deleted; manage
 * or delete it in the Stand app at app.stand.chat.
 *
 * @package StandChat
 */

defined( 'WP_UNINSTALL_PLUGIN' ) || exit;

/**
 * Cleans one site.
 */
function stand_chat_uninstall_site() {
	// End the Stand sessions WordPress kept: the current one and any Stand
	// couldn't be told about before. Nothing can try again once the plugin is
	// gone, so each request waits for Stand's answer; a session Stand can't be
	// told about now ends at its 30-day cap.
	$stored_token = get_option( 'stand_chat_token' );
	$revocations  = (array) get_option( 'stand_chat_revocations', array() );
	if ( file_exists( __DIR__ . '/includes/class-secret-store.php' ) ) {
		require_once __DIR__ . '/includes/class-service-urls.php';
		require_once __DIR__ . '/includes/class-secret-store.php';
		require_once __DIR__ . '/includes/class-connection.php';
		$refresh_tokens = array();
		$plain          = is_string( $stored_token ) && '' !== $stored_token ? \StandChat\Secret_Store::decrypt( $stored_token ) : null;
		$tokens         = null === $plain ? null : json_decode( $plain, true );
		if ( is_array( $tokens ) && ! empty( $tokens['refresh_token'] ) ) {
			$refresh_tokens[] = (string) $tokens['refresh_token'];
		}
		foreach ( $revocations as $queued ) {
			$token = \StandChat\Secret_Store::decrypt( (string) $queued );
			if ( null !== $token ) {
				$refresh_tokens[] = $token;
			}
		}
		foreach ( $refresh_tokens as $refresh_token ) {
			// Stand answered, though maybe that the session had already ended,
			// unless it couldn't be reached or was busy (429, 5xx): then it gets
			// one more try.
			$answered = false;
			for ( $attempt = 0; $attempt < 2 && ! $answered; ++$attempt ) {
				$response = wp_remote_post(
					untrailingslashit( \StandChat\Service_Urls::get( 'server_auth' ) ) . '/protocol/openid-connect/revoke',
					array(
						'timeout' => 5,
						'body'    => array(
							'client_id'       => \StandChat\Connection::client_id(),
							'token'           => $refresh_token,
							'token_type_hint' => 'refresh_token',
						),
					)
				);
				$code     = is_wp_error( $response ) ? 0 : (int) wp_remote_retrieve_response_code( $response );
				$answered = $code > 0 && 429 !== $code && $code < 500;
			}
			if ( ! $answered ) {
				// Stand can't take it now, so the rest would wait in vain.
				break;
			}
		}
	}

	foreach ( array( 'stand_chat_settings', 'stand_chat_state', 'stand_chat_connection', 'stand_chat_token', 'stand_chat_revocations', 'stand_chat_identity_secret', 'stand_chat_cache_generation', 'stand_chat_source_removals', 'stand_chat_adding', 'stand_chat_claims' ) as $option ) {
		delete_option( $option );
	}
	delete_transient( 'stand_chat_activation_redirect' );
	delete_transient( 'stand_chat_api_backoff' );

	global $wpdb;
	// Cached Stand responses and connect attempts are transients named stand_chat_*.
	// There is no API to list transients; delete each through the API so caches clear too.
	// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- One-time cleanup.
	$stand_chat_transients = $wpdb->get_col( "SELECT option_name FROM {$wpdb->options} WHERE option_name LIKE '\\_transient\\_stand\\_chat\\_%'" );
	foreach ( (array) $stand_chat_transients as $stand_chat_transient ) {
		delete_transient( substr( (string) $stand_chat_transient, strlen( '_transient_' ) ) );
	}
	foreach ( array( '_stand_chat_source_id', '_stand_chat_source_url', '_stand_chat_read_requested' ) as $meta_key ) {
		delete_post_meta_by_key( $meta_key );
	}
	// Rereads are scheduled for each page: every event of the hook goes, whatever its arguments.
	wp_unschedule_hook( 'stand_chat_read_again' );
	wp_unschedule_hook( 'stand_chat_retry_removals' );
	wp_unschedule_hook( 'stand_chat_retry_revocations' );
}

if ( is_multisite() ) {
	// Every site, 100 at a time: get_sites() returns 100 unless told otherwise.
	$stand_chat_offset = 0;
	do {
		$stand_chat_blog_ids = get_sites(
			array(
				'fields'  => 'ids',
				'number'  => 100,
				'offset'  => $stand_chat_offset,
				'orderby' => 'id',
			)
		);
		foreach ( $stand_chat_blog_ids as $stand_chat_blog_id ) {
			switch_to_blog( (int) $stand_chat_blog_id );
			stand_chat_uninstall_site();
			restore_current_blog();
		}
		$stand_chat_offset += 100;
		$stand_chat_more    = 100 === count( $stand_chat_blog_ids );
	} while ( $stand_chat_more );
} else {
	stand_chat_uninstall_site();
}