map->linksPerIndex = PHP_INT_MAX;

				if ( 1 === count( $chunks ) ) {
					$filename           = "$postType-$sitemapName.xml";
					$files[ $filename ] = [
						'total'   => $total,
						'entries' => $chunks[0]
					];
				} else {
					for ( $i = 1; $i <= count( $chunks ); $i++ ) {
						$filename           = "$postType-$sitemapName$i.xml";
						$files[ $filename ] = [
							'total'   => $total,
							'entries' => $chunks[ $i - 1 ]
						];
					}
				}
			}
		}

		$taxonomies = aioseo()->sitemap->helpers->includedTaxonomies();
		if ( $taxonomies ) {
			foreach ( $taxonomies as $taxonomy ) {
				aioseo()->sitemap->indexName = $taxonomy;

				$terms = aioseo()->sitemap->content->terms( $taxonomy );
				if ( ! $terms ) {
					continue;
				}

				$total = aioseo()->sitemap->query->terms( $taxonomy, [ 'count' => true ] );

				// We need to temporarily reset the linksPerIndex count here so that we can properly chunk.
				aioseo()->sitemap->linksPerIndex = aioseo()->options->sitemap->general->linksPerIndex;
				$chunks = aioseo()->sitemap->helpers->chunkEntries( $terms );
				aioseo()->sitemap->linksPerIndex = PHP_INT_MAX;

				if ( 1 === count( $chunks ) ) {
					$filename           = "$taxonomy-$sitemapName.xml";
					$files[ $filename ] = [
						'total'   => $total,
						'entries' => $chunks[0]
					];
				} else {
					for ( $i = 1; $i <= count( $chunks ); $i++ ) {
						$filename           = "$taxonomy-$sitemapName$i.xml";
						$files[ $filename ] = [
							'total'   => $total,
							'entries' => $chunks[ $i - 1 ]
						];
					}
				}
			}
		}
		$this->writeSitemaps( $files );
	}

	/**
	 * Writes all sitemap files.
	 *
	 * @since 4.0.0
	 *
	 * @param  array $files The sitemap files.
	 * @return void
	 */
	public function writeSitemaps( $files ) {
		$sitemapName = aioseo()->sitemap->helpers->filename();
		if ( aioseo()->sitemap->indexes ) {
			$indexes = [];
			foreach ( $files as $filename => $data ) {
				if ( empty( $data['entries'] ) ) {
					continue;
				}
				$indexes[] = [
					'loc'     => trailingslashit( home_url() ) . $filename,
					'lastmod' => array_values( $data['entries'] )[0]['lastmod'],
					'count'   => count( $data['entries'] )
				];
			}
			$files[ "$sitemapName.xml" ] = [
				'total'   => 0,
				'entries' => $indexes,
			];
			foreach ( $files as $filename => $data ) {
				$this->writeSitemap( $filename, $data['entries'], $data['total'] );
			}

			return;
		}

		$content = [];
		foreach ( $files as $filename => $data ) {
			foreach ( $data['entries'] as $entry ) {
				$content[] = $entry;
			}
		}
		$this->writeSitemap( "$sitemapName.xml", $content, count( $content ) );
	}

	/**
	 * Writes a given sitemap file to the root dir.
	 *
	 * Helper function for writeSitemaps().
	 *
	 * @since 4.0.0
	 *
	 * @param  string $filename The name of the file.
	 * @param  array  $entries  The sitemap entries for the file.
	 * @return void
	 */
	protected function writeSitemap( $filename, $entries, $total = 0 ) {
		$sitemapName                 = aioseo()->sitemap->helpers->filename();
		aioseo()->sitemap->indexName = $filename;
		if ( "$sitemapName.xml" === $filename && aioseo()->sitemap->indexes ) {
			// Set index name to root so that we use the right output template.
			aioseo()->sitemap->indexName = 'root';
		}

		aioseo()->sitemap->xsl->saveXslData( $filename, $entries, $total );

		ob_start();
		aioseo()->sitemap->output->output( $entries );
		aioseo()->addons->doAddonFunction( 'output', 'output', [ $entries, $total ] );
		$content = ob_get_clean();

		$fs         = aioseo()->core->fs;
		$file       = ABSPATH . sanitize_file_name( $filename );
		$fileExists = $fs->exists( $file );
		if ( ! $fileExists || $fs->isWritable( $file ) ) {
			$fs->putContents( $file, $content );
		}
	}

	/**
	 * Return an array of sitemap files.
	 *
	 * @since 4.0.0
	 *
	 * @return array An array of files.
	 */
	public function files() {
		require_once ABSPATH . 'wp-admin/includes/file.php';
		$files = list_files( get_home_path(), 1 );
		if ( ! count( $files ) ) {
			return [];
		}

		$sitemapFiles = [];
		foreach ( $files as $filename ) {
			if ( preg_match( '#.*sitemap.*#', $filename ) ) {
				$sitemapFiles[] = $filename;
			}
		}

		return $sitemapFiles;
	}
}