*
	 * @param string $email_type The email type.
	 * @return int The post ID of the generated template.
	 * @throws \Exception When post creation fails.
	 */
	public function generate_email_template_if_not_exists( $email_type ) {
		$email_data = $this->default_templates[ $email_type ];

		if ( $this->template_manager->get_email_template_post_id( $email_type ) || empty( $email_data ) ) {
			return $this->template_manager->get_email_template_post_id( $email_type );
		}

		return $this->generate_single_template( $email_type, $email_data );
	}

	/**
	 * Generate email templates.
	 *
	 * This function generates the email templates for the given email types.
	 *
	 * @param array $templates_to_generate The email types to generate.
	 */
	public function generate_email_templates( $templates_to_generate ) {
		global $wpdb;

		$core_emails = array_filter(
			$this->default_templates,
			function ( $email_id ) use ( $templates_to_generate ) {
				return in_array( $email_id, $templates_to_generate, true );
			},
			ARRAY_FILTER_USE_KEY
		);

		if ( empty( $core_emails ) ) {
			return false;
		}

		// Start transaction.
		$wpdb->query( 'START TRANSACTION' );

		try {
			foreach ( $core_emails as $email_type => $email_data ) {
				$this->generate_single_template( $email_type, $email_data );
			}

			$wpdb->query( 'COMMIT' );
			return true;

		} catch ( \Exception $e ) {
			$wpdb->query( 'ROLLBACK' );
			return new \WP_Error( 'email_generation_failed', $e->getMessage() );
		}
	}

	/**
	 * Build the `wp_insert_post()` payload for a given email and apply the
	 * `woocommerce_email_content_post_data` filter.
	 *
	 * Extracted so the generator and the divergence detector observe the exact
	 * same pre-insert post payload, guaranteeing by construction that the hash
	 * stamped in {@see self::generate_single_template()} and the hash recomputed
	 * in `WCEmailTemplateDivergenceDetector` hash identical input.
	 *
	 * @param string    $email_type The email type identifier (e.g. `customer_processing_order`).
	 * @param \WC_Email $email      The transactional email instance.
	 * @return array The post data array after the `woocommerce_email_content_post_data` filter runs.
	 *
	 * @since 10.8.0
	 */
	public static function build_filtered_post_data( string $email_type, $email ): array {
		$post_data = array(
			'post_type'    => Integration::EMAIL_POST_TYPE,
			'post_status'  => 'publish',
			'post_name'    => $email_type,
			'post_title'   => $email->get_title(),
			'post_excerpt' => $email->get_description(),
			'post_content' => self::render_block_template_html( $email ),
			'meta_input'   => array(
				'_wp_page_template' => ( new WooEmailTemplate() )->get_slug(),
			),
		);

		/**
		 * Filter the email content post data before creating the post.
		 *
		 * Allows third-party integrators to modify the post data (title, content, meta, etc.)
		 * before the email content post is created.
		 *
		 * @since 10.5.0
		 * @param array     $post_data  The post data array to be used for wp_insert_post().
		 * @param string    $email_type The email type identifier (e.g., 'customer_processing_order').
		 * @param \WC_Email $email      The WooCommerce email object.
		 */
		$filtered_post_data = apply_filters( 'woocommerce_email_content_post_data', $post_data, $email_type, $email );

		return is_array( $filtered_post_data ) ? $filtered_post_data : $post_data;
	}

	/**
	 * Compute the canonical `post_content` for a given email.
	 *
	 * Returns the `post_content` value that the generator would persist for this
	 * email after the `woocommerce_email_content_post_data` filter runs, i.e.
	 * the exact string whose sha1 is stamped into `_wc_email_template_source_hash`.
	 *
	 * Callers can hash the return value to obtain `currentCoreHash` for
	 * divergence detection.
	 *
	 * @param \WC_Email $email The transactional email instance.
	 * @return string The canonical post content.
	 *
	 * @since 10.8.0
	 */
	public static function compute_canonical_post_content( $email ): string {
		$post_data = self::build_filtered_post_data( (string) $email->id, $email );
		return (string) ( $post_data['post_content'] ?? '' );
	}

	/**
	 * Generate a single email template.
	 *
	 * This function generates a single email template post and sets its postmeta association.
	 *
	 * @param string    $email_type    The email type.
	 * @param \WC_Email $email_data The transactional email data.
	 * @return int The post ID of the generated template.
	 * @throws \Exception When post creation fails.
	 */
	private function generate_single_template( $email_type, $email_data ) {
		$post_data = self::build_filtered_post_data( (string) $email_type, $email_data );

		// Sync meta stamp for emails participating in template update propagation.
		$sync_config = WCEmailTemplateSyncRegistry::get_email_sync_config( (string) $email_data->id );
		if ( null !== $sync_config ) {
			if ( ! isset( $post_data['meta_input'] ) || ! is_array( $post_data['meta_input'] ) ) {
				$post_data['meta_input'] = array();
			}
			$post_data['meta_input'][ WCEmailTemplateDivergenceDetector::VERSION_META_KEY ]          = (string) $sync_config['version'];
			$post_data['meta_input'][ WCEmailTemplateDivergenceDetector::SOURCE_HASH_META_KEY ]      = sha1( (string) ( $post_data['post_content'] ?? '' ) );
			$post_data['meta_input'][ WCEmailTemplateDivergenceDetector::LAST_SYNCED_AT_META_KEY ]   = gmdate( 'Y-m-d H:i:s' );
			$post_data['meta_input'][ WCEmailTemplateDivergenceDetector::LAST_CORE_RENDER_META_KEY ] = (string) ( $post_data['post_content'] ?? '' );
		}

		$post_id = wp_insert_post( $post_data, true );

		if ( is_wp_error( $post_id ) ) {
			throw new \Exception( esc_html( $post_id->get_error_message() ) );
		}

		$this->template_manager->save_email_template_post_id( $email_type, $post_id );

		return $post_id;
	}
}