<?php
/**
 * Permalink structure, read and written from Oorank's own screens.
 *
 * Plain permalinks are the one setting that silently disables half of this
 * plugin: the virtual /llms.txt and /llms-full.txt endpoints need rewrite
 * rules, and without them Oorank has to fall back to writing physical files
 * into the site root. Sending an owner to Settings → Permalinks to fix that
 * means leaving the screen that reported the problem, so the choice is
 * offered where the warning is.
 *
 * Only the structures WordPress itself offers are accepted. A free-text
 * pattern is a footgun — a structure that starts with %postname% collides
 * with every page on the site — and an owner who wants one has the core
 * screen, which this module links to rather than replaces. A site already
 * running a custom structure keeps it: it is listed as the current choice so
 * saving something else is deliberate, never a side effect of opening the
 * drawer.
 *
 * @package Oorank
 */

defined( 'ABSPATH' ) || exit;

/**
 * Reads the permalink structure and writes one of WordPress's own presets.
 */
class Oorank_Permalinks {

	/**
	 * Register hooks.
	 */
	public function hooks() {
		add_action( 'rest_api_init', array( $this, 'register_routes' ) );
	}

	/**
	 * POST /permalinks — write the structure.
	 *
	 * Gated on `manage_options` rather than Oorank's own capability: the
	 * permalink structure belongs to the whole site, and an editor granted
	 * Oorank's screens has no business rewriting every URL on it.
	 */
	public function register_routes() {
		register_rest_route(
			Oorank_Rest::NAMESPACE,
			'/permalinks',
			array(
				'methods'             => WP_REST_Server::CREATABLE,
				'callback'            => array( $this, 'rest_update' ),
				'permission_callback' => static function () {
					return current_user_can( 'manage_options' );
				},
				'args'                => array(
					'key' => array(
						'required' => true,
						'type'     => 'string',
					),
				),
			)
		);
	}

	/**
	 * The presets, in the order the core screen lists them.
	 *
	 * Structures are stored without the leading slash WordPress adds itself,
	 * matching what `options-permalink.php` writes.
	 *
	 * @return array<string, string> key => structure.
	 */
	private static function presets() {
		return array(
			'plain'          => '',
			'day-and-name'   => '/%year%/%monthnum%/%day%/%postname%/',
			'month-and-name' => '/%year%/%monthnum%/%postname%/',
			'numeric'        => '/archives/%post_id%',
			'post-name'      => '/%postname%/',
		);
	}

	/**
	 * Human labels for the presets.
	 *
	 * @return array<string, string> key => label.
	 */
	private static function labels() {
		return array(
			'plain'          => __( 'Plain', 'oorank' ),
			'day-and-name'   => __( 'Day and name', 'oorank' ),
			'month-and-name' => __( 'Month and name', 'oorank' ),
			'numeric'        => __( 'Numeric', 'oorank' ),
			'post-name'      => __( 'Post name', 'oorank' ),
		);
	}

	/**
	 * What a URL looks like under each structure.
	 *
	 * Built the way the core screen builds it — real home URL, today's date,
	 * a sample slug — so the preview is the address the owner will actually
	 * see rather than a template full of percent signs.
	 *
	 * @param string $structure Permalink structure.
	 * @return string Example URL.
	 */
	private static function preview( $structure ) {
		$home = home_url( '/' );

		if ( '' === $structure ) {
			return $home . '?p=123';
		}

		$path = str_replace(
			array( '%year%', '%monthnum%', '%day%', '%postname%', '%post_id%' ),
			array( gmdate( 'Y' ), gmdate( 'm' ), gmdate( 'd' ), 'sample-post', '123' ),
			$structure
		);

		return $home . ltrim( $path, '/' );
	}

	/**
	 * Everything the admin app needs to render the choice.
	 *
	 * A custom structure the site already runs is appended as its own option
	 * so the list always contains the current setting; selecting anything
	 * else is then an explicit choice to abandon it.
	 *
	 * @return array{current:string, structure:string, pretty:bool, choices:array}
	 */
	public static function status() {
		$structure = (string) get_option( 'permalink_structure', '' );
		$presets   = self::presets();
		$labels    = self::labels();
		$current   = array_search( $structure, $presets, true );
		$choices   = array();

		foreach ( $presets as $key => $preset ) {
			$choices[] = array(
				'key'       => $key,
				'label'     => $labels[ $key ],
				'structure' => $preset,
				'preview'   => self::preview( $preset ),
			);
		}

		if ( false === $current ) {
			$current   = 'custom';
			$choices[] = array(
				'key'       => 'custom',
				'label'     => __( 'Custom structure', 'oorank' ),
				'structure' => $structure,
				'preview'   => self::preview( $structure ),
			);
		}

		return array(
			'current'   => $current,
			'structure' => $structure,
			'pretty'    => '' !== $structure,
			'choices'   => $choices,
		);
	}

	/**
	 * POST /permalinks handler.
	 *
	 * `flush_rules( true )` is the hard flush: it rewrites .htaccess on Apache
	 * where the file is writable, which is what makes the virtual endpoints
	 * answer without a second visit to Settings → Permalinks. Where it is not
	 * writable the rules still land in the database and WordPress prints its
	 * own instructions on the core screen, which is why the drawer keeps a
	 * link to it.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function rest_update( WP_REST_Request $request ) {
		$key     = sanitize_key( (string) $request->get_param( 'key' ) );
		$presets = self::presets();

		if ( ! isset( $presets[ $key ] ) ) {
			return new WP_Error(
				'oorank_bad_permalink',
				__( 'That is not one of the permalink structures Oorank can set. Use the WordPress permalink screen for a custom structure.', 'oorank' ),
				array( 'status' => 400 )
			);
		}

		require_once ABSPATH . 'wp-admin/includes/file.php';
		require_once ABSPATH . 'wp-admin/includes/misc.php';

		global $wp_rewrite;

		$wp_rewrite->set_permalink_structure( $presets[ $key ] );
		$wp_rewrite->flush_rules( true );

		return rest_ensure_response(
			array(
				'saved'      => true,
				'permalinks' => self::status(),
			)
		);
	}
}