<?php
/**
 * Per page dropdown for our list table screens (Manage, Imports, Folders)
 */

namespace PluginRx\AdminHelpDocs;

if ( ! defined( 'ABSPATH' ) ) exit;

class PerPage {

    /**
     * Available choices
     *
     * @var array
     */
    public static $choices = [ 10, 20, 50, 100 ];


    /**
     * Default (matches WordPress core)
     *
     * @var int
     */
    public static $default = 20;


    /**
     * User meta key, query arg, and nonce action
     *
     * @var string
     */
    private $key = 'helpdocs_per_page';


    /**
     * The single instance of the class
     *
     * @var self|null
     */
    private static ?PerPage $instance = null;


    /**
     * Get the singleton instance
     *
     * @return self
     */
    public static function instance() : self {
        return self::$instance ??= new self();
    } // End instance()


    /**
     * Constructor
     */
    private function __construct() {

        add_action( 'load-edit.php', [ $this, 'maybe_save' ] );
        add_action( 'load-edit-tags.php', [ $this, 'maybe_save' ] );
        add_filter( 'edit_posts_per_page', [ $this, 'filter_posts_per_page' ], 10, 2 );
        add_filter( 'edit_tags_per_page', [ $this, 'filter_tags_per_page' ] );
        add_action( 'admin_enqueue_scripts', [ $this, 'enqueue_scripts' ] );
        add_action( 'manage_posts_extra_tablenav', [ $this, 'render_field' ] );

    } // End __construct()


    /**
     * Is this one of our list table screens?
     *
     * @param \WP_Screen|null $screen
     * @return bool
     */
    private function is_our_screen( $screen ) : bool {
        if ( ! $screen ) {
            return false;
        }

        $ids = [ 'edit-' . HelpDocs::$post_type, 'edit-' . Imports::$post_type, 'edit-' . Folders::$taxonomy ];

        return in_array( $screen->id, $ids, true );
    } // End is_our_screen()


    /**
     * Get the saved per page value for the current user, or 0 if none
     *
     * @return int
     */
    private function get_saved() : int {
        $value = absint( get_user_meta( get_current_user_id(), $this->key, true ) );

        return in_array( $value, self::$choices, true ) ? $value : 0;
    } // End get_saved()


    /**
     * Save the selection from the dropdown and redirect to a clean URL
     *
     * @return void
     */
    public function maybe_save() {
        if ( ! isset( $_GET[ $this->key ] ) || ! $this->is_our_screen( get_current_screen() ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
            return;
        }

        check_admin_referer( $this->key );

        $value = absint( wp_unslash( $_GET[ $this->key ] ) );
        if ( in_array( $value, self::$choices, true ) ) {
            update_user_meta( get_current_user_id(), $this->key, $value );
        }

        wp_safe_redirect( remove_query_arg( [ $this->key, '_wpnonce', 'paged' ] ) );
        exit;
    } // End maybe_save()


    /**
     * Apply the saved value to our post type list tables
     *
     * @param int $per_page
     * @param string $post_type
     * @return int
     */
    public function filter_posts_per_page( $per_page, $post_type ) {
        if ( ! in_array( $post_type, [ HelpDocs::$post_type, Imports::$post_type ], true ) ) {
            return $per_page;
        }

        $saved = $this->get_saved();

        return $saved ? $saved : $per_page;
    } // End filter_posts_per_page()


    /**
     * Apply the saved value to the Folders list table
     *
     * @param int $per_page
     * @return int
     */
    public function filter_tags_per_page( $per_page ) {
        $screen = get_current_screen();
        if ( ! $screen || $screen->id !== 'edit-' . Folders::$taxonomy ) {
            return $per_page;
        }

        $saved = $this->get_saved();

        return $saved ? $saved : $per_page;
    } // End filter_tags_per_page()


    /**
     * Render the dropdown server side on our post type list tables
     *
     * @param string $which
     * @return void
     */
    public function render_field( $which ) {
        $screen = get_current_screen();
        if ( ! $screen || ! in_array( $screen->post_type, [ HelpDocs::$post_type, Imports::$post_type ], true ) ) {
            return;
        }

        $id = 'helpdocs-per-page-' . sanitize_key( $which );
        $current = $this->get_saved() ?: self::$default;
        ?>
        <div class="alignleft actions">
            <label for="<?php echo esc_attr( $id ); ?>" class="screen-reader-text"><?php esc_html_e( 'Items per page', 'admin-help-docs' ); ?></label>
            <select id="<?php echo esc_attr( $id ); ?>" class="helpdocs-per-page">
                <?php foreach ( self::$choices as $choice ) : ?>
                    <option value="<?php echo esc_attr( $choice ); ?>" <?php selected( $current, $choice ); ?>>
                        <?php
                        /* translators: %d: number of items */
                        echo esc_html( sprintf( __( '%d per page', 'admin-help-docs' ), $choice ) );
                        ?>
                    </option>
                <?php endforeach; ?>
            </select>
        </div>
        <?php
    } // End render_field()


    /**
     * Enqueue the script on our list screens
     *
     * @param string $hook_suffix
     * @return void
     */
    public function enqueue_scripts( $hook_suffix ) {
        $screen = get_current_screen();
        if ( ! in_array( $hook_suffix, [ 'edit.php', 'edit-tags.php' ], true ) || ! $this->is_our_screen( $screen ) ) {
            return;
        }

        $handle = Bootstrap::textdomain() . '-per-page';

        wp_enqueue_script( $handle, Bootstrap::url( 'inc/js/per-page.js' ), [ 'jquery' ], Bootstrap::script_version(), true );

        wp_localize_script( $handle, 'helpdocs_per_page', [
            'inject'  => $screen->id === 'edit-' . Folders::$taxonomy,
            'choices' => self::$choices,
            'current' => $this->get_saved() ?: self::$default,
            'key'     => $this->key,
            'nonce'   => wp_create_nonce( $this->key ),
            'text'    => [
                'label'  => __( 'Items per page', 'admin-help-docs' ),
                'option' => __( '%d per page', 'admin-help-docs' ),
            ],
        ] );
    } // End enqueue_scripts()

}


PerPage::instance();