<?php
/**
 * Breadcrumb Schema Generator
 * Free feature — BreadcrumbList JSON-LD + shortcode + Gutenberg block
 *
 * @package ShadowSync_SEO
 */

if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

class ShadowSync_SEO_Breadcrumbs {

    public function __construct() {
        add_action( 'wp_head',   [ $this, 'output_breadcrumb_schema' ], 5 );
        add_shortcode( 'shadowsync_seo_breadcrumbs', [ $this, 'render_breadcrumb_html' ] );
        add_action( 'init',      [ $this, 'register_block' ] );
    }

    // ── BUILD BREADCRUMB TRAIL ──────────────────────────────

    private function get_trail() {
        $trail = [];

        $trail[] = [
            'name' => get_bloginfo( 'name' ),
            'url'  => home_url( '/' ),
        ];

        if ( is_front_page() ) {
            return $trail;
        }

        if ( is_singular( 'post' ) ) {
            $categories = get_the_category();
            if ( ! empty( $categories ) ) {
                $cat = $categories[0];
                if ( $cat->parent ) {
                    $ancestors = array_reverse( get_ancestors( $cat->term_id, 'category' ) );
                    foreach ( $ancestors as $ancestor_id ) {
                        $ancestor = get_term( $ancestor_id, 'category' );
                        $trail[]  = [
                            'name' => $ancestor->name,
                            'url'  => get_term_link( $ancestor ),
                        ];
                    }
                }
                $trail[] = [
                    'name' => $cat->name,
                    'url'  => get_term_link( $cat ),
                ];
            }
            $trail[] = [
                'name' => get_the_title(),
                'url'  => get_permalink(),
            ];

        } elseif ( is_singular( 'page' ) ) {
            global $post;
            $ancestors = get_post_ancestors( $post );
            $ancestors = array_reverse( $ancestors );

            foreach ( $ancestors as $ancestor_id ) {
                $trail[] = [
                    'name' => get_the_title( $ancestor_id ),
                    'url'  => get_permalink( $ancestor_id ),
                ];
            }

            $trail[] = [
                'name' => get_the_title(),
                'url'  => get_permalink(),
            ];

        } elseif ( is_singular() ) {
            $post_type        = get_post_type();
            $post_type_object = get_post_type_object( $post_type );
            if ( $post_type_object && $post_type_object->has_archive ) {
                $trail[] = [
                    'name' => $post_type_object->labels->name,
                    'url'  => get_post_type_archive_link( $post_type ),
                ];
            }
            $trail[] = [
                'name' => get_the_title(),
                'url'  => get_permalink(),
            ];

        } elseif ( is_category() || is_tag() || is_tax() ) {
            $term = get_queried_object();
            if ( $term && $term->parent ) {
                $ancestors = array_reverse( get_ancestors( $term->term_id, $term->taxonomy ) );
                foreach ( $ancestors as $ancestor_id ) {
                    $ancestor = get_term( $ancestor_id, $term->taxonomy );
                    $trail[]  = [
                        'name' => $ancestor->name,
                        'url'  => get_term_link( $ancestor ),
                    ];
                }
            }
            $trail[] = [
                'name' => $term ? $term->name : '',
                'url'  => $term ? get_term_link( $term ) : '',
            ];

        } elseif ( is_author() ) {
            $trail[] = [
                'name' => get_the_author_meta( 'display_name', get_queried_object_id() ),
                'url'  => get_author_posts_url( get_queried_object_id() ),
            ];

        } elseif ( is_search() ) {
            $trail[] = [
                /* translators: %s: search query */
                'name' => sprintf( __( 'Search results for "%s"', 'shadowsync-seo' ), get_search_query() ),
                'url'  => '',
            ];

        } elseif ( is_404() ) {
            $trail[] = [
                'name' => __( 'Page not found', 'shadowsync-seo' ),
                'url'  => '',
            ];
        }

        return $trail;
    }

    // ── OUTPUT JSON-LD SCHEMA ───────────────────────────────

    public function output_breadcrumb_schema() {
        if ( is_front_page() ) {
            return;
        }

        $trail = $this->get_trail();

        if ( count( $trail ) < 2 ) {
            return;
        }

        $items = [];
        foreach ( $trail as $index => $crumb ) {
            $item = [
                '@type'    => 'ListItem',
                'position' => $index + 1,
                'name'     => $crumb['name'],
            ];
            if ( ! empty( $crumb['url'] ) ) {
                $item['item'] = $crumb['url'];
            }
            $items[] = $item;
        }

        $schema = [
            '@context'        => 'https://schema.org',
            '@type'           => 'BreadcrumbList',
            'itemListElement' => $items,
        ];

        echo '<script type="application/ld+json">' . wp_json_encode( $schema, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_HEX_TAG | JSON_HEX_AMP ) . '</script>' . "\n";
    }

    // ── RENDER VISIBLE HTML BREADCRUMBS ─────────────────────

    public function render_breadcrumb_html( $atts = [] ) {
        $atts = shortcode_atts( [
            'separator' => '›',
        ], $atts );

        $trail = $this->get_trail();

        if ( count( $trail ) < 2 ) {
            return '';
        }

        $html  = '<nav class="shadowsync-seo-breadcrumbs" aria-label="' . esc_attr__( 'Breadcrumb', 'shadowsync-seo' ) . '">';
        $total = count( $trail );

        foreach ( $trail as $index => $crumb ) {
            $is_last = ( $index === $total - 1 );

            if ( $is_last || empty( $crumb['url'] ) ) {
                $html .= '<span class="shadowsync-seo-crumb-current">' . esc_html( $crumb['name'] ) . '</span>';
            } else {
                $html .= '<a href="' . esc_url( $crumb['url'] ) . '" class="shadowsync-seo-crumb-link">' . esc_html( $crumb['name'] ) . '</a>';
                $html .= ' <span class="shadowsync-seo-crumb-sep">' . esc_html( $atts['separator'] ) . '</span> ';
            }
        }

        $html .= '</nav>';

        return $html;
    }

    // ── GUTENBERG BLOCK ──────────────────────────────────────

    public function register_block() {
        if ( ! function_exists( 'register_block_type' ) ) {
            return;
        }

        // Without an editor script the block exists only on the server and
        // never appears in the block inserter.
        wp_register_script(
            'shadowsync-seo-breadcrumbs-block',
            SHADOWSYNC_SEO_URL . 'assets/breadcrumbs-block.js',
            [ 'wp-blocks', 'wp-element', 'wp-server-side-render', 'wp-i18n', 'wp-block-editor' ],
            SHADOWSYNC_SEO_VERSION,
            true
        );

        register_block_type( 'shadowsync-seo/breadcrumbs', [
            'editor_script'   => 'shadowsync-seo-breadcrumbs-block',
            'render_callback' => [ $this, 'render_breadcrumb_html' ],
        ] );
    }
}