<?php
if ( ! defined( 'ABSPATH' ) ) { exit; }

class AIT_AIRCE_Cache {

    protected $logger;
    protected $recommender;

    public function __construct( $logger, $recommender ) {
        $this->logger = $logger;
        $this->recommender = $recommender;

        add_action( 'ait_airce_post_indexed', [ $this, 'invalidate_post_cache' ] );
    }

    public function invalidate_post_cache( $post_id ) {
        global $wpdb;
        $t_cache = AIT_AIRCE_DB::table( 'reco_cache' );
        $wpdb->delete( $t_cache, [ 'source_post_id' => intval( $post_id ), 'algo_version' => 1 ], [ '%d', '%d' ] );
    }

    /**
     * Generate and store related items for a post.
     */
    public function generate_for_post( $post_id, $context_key = 'default' ) {

        global $wpdb;

        $t_cache = AIT_AIRCE_DB::table( 'reco_cache' );

        $max_items = max( 1, intval( AIT_AIRCE_Settings::get( 'related_count' ) ) );

        $items = $this->recommender->get_related( $post_id, $max_items );

        $wpdb->replace(
            $t_cache,
            [
                'source_post_id'   => intval( $post_id ),
                'context_key'      => $context_key,
                'algo_version'     => 1,
                'generated_at_gmt' => gmdate( 'Y-m-d H:i:s' ),
                'items_json'       => wp_json_encode( $items ),
            ],
            [ '%d', '%s', '%d', '%s', '%s' ]
        );

        $this->logger->log( 'Generated cache', [ 'post_id' => $post_id, 'count' => count( $items ) ] );

        return $items;
    }

    /**
     * Read cache for a post.
     */
    public function get_cached( $post_id, $context_key = 'default' ) {

        global $wpdb;

        $t_cache = esc_sql( AIT_AIRCE_DB::table( 'reco_cache' ) );

        // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- table name from trusted source
        $row = $wpdb->get_row( $wpdb->prepare(
            "SELECT items_json FROM {$t_cache} WHERE source_post_id = %d AND context_key = %s AND algo_version = 1",
            intval( $post_id ),
            $context_key
        ), ARRAY_A );

        if ( ! $row ) { return null; }

        $items = json_decode( $row['items_json'], true );
        return is_array( $items ) ? $items : null;
    }

    /**
     * Admin AJAX tools
     */
    public function init_admin_tools_ajax() {
        add_action( 'wp_ajax_ait_airce_rebuild_index', [ $this, 'ajax_rebuild_index' ] );
        add_action( 'wp_ajax_ait_airce_regenerate_cache', [ $this, 'ajax_regenerate_cache' ] );
    }

    protected function verify_ajax() {
        if ( ! current_user_can( 'manage_options' ) ) {
            wp_send_json_error( [ 'message' => 'Forbidden' ], 403 );
        }
        check_ajax_referer( 'ait-airce-admin', 'nonce' );
    }

    public function ajax_rebuild_index() {

        $this->verify_ajax();

        // Batch: index first N eligible items to avoid timeouts (v1).
        $post_types = AIT_AIRCE_Settings::get_enabled_post_types();
        $limit = intval( AIT_AIRCE_Settings::get( 'index_max_items' ) );
        if ( $limit <= 0 ) { $limit = 100; }

        $q = new WP_Query( [
            'post_type'      => $post_types,
            'post_status'    => 'publish',
            'posts_per_page' => $limit,
            'fields'         => 'ids',
            'no_found_rows'  => true,
        ] );

        $logger = $this->logger;
        $extractor = new AIT_AIRCE_Content_Extractor();
        $ai = new AIT_AIRCE_AI_Embeddings( $logger );
        $indexer = new AIT_AIRCE_Indexer( $logger, $extractor, $ai );

        $indexed = 0;
        foreach ( (array) $q->posts as $pid ) {
            $res = $indexer->index_post( intval( $pid ) );
            if ( ! is_wp_error( $res ) ) {
                $indexed++;
            }
        }

        wp_send_json_success( [ 'message' => sprintf( 'Indexed %d item(s).', $indexed ) ] );
    }

    public function ajax_regenerate_cache() {

        $this->verify_ajax();

        $post_types = AIT_AIRCE_Settings::get_enabled_post_types();
        $limit = intval( AIT_AIRCE_Settings::get( 'index_max_items' ) );
        if ( $limit <= 0 ) { $limit = 100; }

        $q = new WP_Query( [
            'post_type'      => $post_types,
            'post_status'    => 'publish',
            'posts_per_page' => $limit,
            'fields'         => 'ids',
            'no_found_rows'  => true,
        ] );

        $generated = 0;
        foreach ( (array) $q->posts as $pid ) {
            $this->generate_for_post( intval( $pid ) );
            $generated++;
        }

        wp_send_json_success( [ 'message' => sprintf( 'Generated cache for %d item(s).', $generated ) ] );
    }
}