<?php

namespace AcademicCrew\Members;

/**
 * Cached member counters shown on the profile hero and archive cards.
 *
 * Citations come only from the member's Google Scholar profile
 * (`_acc_citation_source = scholar`). There is no fallback: a sum of
 * per-publication counts (CrossRef etc.) is not comparable with Scholar, so a
 * member without a Scholar total shows no citation figure at all.
 */
class MemberStats {

    public const SOURCE_SCHOLAR = 'scholar';
    public const ERROR_META     = '_acc_scholar_error';
    public const SYNCED_META    = '_acc_scholar_synced';

    /** Remember (or clear, with '') why the last Scholar fetch failed. */
    public static function record_scholar_error( int $member_id, string $message ): void {
        if ( '' === $message ) {
            delete_post_meta( $member_id, self::ERROR_META );
            return;
        }
        update_post_meta( $member_id, self::ERROR_META, [ 'at' => current_time( 'mysql', true ), 'message' => $message ] );
    }

    /** Remember when Scholar was last fetched completely (queue order of the next full sync). */
    public static function mark_scholar_synced( int $member_id ): void {
        update_post_meta( $member_id, self::SYNCED_META, time() );
    }

    /** @return array{at:string,message:string}|null */
    public static function scholar_error( int $member_id ): ?array {
        $err = get_post_meta( $member_id, self::ERROR_META, true );
        return ( is_array( $err ) && ! empty( $err['message'] ) ) ? $err : null;
    }

    /** Recompute the publication count; drop a citation figure that isn't Scholar's. */
    public static function refresh( int $member_id ): void {
        global $wpdb;
        $rel_table = $wpdb->prefix . 'academiccrew_member_publications';

        $pub_count = (int) $wpdb->get_var( $wpdb->prepare(
            "SELECT COUNT(*) FROM {$rel_table} WHERE member_id = %d",
            $member_id
        ) );
        update_post_meta( $member_id, '_acc_pub_count', $pub_count );

        // Keep the last Scholar figures (a failed fetch must not blank them), but
        // only while the member still has a Scholar profile.
        if ( '' === (string) get_post_meta( $member_id, '_acc_scholar_id', true ) ) {
            self::clear_citations( $member_id );
            delete_post_meta( $member_id, '_acc_h_index' );
            delete_post_meta( $member_id, self::ERROR_META );
        } elseif ( self::SOURCE_SCHOLAR !== get_post_meta( $member_id, '_acc_citation_source', true ) ) {
            self::clear_citations( $member_id );
        }
    }

    public static function clear_citations( int $member_id ): void {
        delete_post_meta( $member_id, '_acc_citation_count' );
        delete_post_meta( $member_id, '_acc_citation_source' );
    }

    /** Store the Scholar profile totals (ignored when Scholar returned nothing). */
    public static function set_scholar( int $member_id, int $citations, int $h_index ): void {
        if ( $citations > 0 ) {
            update_post_meta( $member_id, '_acc_citation_count', $citations );
            update_post_meta( $member_id, '_acc_citation_source', self::SOURCE_SCHOLAR );
        }
        if ( $h_index > 0 ) {
            update_post_meta( $member_id, '_acc_h_index', $h_index );
        }
    }

    /** Where the citation total links to, or '' when it is a local sum. */
    public static function citation_url( int $member_id ): string {
        $scholar_id = (string) get_post_meta( $member_id, '_acc_scholar_id', true );
        if ( $scholar_id === '' || self::SOURCE_SCHOLAR !== get_post_meta( $member_id, '_acc_citation_source', true ) ) {
            return '';
        }
        return 'https://scholar.google.com/citations?user=' . rawurlencode( $scholar_id ) . '&hl=en';
    }
}