<?php
if (!defined('ABSPATH')) exit;
// phpcs:disable WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Every table name is $wpdb->prefix plus a fixed suffix from a private helper (never user input); all runtime values go through $wpdb->prepare() placeholders.

/**
 * Internal link click tracking.
 *
 * Deliberate privacy rules: only the date, the source post, the target post and
 * the anchor are stored. No IP address, no cookies, no user identifiers.
 * Retention is capped by a setting; the feature is disabled by default.
 */
class Linkbraid_Clicks {

    private static function table() { global $wpdb; return $wpdb->prefix . 'lbraid_click_data'; }

    public static function enabled() { return (bool) get_option('lbraid_click_tracking', 0); }

    public static function retention_days() {
        $days = (int) get_option('lbraid_click_retention_days', 90);
        return in_array($days, [30, 90, 180, 365], true) ? $days : 90;
    }

    /** Records a click. Internal URLs pointing at published content only. */
    public static function record($source_post_id, $href, $anchor) {
        global $wpdb;
        if (!self::enabled()) return false;
        $url = Linkbraid_Content::resolve_url((string) $href);
        if (!$url) return false;
        $target = (int) url_to_postid($url);
        if (!$target || get_post_status($target) !== 'publish') return false;
        $source = absint($source_post_id);
        $ok = false !== $wpdb->insert(self::table(), [
            'clicked_at'     => current_time('mysql'),
            'source_post_id' => $source,
            'target_post_id' => $target,
            'anchor_text'    => mb_substr(sanitize_text_field((string) $anchor), 0, 300),
        ]);
        if ($ok && wp_rand(1, 50) === 1) self::cleanup();
        return $ok;
    }

    /** Removes data older than the retention period. */
    public static function cleanup() {
        global $wpdb;
        $table = self::table();
        if (!$wpdb->get_var($wpdb->prepare('SHOW TABLES LIKE %s', $wpdb->esc_like($table)))) return;
        $cutoff = gmdate('Y-m-d H:i:s', strtotime(current_time('mysql')) - self::retention_days() * DAY_IN_SECONDS);
        $wpdb->query($wpdb->prepare("DELETE FROM $table WHERE clicked_at < %s", $cutoff));
    }

    /** Daily click series for the last $days days (zero-filled). */
    public static function series($days = 30) {
        global $wpdb;
        $days = max(7, min(90, (int) $days));
        $start = gmdate('Y-m-d', strtotime(current_time('Y-m-d')) - ($days - 1) * DAY_IN_SECONDS);
        $rows = $wpdb->get_results($wpdb->prepare(
            'SELECT DATE(clicked_at) AS d, COUNT(*) AS c FROM ' . self::table() . ' WHERE clicked_at >= %s GROUP BY DATE(clicked_at)', $start), ARRAY_A);
        $map = [];
        foreach ($rows as $row) $map[$row['d']] = (int) $row['c'];
        $out = [];
        for ($i = 0; $i < $days; $i++) {
            $date = gmdate('Y-m-d', strtotime($start) + $i * DAY_IN_SECONDS);
            $out[] = ['d' => $date, 'c' => $map[$date] ?? 0];
        }
        return $out;
    }

    public static function total($days = 30) {
        global $wpdb;
        $start = gmdate('Y-m-d', strtotime(current_time('Y-m-d')) - (max(1, (int) $days) - 1) * DAY_IN_SECONDS);
        return (int) $wpdb->get_var($wpdb->prepare('SELECT COUNT(*) FROM ' . self::table() . ' WHERE clicked_at >= %s', $start));
    }
}