<?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.

/**
 * Strands — topic clusters defined by the user.
 *
 * A strand groups the content of a single topic (silo). The metrics tell whether
 * the cluster is really braided: how many links run inside the strand and which
 * content are its loose ends. Braid Map colours the connections: inside a strand
 * (mint), between strands (violet), outside strands (neutral).
 */
class Linkbraid_Strands {

    private static function strands() { global $wpdb; return $wpdb->prefix . 'lbraid_strands'; }
    private static function members() { global $wpdb; return $wpdb->prefix . 'lbraid_strand_posts'; }
    private static function links() { global $wpdb; return $wpdb->prefix . 'lbraid_existing_links'; }

    /** Strand list with braid metrics. */
    public static function all() {
        global $wpdb;
        $rows = $wpdb->get_results('SELECT * FROM ' . self::strands() . ' ORDER BY name ASC', ARRAY_A);
        foreach ($rows as &$row) {
            $id = (int) $row['id'];
            $row['posts_count'] = (int) $wpdb->get_var($wpdb->prepare(
                'SELECT COUNT(*) FROM ' . self::members() . ' WHERE strand_id = %d', $id));
            $row['internal_links'] = (int) $wpdb->get_var($wpdb->prepare(
                'SELECT COUNT(*) FROM ' . self::links() . ' l
                 JOIN ' . self::members() . ' a ON a.post_id = l.source_post_id AND a.strand_id = %d
                 JOIN ' . self::members() . ' b ON b.post_id = l.target_post_id AND b.strand_id = %d', $id, $id));
            $row['covered'] = (int) $wpdb->get_var($wpdb->prepare(
                'SELECT COUNT(DISTINCT m.post_id) FROM ' . self::members() . ' m
                 JOIN ' . self::links() . ' l ON l.target_post_id = m.post_id
                 JOIN ' . self::members() . ' src ON src.post_id = l.source_post_id AND src.strand_id = %d
                 WHERE m.strand_id = %d', $id, $id));
            $row['loose'] = max(0, $row['posts_count'] - $row['covered']);
        }
        return $rows;
    }

    public static function create($name) {
        global $wpdb;
        $name = trim(preg_replace('/\s+/u', ' ', (string) $name));
        if (mb_strlen($name) < 2 || mb_strlen($name) > 120) return ['error' => __( 'The strand name must be between 2 and 120 characters.', 'linkbraid' )];
        if ($wpdb->get_var($wpdb->prepare('SELECT id FROM ' . self::strands() . ' WHERE name = %s', $name))) return ['error' => __( 'A strand with this name already exists.', 'linkbraid' )];
        if (false === $wpdb->insert(self::strands(), ['name' => $name, 'created_at' => current_time('mysql')])) return ['error' => __( 'The strand could not be saved.', 'linkbraid' )];
        return ['success' => true, 'id' => (int) $wpdb->insert_id];
    }

    public static function delete($id) {
        global $wpdb;
        $id = absint($id);
        $wpdb->delete(self::members(), ['strand_id' => $id]);
        return false !== $wpdb->delete(self::strands(), ['id' => $id]);
    }

    public static function add_post($strand_id, $post_id) {
        global $wpdb;
        $strand_id = absint($strand_id); $post_id = absint($post_id);
        if (!$wpdb->get_var($wpdb->prepare('SELECT id FROM ' . self::strands() . ' WHERE id = %d', $strand_id))) return ['error' => __( 'The strand does not exist.', 'linkbraid' )];
        $post = get_post($post_id);
        if (!$post || $post->post_status !== 'publish' || !in_array($post->post_type, lbraid_post_types(), true)) return ['error' => __( 'Pick published content from the enabled types.', 'linkbraid' )];
        $wpdb->query($wpdb->prepare(
            'INSERT IGNORE INTO ' . self::members() . ' (strand_id, post_id) VALUES (%d, %d)', $strand_id, $post_id));
        return ['success' => true];
    }

    public static function remove_post($strand_id, $post_id) {
        global $wpdb;
        return false !== $wpdb->delete(self::members(), ['strand_id' => absint($strand_id), 'post_id' => absint($post_id)]);
    }

    /** Strand content with the number of incoming links from inside the strand. */
    public static function posts($strand_id) {
        global $wpdb;
        $strand_id = absint($strand_id);
        $rows = $wpdb->get_results($wpdb->prepare(
            'SELECT m.post_id, p.post_title,
                (SELECT COUNT(*) FROM ' . self::links() . ' l
                 JOIN ' . self::members() . ' src ON src.post_id = l.source_post_id AND src.strand_id = %d
                 WHERE l.target_post_id = m.post_id) AS in_incoming
             FROM ' . self::members() . ' m
             LEFT JOIN ' . $wpdb->posts . ' p ON p.ID = m.post_id
             WHERE m.strand_id = %d ORDER BY in_incoming ASC, p.post_title ASC', $strand_id, $strand_id), ARRAY_A);
        foreach ($rows as &$row) {
            $row['url'] = get_permalink($row['post_id']);
            $row['edit'] = get_edit_post_link($row['post_id'], 'raw');
            $row['post_title'] = $row['post_title'] ?: ('#' . $row['post_id']);
        }
        return $rows;
    }

    /** Map post_id -> strand_id (with several strands: the lowest id) for Braid Map. */
    public static function node_map() {
        global $wpdb;
        $rows = $wpdb->get_results('SELECT post_id, MIN(strand_id) AS strand_id FROM ' . self::members() . ' GROUP BY post_id');
        $map = [];
        foreach ($rows as $row) $map[(int) $row->post_id] = (int) $row->strand_id;
        return $map;
    }
}