<?php

/**
 * Preferenze di interfaccia per utente (posizione, larghezza e visibilità dei riquadri nelle pagine).
 *
 * Tabella user_ui_prefs: una riga per utente e pagina, layout in JSON:
 *   { "order": ["orders","monthly",...], "hidden": ["items"], "sizes": {"monthly": 12} }
 */
class UiPrefs
{
    const SIZES = [4, 5, 6, 7, 8, 12];

    public static function validPage(string $page): bool
    {
        return (bool)preg_match('/^[a-z0-9_]{1,50}$/', $page);
    }

    /** Layout salvato (array vuoto se non c'è o se la tabella non esiste ancora). */
    public static function get(PDO $pdo, int $userId, string $page): array
    {
        if ($userId <= 0 || !self::validPage($page)) return [];
        try {
            $st = $pdo->prepare('SELECT layout FROM user_ui_prefs WHERE user_id = ? AND page = ?');
            $st->execute([$userId, $page]);
            $j = $st->fetchColumn();
            $d = $j ? json_decode($j, true) : null;
            return is_array($d) ? self::clean($d) : [];
        } catch (Throwable $e) {
            return [];
        }
    }

    public static function save(PDO $pdo, int $userId, string $page, array $layout): bool
    {
        if ($userId <= 0 || !self::validPage($page)) return false;
        $json = json_encode(self::clean($layout));
        $st = $pdo->prepare('INSERT INTO user_ui_prefs (user_id, page, layout, updated_at) VALUES (?, ?, ?, NOW())
                             ON DUPLICATE KEY UPDATE layout = VALUES(layout), updated_at = NOW()');
        return $st->execute([$userId, $page, $json]);
    }

    public static function reset(PDO $pdo, int $userId, string $page): bool
    {
        if ($userId <= 0 || !self::validPage($page)) return false;
        $st = $pdo->prepare('DELETE FROM user_ui_prefs WHERE user_id = ? AND page = ?');
        return $st->execute([$userId, $page]);
    }

    /** Attributi HTML per il contenitore dei riquadri: data-layout + data-prefs. */
    public static function attr(PDO $pdo, $userId, string $page): string
    {
        $p = self::get($pdo, (int)$userId, $page);
        return 'data-layout="' . htmlspecialchars($page) . '" data-prefs="'
            . htmlspecialchars(json_encode($p ?: new stdClass()), ENT_QUOTES) . '"';
    }

    private static function clean(array $d): array
    {
        $key = function ($k) {
            return is_string($k) && preg_match('/^[a-z0-9_]{1,40}$/', $k);
        };
        $order = array_values(array_unique(array_filter((array)($d['order'] ?? []), $key)));
        $hidden = array_values(array_unique(array_filter((array)($d['hidden'] ?? []), $key)));
        $sizes = [];
        foreach ((array)($d['sizes'] ?? []) as $k => $v) {
            if ($key($k) && in_array((int)$v, self::SIZES, true)) $sizes[$k] = (int)$v;
        }
        return [
            'order' => array_slice($order, 0, 60),
            'hidden' => array_slice($hidden, 0, 60),
            'sizes' => $sizes ?: new stdClass(),
        ];
    }
}