<?php

/**
 * Elenco delle lezioni in calendario verso cui spostare una prenotazione (uso scuola).
 * GET: id = idbookingclass
 *
 * Restituisce le lezioni future (prossimi 90 giorni) della stessa classe
 * e delle classi associate (associateclass), con posti occupati e flag.
 */
ob_start();
require_once('include/headscript.php');

function jsonOut(array $payload, int $code = 200): void
{
    if (ob_get_length() !== false) ob_end_clean();
    http_response_code($code);
    header('Content-Type: application/json; charset=utf-8');
    echo json_encode($payload, JSON_UNESCAPED_UNICODE);
    exit;
}

$id = (int) ($_GET['id'] ?? 0);
if ($id <= 0) {
    jsonOut(['success' => false, 'message' => 'Prenotazione non valida.'], 400);
}

$pdo = DBHandlerSelect::getInstance()->getConnection();
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

try {
    // Prenotazione + ordine collegato
    $st = $pdo->prepare("
        SELECT bc.idbookingclass, bc.iduser, bc.idservice, bc.idserviceschedule, bc.idorder,
               o.expireon, o.reprogrammed, o.maxreschedule
        FROM bookingclass bc
        LEFT JOIN orderbook o ON o.idorderbook = bc.idorder
        WHERE bc.idbookingclass = ?
    ");
    $st->execute([$id]);
    $bk = $st->fetch(PDO::FETCH_ASSOC);

    if (!$bk) {
        jsonOut(['success' => false, 'message' => 'Prenotazione non trovata.'], 404);
    }

    // Classi ammesse: la stessa + quelle associate
    $services = [(int) $bk['idservice']];
    $as = $pdo->prepare("SELECT idassociateservice FROM associateclass WHERE idmainservice = ?");
    $as->execute([(int) $bk['idservice']]);
    foreach ($as->fetchAll(PDO::FETCH_COLUMN) as $sid) {
        $services[] = (int) $sid;
    }
    $services = array_values(array_unique($services));
    $ph = implode(',', array_fill(0, count($services), '?'));

    $sql = "
        SELECT ss.idserviceschedule, ss.dateschedule,
               s.servicename, s.maxcapacity,
               (SELECT COUNT(*) FROM bookingclass b
                 WHERE b.idserviceschedule = ss.idserviceschedule
                   AND b.status IN ('booked','pending')) AS occupied,
               (SELECT COUNT(*) FROM bookingclass b2
                 WHERE b2.idserviceschedule = ss.idserviceschedule
                   AND b2.iduser = ?) AS mine
        FROM serviceschedule ss
        JOIN service s ON s.idservice = ss.idservice
        WHERE ss.idservice IN ($ph)
          AND ss.dateschedule > NOW()
          AND ss.dateschedule <= DATE_ADD(NOW(), INTERVAL 90 DAY)
        ORDER BY ss.dateschedule
        LIMIT 200";
    $ls = $pdo->prepare($sql);
    $ls->execute(array_merge([(int) $bk['iduser']], $services));

    $giorni = ['Dom', 'Lun', 'Mar', 'Mer', 'Gio', 'Ven', 'Sab'];
    $expiry = $bk['expireon'] ? strtotime($bk['expireon'] . ' 23:59:59') : null;

    $lessons = [];
    foreach ($ls->fetchAll(PDO::FETCH_ASSOC) as $l) {
        $ts  = strtotime($l['dateschedule']);
        $max = $l['maxcapacity'] !== null ? (int) $l['maxcapacity'] : null;
        $occ = (int) $l['occupied'];

        $lessons[] = [
            'id'           => (int) $l['idserviceschedule'],
            'label'        => $giorni[(int) date('w', $ts)] . ' ' . date('d/m/Y H:i', $ts),
            'servicename'  => $l['servicename'],
            'occupied'     => $occ,
            'max'          => $max,
            'full'         => $max !== null && $occ >= $max,
            'mine'         => (int) $l['mine'] > 0,
            'after_expiry' => $expiry !== null && $ts > $expiry,
        ];
    }

    jsonOut([
        'success' => true,
        'lessons' => $lessons,
        'order'   => [
            'has_order'     => $bk['idorder'] !== null,
            'reprogrammed'  => (int) ($bk['reprogrammed'] ?? 0),
            'maxreschedule' => (int) ($bk['maxreschedule'] ?? 0),
            'expireon'      => $bk['expireon'] ? date('d/m/Y', strtotime($bk['expireon'])) : null,
        ],
    ]);
} catch (PDOException $e) {
    error_log("admin_reprogram_lessons #{$id}: " . $e->getMessage());
    jsonOut(['success' => false, 'message' => 'Errore nel caricamento delle lezioni.'], 500);
}