<?php
declare(strict_types=1);

namespace Gatecraft;

use WP_User, WP_Error, WP_Session_Tokens, WP_CLI, RuntimeException, Throwable, Exception, DateTime, DateTimeImmutable, ZipArchive;

if (!defined('ABSPATH')) exit;

/**
 * Price a basket against what is on sale. Throws UserError on invalid selections.
 * $qty: [category_id => quantity]. Returns lines, subtotal, discount, total, requires_approval.
 */
function quote_order(array $event, array $qty, string $code, string $email, bool $lock = false): array
{
    $offer = [];
    foreach (event_offer($event) as $c) $offer[(int)$c['id']] = $c;
    // One line per category: the same category sent twice ("5" and "05", say) must not be checked twice on its own.
    $norm = [];
    foreach ($qty as $k => $v) {
        $k = (string)$k;
        if (!preg_match('/^[1-9][0-9]{0,9}$/', $k)) fail('One of the selected tickets is no longer available.');
        $n = is_scalar($v) && preg_match('/^\s*[0-9]{1,6}\s*$/', (string)$v) ? (int)$v : 0;
        if ($n > 0) $norm[(int)$k] = ($norm[(int)$k] ?? 0) + $n;
    }
    $qty = $norm;
    if (!$qty) fail('Choose at least one ticket.');

    $lines = []; $count = 0; $approval = false;
    foreach ($qty as $catId => $q) {
        $c = $offer[(int)$catId] ?? null;
        if (!$c) fail('One of the selected tickets is no longer available.');
        if ($c['state'] === 'sold_out') fail($c['name'] . ' is sold out.');
        if ($c['state'] !== 'on_sale') fail($c['name'] . ' is not on sale right now.');
        if ($q > $c['available']) fail('Only ' . plural($c['available'], 'ticket') . ' left for ' . $c['name'] . '.');
        if ($q < (int)$c['min_per_order']) fail($c['name'] . ': minimum ' . (int)$c['min_per_order'] . ' per booking.');
        if ($c['max_per_order'] !== null && $q > (int)$c['max_per_order']) fail($c['name'] . ': maximum ' . (int)$c['max_per_order'] . ' per booking.');
        $lines[] = ['category_id' => (int)$c['id'], 'tier_id' => (int)$c['tier']['id'], 'qty' => $q, 'unit_price' => (int)$c['tier']['price'],
                    'name' => $c['name'], 'tier_name' => $c['tier']['name']];
        $count += $q;
        $approval = $approval || (bool)apply_filters('gatecraft_category_needs_approval', false, $c);
    }
    if ($event['max_per_order'] !== null && $count > (int)$event['max_per_order']) fail('You can buy up to ' . (int)$event['max_per_order'] . ' tickets per booking.');
    $cap = event_cap($event);
    if ($cap !== null) {
        $left = max(0, $cap - held_counts((int)$event['id'])['total']);
        if ($count > $left) fail($left > 0 ? 'Only ' . plural($left, 'ticket') . ' left for this event.' : 'This event is sold out.');
    }

    $subtotal = array_sum(array_map(fn($l) => $l['qty'] * $l['unit_price'], $lines));
    $disc = discount_choose((int)$event['id'], $lines, $code, strtolower($email), $lock);
    return [
        'lines' => $lines, 'count' => $count, 'subtotal' => $subtotal,
        'discount' => $disc['discount'], 'discount_amount' => $disc['amount'], 'code_error' => $disc['code_error'],
        'requires_approval' => $approval,
    ] + (function (int $net) {
        $t = tax_compute($net);
        return ['net' => $net, 'total' => $t['total'], 'tax' => $t];
    })(max(0, $subtotal - $disc['amount']));
}

function validate_buyer(array $b): array
{
    $name = mb_substr(trim((string)($b['name'] ?? '')), 0, 120);
    $email = strtolower(trim((string)($b['email'] ?? '')));
    $phone = trim((string)($b['phone'] ?? ''));
    if ($name === '' || preg_match('/[\x00-\x1f<>]/', $name)) fail('Please enter your full name.');
    // Names appear in emails we send, so keep links and addresses out of them.
    if (preg_match('#://|www\.|@|\.(com|net|org|io|ru|cn|xyz|top|link)\b#i', $name)) fail('Please enter your name only.');
    if (strlen($email) > 190 || !filter_var($email, FILTER_VALIDATE_EMAIL)) fail('Please enter a valid email address.');
    if (setting('phone_mode') === 'hidden') $phone = '';
    if ($phone === '' && setting('phone_mode') === 'required') fail('Please enter your phone number.');
    if ($phone !== '' && !preg_match('/^[0-9+()\-\s]{6,40}$/', $phone)) fail('Please enter a valid phone number.');
    return ['name' => $name, 'email' => $email, 'phone' => $phone ?: null];
}

function new_reference(): string
{
    do { $r = random_code(8); } while (qv('SELECT 1 FROM {orders} WHERE reference = ?', [$r]));
    return $r;
}

/** Creates the order and reserves stock. Returns the order row. */
function create_order(int $eventId, array $qty, array $buyerIn, array $answersIn, string $code, ?array $user, string $payWith = '', bool $agreed = true): array
{
    $buyer = validate_buyer($buyerIn) + ['billing' => (array)apply_filters('gatecraft_buyer_billing', ['company' => null, 'tax_id' => null, 'address' => null], $buyerIn)];
    if ($user) $buyer['email'] = strtolower($user['email']); // signed-in buyers use their verified email
    if (setting_on('require_terms') && !$agreed) fail('Please agree to the terms to continue.');
    $catIds = array_map('intval', array_keys(array_filter(array_map('intval', $qty), fn($q) => $q > 0)));
    // Checkout questions come from add-ons. They validate the input and return [['q' => label, 'a' => answer], ...].
    $answers = (array)apply_filters('gatecraft_checkout_answers', [], $eventId, $answersIn, $catIds);
    $evRow = q1('SELECT * FROM {events} WHERE id = ?', [$eventId]);
    $options = $evRow ? event_payment_options($evRow) : [];
    $opt = $options[$payWith] ?? (count($options) === 1 ? reset($options) : null);
    $mode = $opt ? ($opt['key'] === 'stripe' ? 'stripe' : 'offline') : 'offline';

    $ipHash = PHP_SAPI === 'cli' ? null : substr(hash_hmac('sha256', 'order-ip|' . ip_bucket(client_ip()), app_key()), 0, 16);
    $orderId = tx(function () use ($eventId, $qty, $buyer, $answers, $code, $user, $mode, $opt, $options, $ipHash) {
        // Locking the event row serialises checkouts per event, so capacity checks cannot race.
        $event = q1('SELECT * FROM {events} WHERE id = ? FOR UPDATE', [$eventId]);
        if (!$event || $event['status'] !== 'published') fail('This event is not available.');
        if ($event['starts_at'] <= now()) fail('Ticket sales for this event have closed.');

        // Limit open (unpaid or unapproved) orders per email, so one person cannot hold the whole event.
        $open = (int)qv("SELECT COUNT(*) FROM {orders} WHERE event_id = ? AND buyer_email = ? AND status IN ('awaiting_approval','pending_payment') AND expires_at > ?", [$eventId, $buyer['email'], now()]);
        if ($open >= 2) fail('You already have open bookings for this event. Complete or cancel them first, or wait for them to expire.');
        // And per network address (hashed, never stored as an address), so changing the email does not let one person hold every seat.
        $openByIp = (int)qv("SELECT COUNT(*) FROM {orders} WHERE event_id = ? AND ip_hash = ? AND status IN ('awaiting_approval','pending_payment') AND expires_at > ?", [$eventId, $ipHash, now()]);
        if ($openByIp >= 5) fail('There are already several unpaid bookings for this event from your connection. Complete one of them, or wait for them to expire.');
        $quote = quote_order($event, $qty, $code, $buyer['email'], true);
        if ($quote['code_error']) fail($quote['code_error']);

        // A paid order needs a payment method. A free one, or an approval request for free tickets, does not.
        if ($quote['total'] > 0 && !$opt) fail($options ? 'Choose how you want to pay.' : 'Payment is not available for this event yet. Please contact the organiser.');
        if ($quote['requires_approval']) {
            $status = 'awaiting_approval';
            $expires = ldate('Y-m-d H:i:s', lstrtotime('+' . setting_int('approval_hold_days', 1, 60) . ' days'));
            $method = $quote['total'] === 0 ? 'free' : $mode;
        } elseif ($quote['total'] === 0) {
            $status = 'pending_payment'; // flipped to paid right after commit
            $expires = ldate('Y-m-d H:i:s', lstrtotime('+1 hour'));
            $method = 'free';
        } else {
            $status = 'pending_payment';
            $hold = $mode === 'stripe' ? '+' . setting_int('hold_minutes', 10, 120) . ' minutes' : '+' . setting_int('offline_hold_hours', 1, 336) . ' hours';
            $expires = ldate('Y-m-d H:i:s', lstrtotime($hold));
            $method = $mode;
        }

        $tax = $quote['tax'];
        q('INSERT INTO {orders} (reference, public_token, event_id, user_id, buyer_name, buyer_email, buyer_phone, subtotal, discount_amount, total,
           currency, discount_id, status, answers, expires_at, payment_method, pay_option, pay_instructions, ip_hash,
           tax_mode, tax_rate, tax_label, tax_amount, buyer_company, buyer_tax_id, buyer_address, language, created_at) VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)', [
            new_reference(), bin2hex(random_bytes(32)), $eventId, $user['id'] ?? null, $buyer['name'], $buyer['email'], $buyer['phone'],
            $quote['subtotal'], $quote['discount_amount'], $quote['total'], cfg('currency'), $quote['discount']['id'] ?? null,
            $status, $answers ? wp_json_encode($answers, JSON_UNESCAPED_UNICODE) : null, $expires, $method,
            $method === 'offline' ? $opt['name'] : null, $method === 'offline' ? $opt['instructions'] : null, $ipHash,
            $tax['mode'] === 'none' ? null : $tax['mode'], $tax['rate'], $tax['label'], $tax['amount'],
            $buyer['billing']['company'], $buyer['billing']['tax_id'], $buyer['billing']['address'], current_language(), now(),
        ]);
        $id = (int)db_insert_id();
        foreach ($quote['lines'] as $l) q('INSERT INTO {order_items} (order_id, category_id, tier_id, qty, unit_price) VALUES (?,?,?,?,?)', [$id, $l['category_id'], $l['tier_id'], $l['qty'], $l['unit_price']]);
        return $id;
    });

    $o = get_order($orderId);
    if ($o['status'] === 'awaiting_approval') {
        email_order($orderId, 'approval_pending');
        notify_staff('approval', 'Approval needed: ' . $o['reference'], $o['buyer_name'] . ' requested tickets for ' . $o['event_title'], '/admin/approvals');
        check_capacity_alert((int)$o['event_id']);
    } elseif ($o['payment_method'] === 'free') {
        // Free tickets go out once the buyer opens a link sent to the address, so a script cannot claim every free place
        // with made-up addresses. A signed-in buyer booking with their own address has shown it is theirs already.
        if (free_booking_needs_confirm($o, $user)) email_order($orderId, 'confirm_email');
        else mark_paid($orderId, 'free');
    } elseif ($o['payment_method'] === 'offline') {
        email_order($orderId, 'payment_pending');
        notify_staff('bank', 'Payment to confirm: ' . ($o['pay_option'] ?: 'offline') . ', booking ' . $o['reference'], $o['buyer_name'] . ', ' . money((int)$o['total']) . ', ' . $o['event_title'], '/admin/orders/' . $orderId);
        check_capacity_alert((int)$o['event_id']);
    }
    return get_order($orderId);
}

function free_booking_needs_confirm(array $o, ?array $user): bool
{
    if (!setting_on('free_email_confirm')) return false;
    return !($user && strtolower((string)$user['email']) === strtolower((string)$o['buyer_email']));
}

/** The secret part of the link that confirms a free booking. Not derivable from the booking page address. */
function free_confirm_code(array $o): string
{
    return substr(hash_hmac('sha256', 'free-confirm|' . $o['id'] . '|' . $o['public_token'], app_key()), 0, 32);
}

function free_confirm_url(array $o): string
{
    return url('/order/' . $o['public_token'] . '/confirm', ['c' => free_confirm_code($o)]);
}

/** True while a free booking waits for its email link. */
function awaiting_email_confirm(array $o): bool
{
    return $o['status'] === 'pending_payment' && $o['payment_method'] === 'free';
}

function get_order(int $id): ?array
{
    return q1('SELECT o.*, e.title AS event_title, e.slug AS event_slug, e.starts_at, e.ends_at, e.doors_at, e.venue_id,
               v.name AS venue_name, v.address AS venue_address, v.city AS venue_city, v.map_url AS venue_map
               FROM {orders} o JOIN {events} e ON e.id = o.event_id LEFT JOIN {venues} v ON v.id = e.venue_id WHERE o.id = ?', [$id]);
}

function get_order_by_token(string $token): ?array
{
    if (!preg_match('/^[a-f0-9]{64}$/', $token)) return null;
    $id = qv('SELECT id FROM {orders} WHERE public_token = ?', [$token]);
    return $id ? get_order((int)$id) : null;
}

function order_items(int $orderId): array
{
    return q('SELECT oi.*, c.name AS category_name, t.name AS tier_name FROM {order_items} oi
              JOIN {ticket_categories} c ON c.id = oi.category_id JOIN {ticket_tiers} t ON t.id = oi.tier_id WHERE oi.order_id = ? ORDER BY oi.id', [$orderId])->fetchAll();
}

function order_tickets(int $orderId): array
{
    return q('SELECT tk.*, c.name AS category_name, t.name AS tier_name FROM {tickets} tk
              JOIN {ticket_categories} c ON c.id = tk.category_id JOIN {ticket_tiers} t ON t.id = tk.tier_id WHERE tk.order_id = ? ORDER BY tk.id', [$orderId])->fetchAll();
}

function order_link(array $o): string
{
    return url('/order/' . $o['public_token']);
}

/** True if the items of an order still fit, ignoring this order's own hold. Call inside a transaction holding the event lock. */
function order_still_fits(array $order): bool
{
    $event = q1('SELECT * FROM {events} WHERE id = ?', [$order['event_id']]);
    $held = held_counts((int)$order['event_id']);
    $self = q('SELECT category_id, tier_id, qty FROM {order_items} WHERE order_id = ?', [$order['id']])->fetchAll();
    $selfHeld = $order['status'] === 'paid' || $order['expires_at'] > now();
    $cap = event_cap($event);
    $total = array_sum(array_column($self, 'qty'));
    foreach ($self as $it) {
        $cat = q1('SELECT capacity FROM {ticket_categories} WHERE id = ?', [$it['category_id']]);
        $tier = q1('SELECT quantity FROM {ticket_tiers} WHERE id = ?', [$it['tier_id']]);
        $catHeld = ($held['cat'][$it['category_id']] ?? 0) - ($selfHeld ? $it['qty'] : 0);
        $tierHeld = ($held['tier'][$it['tier_id']] ?? 0) - ($selfHeld ? $it['qty'] : 0);
        if ($catHeld + $it['qty'] > (int)$cat['capacity']) return false;
        if ($tier['quantity'] !== null && $tierHeld + $it['qty'] > (int)$tier['quantity']) return false;
    }
    if ($cap !== null && $held['total'] - ($selfHeld ? $total : 0) + $total > $cap) return false;
    return true;
}

/** Idempotent: confirms the order, issues one ticket per seat, emails the buyer. */
function mark_paid(int $orderId, string $method, ?int $actorId = null, bool $force = false): bool
{
    $result = tx(function () use ($orderId, $method, $force) {
        $o = q1('SELECT * FROM {orders} WHERE id = ? FOR UPDATE', [$orderId]);
        if (!$o || $o['status'] === 'paid') return false;
        $allowed = $o['status'] === 'pending_payment' || ($o['status'] === 'expired' && in_array($method, ['stripe', 'offline'], true));
        if (!$allowed) fail('This booking cannot be marked as paid from its current status.');
        q('SELECT id FROM {events} WHERE id = ? FOR UPDATE', [$o['event_id']]);
        $overflow = false;
        if ($o['expires_at'] <= now() || $o['status'] === 'expired') {
            if (!order_still_fits($o)) {
                // Stripe already took the money: confirm and warn staff. Manual confirmations must not oversell.
                if ($method !== 'stripe' && !$force) fail('The hold on this booking expired and there is no longer enough capacity. Increase capacity first.');
                $overflow = true;
            }
        }
        q("UPDATE {orders} SET status = 'paid', paid_at = ?, payment_method = ?, expires_at = NULL WHERE id = ?", [now(), $method, $orderId]);
        do_action('gatecraft_order_paid_tx', $orderId); // inside the transaction, e.g. for an invoice number
        issue_tickets($orderId);
        return ['overflow' => $overflow, 'ref' => $o['reference']];
    });
    if ($result === false) return false;
    if ($actorId !== null) audit('order.mark_paid', 'order', $orderId, ['method' => $method]);
    contact_refresh((string)qv('SELECT buyer_email FROM {orders} WHERE id = ?', [$orderId]));
    do_action('gatecraft_order_paid', $orderId);
    email_order($orderId, 'tickets');
    if ($result['overflow']) notify_staff('payment', 'Capacity exceeded by booking ' . $result['ref'], 'Payment arrived after the hold expired. Check capacity for this event.', '/admin/orders/' . $orderId);
    elseif ($method !== 'free') notify_staff('paid', 'Paid booking ' . $result['ref'], 'Payment received (' . ($method === 'stripe' ? 'card' : 'confirmed by staff') . ').', '/admin/orders/' . $orderId);
    check_capacity_alert((int)qv('SELECT event_id FROM {orders} WHERE id = ?', [$orderId]));
    return true;
}

/** One ticket per seat of an order. Call inside the transaction that confirms it. */
function issue_tickets(int $orderId): void
{
    $items = q('SELECT category_id, tier_id, qty FROM {order_items} WHERE order_id = ?', [$orderId])->fetchAll();
    foreach ($items as $it) {
        for ($i = 0; $i < (int)$it['qty']; $i++) {
            for ($try = 0; ; $try++) {
                try { q('INSERT INTO {tickets} (order_id, category_id, tier_id, code, created_at) VALUES (?,?,?,?,?)', [$orderId, $it['category_id'], $it['tier_id'], random_code(16), now()]); break; }
                catch (DbError $ex) { if ($try >= 3 || $ex->getCode() !== 1062) throw $ex; } // 1062: duplicate code, try another
            }
        }
    }
}

function cancel_order(int $orderId, string $reason = '', bool $notify = true): void
{
    tx(function () use ($orderId, $reason) {
        $o = q1('SELECT * FROM {orders} WHERE id = ? FOR UPDATE', [$orderId]);
        if (!$o || !in_array($o['status'], ['awaiting_approval', 'pending_payment', 'paid'], true)) fail('This booking cannot be cancelled.');
        // A card payment taken through Stripe has to go back to the buyer, so it is refunded rather than cancelled.
        if ($o['status'] === 'paid' && $o['payment_method'] === 'stripe' && (int)$o['total'] > 0) fail('This booking was paid by card. Use Refund so the money goes back to the buyer.');
        q("UPDATE {orders} SET status = 'cancelled', decision_note = ?, closed_at = ? WHERE id = ?", [mb_substr($reason, 0, 500) ?: null, now(), $orderId]);
        q("UPDATE {tickets} SET status = 'void' WHERE order_id = ?", [$orderId]);
    });
    audit('order.cancel', 'order', $orderId, ['reason' => $reason]);
    contact_refresh((string)qv('SELECT buyer_email FROM {orders} WHERE id = ?', [$orderId]));
    if ($notify) email_order($orderId, 'cancelled');
}

function refund_order(int $orderId, string $reason = ''): void
{
    $o = get_order($orderId);
    if (!$o || $o['status'] !== 'paid') fail('Only confirmed bookings can be refunded.');
    if ($o['payment_method'] === 'stripe' && (int)$o['total'] > 0) stripe_refund($o); // throws on failure, before we change anything
    tx(function () use ($orderId, $reason) {
        $upd = q("UPDATE {orders} SET status = 'refunded', decision_note = ?, closed_at = ? WHERE id = ? AND status = 'paid'", [mb_substr($reason, 0, 500) ?: null, now(), $orderId]);
        if ($upd->rowCount() !== 1) fail('Booking changed while refunding. Reload and check.');
        q("UPDATE {tickets} SET status = 'void' WHERE order_id = ?", [$orderId]);
    });
    audit('order.refund', 'order', $orderId, ['reason' => $reason]);
    contact_refresh((string)qv('SELECT buyer_email FROM {orders} WHERE id = ?', [$orderId]));
    email_order($orderId, 'refunded');
}

/** Moves stale holds to expired. Safe to run often. */
function expire_orders(): int
{
    $ids = q("SELECT id, status FROM {orders} WHERE status IN ('awaiting_approval','pending_payment') AND expires_at <= ? LIMIT 500", [now()])->fetchAll();
    $n = 0;
    foreach ($ids as $r) {
        $upd = q("UPDATE {orders} SET status = 'expired', closed_at = ? WHERE id = ? AND status = ? AND expires_at <= ?", [now(), $r['id'], $r['status'], now()]);
        if ($upd->rowCount() === 1) {
            $n++;
            if ($r['status'] === 'pending_payment' && qv('SELECT payment_method FROM {orders} WHERE id = ?', [$r['id']]) !== 'free') email_order((int)$r['id'], 'expired');
            elseif ($r['status'] === 'awaiting_approval') email_order((int)$r['id'], 'expired');
        }
    }
    return $n;
}

function answers_list(?string $json): array
{
    $a = $json ? json_decode($json, true) : [];
    return is_array($a) ? $a : [];
}