<?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;

function normalize_code(string $c): string
{
    return strtoupper(preg_replace('/[^A-Za-z0-9_-]/', '', $c));
}

/** Count orders that consume a use of this discount. */
function discount_uses(int $discountId, ?string $email = null): int
{
    $sql = 'SELECT COUNT(*) FROM {orders} o WHERE o.discount_id = ? AND ' . HELD_SQL;
    $args = [$discountId, now()];
    if ($email !== null) { $sql .= ' AND o.buyer_email = ?'; $args[] = $email; }
    return (int)qv($sql, $args);
}

/**
 * Evaluate one discount against priced lines. Lines: [['category_id'=>, 'qty'=>, 'unit_price'=>], ...]
 * Returns [amount, errorMessage|null].
 */
function discount_evaluate(array $d, int $eventId, array $lines, string $email): array
{
    $n = now();
    if (!$d['is_active']) return [0, 'This code is not active.'];
    if ($d['event_id'] !== null && (int)$d['event_id'] !== $eventId) return [0, 'This code is not valid for this event.'];
    if ($d['starts_at'] !== null && $d['starts_at'] > $n) return [0, 'This code is not active yet.'];
    if ($d['ends_at'] !== null && $d['ends_at'] < $n) return [0, 'This code has expired.'];

    $eligQty = 0; $eligSub = 0;
    foreach ($lines as $l) {
        if ($d['category_id'] !== null && (int)$d['category_id'] !== (int)$l['category_id']) continue;
        $eligQty += $l['qty'];
        $eligSub += $l['qty'] * $l['unit_price'];
    }
    if ($eligQty === 0) return [0, 'This code does not apply to the selected tickets.'];
    if ($eligQty < (int)$d['min_qty']) return [0, 'This code needs at least ' . plural((int)$d['min_qty'], 'ticket') . '.'];
    if ($d['max_uses'] !== null && discount_uses((int)$d['id']) >= (int)$d['max_uses']) return [0, 'This code has been fully used.'];
    if ($d['max_per_email'] !== null && $email !== '' && discount_uses((int)$d['id'], $email) >= (int)$d['max_per_email']) {
        return [0, 'You have already used this code.'];
    }

    if ($d['type'] === 'percent') {
        $amount = intdiv($eligSub * min(100, (int)$d['value']), 100);
    } else {
        $amount = $d['applies_per'] === 'ticket' ? (int)$d['value'] * $eligQty : (int)$d['value'];
    }
    return [min($amount, $eligSub), null];
}

/**
 * Pick the discount for an order: the entered code, if valid.
 * Returns ['discount' => row|null, 'amount' => int, 'code_error' => string|null].
 * When $lock is true the chosen rows are locked FOR UPDATE (call inside a transaction).
 */
function discount_choose(int $eventId, array $lines, string $code, string $email, bool $lock = false): array
{
    $best = ['discount' => null, 'amount' => 0, 'code_error' => null];
    $suffix = $lock ? ' FOR UPDATE' : '';
    $code = normalize_code($code);
    if ($code !== '') {
        $d = q1('SELECT * FROM {discounts} WHERE code = ?' . $suffix, [$code]);
        if (!$d) {
            $best['code_error'] = 'That code is not valid.';
        } else {
            [$amt, $err] = discount_evaluate($d, $eventId, $lines, $email);
            if ($err) $best['code_error'] = $err;
            else $best = ['discount' => $d, 'amount' => $amt, 'code_error' => null];
        }
    }
    // Add-ons can offer other discounts (for example automatic ones) and keep whichever saves the buyer more.
    return (array)apply_filters('gatecraft_discount_choice', $best, $eventId, $lines, $email, $lock);
}

function discount_describe(array $d): string
{
    $v = $d['type'] === 'percent' ? (int)$d['value'] . '% off' : money((int)$d['value']) . ' off' . ($d['applies_per'] === 'ticket' ? ' per ticket' : '');
    return $v . ($d['min_qty'] > 1 ? ', min ' . (int)$d['min_qty'] . ' tickets' : '');
}