<?php
declare(strict_types=1);

/**
 * KAPVOE Stripe Checkout helpers
 * Plain PHP + cURL. No Composer dependency required.
 */

function kapvoe_load_config(): array {
    $configFile = __DIR__ . '/config.php';
    if (!file_exists($configFile)) {
        http_response_code(500);
        header('Content-Type: application/json; charset=utf-8');
        echo json_encode([
            'ok' => false,
            'error' => 'Falta el fitxer config.php'
        ], JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
        exit;
    }

    /** @var array $config */
    $config = require $configFile;
    return $config;
}

function kapvoe_json_input(): array {
    $raw = file_get_contents('php://input') ?: '{}';
    $decoded = json_decode($raw, true);
    return is_array($decoded) ? $decoded : [];
}

function kapvoe_json_response(array $payload, int $status = 200): never {
    http_response_code($status);
    header('Content-Type: application/json; charset=utf-8');
    echo json_encode($payload, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
    exit;
}

function kapvoe_require_post(): void {
    if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
        kapvoe_json_response(['ok' => false, 'error' => 'Mètode no permès'], 405);
    }
}

function kapvoe_validate_required(array $data, array $fields): array {
    $errors = [];
    foreach ($fields as $field) {
        if (!isset($data[$field]) || trim((string)$data[$field]) === '') {
            $errors[$field] = 'Camp obligatori';
        }
    }
    return $errors;
}

function kapvoe_orders_csv_path(array $config): string {
    $dir = rtrim((string)$config['orders_storage_dir'], DIRECTORY_SEPARATOR);
    if (!is_dir($dir)) {
        mkdir($dir, 0775, true);
    }
    return $dir . DIRECTORY_SEPARATOR . 'orders.csv';
}

function kapvoe_append_order(array $config, array $order): void {
    $path = kapvoe_orders_csv_path($config);
    $exists = file_exists($path);
    $fh = fopen($path, 'ab');
    if (!$fh) {
        throw new RuntimeException('No s\'ha pogut obrir orders.csv');
    }

    if (!$exists) {
        fputcsv($fh, array_keys($order), ';');
    }
    fputcsv($fh, array_values($order), ';');
    fclose($fh);
}

function kapvoe_update_order_status(array $config, string $sessionId, string $newStatus, string $paymentIntent = ''): void {
    $path = kapvoe_orders_csv_path($config);
    if (!file_exists($path)) {
        return;
    }

    $rows = [];
    $fh = fopen($path, 'rb');
    if (!$fh) {
        return;
    }
    while (($row = fgetcsv($fh, 0, ';')) !== false) {
        $rows[] = $row;
    }
    fclose($fh);

    if (count($rows) < 2) {
        return;
    }

    $header = $rows[0];
    $sessionIdx = array_search('stripe_session_id', $header, true);
    $statusIdx = array_search('payment_status', $header, true);
    $intentIdx = array_search('payment_intent_id', $header, true);

    if ($sessionIdx === false || $statusIdx === false) {
        return;
    }

    for ($i = 1; $i < count($rows); $i++) {
        while (count($rows[$i]) < count($header)) {
            $rows[$i][] = '';
        }

        if (($rows[$i][$sessionIdx] ?? '') === $sessionId) {
            $rows[$i][$statusIdx] = $newStatus;
            if ($intentIdx !== false) {
                $rows[$i][$intentIdx] = $paymentIntent;
            }
            break;
        }
    }

    $fh = fopen($path, 'wb');
    if (!$fh) {
        return;
    }
    foreach ($rows as $row) {
        while (count($row) < count($header)) {
            $row[] = '';
        }
        fputcsv($fh, $row, ';');
    }
    fclose($fh);
}

function kapvoe_get_order_by_session_id(array $config, string $sessionId): ?array {
    $path = kapvoe_orders_csv_path($config);
    if (!file_exists($path)) {
        return null;
    }

    $fh = fopen($path, 'rb');
    if (!$fh) {
        return null;
    }

    $header = fgetcsv($fh, 0, ';');
    if (!$header) {
        fclose($fh);
        return null;
    }

    while (($row = fgetcsv($fh, 0, ';')) !== false) {
        while (count($row) < count($header)) {
            $row[] = '';
        }
        $assoc = array_combine($header, $row);
        if (($assoc['stripe_session_id'] ?? '') === $sessionId) {
            fclose($fh);
            return $assoc ?: null;
        }
    }

    fclose($fh);
    return null;
}

function kapvoe_mark_order_stock_updated(array $config, string $sessionId): void {
    $path = kapvoe_orders_csv_path($config);
    if (!file_exists($path)) {
        return;
    }

    $rows = [];
    $fh = fopen($path, 'rb');
    if (!$fh) {
        return;
    }

    while (($row = fgetcsv($fh, 0, ';')) !== false) {
        $rows[] = $row;
    }
    fclose($fh);

    if (count($rows) < 1) {
        return;
    }

    $header = $rows[0];

    $sessionIdx = array_search('stripe_session_id', $header, true);
    $stockUpdatedIdx = array_search('stock_updated', $header, true);
    $stockUpdatedAtIdx = array_search('stock_updated_at', $header, true);
    $webhookProcessedIdx = array_search('webhook_processed_at', $header, true);

    if ($sessionIdx === false) {
        return;
    }

    if ($stockUpdatedIdx === false) {
        $header[] = 'stock_updated';
        $stockUpdatedIdx = count($header) - 1;
    }

    if ($stockUpdatedAtIdx === false) {
        $header[] = 'stock_updated_at';
        $stockUpdatedAtIdx = count($header) - 1;
    }

    if ($webhookProcessedIdx === false) {
        $header[] = 'webhook_processed_at';
        $webhookProcessedIdx = count($header) - 1;
    }

    $rows[0] = $header;
    $now = date('Y-m-d H:i:s');

    for ($i = 1; $i < count($rows); $i++) {
        while (count($rows[$i]) < count($header)) {
            $rows[$i][] = '';
        }

        if (($rows[$i][$sessionIdx] ?? '') === $sessionId) {
            if (($rows[$i][$stockUpdatedIdx] ?? '') === '1') {
                return;
            }

            $rows[$i][$stockUpdatedIdx] = '1';
            $rows[$i][$stockUpdatedAtIdx] = $now;
            $rows[$i][$webhookProcessedIdx] = $now;
            break;
        }
    }

    $fh = fopen($path, 'wb');
    if (!$fh) {
        return;
    }

    foreach ($rows as $row) {
        while (count($row) < count($header)) {
            $row[] = '';
        }
        fputcsv($fh, $row, ';');
    }

    fclose($fh);
}

function kapvoe_create_checkout_session(array $config, array $payload): array {
    $secretKey = (string)$config['stripe_secret_key'];

    $fields = [
        'mode' => 'payment',
        'success_url' => (string)$config['success_url'] . '?session_id={CHECKOUT_SESSION_ID}',
        'cancel_url' => (string)$config['cancel_url'],
        'customer_email' => (string)$payload['email'],
        'client_reference_id' => (string)$payload['order_id'],
        'locale' => 'es',
        'payment_method_types[0]' => 'card',
        'line_items[0][price_data][currency]' => (string)$config['currency'],
        'line_items[0][price_data][product_data][name]' => (string)$payload['product_name'],
        'line_items[0][price_data][unit_amount]' => (string)$payload['unit_amount_cents'],
        'line_items[0][quantity]' => (string)$payload['quantity'],
        'metadata[order_id]' => (string)$payload['order_id'],
        'metadata[product_code]' => (string)$payload['product_code'],
        'metadata[customer_name]' => (string)$payload['customer_name'],
        'metadata[phone]' => (string)$payload['phone'],
        'metadata[postal_code]' => (string)$payload['postal_code'],
        'metadata[city]' => (string)$payload['city'],
        'metadata[province]' => (string)$payload['province'],
    ];

    $ch = curl_init('https://api.stripe.com/v1/checkout/sessions');
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_POST => true,
        CURLOPT_POSTFIELDS => http_build_query($fields),
        CURLOPT_HTTPHEADER => [
            'Authorization: Bearer ' . $secretKey
        ],
    ]);

    $raw = curl_exec($ch);
    if ($raw === false) {
        throw new RuntimeException('Error cURL Stripe: ' . curl_error($ch));
    }

    $httpCode = (int)curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    $decoded = json_decode($raw, true);
    if ($httpCode >= 400 || !is_array($decoded)) {
        throw new RuntimeException('Stripe ha retornat un error: ' . $raw);
    }

    return $decoded;
}

function kapvoe_decrement_sheet_stock(array $config, array $order, string $sessionId): array
{
    $url = (string)($config['stock_sync_url'] ?? '');
    $token = (string)($config['stock_sync_token'] ?? '');

    if ($url === '' || $token === '') {
        throw new RuntimeException('Falta configurar stock_sync_url o stock_sync_token');
    }

    $payload = [
        'action' => 'decrement_stock',
        'token' => $token,
        'product_code' => (string)($order['product_code'] ?? ''),
        'quantity' => max(1, (int)($order['quantity'] ?? 1)),
        'order_id' => (string)($order['order_id'] ?? ''),
        'session_id' => $sessionId,
    ];

    if ($payload['product_code'] === '') {
        throw new RuntimeException('La comanda no té product_code');
    }

    if ($payload['order_id'] === '') {
        throw new RuntimeException('La comanda no té order_id');
    }

    if (!function_exists('curl_init')) {
        throw new RuntimeException('cURL no està disponible al PHP');
    }

    $ch = curl_init($url);

    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_POST => true,
        CURLOPT_POSTFIELDS => json_encode($payload, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES),
        CURLOPT_HTTPHEADER => [
            'Content-Type: application/json',
            'Accept: application/json',
        ],
        CURLOPT_TIMEOUT => 20,
        CURLOPT_CONNECTTIMEOUT => 10,
    ]);

    $response = curl_exec($ch);

    if ($response === false) {
        $error = curl_error($ch);
        curl_close($ch);
        throw new RuntimeException("Error cURL stock sync: {$error}");
    }

    $statusCode = (int)curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    if ($statusCode < 200 || $statusCode >= 300) {
        throw new RuntimeException("Stock sync HTTP {$statusCode}: {$response}");
    }

    $json = json_decode($response, true);

    if (!is_array($json)) {
        throw new RuntimeException('Resposta no JSON del stock sync: ' . $response);
    }

    if (!($json['ok'] ?? false)) {
        throw new RuntimeException('Stock sync error: ' . ($json['error'] ?? 'error desconegut'));
    }

    return $json;
}

function kapvoe_verify_stripe_signature(string $payload, string $header, string $secret, int $tolerance = 300): bool {
    if (!$header || !$secret) {
        return false;
    }

    $parts = explode(',', $header);
    $timestamp = null;
    $signature = null;

    foreach ($parts as $part) {
        [$k, $v] = array_pad(explode('=', trim($part), 2), 2, null);
        if ($k === 't') {
            $timestamp = $v;
        }
        if ($k === 'v1') {
            $signature = $v;
        }
    }

    if (!$timestamp || !$signature) {
        return false;
    }

    if (abs(time() - (int)$timestamp) > $tolerance) {
        return false;
    }

    $signedPayload = $timestamp . '.' . $payload;
    $expected = hash_hmac('sha256', $signedPayload, $secret);

    return hash_equals($expected, $signature);
}