<?php
declare(strict_types=1);

require_once __DIR__ . '/service.php';

function erp_lager_mcp_token(array $env): string
{
    $token = env_value('MARKET_MCP_TOKEN', $env);
    if ($token === '') {
        throw new RuntimeException('MARKET_MCP_TOKEN ist nicht konfiguriert.');
    }

    return $token;
}

function erp_lager_mcp_authorize(array $env): string
{
    $header = $_SERVER['HTTP_AUTHORIZATION'] ?? '';
    if (!preg_match('/^Bearer\s+(.+)$/i', $header, $matches)) {
        throw new RuntimeException('MCP Authorization Bearer Token fehlt.');
    }

    $token = trim($matches[1]);
    if (!hash_equals(erp_lager_mcp_token($env), $token)) {
        throw new RuntimeException('MCP Authorization Bearer Token ist ungültig.');
    }

    return 'hermes';
}

function erp_lager_mcp_tools(): array
{
    return [
        [
            'name' => 'erp_lager.list_products',
            'description' => 'Aktive ERP-Lagerprodukte zur Ermittlung der Produkt-IDs lesen',
            'inputSchema' => ['type' => 'object', 'properties' => (object) []],
        ],
        [
            'name' => 'erp_lager.get_product',
            'description' => 'Produkt, aktuelle Lagermenge, Chargen und Ausverkaufsprognose lesen',
            'inputSchema' => [
                'type' => 'object',
                'required' => ['product_id'],
                'properties' => [
                    'product_id' => ['type' => 'integer'],
                ],
            ],
        ],
    ];
}

function erp_lager_mcp_list_products(PDO $pdo): array
{
    return array_map(
        static fn (array $product): array => [
            'id' => $product['id'],
            'name' => $product['name'],
            'sku' => $product['sku'],
            'uom' => $product['uom'],
        ],
        get_otc_order_form_products($pdo)
    );
}

function erp_lager_mcp_get_product(PDO $pdo, int $productId): array
{
    if ($productId < 1) {
        throw new InvalidArgumentException('product_id muss eine positive Ganzzahl sein.');
    }

    foreach (get_lager_product_overview($pdo) as $product) {
        if ((int) $product['id'] === $productId) {
            return $product;
        }
    }

    throw new InvalidArgumentException('Aktives Lagerprodukt nicht gefunden.');
}

function erp_lager_mcp_call(PDO $pdo, string $tool, array $arguments): array
{
    return match ($tool) {
        'erp_lager.list_products' => erp_lager_mcp_list_products($pdo),
        'erp_lager.get_product' => erp_lager_mcp_get_product(
            $pdo,
            (int) ($arguments['product_id'] ?? 0)
        ),
        default => throw new InvalidArgumentException('Unbekanntes Lager-MCP-Tool: ' . $tool),
    };
}