<?php

declare(strict_types=1);

require_once __DIR__ . '/bootstrap.php';

function dolibarr_base_url(): string
{
    $url = getenv('DOLIBARR_URL');
    if ($url === false || $url === '') {
        throw new RuntimeException('DOLIBARR_URL ist nicht gesetzt.');
    }

    return rtrim($url, '/');
}

function dolibarr_api_key(): string
{
    $key = getenv('DOLIBARR_API_KEY');
    if ($key === false || $key === '') {
        throw new RuntimeException('DOLIBARR_API_KEY ist nicht gesetzt.');
    }

    return $key;
}

/**
 * @return array{ok: bool, status: int, data: array, error: ?string}
 */
function dolibarr_request(string $method, string $path, ?array $jsonBody = null): array
{
    $headers = 'DOLAPIKEY: ' . dolibarr_api_key() . "\r\nAccept: application/json\r\n";
    $content = null;
    if ($jsonBody !== null) {
        $content = json_encode($jsonBody, JSON_THROW_ON_ERROR);
        $headers .= "Content-Type: application/json\r\n";
    }

    $context = stream_context_create([
        'http' => [
            'method' => $method,
            'timeout' => 20,
            'ignore_errors' => true,
            'header' => $headers,
            'content' => $content,
        ],
    ]);

    $url = dolibarr_base_url() . '/api/index.php' . $path;
    $body = @file_get_contents($url, false, $context);

    $status = 0;
    foreach ($http_response_header ?? [] as $header) {
        if (preg_match('~^HTTP/\S+\s+(\d{3})~', $header, $matches) === 1) {
            $status = (int)$matches[1];
        }
    }

    if ($body === false) {
        $error = error_get_last();
        return ['ok' => false, 'status' => $status, 'data' => [], 'error' => $error['message'] ?? 'Unbekannter HTTP-Fehler'];
    }

    $decoded = json_decode($body, true);
    if ($status < 200 || $status >= 300) {
        $message = is_array($decoded) ? ($decoded['error']['message'] ?? $body) : $body;
        return ['ok' => false, 'status' => $status, 'data' => is_array($decoded) ? $decoded : [], 'error' => (string)$message];
    }

    // Dolibarr's create-endpoints return a bare numeric id, not JSON.
    if (!is_array($decoded)) {
        return ['ok' => true, 'status' => $status, 'data' => ['id' => trim($body, "\" \n")], 'error' => null];
    }

    return ['ok' => true, 'status' => $status, 'data' => $decoded, 'error' => null];
}

/**
 * Resolves the Dolibarr thirdparty (customer) id for a tenant, creating it
 * on first use and caching it in tenant_billing.dolibarr_thirdparty_id.
 */
function dolibarr_find_or_create_thirdparty(PDO $pdo, int $tenantId): ?int
{
    $billing = billing_fetch_or_init($pdo, $tenantId);
    if (!empty($billing['dolibarr_thirdparty_id'])) {
        return (int)$billing['dolibarr_thirdparty_id'];
    }

    $stmt = $pdo->prepare('SELECT name FROM tenants WHERE id = ?');
    $stmt->execute([$tenantId]);
    $tenantName = (string)($stmt->fetchColumn() ?: "Mandant #{$tenantId}");

    $stmt = $pdo->prepare(
        "SELECT u.email FROM users u
         INNER JOIN tenant_memberships tm ON tm.user_id = u.id
         WHERE tm.tenant_id = ? AND tm.role = 'owner' AND tm.status = 'active'
         ORDER BY tm.id ASC LIMIT 1"
    );
    $stmt->execute([$tenantId]);
    $ownerEmail = $stmt->fetchColumn();

    $result = dolibarr_request('POST', '/thirdparties', [
        'name' => "Kaffeeliste - {$tenantName}",
        'client' => 1,
        'code_client' => 'auto',
        'email' => $ownerEmail !== false ? (string)$ownerEmail : '',
        'note_private' => "Automatisch angelegt durch die Kaffeeliste-App fuer Mandant #{$tenantId}.",
    ]);

    if (!$result['ok']) {
        return null;
    }

    $thirdpartyId = (int)$result['data']['id'];
    billing_update($pdo, $tenantId, ['dolibarr_thirdparty_id' => (string)$thirdpartyId]);

    return $thirdpartyId;
}

/**
 * Creates a single-line invoice for a thirdparty and validates it
 * immediately (assigns the permanent, sequential invoice number). Intended
 * to be called only for genuine, already-collected Stripe payments.
 *
 * @return array{ok: bool, invoice_id: ?int, ref: ?string, error: ?string}
 */
function dolibarr_create_and_validate_invoice(int $thirdpartyId, string $description, int $amountCents): array
{
    $created = dolibarr_request('POST', '/invoices', [
        'socid' => $thirdpartyId,
        'type' => 0,
        'note_private' => 'Automatisch erzeugt durch die Kaffeeliste-App aus einer erfolgreichen Stripe-Zahlung.',
    ]);
    if (!$created['ok']) {
        return ['ok' => false, 'invoice_id' => null, 'ref' => null, 'error' => 'Rechnung anlegen fehlgeschlagen: ' . $created['error']];
    }

    $invoiceId = (int)$created['data']['id'];

    $line = dolibarr_request('POST', "/invoices/{$invoiceId}/lines", [
        'desc' => $description,
        'qty' => 1,
        'subprice' => round($amountCents / 100, 2),
        // Kleinunternehmer nach § 19 UStG: keine Umsatzsteuer ausgewiesen.
        'tva_tx' => 0,
    ]);
    if (!$line['ok']) {
        return ['ok' => false, 'invoice_id' => $invoiceId, 'ref' => null, 'error' => 'Rechnungsposition anlegen fehlgeschlagen: ' . $line['error']];
    }

    $validated = dolibarr_request('POST', "/invoices/{$invoiceId}/validate", []);
    if (!$validated['ok']) {
        return ['ok' => false, 'invoice_id' => $invoiceId, 'ref' => null, 'error' => 'Rechnung validieren fehlgeschlagen: ' . $validated['error']];
    }

    $fetched = dolibarr_request('GET', "/invoices/{$invoiceId}");
    $ref = $fetched['ok'] ? (string)($fetched['data']['ref'] ?? '') : null;

    return ['ok' => true, 'invoice_id' => $invoiceId, 'ref' => $ref, 'error' => null];
}

/**
 * Orchestrates the Dolibarr side of a successful Stripe payment: resolves
 * (or creates) the tenant's Dolibarr customer, then creates and validates
 * a mirrored invoice. Stripe remains the sole payment channel; Dolibarr is
 * populated purely as a bookkeeping mirror, never invoked to collect money.
 *
 * @return array{ok: bool, invoice_id: ?int, ref: ?string, error: ?string}
 */
function dolibarr_sync_invoice_paid(PDO $pdo, int $tenantId, string $planCode, int $amountCents): array
{
    $thirdpartyId = dolibarr_find_or_create_thirdparty($pdo, $tenantId);
    if ($thirdpartyId === null) {
        return ['ok' => false, 'invoice_id' => null, 'ref' => null, 'error' => 'Dolibarr-Kunde konnte nicht ermittelt/angelegt werden.'];
    }

    $plans = billing_plans();
    $planLabel = $plans[$planCode]['label'] ?? $planCode;
    $description = "Kaffeeliste SaaS-Abo - Tarif {$planLabel} - " . date('m/Y');

    return dolibarr_create_and_validate_invoice($thirdpartyId, $description, $amountCents);
}