<?php

declare(strict_types=1);

/** @return list<string> */
function getValidTransitions(string $currentStatus): array
{
    $map = [
        'prijata' => ['v_realizaci', 'stornovana'],
        'v_realizaci' => ['dokoncena', 'stornovana'],
        'dokoncena' => [],
        'stornovana' => [],
    ];
    return $map[$currentStatus] ?? [];
}

// --- Number generation ---

function generateOrderNumber(PDO $pdo): string
{
    return generateSharedNumber($pdo);
}

// --- Handlers ---

function handleGetList(PDO $pdo): void
{
    $sortMap = [
        'OrderNumber' => 'o.order_number',
        'order_number' => 'o.order_number',
        'CreatedAt' => 'o.created_at',
        'created_at' => 'o.created_at',
        'Status' => 'o.status',
        'status' => 'o.status',
        'Currency' => 'o.currency',
        'currency' => 'o.currency',
    ];

    $p = PaginationHelper::parseParams($sortMap);
    $where = 'WHERE 1=1';
    $params = [];

    if ($p['search']) {
        $where .= ' AND (o.order_number LIKE ? OR q.quotation_number LIKE ? OR q.project_code LIKE ? OR c.name LIKE ?)';
        $searchParam = "%{$p['search']}%";
        $params = [$searchParam, $searchParam, $searchParam, $searchParam];
    }

    $from = "FROM orders o
        LEFT JOIN quotations q ON o.quotation_id = q.id
        LEFT JOIN customers c ON o.customer_id = c.id";

    $result = PaginationHelper::paginate(
        $pdo,
        "SELECT COUNT(*) {$from} {$where}",
        "SELECT o.id, o.order_number, o.quotation_id, o.status, o.currency,
               o.created_at, o.apply_vat, o.vat_rate,
               q.quotation_number, q.project_code,
               c.name as customer_name,
               (SELECT COALESCE(SUM(CASE WHEN oi.is_included_in_total THEN oi.quantity * oi.unit_price ELSE 0 END), 0)
                FROM order_items oi WHERE oi.order_id = o.id) as total,
               (SELECT inv.id FROM invoices inv WHERE inv.order_id = o.id LIMIT 1) as invoice_id,
               (SELECT inv.invoice_number FROM invoices inv WHERE inv.order_id = o.id LIMIT 1) as invoice_number
        {$from} {$where}
        ORDER BY {$p['sort']} {$p['order']}",
        $params,
        $p
    );

    successResponse([
        'orders' => $result['items'],
        'pagination' => $result['pagination'],
    ]);
}

function handleGetDetail(PDO $pdo, int $id): void
{
    // BLOB vynechany - stahuje se pres action=attachment
    $stmt = $pdo->prepare('
        SELECT o.id, o.order_number, o.customer_order_number, o.attachment_name,
               o.quotation_id, o.customer_id, o.status, o.currency, o.language,
               o.vat_rate, o.apply_vat, o.exchange_rate, o.scope_title, o.scope_description,
               o.notes, o.created_at, o.modified_at,
               q.quotation_number, q.project_code,
               c.name as customer_name
        FROM orders o
        LEFT JOIN quotations q ON o.quotation_id = q.id
        LEFT JOIN customers c ON o.customer_id = c.id
        WHERE o.id = ?
    ');
    $stmt->execute([$id]);
    $order = $stmt->fetch();

    if (!$order) {
        errorResponse('Objednávka nebyla nalezena', 404);
    }

    // Get items
    $stmt = $pdo->prepare('SELECT * FROM order_items WHERE order_id = ? ORDER BY position');
    $stmt->execute([$id]);
    $order['items'] = $stmt->fetchAll();

    // Get sections
    $stmt = $pdo->prepare('SELECT * FROM order_sections WHERE order_id = ? ORDER BY position');
    $stmt->execute([$id]);
    $order['sections'] = $stmt->fetchAll();

    // Get customer
    if ($order['customer_id']) {
        $stmt = $pdo->prepare(
            'SELECT id, name, company_id, vat_id, street, city,
                postal_code, country, custom_fields
            FROM customers WHERE id = ?'
        );
        $stmt->execute([$order['customer_id']]);
        $order['customer'] = $stmt->fetch();
    }

    // Get linked project
    $stmt = $pdo->prepare('SELECT id, project_number, name, status FROM projects WHERE order_id = ?');
    $stmt->execute([$id]);
    $order['project'] = $stmt->fetch() ?: null;

    // Get linked invoice
    $stmt = $pdo->prepare('SELECT id, invoice_number, status FROM invoices WHERE order_id = ? LIMIT 1');
    $stmt->execute([$id]);
    $order['invoice'] = $stmt->fetch() ?: null;

    // Valid transitions
    $order['valid_transitions'] = getValidTransitions($order['status']);

    successResponse($order);
}

function handleGetAttachment(PDO $pdo, int $id): void
{
    $stmt = $pdo->prepare('SELECT attachment_data, attachment_name FROM orders WHERE id = ?');
    $stmt->execute([$id]);
    $row = $stmt->fetch();

    if (!$row || !$row['attachment_data']) {
        errorResponse('Příloha nebyla nalezena', 404);
    }

    $finfo = new finfo(FILEINFO_MIME_TYPE);
    $mime = $finfo->buffer($row['attachment_data']);
    if ($mime !== 'application/pdf') {
        errorResponse('Příloha není platný PDF soubor', 415);
    }

    header_remove('Content-Type');
    header('Content-Type: application/pdf');
    $safeName = preg_replace('/[^a-zA-Z0-9._-]/', '_', basename($row['attachment_name'] ?: 'priloha.pdf'));
    header('Content-Disposition: attachment; filename="' . $safeName . '"');
    header('Content-Length: ' . strlen($row['attachment_data']));
    echo $row['attachment_data'];
    exit;
}

function handleCreateOrder(PDO $pdo): void
{
    // Podporuje JSON i FormData (kvuli nahravani prilohy)
    $contentType = $_SERVER['CONTENT_TYPE'] ?? '';
    if (str_contains($contentType, 'multipart/form-data')) {
        $quotationId = (int)($_POST['quotationId'] ?? 0);
        $customerOrderNumber = trim($_POST['customerOrderNumber'] ?? '');
    } else {
        $input = getJsonInput();
        $quotationId = (int)($input['quotationId'] ?? 0);
        $customerOrderNumber = trim($input['customerOrderNumber'] ?? '');
    }

    if (!$quotationId) {
        errorResponse('ID nabídky je povinné');
    }

    if ($customerOrderNumber === '') {
        errorResponse('Číslo objednávky zákazníka je povinné');
    }
    if (mb_strlen($customerOrderNumber) > 100) {
        errorResponse('Číslo objednávky zákazníka je příliš dlouhé (max 100 znaků)');
    }

    // Validace prilohy
    $attachmentData = null;
    $attachmentName = null;
    if (!empty($_FILES['attachment']['tmp_name'])) {
        $file = $_FILES['attachment'];
        if ($file['error'] !== UPLOAD_ERR_OK) {
            errorResponse('Chyba při nahrávání souboru');
        }
        $finfo = new finfo(FILEINFO_MIME_TYPE);
        $mime = $finfo->file($file['tmp_name']);
        if ($mime !== 'application/pdf') {
            errorResponse('Příloha musí být ve formátu PDF');
        }
        if ($file['size'] > 10 * 1024 * 1024) {
            errorResponse('Příloha nesmí být větší než 10 MB');
        }
        $attachmentData = file_get_contents($file['tmp_name']);
        $attachmentName = preg_replace('/[^a-zA-Z0-9._-]/', '_', basename($file['name']));
    }

    // Verify quotation exists and has no order yet
    $stmt = $pdo->prepare('SELECT * FROM quotations WHERE id = ?');
    $stmt->execute([$quotationId]);
    $quotation = $stmt->fetch();

    if (!$quotation) {
        errorResponse('Nabídka nebyla nalezena', 404);
    }

    if ($quotation['order_id']) {
        errorResponse('Tato nabídka již má objednávku');
    }

    // Get quotation items and sections
    $stmt = $pdo->prepare('SELECT * FROM quotation_items WHERE quotation_id = ? ORDER BY position');
    $stmt->execute([$quotationId]);
    $quotationItems = $stmt->fetchAll();

    $stmt = $pdo->prepare('SELECT * FROM scope_sections WHERE quotation_id = ? ORDER BY position');
    $stmt->execute([$quotationId]);
    $quotationSections = $stmt->fetchAll();

    // Lock for concurrent number generation
    $locked = $pdo->query("SELECT GET_LOCK('boha_order_number', 5)")->fetchColumn();
    if (!$locked) {
        errorResponse('Nepodařilo se získat zámek pro číslo objednávky, zkuste to znovu', 503);
    }

    $pdo->beginTransaction();
    try {
        $orderNumber = generateOrderNumber($pdo);

        $stmt = $pdo->prepare("
            INSERT INTO orders (
                order_number, customer_order_number, attachment_data, attachment_name,
                quotation_id, customer_id, status,
                currency, language, vat_rate, apply_vat, exchange_rate,
                scope_title, scope_description, created_at, modified_at
            ) VALUES (?, ?, ?, ?, ?, ?, 'prijata', ?, ?, ?, ?, ?, ?, ?, NOW(), NOW())
        ");
        $stmt->execute([
            $orderNumber,
            $customerOrderNumber,
            $attachmentData,
            $attachmentName,
            $quotationId,
            $quotation['customer_id'],
            $quotation['currency'] ?? 'EUR',
            $quotation['language'] ?? 'EN',
            $quotation['vat_rate'] ?? 0,
            $quotation['apply_vat'] ?? 0,
            $quotation['exchange_rate'],
            $quotation['scope_title'] ?? '',
            $quotation['scope_description'] ?? '',
        ]);
        $orderId = (int)$pdo->lastInsertId();

        // Copy items
        if (!empty($quotationItems)) {
            $itemStmt = $pdo->prepare('
                INSERT INTO order_items (
                    order_id, description, item_description, quantity, unit,
                    unit_price, is_included_in_total, position, modified_at
                ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, NOW())
            ');
            foreach ($quotationItems as $item) {
                $itemStmt->execute([
                    $orderId,
                    $item['description'] ?? '',
                    $item['item_description'] ?? '',
                    $item['quantity'] ?? 1,
                    $item['unit'] ?? '',
                    $item['unit_price'] ?? 0,
                    $item['is_included_in_total'] ?? 1,
                    $item['position'] ?? 0,
                ]);
            }
        }

        // Copy sections
        if (!empty($quotationSections)) {
            $sectionStmt = $pdo->prepare('
                INSERT INTO order_sections (
                    order_id, title, title_cz, content, position, modified_at
                ) VALUES (?, ?, ?, ?, ?, NOW())
            ');
            foreach ($quotationSections as $section) {
                $sectionStmt->execute([
                    $orderId,
                    $section['title'] ?? '',
                    $section['title_cz'] ?? '',
                    $section['content'] ?? '',
                    $section['position'] ?? 0,
                ]);
            }
        }

        // Create project with same number
        $projectName = $quotation['project_code'] ?: ($quotation['customer_name'] ?? 'Projekt ' . $orderNumber);
        // Need customer name
        if (!$quotation['project_code'] && $quotation['customer_id']) {
            $custStmt = $pdo->prepare('SELECT name FROM customers WHERE id = ?');
            $custStmt->execute([$quotation['customer_id']]);
            $custName = $custStmt->fetchColumn();
            if ($custName) {
                $projectName = $custName;
            }
        }

        $stmt = $pdo->prepare("
            INSERT INTO projects (
                project_number, name, customer_id, quotation_id, order_id,
                status, start_date, created_at, modified_at
            ) VALUES (?, ?, ?, ?, ?, 'aktivni', CURDATE(), NOW(), NOW())
        ");
        $stmt->execute([
            $orderNumber,
            $projectName,
            $quotation['customer_id'],
            $quotationId,
            $orderId,
        ]);
        $projectId = (int)$pdo->lastInsertId();

        // Update quotation with back-reference
        $stmt = $pdo->prepare('UPDATE quotations SET order_id = ?, modified_at = NOW() WHERE id = ?');
        $stmt->execute([$orderId, $quotationId]);


        $pdo->commit();
        $pdo->query("SELECT RELEASE_LOCK('boha_order_number')");

        AuditLog::logCreate('orders_order', $orderId, [
            'order_number' => $orderNumber,
            'quotation_number' => $quotation['quotation_number'],
            'project_id' => $projectId,
        ], "Vytvořena objednávka '$orderNumber' z nabídky '{$quotation['quotation_number']}'");

        successResponse([
            'order_id' => $orderId,
            'order_number' => $orderNumber,
            'project_id' => $projectId,
            'project_number' => $orderNumber,
        ], 'Objednávka byla vytvořena');
    } catch (PDOException $e) {
        $pdo->rollBack();
        $pdo->query("SELECT RELEASE_LOCK('boha_order_number')");
        throw $e;
    }
}

function handleUpdateOrder(PDO $pdo, int $id): void
{
    $stmt = $pdo->prepare('SELECT * FROM orders WHERE id = ?');
    $stmt->execute([$id]);
    $order = $stmt->fetch();

    if (!$order) {
        errorResponse('Objednávka nebyla nalezena', 404);
    }

    $input = getJsonInput();
    $newStatus = $input['status'] ?? null;
    $notes = $input['notes'] ?? null;
    $newOrderNumber = isset($input['order_number']) ? trim($input['order_number']) : null;

    // Delkove limity
    if ($notes !== null && mb_strlen($notes) > 5000) {
        errorResponse('Poznámky jsou příliš dlouhé (max 5000 znaků)');
    }
    if ($newOrderNumber !== null && mb_strlen($newOrderNumber) > 50) {
        errorResponse('Číslo objednávky je příliš dlouhé (max 50 znaků)');
    }

    // Validate status transition
    if ($newStatus && $newStatus !== $order['status']) {
        $valid = getValidTransitions($order['status']);
        if (!in_array($newStatus, $valid)) {
            errorResponse("Neplatný přechod stavu z '{$order['status']}' na '$newStatus'");
        }
    }

    // Validate order number uniqueness
    if ($newOrderNumber !== null && $newOrderNumber !== $order['order_number']) {
        if (empty($newOrderNumber)) {
            errorResponse('Číslo objednávky nesmí být prázdné');
        }
        $stmt = $pdo->prepare('SELECT id FROM orders WHERE order_number = ? AND id != ?');
        $stmt->execute([$newOrderNumber, $id]);
        if ($stmt->fetch()) {
            errorResponse('Toto číslo objednávky již existuje');
        }
    }

    $pdo->beginTransaction();
    try {
        $updates = [];
        $params = [];

        if ($newOrderNumber !== null && $newOrderNumber !== $order['order_number']) {
            $updates[] = 'order_number = ?';
            $params[] = $newOrderNumber;

            // Sync project number
            $stmt = $pdo->prepare('UPDATE projects SET project_number = ?, modified_at = NOW() WHERE order_id = ?');
            $stmt->execute([$newOrderNumber, $id]);
        }
        if ($newStatus !== null) {
            $updates[] = 'status = ?';
            $params[] = $newStatus;
        }
        if ($notes !== null) {
            $updates[] = 'notes = ?';
            $params[] = $notes;
        }

        if (!empty($updates)) {
            $updates[] = 'modified_at = NOW()';
            $params[] = $id;
            $sql = 'UPDATE orders SET ' . implode(', ', $updates) . ' WHERE id = ?';
            $stmt = $pdo->prepare($sql);
            $stmt->execute($params);
        }

        // Sync project status with order status
        if ($newStatus && $newStatus !== $order['status']) {
            $projectStatus = null;
            if ($newStatus === 'stornovana') {
                $projectStatus = 'zruseny';
            } elseif ($newStatus === 'dokoncena') {
                $projectStatus = 'dokonceny';
            } elseif ($newStatus === 'v_realizaci') {
                $projectStatus = 'aktivni';
            }

            if ($projectStatus) {
                $stmt = $pdo->prepare('UPDATE projects SET status = ?, modified_at = NOW() WHERE order_id = ?');
                $stmt->execute([$projectStatus, $id]);
            }
        }

        $pdo->commit();

        AuditLog::logUpdate(
            'orders_order',
            $id,
            ['status' => $order['status'], 'notes' => $order['notes']],
            ['status' => $newStatus ?? $order['status'], 'notes' => $notes ?? $order['notes']],
            "Upravena objednávka '{$order['order_number']}'"
        );

        successResponse(null, 'Objednávka byla aktualizována');
    } catch (PDOException $e) {
        $pdo->rollBack();
        throw $e;
    }
}

function handleDeleteOrder(PDO $pdo, int $id): void
{
    $stmt = $pdo->prepare('SELECT * FROM orders WHERE id = ?');
    $stmt->execute([$id]);
    $order = $stmt->fetch();

    if (!$order) {
        errorResponse('Objednávka nebyla nalezena', 404);
    }

    $pdo->beginTransaction();
    try {
        // Delete project linked to this order
        $stmt = $pdo->prepare('DELETE FROM projects WHERE order_id = ?');
        $stmt->execute([$id]);

        // Delete order items and sections
        $stmt = $pdo->prepare('DELETE FROM order_items WHERE order_id = ?');
        $stmt->execute([$id]);

        $stmt = $pdo->prepare('DELETE FROM order_sections WHERE order_id = ?');
        $stmt->execute([$id]);

        // Delete order
        $stmt = $pdo->prepare('DELETE FROM orders WHERE id = ?');
        $stmt->execute([$id]);

        // Remove back-reference from quotation
        $stmt = $pdo->prepare('UPDATE quotations SET order_id = NULL, modified_at = NOW() WHERE order_id = ?');
        $stmt->execute([$id]);

        $pdo->commit();

        AuditLog::logDelete('orders_order', $id, [
            'order_number' => $order['order_number'],
            'quotation_id' => $order['quotation_id'],
        ], "Smazána objednávka '{$order['order_number']}'");

        successResponse(null, 'Objednávka byla smazána');
    } catch (PDOException $e) {
        $pdo->rollBack();
        throw $e;
    }
}