<?php

namespace App\Form;

use App\Gui\Units;
use App\Model\Connection;
use App\Model\Session;
use JumPHP\Gui\Button;
use JumPHP\Gui\CheckBox;
use JumPHP\Gui\Form;
use JumPHP\Gui\Label;
use JumPHP\Gui\TextBox;
use JumPHP\Kernel\Platform;
use JumPHP\Native\FilePicker;
use JumPHP\Native\Native;

/**
 * VM > Export…: where to save the XVA file (typed, or the system's Save dialog when this target has one: a desktop app), compressed
 * or not. A browser cannot write a file of that size anywhere: the dialog says so. Closes with ['xva' => ['op' => 'export', ...]],
 * src/Feature/Xva/XvaTransfers streams it.
 *
 * @property Label $heading
 * @property Label $where
 * @property TextBox $path
 * @property Button $browse
 * @property CheckBox $compress
 * @property Label $size
 * @property Label $error
 * @property Button $export
 * @property Button $cancel
 */
final class ExportForm extends Form
{
    private array $params = [];

    public function __construct(private Session $session)
    {
        parent::__construct();
    }

    /** XAPI's answers, events and the console go on while this dialog is open. */
    protected function tick(float $dt): void
    {
        $this->session->tick($dt);
    }

    /** @return array<string, mixed> */
    public static function paramsFor(Connection $c, string $vm): array
    {
        $size = 0.0;
        foreach ($c->cache->disksOf($vm) as $d) {
            if ($d['vdi'] !== null && ($d['vbd']['type'] ?? '') !== 'CD') {
                $size += (float)($d['vdi']['physical_utilisation'] ?? 0);
            }
        }
        $name = $c->cache->name($vm);
        $dir = rtrim((string)(getenv('HOME') ?: sys_get_temp_dir()), '/');
        return ['target' => $vm, 'name' => $name, 'server' => $c->name(), 'size' => $size,
            'file' => $dir . '/' . (trim((string)preg_replace('/[^A-Za-z0-9._-]+/', '-', $name), '-') ?: 'vm') . '.xva',
            'halted' => in_array($c->cache->field($vm, 'power_state', ''), ['Halted'], true) || !empty($c->cache->field($vm, 'is_a_snapshot'))];
    }

    protected function loaded(array $params = []): void
    {
        $this->params = $params;
        $this->heading->text = "Export VM '" . ($params['name'] ?? '') . "'";
        $this->where->text = "In '" . ($params['server'] ?? '') . "'";
        $this->path->text = (string)($params['file'] ?? '');
        $this->browse->enabled = Native::supports('save');
        $this->size->text = 'Its disks hold ' . Units::bytes((float)($params['size'] ?? 0)) . ': the file is about that size (less when compressed).';
        $this->error->text = '';
        $this->export->enabled = true;
        if (Platform::isWasm()) {
            // a web page can only hand a file to the browser's downloads, all in memory: not for a VM's disks
            $this->error->text = 'Exporting to a file is not possible in a browser (a VM does not fit in the page\'s memory): use XenCenter on the desktop, or xe vm-export on the server.';
            $this->export->enabled = false;
        } elseif (empty($params['halted'])) {
            $this->error->text = 'Shut the VM down first: XAPI exports halted VMs (or snapshots) only.';
            $this->export->enabled = false;
        }
        $this->setFocus($this->path);
    }

    public function onBrowseClick(Button $sender): void
    {
        if (!Native::supports('save')) {
            return;
        }
        FilePicker::save(['title' => 'Export VM', 'file_name' => basename($this->path->text), 'directory' => dirname($this->path->text),
            'filters' => ['XVA files' => ['xva']]])->then(function (?string $file): void {
                if ($file !== null) {
                    $this->path->text = str_ends_with(strtolower($file), '.xva') ? $file : $file . '.xva';
                }
            }, fn (\Throwable $e) => $this->error->text = $e->getMessage());
    }

    public function onExportClick(mixed $sender = null): void
    {
        if (!$this->export->enabled) {
            return;
        }
        $file = trim($this->path->text);
        if ($file === '' || str_ends_with($file, '/')) {
            $this->error->text = 'Enter the file to write.';
            return;
        }
        if (!is_dir(dirname($file)) || !is_writable(dirname($file))) {
            $this->error->text = 'The folder ' . dirname($file) . ' does not exist or cannot be written.';
            return;
        }
        $this->close(['xva' => ['op' => 'export', 'target' => $this->params['target'] ?? '', 'file' => $file, 'compress' => $this->compress->checked]]);
    }

    public function onCancelClick(Button $sender): void
    {
        $this->close();
    }
}