<?php

define('TMP_FILE', __DIR__ . '/backup_tmp.json');
define('FILES_PER_STEP', 50);

// Sprawdzenie czy możemy użyć shell_exec + zip/tar
function canUseShell() {
    return function_exists('shell_exec') && !in_array('shell_exec', explode(',', ini_get('disable_functions')));
}

function commandAvailable($cmd) {
    $check = shell_exec("command -v $cmd 2>/dev/null");
    return !empty($check);
}

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    header('Content-Type: application/json');

    $action = $_POST['action'] ?? '';

    if ($action === 'init') {
        $filename = 'backup_' . date("Ymd_His");
        $response = ['success' => false];

        if (canUseShell()) {
            if (commandAvailable('tar')) {
                $tarName = "$filename.tar";
                shell_exec("tar -cf $tarName .");
                if (file_exists($tarName)) {
                    $response = [
                        'success' => true,
                        'method' => 'shell_tar',
                        'file' => $tarName
                    ];
                    echo json_encode($response);
                    exit;
                }
            } elseif (commandAvailable('zip')) {
                $zipName = "$filename.zip";
                shell_exec("zip -r $zipName . -x '*backup_*.zip' '*.git*' 'node_modules/*' 'vendor/*'");
                if (file_exists($zipName)) {
                    $response = [
                        'success' => true,
                        'method' => 'shell_zip',
                        'file' => $zipName
                    ];
                    echo json_encode($response);
                    exit;
                }
            }
        }

        // Jeśli nie ma shell_exec lub zip/tar — fallback na ZipArchive krok po kroku
        $zipName = "$filename.zip";
        $zipPath = __DIR__ . '/' . $zipName;

        $iterator = new RecursiveIteratorIterator(
            new RecursiveDirectoryIterator(__DIR__, RecursiveDirectoryIterator::SKIP_DOTS)
        );

        $files = [];
        foreach ($iterator as $file) {
            $path = $file->getPathname();
            if (strpos($path, $zipName) !== false) continue;
            $files[] = $path;
        }

        $zip = new ZipArchive();
        if ($zip->open($zipPath, ZipArchive::CREATE | ZipArchive::OVERWRITE) !== true) {
            echo json_encode(['success' => false, 'message' => 'Nie można utworzyć ZIP']);
            exit;
        }
        $zip->addEmptyDir('__INIT__');
        $zip->close();

        file_put_contents(TMP_FILE, json_encode([
            'method' => 'php_zip',
            'files' => $files,
            'index' => 0,
            'zipfile' => $zipPath,
            'zipname' => $zipName
        ]));

        echo json_encode([
            'success' => true,
            'method' => 'php_zip'
        ]);
        exit;
    }

    if ($action === 'step') {
        if (!file_exists(TMP_FILE)) {
            echo json_encode(['success' => false, 'message' => 'Brak danych tymczasowych']);
            exit;
        }

        $data = json_decode(file_get_contents(TMP_FILE), true);
        $files = $data['files'];
        $index = $data['index'];
        $zipfile = $data['zipfile'];
        $zipname = $data['zipname'];

        $zip = new ZipArchive();
        if ($zip->open($zipfile) !== true) {
            echo json_encode(['success' => false, 'message' => 'Nie można otworzyć ZIP']);
            exit;
        }

        $end = min($index + FILES_PER_STEP, count($files));
        for ($i = $index; $i < $end; $i++) {
            $filePath = $files[$i];
            if (is_file($filePath)) {
                $localname = substr($filePath, strlen(__DIR__) + 1);
                $zip->addFile($filePath, $localname);
            }
        }

        $zip->close();

        $data['index'] = $end;
        file_put_contents(TMP_FILE, json_encode($data));

        $progress = $end / count($files);

        echo json_encode([
            'success' => true,
            'method' => 'php_zip',
            'progress' => round($progress * 100, 2),
            'done' => $end >= count($files),
            'zipfile' => $zipname
        ]);
        exit;
    }
}
?>

<!DOCTYPE html>
<html lang="pl">
<head>
  <meta charset="UTF-8">
  <title>Backup dynamiczny</title>
  <script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
  <style>
    #progress-bar {
      width: 100%;
      background-color: #eee;
      border: 1px solid #ccc;
      margin-top: 10px;
    }
    #progress-bar-inner {
      height: 20px;
      width: 0;
      background-color: #4caf50;
      text-align: center;
      color: white;
      line-height: 20px;
      transition: width 0.3s ease;
    }
  </style>
</head>
<body>

<h2>Automatyczny backup plików</h2>
<button id="start-backup">Rozpocznij</button>

<div id="progress-bar" style="display:none;">
  <div id="progress-bar-inner">0.00%</div>
</div>

<div id="status"></div>

<script>
$(document).ready(function(){
  let method = '';
  let zipFile = '';

  $("#start-backup").click(function(){
    $("#status").text("Inicjalizowanie...");
    $("#progress-bar").show();
    $("#progress-bar-inner").css("width", "0%").text("0.00%");

    $.post("", { action: "init" }, function(res){
      if (!res.success) {
        $("#status").text("Błąd: " + res.message);
        return;
      }

      method = res.method;

      if (method === 'shell_tar' || method === 'shell_zip') {
        $("#progress-bar-inner").css("width", "100%").text("100%");
        $("#status").html("✅ Gotowe! <a href='" + res.file + "' download>Pobierz</a>");
      } else if (method === 'php_zip') {
        doStep();
      }
    }, "json");
  });

  function doStep() {
    $.post("", { action: "step" }, function(res){
      if (res.success && res.method === 'php_zip') {
        let percent = parseFloat(res.progress).toFixed(2);
        $("#progress-bar-inner").css("width", percent + "%").text(percent + "%");

        if (res.done) {
          $("#status").html("✅ Backup gotowy! <a href='" + res.zipfile + "' download>Pobierz ZIP</a>");
        } else {
          setTimeout(doStep, 300);
        }
      } else {
        $("#status").text("Błąd: " + res.message);
      }
    }, "json");
  }
});
</script>

</body>
</html>