#!/usr/bin/env node

import fs from 'fs';
import path from 'path';
import zlib from 'zlib';
import { fileURLToPath } from 'url';
import { pipeline } from 'stream/promises';

// --- Konfiguration ---
const GZIP_OPTIONS = { level: zlib.constants.Z_BEST_COMPRESSION };
// --------------------

/**
 * Kopiert und komprimiert nur die index.html Datei von sourceDir nach destDir.
 * Die Datei wird nur als .gz gespeichert.
 *
 * @param {string} sourceDir - Quellordner
 * @param {string} destDir - Zielordner
 */
async function processIndexHtml(sourceDir, destDir) {
  console.log(`Processing index.html from '${sourceDir}' to '${destDir}'`);

  // Erstelle Zielverzeichnis, wenn es nicht existiert
  if (!fs.existsSync(destDir)) {
    fs.mkdirSync(destDir, { recursive: true });
  }

  const sourcePath = path.join(sourceDir, 'index.html');
  const destPathGz = path.join(destDir, 'index.html.gz');

  // Prüfe ob index.html existiert
  if (!fs.existsSync(sourcePath)) {
    throw new Error(`index.html not found in '${sourceDir}'`);
  }

  // Komprimiere index.html
  console.log(`Compressing ${sourcePath} -> ${destPathGz}`);
  try {
    const readStream = fs.createReadStream(sourcePath);
    const gzipStream = zlib.createGzip(GZIP_OPTIONS);
    const writeStream = fs.createWriteStream(destPathGz);
    await pipeline(readStream, gzipStream, writeStream);
  } catch (err) {
    console.error(`Error compressing ${sourcePath}:`, err);
    throw err;
  }
}

/**
 * Lösche den Ordner und seinen gesamten Inhalt
 *
 * @param {string} dir - Der zu löschende Ordner
 */
function removeDir(dir) {
  if (fs.existsSync(dir)) {
    console.log(`Removing existing directory '${dir}'`);
    fs.rmSync(dir, { recursive: true, force: true });
  }
}

// Hauptfunktion
async function main() {
  // Projekt-Root-Verzeichnis ermitteln
  const __filename = fileURLToPath(import.meta.url);
  const __dirname = path.dirname(__filename);
  
  const scriptDir = __dirname;
  const projectRoot = path.resolve(scriptDir, '..');
  const rootDir = path.resolve(projectRoot, '..');
  
  // Quell- und Zielverzeichnisse
  const sourceDir = path.join(projectRoot, 'build');
  const destDir = path.join(rootDir, 'data', 'web');

  if (!fs.existsSync(sourceDir) || !fs.statSync(sourceDir).isDirectory()) {
    console.error(`Error: Source directory '${sourceDir}' doesn't exist or is not a directory!`);
    console.error("Make sure to build the Svelte app first with 'npm run build'");
    process.exit(1);
  }

  removeDir(destDir);

  try {
     await processIndexHtml(sourceDir, destDir);
     console.log("index.html processed successfully!");
  } catch(err) {
     console.error("Error during file processing:", err);
     process.exit(1);
  }
}

// Ausführen des Skripts
main();