const unzipper = require('unzipper');
const fs = require('fs-extra');
const path = require('path');
const { pipeline } = require('stream/promises');
const { getDestinationDecision, isCadFile } = require('./router');
const { buildDestinationIndex } = require('./destinationIndex');

async function processZip(zipPath, config) {
  const stream = fs.createReadStream(zipPath).pipe(unzipper.Parse({ forceStream: true }));
  const destinationIndex = await buildDestinationIndex(config?.destination);
  const result = {
    scanned: 0,
    copied: 0,
    skipped: 0,
    details: [],
  };

  for await (const entry of stream) {
    if (entry.type !== 'File') {
      entry.autodrain();
      continue;
    }

    const file = entry.path;
    const baseName = path.basename(file);
    result.scanned += 1;

    if (!isCadFile(baseName)) {
      result.skipped += 1;
      entry.autodrain();
      continue;
    }

    const decision = getDestinationDecision(baseName, config, destinationIndex);
    const destDir = decision.destination;

    if (!destDir) {
      result.skipped += 1;
      result.details.push({ file: baseName, reason: decision.reason || 'Nessuna regola trovata' });
      entry.autodrain();
      continue;
    }

    const dest = path.join(destDir, baseName);
    await pipeline(entry, fs.createWriteStream(dest));

    result.copied += 1;
    result.details.push({ file: baseName, destination: destDir });
  }

  return result;
}

module.exports = { processZip };