const unzipper = require('unzipper');
const fs = require('fs-extra');
const path = require('path');
const { pipeline } = require('stream/promises');
const { getDestinationDecision, getCadInfo } = require('./router');
const { buildDestinationIndex } = require('./destinationIndex');
const { buildExistingCadKeyIndex, toCadKey } = require('./duplicateIndex');
const { getUnroutedTarget, getDuplicateTarget } = require('./unrouted');

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

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

    if (existingCadKeys.has(toCadKey(cadInfo))) {
      const duplicateTarget = await getDuplicateTarget(baseName);
      await pipeline(entry, fs.createWriteStream(duplicateTarget.destinationPath));

      result.copied += 1;
      result.duplicates += 1;
      result.details.push({
        file: baseName,
        destination: duplicateTarget.destinationDir,
        reason: 'Duplicato gia presente prima dello smistamento',
      });
      continue;
    }

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

    if (!destDir) {
      const unroutedTarget = await getUnroutedTarget(baseName);
      await pipeline(entry, fs.createWriteStream(unroutedTarget.destinationPath));

      result.copied += 1;
      result.unrouted += 1;
      result.details.push({
        file: baseName,
        destination: unroutedTarget.destinationDir,
        reason: decision.reason || 'Nessuna regola trovata',
      });
      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 };