const fs = require("fs");
const path = require("path");
const SRIToolbox = require("sri-toolbox");

const getFileContentType = require("./getFileContentType");
const getFileStats = require("./getFileStats");
const getFileType = require("./getFileType");

function getEntries(dir, file, maximumDepth) {
  return new Promise((resolve, reject) => {
    fs.readdir(path.join(dir, file), (error, files) => {
      if (error) {
        reject(error);
      } else {
        resolve(
          Promise.all(
            files.map(f => getFileStats(path.join(dir, file, f)))
          ).then(statsArray => {
            return Promise.all(
              statsArray.map((stats, index) =>
                getMetadataRecursive(
                  dir,
                  path.join(file, files[index]),
                  stats,
                  maximumDepth - 1
                )
              )
            );
          })
        );
      }
    });
  });
}

function formatTime(time) {
  return new Date(time).toISOString();
}

function getIntegrity(file) {
  return new Promise((resolve, reject) => {
    fs.readFile(file, (error, data) => {
      if (error) {
        reject(error);
      } else {
        resolve(SRIToolbox.generate({ algorithms: ["sha384"] }, data));
      }
    });
  });
}

function getMetadataRecursive(dir, file, stats, maximumDepth) {
  const metadata = {
    lastModified: formatTime(stats.mtime),
    contentType: getFileContentType(file),
    path: file,
    size: stats.size,
    type: getFileType(stats)
  };

  if (stats.isFile()) {
    return getIntegrity(path.join(dir, file)).then(integrity => {
      metadata.integrity = integrity;
      return metadata;
    });
  }

  if (!stats.isDirectory() || maximumDepth === 0)
    return Promise.resolve(metadata);

  return getEntries(dir, file, maximumDepth).then(files => {
    metadata.files = files;
    return metadata;
  });
}

function getMetadata(baseDir, path, stats, maximumDepth, callback) {
  getMetadataRecursive(baseDir, path, stats, maximumDepth).then(metadata => {
    callback(null, metadata);
  }, callback);
}

module.exports = getMetadata;