import klaw from "klaw";
import through2 from "through2";

export default function(directory, extensions, options = {}) {
  return new Promise(resolve => {
    const items = []; // NOTE: files, directories, symlinks, etc

    klaw(directory, { depthLimit: options.depthLimit || -1 })
      .pipe(
        through2.obj(function(item, enc, next) {
          if (
            !item.stats.isDirectory() &&
            shouldIncludeItem(item, extensions) &&
            pipeFilter(options, item)
          ) {
            this.push(item);
          }

          next();
        })
      )
      .on("data", item => items.push(item.path))
      .on("end", () => resolve(items));
  });
}

function shouldIncludeItem(item, extensions) {
  if (!extensions) {
    return item;
  } else if (
    Array.isArray(extensions) &&
    extensions.some(ext => item.path.endsWith(ext))
  ) {
    return item;
  } else if (item.path.endsWith(extensions)) {
    return item;
  }
}

function pipeFilter(options, item) {
  if (!options.filter) {
    return true;
  } else if (Array.isArray(options.filter)) {
    return options.filter.every(filterFunc => filterFunc(item));
  }

  return options.filter(item);
}