/**
 *
 * © Evgeniy Malyarov http://www.oknosoft.ru 2014-2016
 * @module  gulp-resource-concat
 */

"use strict";

var through = require('through2');
var path = require('path');
var gutil = require('gulp-util');

var PluginError = gutil.PluginError;
var File = gutil.File;

module.exports = function (fileName, converter) {
  if (!fileName) {
    throw new PluginError('gulp-resource-concat', 'Missing fileName option for gulp-resource-concat');
  }

  var data = {};
  var firstFile = null;
  //We keep track of when we should skip the conversion for error cases
  var skipConversion = false;

  function bufferContents(file, enc, cb) {
    // ignore empty files
    if (file.isNull()) {
      cb();
      return;
    }

    // we don't do streams (yet)
    if (file.isStream()) {
      this.emit('error', new PluginError('gulp-concat',  'Streaming not supported'));
      cb();
      return;
    }

    if (!firstFile) {
      firstFile = file;
    }

    if(path.extname(file.path) == ".json"){
      data[path.basename(file.path)] = JSON.parse(file.contents.toString());

    }else if(path.extname(file.path) == ".js"){
      data[path.basename(file.path)] = new Function("return " + file.contents.toString());

    }else
      data[path.basename(file.path)] = file.contents.toString();

    cb();
  }

  function endStream(cb) {

    // no files passed in, no file goes out
    if (!firstFile) {
      cb();
      return;
    }

    var joinedFile;

    // if file opt was a file path
    // clone everything from the latest file
    if (typeof fileName === 'string') {
      joinedFile = firstFile.clone({contents: false});
      joinedFile.path = path.join(firstFile.base, fileName);
    } else {
      joinedFile = new File(fileName);
    }

    joinedFile.contents = converter(data);

    this.push(joinedFile);
    cb();
  }

  return through.obj(bufferContents, endStream);
};