/*
 * Compiles a Node.js project that uses JavaScript and React
 *
 * - generates a main.js file in JS_DIR by calling browserify on app.jsx in
 *   SRC_DIR
 *
 * Usage:
 *
 * - gulp
 *   -> gulp scripts
 * - gulp clean
 *   -> rm -rf $CSS_DIR $JS_DIR
 *
 * - gulp watch
 * - gulp watchify
 *   - starts watchers for JavaScript
 */

var _          = require('lodash');

var buffer     = require('vinyl-buffer');
var del        = require('del');
var gulp       = require('gulp');
var gutil      = require('gulp-util');
var source     = require('vinyl-source-stream');

var browserify = require('browserify');
var sourcemaps = require('gulp-sourcemaps');
var uglify     = require('gulp-uglify');
var watchify   = require('watchify');

// input JavaScirpt folder
var SRC_DIR = './public/src';
// output JavaScirpt folder
var JS_DIR = './public/javascripts';

gulp.task('clean', function(cb) {
  return del([JS_DIR], cb);
});

var scripts = function(devMode) {
  var config = {};
  if (devMode) {
    _.extend(config, watchify.args);
  }
  _.extend(config, { debug: devMode });

  // Initialize browserify
  // (it does it's own stream things when you call b.bundle())
  var b = browserify(SRC_DIR + "/app.jsx", config);

  if (devMode) {
    b = watchify(b);
    b.on('log', gutil.log.bind(gutil, 'watchify log'));
  }

  // This is where the real heavy lifting is done. In devMode, this will get
  // called by watchify on every update. Otherwise, it's called just once (as
  // the return of calling scripts(false) ).
  var compile = function() {
    var result;
    result = b.bundle()
        .on('error', gutil.log.bind(gutil, 'browserify error'))
        // "call my the actual file of my bundle ..."
        .pipe(source('main.js'))
        // uglify and sourcemaps need a buffer, not a stream
        .pipe(buffer());

    if (devMode) {
      result = result.pipe(sourcemaps.init({
        loadMaps: true
      })).pipe(sourcemaps.write({
        sourceRoot: '/src'
      }));
    } else {
      result = result
          .pipe(uglify())
          .on('error', gutil.log.bind(gutil, 'uglify error'));
    }

    // "write my bundle to this directory"
    return result.pipe(gulp.dest(JS_DIR));
  };

  if (devMode) {
    // Recompile on changes for watchify
    b.on('update', compile);
  }

  return compile();
};

gulp.task('scripts', function() {
  return scripts(false);
});

gulp.task('watchify', function() {
  return scripts(true);
});

gulp.task('watch', ['watchify'], function() {});

gulp.task('default', function() {
  gulp.start('scripts');
  return null;
});