var gulp          = require('gulp'); // Gulp itself
var less          = require('gulp-less'); // Compiling LESS
var watch         = require('gulp-watch'); // Watch for files that changed
var filter        = require('gulp-filter'); // Filters the pipeline
var plumber       = require('gulp-plumber'); // Handles errors without breaking pipeline
var minifyCss     = require('gulp-minify-css'); // Minify CSS
var sourcemaps    = require('gulp-sourcemaps'); // Generates source maps
var autoprefixer  = require('gulp-autoprefixer'); // Post process CSS
var browserSync   = require('browser-sync').create(); // Live reload server

// Paths to LESS files and destination for CSS
// [Note: we are bypassing LESS files prepended with
//    an underscore which are files that we only import
//    to other LESS files]
var paths = {
  less: ['public/less/*.less','!public/less/_*.less'],
  dest: ['public/stylesheets']
};

// By default 'gulp' would run this task
gulp.task('default', ['less']);

// This task 'gulp less' will compile all LESS files from the
//  LESS directory
gulp.task('less', function(done) {
  return gulp.src(paths.less)
    .pipe(plumber())
    .pipe(sourcemaps.init())
    .pipe(less({
      paths: ['.']
    }))
    .pipe(minifyCss())
    .pipe(autoprefixer({ cascade: false }))
    .pipe(sourcemaps.write('source', {includeContent: true}))
    .pipe(gulp.dest(paths.dest[0]))
    .on('end', done);
});

// This task 'gulp watch' will start a server, opens in the browser, and
//  compile LESS files as they are changed
gulp.task('watch', function() {
  browserSync.init({
    // Please change this proxy to the file path you use for local dev
    proxy: "<YOUR LOCAL DEV PATH>"
  });
  return gulp.src(paths.less)
    .pipe(watch(paths.less, {verbose: true}))
    .pipe(plumber())
    .pipe(sourcemaps.init())
    .pipe(less({
      paths: ['.']
    }))
    .pipe(minifyCss())
    .pipe(autoprefixer({ cascade: false }))
    .pipe(sourcemaps.write('source', {includeContent: true}))
    .pipe(gulp.dest(paths.dest[0]))
    .pipe(filter('**/*.css'))
    .pipe(browserSync.reload({stream: true}));
});