gulpfile.js

// Define variables.
var appendPrepend  = require('gulp-append-prepend');
var autoprefixer   = require('autoprefixer');
var browserSync    = require('browser-sync').create();
var cleancss       = require('gulp-clean-css');
var concat         = require('gulp-concat');
var del            = require('del');
var gulp           = require('gulp');
var gutil          = require('gulp-util');
var imagemin       = require('gulp-imagemin');
var jpegRecompress = require('imagemin-jpeg-recompress');
var notify         = require('gulp-notify');
var postcss        = require('gulp-postcss');
var rename         = require('gulp-rename');
var run            = require('gulp-run');
var runSequence    = require('run-sequence');
var sass           = require('gulp-ruby-sass');
var uglify         = require('gulp-uglify');

var paths          = require('./_assets/gulp_config/paths');

// Uses Sass compiler to process styles, adds vendor prefixes, minifies, then
// outputs file to the appropriate location.
gulp.task('build:styles:main', function() {
    return sass(paths.sassFiles + '/main.scss', {
        style: 'compressed',
        trace: true,
        loadPath: [paths.sassFiles]
    }).pipe(postcss([ autoprefixer({ browsers: ['last 2 versions'] }) ]))
        .pipe(cleancss())
        .pipe(gulp.dest(paths.jekyllCssFiles))
        .pipe(gulp.dest(paths.siteCssFiles))
        .pipe(browserSync.stream())
        .on('error', gutil.log);
});

// Processes critical CSS, to be included in head.html.
gulp.task('build:styles:critical', function() {
    return sass(paths.sassFiles + '/critical.scss', {
        style: 'compressed',
        trace: true,
        loadPath: [paths.sassFiles]
    }).pipe(postcss([ autoprefixer({ browsers: ['last 2 versions'] }) ]))
        .pipe(cleancss())
        .pipe(gulp.dest('_includes'))
        .on('error', gutil.log);
});

// Copies any other CSS files to the assets directory, to be used by pages/posts
// that specify custom CSS files.
gulp.task('build:styles:css', function() {
    return gulp.src([paths.sassFiles + '/*.css'])
      .pipe(postcss([ autoprefixer({ browsers: ['last 2 versions'] }) ]))
      .pipe(cleancss())
      .pipe(gulp.dest(paths.jekyllCssFiles))
      .pipe(gulp.dest(paths.siteCssFiles))
      .on('error', gutil.log);
});

// Builds all styles.
gulp.task('build:styles', [
    'build:styles:main',
    'build:styles:critical',
    'build:styles:css'
]);

gulp.task('clean:styles', function(callback) {
    del([paths.jekyllCssFiles, paths.siteCssFiles, '_includes/critical.css']);
    callback();
});

// Concatenates and uglifies global JS files and outputs result to the
// appropriate location.
gulp.task('build:scripts:global', function() {
    return gulp.src([
        paths.jsFiles + '/global/lib' + paths.jsPattern,
        paths.jsFiles + '/global/*.js'
    ])
        .pipe(concat('main.js'))
        .pipe(uglify())

        // We need to add front matter so Jekyll will process variables.
        .pipe(appendPrepend.prependFile('./_assets/gulp_config/front-matter.txt'))

        // Only place in `assets` because Jekyll needs to process the file.
        .pipe(gulp.dest(paths.jekyllJsFiles))
        .on('error', gutil.log);
});

// Concatenates and uglifies leaflet JS files and outputs result to the
// appropriate location.
gulp.task('build:scripts:leaflet', function() {
    return gulp.src([
        paths.jsFiles + '/leaflet/leaflet.js',
        paths.jsFiles + '/leaflet/leaflet-providers.js'
    ])
        .pipe(concat('leaflet.js'))
        .pipe(uglify())
        .pipe(gulp.dest(paths.jekyllJsFiles))
        .pipe(gulp.dest(paths.siteJsFiles))
        .on('error', gutil.log);
});

// Builds all scripts.
gulp.task('build:scripts', ['build:scripts:global', 'build:scripts:leaflet']);

gulp.task('clean:scripts', function(callback) {
    del([paths.jekyllJsFiles, paths.siteJsFiles]);
    callback();
});

// Optimizes and copies image files.
// We're including imagemin options because we're overriding the default
// JPEG optimization plugin.
gulp.task('build:images', function() {
    return gulp.src(paths.imageFilesGlob)
        .pipe(imagemin([
            imagemin.gifsicle(),
            jpegRecompress(),
            imagemin.optipng(),
            imagemin.svgo()
        ]))
        .pipe(gulp.dest(paths.jekyllImageFiles))
        .pipe(gulp.dest(paths.siteImageFiles))
        .pipe(browserSync.stream());
});

gulp.task('clean:images', function(callback) {
    del([paths.jekyllImageFiles, paths.siteImageFiles]);
    callback();
});

// Copies fonts.
gulp.task('build:fonts', ['fontawesome']);

// Places Font Awesome fonts in proper location.
gulp.task('fontawesome', function() {
    return gulp.src(paths.fontFiles + '/font-awesome/**.*')
        .pipe(rename(function(path) {path.dirname = '';}))
        .pipe(gulp.dest(paths.jekyllFontFiles))
        .pipe(gulp.dest(paths.siteFontFiles))
        .pipe(browserSync.stream())
        .on('error', gutil.log);
});

gulp.task('clean:fonts', function(callback) {
    del([paths.jekyllFontFiles, paths.siteFontFiles]);
    callback();
});

// Runs jekyll build command.
gulp.task('build:jekyll', function() {
    var shellCommand = 'bundle exec jekyll build --config _config.yml';

    return gulp.src('')
        .pipe(run(shellCommand))
        .on('error', gutil.log);
});

// Runs jekyll build command using test config.
gulp.task('build:jekyll:test', function() {
    var shellCommand = 'bundle exec jekyll build --future --config _config.yml,_config.test.yml';

    return gulp.src('')
        .pipe(run(shellCommand))
        .on('error', gutil.log);
});

// Runs jekyll build command using local config.
gulp.task('build:jekyll:local', function() {
    var shellCommand = 'bundle exec jekyll build --future --config _config.yml,_config.test.yml,_config.dev.yml';

    return gulp.src('')
        .pipe(run(shellCommand))
        .on('error', gutil.log);
});

// Deletes the entire _site directory.
gulp.task('clean:jekyll', function(callback) {
    del(['_site']);
    callback();
});

gulp.task('clean', ['clean:jekyll',
    'clean:fonts',
    'clean:images',
    'clean:scripts',
    'clean:styles']);

// Builds site anew.
gulp.task('build', function(callback) {
    runSequence('clean',
        ['build:scripts', 'build:images', 'build:styles', 'build:fonts'],
        'build:jekyll',
        callback);
});

// Builds site anew using test config.
gulp.task('build:test', function(callback) {
    runSequence('clean',
        ['build:scripts', 'build:images', 'build:styles', 'build:fonts'],
        'build:jekyll:test',
        callback);
});

// Builds site anew using local config.
gulp.task('build:local', function(callback) {
    runSequence('clean',
        ['build:scripts', 'build:images', 'build:styles', 'build:fonts'],
        'build:jekyll:local',
        callback);
});

// Default Task: builds site.
gulp.task('default', ['build']);

// Special tasks for building and then reloading BrowserSync.
gulp.task('build:jekyll:watch', ['build:jekyll:local'], function(callback) {
    browserSync.reload();
    callback();
});

gulp.task('build:scripts:watch', ['build:scripts'], function(callback) {
    runSequence('build:jekyll:local');
    browserSync.reload();
    callback();
});

// Static Server + watching files.
// Note: passing anything besides hard-coded literal paths with globs doesn't
// seem to work with gulp.watch().
gulp.task('serve', ['build:local'], function() {

    browserSync.init({
        server: paths.siteDir,
        ghostMode: false, // Toggle to mirror clicks, reloads etc. (performance)
        logFileChanges: true,
        logLevel: 'debug',
        open: true        // Toggle to automatically open page when starting.
    });

    // Watch site settings.
    gulp.watch(['_config*.yml'], ['build:jekyll:watch']);

    // Watch .scss files; changes are piped to browserSync.
    gulp.watch('_assets/styles/**/*.scss', ['build:styles']);

    // Watch .js files.
    gulp.watch('_assets/js/**/*.js', ['build:scripts:watch']);

    // Watch image files; changes are piped to browserSync.
    gulp.watch('_assets/img/**/*', ['build:images']);

    // Watch posts.
    gulp.watch('_posts/**/*.+(md|markdown|MD)', ['build:jekyll:watch']);

    // Watch drafts if --drafts flag was passed.
    if (module.exports.drafts) {
        gulp.watch('_drafts/*.+(md|markdown|MD)', ['build:jekyll:watch']);
    }

    // Watch html and markdown files.
    gulp.watch(['**/*.+(html|md|markdown|MD)', '!_site/**/*.*'], ['build:jekyll:watch']);

    // Watch RSS feed XML files.
    gulp.watch('**.xml', ['build:jekyll:watch']);

    // Watch data files.
    gulp.watch('_data/**.*+(yml|yaml|csv|json)', ['build:jekyll:watch']);

    // Watch favicon.png.
    gulp.watch('favicon.png', ['build:jekyll:watch']);
});

// Updates Ruby gems
gulp.task('update:bundle', function() {
    return gulp.src('')
        .pipe(run('bundle install'))
        .pipe(run('bundle update'))
        .pipe(notify({ message: 'Bundle Update Complete' }))
        .on('error', gutil.log);
});