stackdot/sketch-preview

module.exports = function( ops ){

    const gulp = ops.gulp
    const config = ops.config
    const env = ops.env
    const browserSync = ops.browserSync

    if(!config.tasks.sass) return

    const path                 = require('path')
    const lodash             = require('lodash')
    const minifyCSS         = require('gulp-minify-css')
    const sourcemaps         = require('gulp-sourcemaps')
    const sass                 = require('gulp-sass')
    const concat             = require('gulp-concat')
    const notify             = require('gulp-notify')

    let tasks = []
    const DEST = path.resolve( config.dest, config.tasks.sass.dest )

    const sassTask = function( artifact, output ){

        const PROD = Boolean.parse(process.env.prod)

        const filename = output+'.css'
        const paths = lodash.map(config.tasks.sass.paths, function(dir){
            return path.resolve( __dirname, '../../', dir )
        })

        let stream = gulp.src( artifact.src )

        if(!PROD){
            stream = stream.pipe(sourcemaps.init())
        }

        stream = stream.pipe(sass({
            includePaths: paths
        }).on('error', notify.onError(function(err){
            return {
                title: '',
                'subtitle': 'SASS Error',
                'message': err.message,
                'icon': path.resolve(__dirname, 'app/images/logo.png'), // case sensitive
            }
        }))).pipe(concat( filename ))

        if(PROD){
            stream = stream.pipe(minifyCSS())
        }else{
            // sourcemap LESS files, easy debugging:
            stream = stream.pipe(sourcemaps.write('.'))
        }
        stream = stream.pipe(gulp.dest(DEST))
        return stream
    }


    const sassTask_Watch = function( cb ){
        lodash.each(config.tasks.sass.artifacts, function( artifact, output ){
            gulp.watch(artifact.src, ['sass-'+output])
        })
        // Inject on css changes in destination directory:
        gulp.watch([DEST+'/**/*.css']).on('change', function(){
            gulp.src(DEST+'/**/*.css')
                .pipe(browserSync.stream())
        })
        cb()
    }

    lodash.each(config.tasks.sass.artifacts, function( artifact, output ){
        const task = 'sass-'+output
        gulp.task(task, function(){
            return sassTask( artifact, output )
        })
        tasks.push(task)
    })

    gulp.task('sass', tasks)
    gulp.task('sass:watch', ['sass'], sassTask_Watch)
    return sassTask

}