const gulp = require('gulp'),
  HelperUnit = require('./../tools/helperUnit'),
  sass = require('gulp-sass'),
  clean = require('gulp-clean-css'),
  path = require('path'),
  workers = [];

class SCSSWorker {
  constructor(config, helper) {
    this.config = config;
    this.helper = helper.clone();
    this.input = this.helper.replaceVariables(this.config.input);
    this.helper.addConfigItem("$name", this.config.name);
    this.helper.addConfigItem("$", this.input);
    this.out = this.helper.replaceVariables(this.config.output);
    this.watch = this.helper.replaceVariables(this.config.watch || '$/**/*.{scss,sass}');
    gulp.task(this.taskName, this.work.bind(this));
  }

  startWatch() {
    gulp.watch(this.watch, gulp.series(this.taskName))
  }

  get taskName() {
    return `scss-${this.config.name || 'unknown'}`;
  }

  work() {
    return gulp.src(this.input)
      .pipe(sass().on('error', sass.logError))
      .pipe(clean())
      .pipe(gulp.dest(this.out));
  }
}

module.exports = {
  build: function () {
    let array = [];
    for (let worker of workers) {
      array.push(worker.taskName);
    }
    return array;
  },
  prepare: function (config) {
    const scss = config.scss || [];
    for (let scssItem of scss) {
      workers.push(new SCSSWorker(scssItem, config.helper));
    }
  },
  startWatch: function () {
    for (let worker of workers) {
      worker.startWatch();
    }
  }
}