const gulp = require('gulp');
const pug = require('pug');
const fs = require('fs-extra');
const less = require('gulp-less');
const path = require('path');
const yaml = require('yaml-js');
const marked = require('marked');
const watch = require('gulp-watch');
const highlight = require('gulp-highlight-code');

const DOCS_SRC = '../../docs';

const homePageTasks = (function () {

  const templates = {

    index: pug.compile(
      fs.readFileSync('./template/index.pug', 'utf-8'),
      {
        filename: './template/index.pug',
        pretty: true
      }
    ),
    doc: pug.compile(
      fs.readFileSync('./template/doc.pug', 'utf-8'),
      {
        filename: './template/doc.pug',
        pretty: true
      }
    ),
    community: pug.compile(
      fs.readFileSync('./template/community.pug', 'utf-8'),
      {
        filename: './template/community.pug',
        pretty: true
      }
    ),
    playground: pug.compile(
      fs.readFileSync('./template/playground.pug', 'utf-8'),
      {
        filename: './template/playground.pug',
        pretty: true
      }
    )
  }

  function build() {

    const option = {
      root: './',
    }

    fs.writeFileSync('../website/index.html', templates.index(option));
    fs.writeFileSync('../website/community.html', templates.community(option));
    fs.writeFileSync('../website/playground.html', templates.playground({
      root: option.root,
      content: marked(fs.readFileSync(path.join(DOCS_SRC, 'playground.md'), 'utf-8'))
    }));

    const doc = yaml.load(fs.readFileSync('./index.yaml')).docs;

    function deal(docs, k, s) {
      if (typeof docs === 'string') {
        const content = fs.readFileSync(path.join(DOCS_SRC, docs), 'utf-8');

        if (content) {
          fs.outputFileSync(`../website/docs/${k}.html`, templates.doc(
            {
              index: doc,
              content: marked(content),
              root: '../'
            }
          ));
        } else {
          throw new Error('Read source file failed, please run gulp fetch first.');
        }
      } else {
        for (let key in docs) {
          deal(docs[key], key, docs);
        }
      }
    }

    deal(doc);

    return gulp.src('../website/docs/*.html')
      .pipe(highlight())
      .pipe(gulp.dest('../website/docs/'));
  }

  function lessTask() {
    return gulp.src('./style/index.less')
      .pipe(less())
      .pipe(gulp.dest('../website/'));
  }

  function watchLessTask() {
    return watch('./style/index.less')
      .pipe(less())
      .pipe(gulp.dest('../website/'));
  }

  function assets() {
    return gulp.src('./assets/**')
      .pipe(gulp.dest('../website/assets/'));
  }

  return { build, less: lessTask, watchLess: watchLessTask, assets };

})();

gulp.task('homepage-less', homePageTasks.less);
gulp.task('homepage-less-watch', homePageTasks.watchLess);
gulp.task('homepage-assets', homePageTasks.assets);
gulp.task('homepage-build', ['homepage-less', 'homepage-assets'], homePageTasks.build);

gulp.task('default', ['homepage-build'], function () { });