const fs = require('fs')
const path = require('path')
const mkdirp = require('mkdirp')
const assign = require('assign-deep')

const configStore = require('./config.js')

const Engine = require('./engines/nunjucks.js')
const Sitemap = require('./factories/sitemap.js')

const PagesQuery = require('./queries/pages.js')
const parseYamlFile = require('./parsers/yaml.js')

/**
 *  Siteomat
 *
 *
 *
 *  @author Björn Hase <me@herr-hase.wtf>
 *  @license http://opensource.org/licenses/MIT The MIT License
 *  @link https://gitea.node001.net/HerrHase/siteomat-webpack-plugin.git
 *
 */
class Siteomat {

    /**
     *
     *
     *  @param  {string} source
     *  @param  {string} destination
     *
     */
    constructor(source, views, options = {}) {

        if (options.destination === undefined) {
            throw new Error('Destination is undefined')
        }

        this._source = source
        this._views = views
        this._destination = options.destination

        // fill singleton for configuration
        configStore.set('source', source)
        configStore.set('destination', this._destination)
        configStore.set('views', views)
        configStore.set('options', assign({
            'minifyHtml': true
        }, options))

        // get config for site
        if (fs.existsSync(this._source + '/site.yml')) {
            const file = fs.readFileSync(this._source + '/site.yml', 'utf8')
            this._site = parseYamlFile(file)
        } else {
            throw new Error('site.yml not found in ' + this._source + '!')
        }

        configStore.set('site', this._site)

        this._engine = new Engine(views, this._site)
    }

    /**
     *  let it rain \o/
     *
     */
    run() {
        const query = new PagesQuery(this._source)
        const results = query.find()

        const sitemap = new Sitemap(this._site)

        // run through pages and generate html files
        results.forEach((page, index) => {
            this._engine.render(page, (error, content) => {

                // show errors
                if (error) {
                    console.error(error)
                }

                // if no content show error message
                if (!content) {
                    console.error('Error! Rendering Page ' + '"' + page.filename + '" is null')
                    return;
                }

                // create directories and write file = page
                mkdirp(this._destination + page.pathname).then(() => {
                    fs.writeFileSync(this._destination + page.pathname + '/' + page.filename, content)
                })

                sitemap.addPage(page)

                // if run is finish, write sitemap.xml
                if ((index + 1) === results.length) {
                    fs.writeFileSync(this._destination + '/sitemap.xml', sitemap.getXmlAsString())
                }

            })
        })
    }
}

module.exports = Siteomat