const { Buffer } = require('node:buffer')
const debug = require('debug')('metalsmith-tinuage-services')
const config = require('./config.js')
const fs = require('node:fs')
const path = require('path')

module.exports = plugin

/**
 * Un plugin pour Metalsmith qui lit une collection de fichiers JSON décrivant
 * les services de l'association pour composer la page services.html du site.
 *
 * @return {Function}
 */
function plugin () {
  const Sections = Object.freeze({
    OPEN: Symbol('open'),
    MEMBERS: Symbol('members')
  })

  const PageFiller = {
    setup: function (page, services) {
      this.page = page
      this.registry = services.reduce((registry, service) => {
        registry[service.section].push(service)
        return registry
      }, {
        [Sections.OPEN]: [],
        [Sections.MEMBERS]: []
      })

      return this
    },

    fill: function () {
      let html = ''

      html += this.createSection('Services réservés aux adhérents', Sections.MEMBERS)
      html += this.createSection('Services en libre accès, sans adhésion', Sections.OPEN)

      this.page.contents = Buffer.concat([
        this.page.contents,
        Buffer.from(html)
      ])
    },

    createSection: function (title, section) {
      let html = '<section class="Services">\n' +
          '<h2 class="tac mt128 mb64">' + title + '</h2>\n' +
          '<div class="Two-cols-One-row">\n'

      this.registry[section].forEach((service) => { html += service.html })
      html += '</section>'

      return html
    }
  }

  const Parser = {
    /**
     * Traduit la description JSON du service donné en paramètre en un extrait
     * HTML.
     */
    parseService: function (service) {
      let html = '<div class="services">\n' +
          '<h3 class="services-title services-icon-' + service.icon + '">' + service.title + '</h3>\n' +
          '<p>' + service.description + '</p>\n'

      if (service.buttons !== undefined) {
        html += '<p class="tac">\n'
        service.buttons.forEach((b) => { html += this.createButton(b) })
        html += '</p>'
      }

      if (service.softwares !== undefined) {
        html += '<div class="services-software">\n'
        service.softwares.forEach((s) => { html += this.createSoftwareDescription(s) })
        html += '</div>\n'
      }

      if (service.links !== undefined) {
        html += '<div><p>Autres liens :</p>\n<ul>'
        service.links.forEach((l) => { html += this.createListLink(l) })
        html += '</ul></div>\n'
      }
      html += '</div>'

      debug('Parsed ' + service.title + '(' + service.order + ')')
      service.html = html
      service.section = service.open ? Sections.OPEN : Sections.MEMBERS

      return service
    },

    createButton: function (button) {
      const cls = button.class || ''
      return '<a class="button ' + cls + '" href="' + button.url + '">' + button.label + '</a>\n'
    },

    createListLink: function (link) {
      return '<li><a class="external" href="' + link.url + '">' + link.label + '</a></li>\n'
    },

    createSoftwareDescription: function (soft) {
      let html = '<p>' + soft.description + '</p>\n' +
          '<div>'

      if (soft.url !== undefined) {
        html += this.createSoftwareLink('home.svg', 'Page Web', soft.url)
      }
      if (soft.sources !== undefined) {
        html += this.createSoftwareLink('files.svg', 'Sources du logiciel', soft.sources)
      }
      soft.licenses.forEach((l) => { html += this.createSoftwareLink('copyright.svg', 'Licence', l.url, l.name) })

      html += '</div>\n'

      return html
    },

    createSoftwareLink: function (icon, alt, url, title) {
      let element = '<div class="services-link">\n' +
        '<a href="' + url + '"><img src="/images/uicons/' + icon + '" alt="' + alt + '"/></a>\n'

      if (title !== undefined) {
        element += '<br><p>' + title + '</p>'
      }

      element += '</div>'

      return element
    }
  }

  /**
   * Lit de manière asynchrone l'ensemble des fichiers JSON décrivant les services.
   *
   * Seuls les fichiers ayant .json comme extension sont chargés depuis le répertoire fourni.
   */
  function loadServices (root, filenames) {
    const promises = filenames
      .filter(f => { return f.indexOf('.json') !== -1 })
      .map(function (f) {
        debug('Loading ' + f)
        return fs.promises
          .readFile(path.join(root, f), 'utf8')
          .then((data) => { return JSON.parse(data) })
      })

    return Promise.all(promises)
  }

  return function (files, metalsmith, done) {
    const root = path.join(config.paths.projectRoot, 'services')

    debug('Looking for services in ' + root)
    fs.readdir(root, (err, filenames) => {
      if (err) {
        console.error('%s: %s', root, err)
      } else {
        loadServices(root, filenames)
          .then(function (services) {
            const p = Object.create(Parser)
            const parsed = services
              .sort((a, b) => { return a.order - b.order })
              .map((s) => p.parseService(s))
            Object.create(PageFiller).setup(files['services.html'], parsed).fill()
            done()
          })
          .catch(function (err) {
            console.log(err)
          })
      }
    })
  }
}