util.js

import ejs from 'ejs'

import config from './package.json'

let Gitalk, Valine
loadScript(COMMENT_CHOOSEN)

const defaultChoosen = 'comment plugins'
console.log(
  `How to use "${COMMENT_CHOOSEN || defaultChoosen}" in ${config.name}@v${config.version}:`,
  config.homepage
)

/**
 * Lazy load pkg
 * 
 * @param {String} name 
 */
export function loadScript (name) {
  if (name === 'valine') {
    import('valine')
    .then(pkg => Valine = pkg.default)
  } else if (name === 'gitalk') {
    import('gitalk/dist/gitalk.css')
    .then(() => import('gitalk'))
    .then(pkg => Gitalk = pkg.default)
  }
}

/**
 * Render ejs strings in configuration
 * 
 * @param {Object} config 
 * @param {Object} data 
 */
export function renderConfig (config, data) {
  const result = {}

  Reflect.ownKeys(config)
    .forEach(key => {
      if (typeof config[key] === 'string') {
        try {
          result[key] = ejs.render(config[key], data)
        } catch (error) {
          console.warn(`Comment config option error at key named "${key}"`)
          console.warn(`More info: ${error.message}`)
          result[key] = config[key]
        }
      } else {
        result[key] = config[key]
      }
    })
  
  return result
}

/**
 * Support Gitalk and so on.
 */
export const provider = {
  gitalk: {
    render (frontmatter, commentDomID) {
      const commentDOM = document.createElement('div')
      commentDOM.id = commentDomID

      const parentDOM = document.querySelector(COMMENT_CONTAINER)
      parentDOM.appendChild(commentDOM)
      
      const gittalk = new Gitalk(renderConfig(COMMENT_OPTIONS, { frontmatter }))
      gittalk.render(commentDomID)
    },
    clear (commentDomID) {
      const last = document.querySelector(`#${commentDomID}`)
      if (last) {
        last.remove()
      }
      return true
    }
  },
  valine: {
    render (frontmatter, commentDomID) {
      const commentDOM = document.createElement('div')
      commentDOM.id = commentDomID

      const parentDOM = document.querySelector(COMMENT_CONTAINER)
      parentDOM.appendChild(commentDOM)

      new Valine({
        ...renderConfig(COMMENT_OPTIONS, { frontmatter }),
        el: `#${commentDomID}`
      })
    },
    clear (commentDomID) {
      const last = document.querySelector(`#${commentDomID}`)
      if (last) {
        last.remove()
      }
      return true
    }
  }
}