module.exports = function() {
  this.compilePostCommentsHtml = (comments, next_comment, post_id, post_url, morechildren_ids, post_author, viewing_comment, user_preferences, last_known_depth) => {
    return new Promise((resolve, reject) => {
      (async () => {
        let comments_html
        function commentAuthor(comment, classlist, submitter, moderator) {
          let classes = classlist.join(' ')
          if (comment.author === '[deleted]')
            return `<span class="${classes}">[deleted]</span>`
          else
            return `<a href="/u/${comment.author}" class="${classes}">${comment.author}</a>${submitter || ''}${moderator || ''}`
        }
        
        if(!user_preferences)
          user_preferences = {}
          
        if(comments.author !== undefined && comments.body_html !== undefined) {
          let classlist = []
          let submitter_link = ''
          let moderator = false
          let submitter = false
          let edited_span = ''
          let controversial_span = ''

          if(post_author === comments.author) {
            classlist.push('submitter')
            submitter_link = `<a href="${post_url}" title="submitter">[S]</a>`
            submitter = true
          }
          if(comments.distinguished === 'moderator') {
            classlist.push('green')
            moderator_badge = ` <span class="green" title="moderator of this subreddit">[M]</span>`
            moderator = true
          }
          if(comments.score_hidden) {
            ups = `<span class="score-hidden">[score hidden]</span>`
          } else {
            ups = `${kFormatter(comments.ups)} points`
          }
          if(comments.edited) {
            edited_span = `<span title="last edited ${toUTCString(comments.edited)}">*</span>`
          }
          if(comments.controversiality > 0) {
            controversial_span = `<span class="controversial" title="this comment is voted as controversial">†</span>`
          }
          comments_html = `
            <div class="comment ${comments.depth % 2 === 0 ? 'even-depth' : 'odd-depth'}" id="${comments.id}">
              <details ${user_preferences.collapse_child_comments === 'true' && comments.depth > 0 && comments.depth < 2 ? '' : 'open'}>
                <summary>
                  <p class="author">${commentAuthor(comments, classlist, submitter && submitter_link, moderator && moderator_badge)}</p>
                  <p class="ups">${ups}</p>
                  <p class="created" title="${toUTCString(comments.created)}">${timeDifference(comments.created)}${edited_span}</p>
                  <p class="stickied">${comments.stickied ? 'stickied comment' : ''}</p>
                </summary>
              <div class="meta">
                <p class="author">${commentAuthor(comments, classlist, submitter && submitter_link, moderator && moderator_badge)}</p>
                <p>${comments.user_flair}</p>
                <p class="ups">${ups}${controversial_span}</p>
                <p class="created" title="${toUTCString(comments.created)}">
                   <a href="${comments.permalink}#c">${timeDifference(comments.created)}${edited_span}</a>
                </p>
                <p class="stickied">${comments.stickied ? 'stickied comment' : ''}</p>
              </div>
              <div class="body">${unescape(comments.body_html)}</div>
          `
        } else {
          if(comments.children) {
            if(comments.children.length > 0) {
              let parent_id = comments.parent_id.split('_')[1]
              if(post_id === parent_id && !morechildren_ids) {
                let more_comments = []
                if(comments.children.length > 100) {
                  more_comments = comments.children.slice(0, 100)
                } else {
                  more_comments = comments.children
                }
                
                comments_html = `
                  <form method="POST">
                    <button type="submit">load more comments (${comments.count})</button>
                    <input type="hidden" name="comment_ids" id="comment_ids" value="${more_comments.join()}">
                  </form>
                `
              } else {
                let load_comms_href = parent_id
                if(!morechildren_ids) {
                  comments_html = `
                    <div class="load-more-comments">
                      <a href="${load_comms_href}#c">load more comments (${comments.count})</a>
                    </div>
                  `
                } else {
                  if(next_comment === false) {
                    let more_comments = morechildren_ids[morechildren_ids.length - 1].data.children
                    if(more_comments.length > 100) {
                      more_comments = more_comments.slice(0, 100)
                    } else {
                      more_comments = more_comments
                    }
                    comments_html = `
                      <form method="POST">
                        <button type="submit">load more comments (${more_comments.length})</button>
                        <input type="hidden" name="comment_ids" id="comment_ids" value="${more_comments.join()}">
                      </form>
                    `
                  } else {
                    comments_html = `
                      <div class="load-more-comments">
                        <a href="${load_comms_href}#c">load more comments (${comments.count})</a>
                      </div>
                    `
                  }
        
                }
              }
            } else {
              let link = comments.parent_id.split('_')[1]
              link = post_url + link
              comments_html = `
                <div class="load-more-comments">
                  <a href="${link}/#c">continue this thread</a>
                </div>
              `
            }
          }
        }
      
        if(morechildren_ids) {
          if(next_comment.depth != undefined) {
            if(next_comment.depth < last_known_depth) {
              let times = last_known_depth - next_comment.depth
              if(next_comment.depth == 0) {
                times = last_known_depth
              }
              for(var i = 0; i < times; i++) {
                comments_html += `</details></div>`
              }
            }
          }
        }
        
        if(comments.replies) {
          for(var i = 0; i < comments.replies.length; i++) {
            let comment = comments.replies[i]
            if(comment.type !== 'load_more') {
              let classlist = []
              let submitter_link = ''
              let moderator = false
              let submitter = false
              let ups = ''
              let edited_span = ''
              let controversial_span = ''

              if(post_author === comment.author) {
                classlist.push('submitter')
                submitter_link = `<a href="${post_url}" title="submitter">[S]</a>`
                submitter = true
              }
              if(comment.distinguished === 'moderator') {
                classlist.push('green')
                moderator_badge = ` <span class="green" title="moderator of this subreddit">[M]</span>`
                moderator = true
              }
              if(comment.score_hidden) {
                ups = `<span class="score-hidden">[score hidden]</span>`
              } else {
                ups = `${kFormatter(comment.ups)} points`
              }
              if(comment.edited) {
                edited_span = `<span title="last edited ${toUTCString(comment.edited)}">*</span>`
              }
              if(comment.controversiality > 0) {
                controversial_span = `<span class="controversial" title="this comment is voted as controversial">†</span>`
              }
              comments_html += `
                <div class="comment ${comment.depth % 2 === 0 ? 'even-depth' : 'odd-depth'}" id="${comment.id}">
                <details ${user_preferences.collapse_child_comments === 'true' && comments.depth === 0 ? '' : 'open'}>
                  <summary>
                    <p class="author">${commentAuthor(comment, classlist, submitter && submitter_link, moderator && moderator_badge)}</p>
                    <p class="ups">${ups}</p>
                    <p class="created" title="${toUTCString(comment.created)}">${timeDifference(comment.created)}${edited_span}</p>
                    <p class="stickied">${comment.stickied ? 'stickied comment' : ''}</p>
                  </summary>
                  <div class="meta">
                    <p class="author">${commentAuthor(comment, classlist, submitter && submitter_link, moderator && moderator_badge)}</p>
                    <p>${comment.user_flair}</p>
                    <p class="ups">${ups}${controversial_span}</p>
                    <p class="created" title="${toUTCString(comment.created)}">
                      <a href="${comment.permalink}#c">${timeDifference(comment.created)}${edited_span}</a>
                    </p>
                    <p class="stickied">${comment.stickied ? 'stickied comment' : ''}</p>
                  </div>
                  <div class="body">${unescape(comment.body_html)}</div>
              `
              let replies_html = ''
              if(comment.replies) {
                if(comment.replies.length) {
                  for(var j = 0; j < comment.replies.length; j++) {
                    let next_reply = false
                    if(comment.replies[j+1]) {
                      next_reply = comment.replies[j+1]
                    }
                    replies_html += await compilePostCommentsHtml(comment.replies[j], next_reply, post_id, post_url, null, post_author, viewing_comment, user_preferences)
                  }
                }
              }
              comments_html += replies_html + '</details></div>'
            } else {
              if(comment.children.length > 0) {
                let parent_id = comment.parent_id.split('_')[1]
                let load_comms_href = parent_id

                comments_html += `
                  <div class="load-more-comments">
                    <a href="${load_comms_href}#c">load more comments (${comment.count})</a>
                  </div>
                `
              } else {
                let link = comment.parent_id.split('_')[1] 
                link = post_url + link
                comments_html = `
                  <div class="load-more-comments">
                    <a href="${link}/#c">continue this thread</a>
                  </div>
                `
              }
            }
          }
        }

        let next_comment_parent_id = null
        if(next_comment) {
          if(next_comment.parent_id) {
            next_comment_parent_id = next_comment.parent_id.split('_')[1]
          }
        }
        
        if((comments.replies || comments.author !== undefined) && next_comment_parent_id !== comments.id) {
          comments_html += `</details></div>`
        }
        next_comment_parent_id = null

        resolve(comments_html)
      })()
    })
  }
}