docbrown/app/models/message.rb

class Message < ApplicationRecord
  belongs_to :user
  belongs_to :chat_channel

  validates :message_html, presence: true
  validates :message_markdown, presence: true, length: { maximum: 1024 }
  validate :channel_permission

  before_validation :determine_user_validity
  before_validation :evaluate_markdown
  after_create      :send_email_if_appropriate
  after_create      :update_chat_channel_last_message_at
  after_create      :update_all_has_unopened_messages_statuses

  def preferred_user_color
    color_options = [user.setting.brand_color1 || "#000000", user.setting.brand_color2 || "#000000"]
    Color::CompareHex.new(color_options).brightness(0.9)
  end

  def direct_receiver
    return if chat_channel.group?

    chat_channel.users.where.not(id: user.id).first
  end

  def left_channel?
    chat_action == "removed_from_channel" || chat_action == "left_channel"
  end

  private

  def update_chat_channel_last_message_at
    chat_channel.touch(:last_message_at)
  end

  def update_all_has_unopened_messages_statuses
    return if left_channel?

    chat_channel
      .chat_channel_memberships
      .where("last_opened_at < ?", 10.seconds.ago)
      .where.not(user_id: user_id)
      .update_all(has_unopened_messages: true)
  end

  def evaluate_markdown
    html = MarkdownProcessor::Parser.new(message_markdown).evaluate_markdown
    html = target_blank_links(html)
    html = append_rich_links(html)
    html = wrap_mentions_with_links(html)
    html = handle_slash_command(html)
    self.message_html = html
  end

  def wrap_mentions_with_links(html)
    return unless html

    html_doc = Nokogiri::HTML(html)

    # looks for nodes that isn't <code>, <a>, and contains "@"
    targets = html_doc.xpath('//html/body/*[not (self::code) and not(self::a) and contains(., "@")]').to_a

    # A Queue system to look for and replace possible usernames
    until targets.empty?
      node = targets.shift

      # only focus on portion of text with "@"
      node.xpath("text()[contains(.,'@')]").each do |el|
        el.replace(el.text.gsub(/\B@[a-z0-9_-]+/i) { |text| user_link_if_exists(text) })
      end

      # enqueue children that has @ in it's text
      children = node.xpath('*[not(self::code) and not(self::a) and contains(., "@")]').to_a
      targets.concat(children)
    end

    if html_doc.at_css("body")
      html_doc.at_css("body").inner_html
    else
      html_doc.to_html
    end
  end

  def user_link_if_exists(mention)
    username = mention.delete("@").downcase
    if User.find_by(username: username) && chat_channel.group?
      <<~HTML
        <a class='mentioned-user' data-content="sidecar-user" href='/#{username}' target="_blank" rel="noopener">@#{username}</a>
      HTML
    elsif username == "all" && chat_channel.channel_type == "invite_only"
      <<~HTML
        <a class='mentioned-user mentioned-all' data-content="chat_channel_setting" href="#">@#{username}</a>
      HTML
    else
      mention
    end
  end

  def target_blank_links(html)
    return html if html.blank?

    html.gsub("<a href", "<a target='_blank' rel='noopener nofollow' href")
  end

  # rubocop:disable Layout/LineLength
  # rubocop:disable Metrics/BlockLength
  # rubocop:disable Rails/OutputSafety
  def append_rich_links(html)
    doc = Nokogiri::HTML(html)
    doc.css("a").each do |anchor|
      if (article = rich_link_article(anchor))
        html += "<a href='#{article.current_state_path}'
        class='chatchannels__richlink'
          target='_blank' rel='noopener' data-content='sidecar-article'>
            #{"<div class='chatchannels__richlinkmainimage' style='background-image:url(#{cl_path(article.main_image)})' data-content='sidecar-article' ></div>" if article.main_image.present?}
          <h1 data-content='sidecar-article'>#{article.title}</h1>
          <h4 data-content='sidecar-article'><img src='#{Images::Profile.call(article.cached_user.profile_image_url, length: 90)}' /> #{article.cached_user.name}・#{article.readable_publish_date || 'Draft Post'}</h4>
          </a>".html_safe
      elsif (tag = rich_link_tag(anchor))
        html += "<a href='/t/#{tag.name}'
        class='chatchannels__richlink'
          target='_blank' rel='noopener' data-content='sidecar-tag'>
          <h1 data-content='sidecar-tag'>
            #{"<img src='#{cl_path(tag.badge.badge_image_url)}' data-content='sidecar-tag' style='transform:rotate(-5deg)' />" if tag.badge_id.present?}
            ##{tag.name}
          </h1>
          </a>".html_safe
      elsif (user = rich_user_link(anchor))
        html += "<a href='#{user.path}'
        class='chatchannels__richlink'
          target='_blank' rel='noopener' data-content='sidecar-user'>
          <h1 data-content='sidecar-user'>
            <img src='#{Images::Profile.call(user.profile_image_url, length: 90)}' data-content='sidecar-user' class='chatchannels__richlinkprofilepic' />
            #{user.name}
          </h1>
          </a>".html_safe
      elsif anchor["href"].include?("https://www.figma.com/file/") # Proof of concept
        html += "<a href='https://www.figma.com/embed?embed_host=astra&url=#{anchor['href']}' class='chatchannels__richlink chatchannels__richlink--base' data-content='sidecar-embeddable' target='_blank'>
        <h1 data-content='sidecar-embeddable'>Figma File</h1>
          </a>".html_safe
      elsif anchor["href"].starts_with?("https://docs.google.com/") # Proof of concept
        html += "<a href='#{anchor['href']}' class='chatchannels__richlink chatchannels__richlink--base' data-content='sidecar-embeddable' target='_blank'>
        <h1 data-content='sidecar-embeddable'>Google Docs</h1>
          </a>".html_safe
      elsif anchor["href"].starts_with?("https://remote-hands.glitch.me/") # Proof of concept
        html += "<a href='#{anchor['href']}' class='chatchannels__richlink chatchannels__richlink--base' data-content='sidecar-embeddable' target='_blank'>
        <h1 data-content='sidecar-embeddable'>Glitch ~ Remote Hands</h1>
          </a>".html_safe
      end
    end
    html
  end
  # rubocop:enable Layout/LineLength
  # rubocop:enable Metrics/BlockLength
  # rubocop:enable Rails/OutputSafety

  # rubocop:disable Rails/OutputSafety
  def handle_slash_command(html)
    response = case html.to_s.strip
               when "<p>/play codenames</p>" # proof of concept
                 "<a href='https://www.horsepaste.com/connect-channel-#{rand(1_000_000_000)}'
                    class='chatchannels__richlink chatchannels__richlink--base'
                    target='_blank' rel='noopener' data-content='sidecar-content-plus-video'>
                    <h1 data-content='sidecar-content-plus-video'>
                      Let's play codenames 🤐
                    </h1>
                    </a>".html_safe
               end
    html = response if response
    html
  end
  # rubocop:enable Rails/OutputSafety

  def cl_path(img_src)
    Images::Optimizer.call(img_src, width: 725)
  end

  def determine_user_validity
    return unless chat_channel

    user_ok = chat_channel.status == "active" && (chat_channel.has_member?(user) || chat_channel.channel_type == "open")
    errors.add(:base, "You are not a participant of this chat channel.") unless user_ok
  end

  def channel_permission
    errors.add(:base, "Must be part of channel.") if chat_channel_id.blank?

    channel = chat_channel || ChatChannel.find(chat_channel_id)
    return if channel.open?

    errors.add(:base, "You are not a participant of this chat channel.") unless channel.has_member?(user)
    errors.add(:base, "Something went wrong") if channel.status == "blocked"
  end

  def rich_link_article(link)
    return unless link["href"].include?("//#{Settings::General.app_domain}/") && link["href"].split("/")[4]

    Article.find_by(slug: link["href"].split("/")[4].split("?")[0])
  end

  def rich_link_tag(link)
    return unless link["href"].include?("//#{Settings::General.app_domain}/t/")

    Tag.find_by(name: link["href"].split("/t/")[1].split("/")[0])
  end

  def rich_user_link(link)
    return unless link["href"].include?("//#{Settings::General.app_domain}/")

    User.find_by(username: link["href"].split("/")[3].split("/")[0])
  end

  def send_email_if_appropriate
    recipient = direct_receiver
    return if !chat_channel.direct? ||
      recipient.updated_at > 1.hour.ago ||
      recipient.chat_channel_memberships.order(last_opened_at: :desc)
        .first.last_opened_at > 15.hours.ago ||
      chat_channel.last_message_at > 30.minutes.ago ||
      recipient.notification_setting.email_connect_messages == false

    NotifyMailer.with(message: self).new_message_email.deliver_now
  end
end