require 'thredded/at_notifier'
require 'gravtastic'

module Thredded
  class Post  < ActiveRecord::Base
    include Gravtastic

    gravtastic :user_email, default: Thredded.avatar_default
    paginates_per 50

    belongs_to :messageboard, counter_cache: true
    belongs_to :topic, counter_cache: true
    belongs_to :user, class_name: Thredded.user_class
    has_many   :attachments
    has_many   :post_notifications

    accepts_nested_attributes_for :attachments

    validates_presence_of :content, :messageboard_id

    before_validation :set_user_email
    after_save :notify_at_users
    after_create :modify_parent_posts_counts

    def created_date
      created_at.strftime("%b %d, %Y %I:%M:%S %Z") if created_at
    end

    def created_timestamp
      created_at.strftime("%Y-%m-%dT%H:%M:%S") if created_at
    end

    def gravatar_url
      super.gsub(/http:/, '')
    end

    def self.filters
      ['bbcode', 'markdown']
    end

    def filtered_content
      pipeline = HTML::Pipeline.new [
        HTML::Pipeline::AttachedImageFilter,
        html_filter_for_pipeline,
        HTML::Pipeline::SanitizationFilter,
        HTML::Pipeline::AtMentionFilter,
        HTML::Pipeline::EmojiFilter,
        HTML::Pipeline::AutolinkFilter,
      ], context_options

      result = pipeline.call(content)
      result[:output].to_s
    end

    private

    def context_options
      {
        asset_root: Thredded.asset_root,
        post: self,
        whitelist: sanitize_whitelist
      }
    end

    def sanitize_whitelist
      HTML::Pipeline::SanitizationFilter::WHITELIST.deep_merge({
        attributes: {
          'code' => ['class'],
          'img' => ['src', 'class', 'width', 'height'],
          'blockquote' => ['class'],
        },
        transformers: [
          lambda do |env|
            node      = env[:node]
            node_name = env[:node_name]

            return if env[:is_whitelisted] || !node.element?
            return if node_name != 'iframe'
            return if (node['src'] =~ /\A(https?:)?\/\/(?:www\.)?youtube(?:-nocookie)?\.com\//).nil?

            Sanitize.clean_node!(node, {
              elements: %w[iframe],

              attributes: {
                'iframe' => %w[allowfullscreen frameborder height src width]
              }
            })

            { node_whitelist: [node]}
          end
        ]
      })
    end

    def html_filter_for_pipeline
      if filter == 'bbcode'
        HTML::Pipeline::BbcodeFilter
      else
        HTML::Pipeline::MarkdownFilter
      end
    end

    def modify_parent_posts_counts
      Thredded::UserDetail.increment_counter(:posts_count, user_id)
      topic.last_user = user
      topic.touch
      topic.save
    end

    def set_user_email
      if user
        self.user_email = user.email
      end
    end

    def notify_at_users
      Thredded::AtNotifier.new(self).notifications_for_at_users
    end
  end
end