# frozen_string_literal: true

module Thredded
  # @abstract Classes that include this module are expected to implement {#readers}.
  # @!method readers
  #     @abstract
  #     @return [ActiveRecord::Relation<Thredded.user_class>] users from that can read this post.
  module PostCommon
    extend ActiveSupport::Concern

    included do
      paginates_per Thredded.posts_per_page

      delegate :email, to: :user, prefix: true, allow_nil: true

      validates :content, presence: true

      scope :order_oldest_first, -> { order(created_at: :asc, id: :asc) }
      scope :order_newest_first, -> { order(created_at: :desc, id: :desc) }

      before_validation :ensure_user_detail, on: :create

      after_commit :update_unread_posts_count, on: %i[create destroy]
    end

    def avatar_url
      Thredded.avatar_url.call(user)
    end

    def calculate_page(postable_posts, per_page)
      1 + postable_posts.where(postable_posts.arel_table[:created_at].lt(created_at)).count / per_page
    end

    # @param view_context [Object] the context of the rendering view.
    # @return [String] formatted and sanitized html-safe post content.
    def filtered_content(view_context, users_provider: ->(names) { readers_from_user_names(names) }, **options)
      Thredded::ContentFormatter.new(view_context, users_provider: users_provider, **options).format_content(content)
    end

    def first_post_in_topic?
      postable.first_post == self
    end

    # @return [ActiveRecord::Relation<Thredded.user_class>] users from the list of user names that can read this post.
    # @api private
    def readers_from_user_names(user_names)
      DbTextSearch::CaseInsensitive
        .new(readers, Thredded.user_name_column)
        .in(user_names)
    end

    # Marks all the posts from the given one as unread for the given user
    # @param [Thredded.user_class] user
    def mark_as_unread(user)
      if previous_post.nil?
        read_state = postable.user_read_states.find_by(user_id: user.id)
        read_state.destroy if read_state
      else
        postable.user_read_states.touch!(user.id, previous_post, overwrite_newer: true)
      end
    end

    def previous_post
      @previous_post ||= postable.posts.order_newest_first.find_by('created_at < ?', created_at)
    end

    protected

    def update_unread_posts_count
      postable.user_read_states.update_post_counts!
    end

    private

    def ensure_user_detail
      build_user_detail if user && !user_detail
    end
  end
end